FREE ESTIMATES COMMERCAIL REFRIGERATION FURNACE COOLING AC HEATING HVAC
Posted on May 15, 2018
FOUR BASIC COMPONENTS
THE FOUR BASIC COMPONENTS
Compression systems must have a compressor, condenser, expansion device, and evaporator
Other components enhance system operation
Controls can be electrical, mechanical, or electromechanical devices
Mechanical controls start, stop or modulate fluid flow to increase system
Two-temperature operation is utilized when there are multiple evaporators in the system
These evaporators typically operate at different temperatures
The pressures in these evaporators are therefore different
Two-temperature operation is normally accomplished with mechanical
Evaporator pressure regulator (EPR)
Prevents the pressure in an evaporator from dropping below a predetermined pressure
Two pressures control the valve – Spring pressure – pushes to close the valve – Evaporator pressure – pushes to open the valve
Evaporator superheat may be high when the EPR is closed
An EPR is needed in the suction line of each evaporator except the lowest temperature coil
EPR valves are equipped with Schrader valves to read evaporator pressure
Multiple EPRs can be set at different pressures so each evaporator can be maintained at a different temperature
PRESSURE REGULATOR (EEPR)
Provide more accurate control
Located at the evaporator outlet
Used on single or multiple evaporator systems
Microprocessor senses case discharge air temperature
Designed to maintain discharge air temperature in there frigerated case
Controlled by a bipolar step motor
Located close to the compressor
Prevents compressor from overloading on start-up
Provides a limit to the pressure that can enter the compressor
Referred to as a close on rise of outlet (CRO) valve
Resembles an EPR valve
ADJUSTING THE CPR
Valve is best adjusted under a high load condition
An ammeter should be used when setting the valve
Excessive amperage indicates that too much refrigerant is entering thecompressor
Turning the adjusting screw into the valve reduces the refrigerant pressure returning to the compressor
Turning the screw out of the valve increases the refrigerant pressure returning to the compressor
Release refrigerant from a system when a high-pressure condition exists
Spring-loaded type– Located in the vapor space – Resets after opening
One-time type– Fittings filled with low-temperature solder – Usually located in the suction line near the compressor
ONE-TIME RELIEF VALVE
LOW AMBIENT CONTROLS
Used on refrigeration systems that are operated year round to maintain head pressure
Fan cycling, fan speed control, air volume control, condenser flooding
Intended to simulate design operating conditions
Help to keep the system’s operating pressures within desired ranges
FAN CYLING HEAD PRESSURE
Device opens on a drop in head pressure, turning condenser fan off
Device closes on a rise in head pressure, turning condenser fan on
Fan cycling causes large variances in the head pressure
Best used on systems with multiple fans
FAN SPEED CONTROL FOR
As the outside temperature drops, the fan slows down to reduce the amount of airflow through the condenser coil
As the outside temperature rises, the fan speeds up to increase airflow through the condenser
Some controls monitor the refrigerant’s condensing temperature
AIR VOLUME CONTROL FOR
Utilizes piston-controlled shutters and/or dampers
As the head pressure drops, the shutters close, reducing airflow through the condenser
Reduced airflow causes the head pressure to rise
During periods of warm ambient temperatures, the dampers are fully
open to maximize airflow through the condenser coil
CONDENSER FLOODING FOR
CONTROLLING HEAD PRESSURE
Flooding valves cause liquid refrigerant to move from the receiver to the condenser, reducing its effective surface area, in cold weather
Systems with flooding valves have oversized receivers to hold excess refrigerant charge in warm weather
The valve is closed when outdoor temperature is high (all refrigerant is directed to the condenser)
THE SOLENOID VALVE
Used to start or stop refrigerant flow
Normally open (NO) or normally closed (NC)
Snap-acting valves (open or closed)
Valves must be installed with the arrow pointing in the direction of flow
Often used in conjunction with automatic pump down cycles
Valve position controlled by a solenoid coil
Start and stop current flow to components
Low pressure switch – Closes on a rise in pressure
High pressure switch – Opens on a rise in pressure
Low ambient control – Closes on a rise in pressure
Oil safety switch – Opens on a rise in pressure
Can be used as low-charge protection and space temperature control
Low-charge protection – Cut-out pressure set well below normal operating pressure – Cut out pressure should be set above atmospheric pressure to prevent atmosphere from being pulled into the system – Prevents system from operating in a vacuum – Control is normally reset automatically
APPLIED AS A THERMOSTAT
Control will cut off the compressor when the pressure equals the system pressure that corresponds to a temperature about 15° cooler than desired box temperature
Control is rated by pressure range and current draw of the contacts
APPLIED AS A THERMOSTAT
Control will cut off the compressor when the pressure equals the system pressure that corresponds to a temperature about 15° cooler than desired box temperature
Control is rated by pressure range and current draw of the contacts
AUTOMATIC PUMP-DOWN SYSTEMS –
(STARTUP) SEQUENCE OF OPERATION
When the box temperature rises, the thermostat closes
The liquid-line solenoid is energized
Refrigerant flows to the evaporator
The compressor is still off
When the low-side pressure increases, the low-pressure control closes
The compressor is once again energized
Prevents compressor from operating at high head pressures
Control opens on a rise in pressure
Can be automatically or manually reset
Should be set at a pressure higher than the normal operating head pressure
Manual reset controls provide better equipment protection
LOW-AMBIENT FAN CONTROL
Starts and stops the condenser fan motor in response to head pressure
Starts the condenser fan motor when the head pressure rises
This setting should be lower than the set point on the highpressure control
OIL PRESSURE SAFETY
Larger compressors are equipped with oil pumps
Oil pump is connected to the compressor crankshaft
Oil is forced through holes in the crankshaft
Measures net oil pressure
Net oil pressure = pump outlet pressure – suction pressure
Control uses a double bellows
Has a time delay built into the control to allow oil pressure to build up
DEFROST CYCLE (MEDIUMTEMPERATURE
Typical box temperature ranges from 34°F to 45°F
Coil temperatures are normally 10° to 15°F cooler than the box
Coil will be operating below 32°F but box will be above 32°F
Air in box is used to defrost the coil in the off cycle
RANDOM OR OFF-CYCLE
Coil defrosts using box temperature air compressor cycles off on the thermostat
Evaporator fan will continue to run while the compressor is off
Air in box defrost coil
Coil defrosts whenever compressor cycles off
Defrost is controlled by a timer
System goes into defrost at predetermined times
Defrost cycle is initiated during low load periods
Systems in retail establishments often go into defrost when the store is closed
Box and coil temperatures are both below 32°F
Coil is defrosted using internal or external heat
Air in the box cannot be used to defrost the evaporator coil
Internal heat – Hot gas from the compressor
External heat – Electric strip heaters
DEFROST USING INTERNAL HEAT
(HOT GAS DEFROST)
Uses hot gas from the compressor’s discharge
Discharge gas is directed into the evaporator
Utilizes a hot gas solenoid defrost is initiated by a timer
Defrost is terminated by either time or coil temperature
Evaporator fan is de-energized during defrost
Compressor runs during defrost
Refrigerant condenses in the evaporator
EXTERNAL HEAT TYPE OF
Usually accomplished with electric heaters mounted to the evaporator coil
Defrost is initiated by a timer
Defrost is terminated by either time or coil temperature
Evaporator fan is de-energized during defrost
Compressor is de-energized during defrost
DEFROST TERMINATION AND
FAN DELAY CONTROL
Single pole, double throw switch
Terminates defrost when frost has all been removed
Delays evaporator fan start until coil temperature drops
When ice has been removed, the evaporator surface temperature increases
The control senses this increase in temperature and the system is putback into refrigeration mode mechanically
When the coil temperature drops to the set point temperature, the fan is energized
DEFROST TERMINATION AND FAN
Single pole, double throw switch
Located in the liquid line
The device stores liquid refrigerant
Refrigerant leaves the receiver as 100% liquid
A dip tube is used to remove the liquid from the bottom
Must be used on systems with condenser flooding valves
Found on systems with automatic or thermostatic expansion valves
Not found on critically charged (capillary tube) systems
THE KING VALVE ON THE RECEIVER
Located in the liquid line between the receiver and expansion device
Under normal operating conditions, the valve is back seated
Valve can be front seated in order to pump system down
Has a service port to enable the technician to take pressure readings
Valve must be cracked off the back seat to take pressure readings
Service port is sealed, line port is open to the device port
Normal operating position
Cracked off the Backseat Position
Service port is open to the line port and device port
Position used for taking system pressure readings
Position used for adding or removing system refrigerant
Service port is open to the line port and device port
Position used for system evacuation and leak checking
Service port is open to the device port
Position used for pumping the system down
Line port is sealed off
Located in the liquid line
Removes dirt, moisture, and acid from the refrigeration system
Desiccant – Activated alumina, molecular sieve, silica gel
Can be permanent or replaceable core type
Connected to system with either solder joints or flare connections
Allows refrigerant to flow in only one direction
Can be either the ball type or magnetic type
Must be installed with the arrow pointing in the direction of refrigerant flow
Installed at the outlet of the lowest temperature coil on multievaporator systems
REFRIGERANT SIGHT GLASSES
Installed in the liquid line
Enables the technician to determine if a solid column of liquid is reaching the expansion device
Can also be supplied with a moisture indicator
Usually installed after the filter drier
Used on multi-circuit evaporators
Located at the outlet of the expansion device
Designed to allow equal refrigerant flow to all evaporator circuits
Some distributors are made with side inlets used for hot gas defrost
In the suction line leaving the evaporator
Suction and liquid lines are connected to allow heat to transfer between them
Increases the amount of subcooling in the liquid entering the expansion device
Prevents liquid from moving through the suction line into the compressor
SUCTION LINE ACCUMULATORS
Located in the suction line, close to the compressor
Prevents liquid refrigerant from entering the compressor
Gives liquid a place to boil off before entering compressor
Sometimes, the liquid line is routed through the accumulator to help boil away any liquid and also increase liquid subcooling
CAUSES OF LIQUID FLOODBACK
Improper TXV setting
Loose TXV thermal bulb
Reduced airflow through evaporator coil
Low system load
SUCTION-LINE FILTER DRIERS
Located in the suction line
Good compressor protection
Must be installed when system has become contaminated
Usually have two pressure ports to read the pressure drop across the device
SUCTION SERVICE VALVES
Normally attached to the compressor• Valve positions – Back seated – Normal operating position – Front seated – used for pump down and service
Mid seated – Used for system evacuation
Cracked off the back seat – Used for taking pressure readings, charging refrigerant into the system, or removing refrigerant from the system
Located in the discharge line
Normally attached to the compressor
Used as a gage port and to valve off the compressor for service
Same positions as the suction service valve
This valve should not be front seated when the compressor is running except during closed-loop capacity tests
Installed in the discharge line
Separates oil from the refrigerant and returns the oil to the compressor
Oil drops fall to the bottom of the separator
Oil level raises a float and opens a valve
Difference between high- and low-side pressures push oil back to the compressor
Device needs to be kept warm
PRESSURE ACCESS PORTS
Installed to take pressure readings at various points in the system
Line piercing valves can be installed while the system is running
Can be saddle type or solder type
Can either have a Schrader pin or a small valve
Prevents refrigerant from migrating to the oil in the off cycle
Prevents oil from foaming and being pumped out of the compressor
External type heaters
Crankcase heat is needed during the off cycle and is sometimes controlled by a set of normally closed contacts that open when the compressor is energized
1 Additional components enhance system operation
2 The EPR is used on multiple evaporator systems to maintain different pressures in each evaporator
3 EPR valves are located in all evaporators except the lowest pressure evaporator
4 The CPR provides a limit to the pressure that can enter the compressor
5 Relief valves release refrigerant from a system when a high-pressure condition exists
6 Low ambient controls are used on refrigeration systems that operate year round
7 Common low ambient controls include fan cycling, shutters, dampers and condenser flooding
8 Solenoid valves are used to start and stop the flow of refrigerant (Snapacting valve)
9 Liquid line solenoids are used as part of the automatic pump down cycle
10 Pressure witches open and close in response to sensed pressures
11 Pressure switches can be operational or safety devices The oil pressure safety control ensures that compressors operate with sufficient oil pressure
12 Defrosting medium temperature refrigeration systems can be accomplished with planned, random or off-cycle defrost
13 Defrosting low temperature refrigeration systems is accomplished with hot discharge gas (internal) or electric strip heaters (external) Receivers are refrigerant storage tanks located at the outlet of the condenser
14 Receivers are equipped with service valves that can be beackseated, cracked off the backseat, midseated or frontseated
15 Filter driers remove dirt, moisture, and acid from the refrigeration system
16 Check valves ensure that refrigerant flows through the circuit in only one direction
17 Refrigerant distributor allow equal amounts of refrigerant flow to all evaporator circuits Suction line/liquid line heat exchangers increase subcooling and help ensure that 100% vapor enters the compressor
18 Accumulators help liquid refrigerant boil before it enters the compressor
19 Oil separators help remove oil from the hot vapor that is discharged from the compressor
20 Crankcase heat helps boil refrigerant from the oil in the compressor crankcase
HOW AN AIR CONDITIONER WORKS
The job of your home air conditioner is move heat from inside your home to the outside, thereby cooling you and your home. Air conditioners blow cool air into your home by pulling the heat out of that air. The air is cooled by blowing it over a set of cold pipes called an evaporator coil. This works just like the cooling that happens when water evaporates from your skin. The evaporator coil is filled with a special liquid called a refrigerant, which changes from a liquid to a gas as it absorbs heat from the air. The refrigerant is pumped outside the house to another coil where it gives up its heat and changes back into a liquid. This outside coil is called the condenser because the refrigerant is condensing from a gas back to a fluid just like moisture on a cold window. A pump, called a compressor, is used to move the refrigerant between the two coils and to change the pressure of the refrigerant so that all the refrigerant evaporates or condenses in the appropriate coils.
The energy to do all of this is used by the motor that runs the compressor. The entire system will normally give about three times the cooling energy that the compressor uses. This odd fact happens because the changing of refrigerant from a liquid to a gas and back again lets the system move much more energy than the compressor uses.
WHAT A 'TON' OF COOLING IS
Before refrigeration air conditioning was invented, cooling was done by saving big blocks of ice. When cooling machines started to get used, they rated their capacity by the equivalent amount of ice melted in a day, which is where the term “ton” came from sizing air conditioning.
A ton of cooling is now defined as delivering 12,000 BTU/hour of cooling. BTU is short for British Thermal Unit (and is a unit that the British do not use) The BTU is a unit of heating - or in this case, cooling - energy. It’s more important, however, to keep in perspective that a window air conditioner is usually less than one ton. A small home central air conditioner would be about two tons and a large one about five tons.
WHAT GOES WRONG
Unlike most furnaces, air conditioners are complex mechanical systems that depend on a wide variety of conditions to work correctly. They are sized to meet a certain “load” on the house. They are designed to have certain amount of refrigerant, known as the “charge”. They are designed to have a certain amount of air flow across the coils. When any of these things changes, the system will have problems.
If you produce more heat indoors either from having more people or appliances or because of changes in the house, the air conditioning may not be able to keep up.
If the refrigerant charge on the system leaks out, it lowers the capacity of the system. You will simply get less cooling and system will not be able to keep up when the load gets high.
If airflow across the outdoor (condenser) coil is reduced, the ability to reject heat outdoors is reduced and the again the capacity of the system may go down, especially at higher outdoor temperatures.<
In dry climates such as the Southwest United States, the same issues happen with regard to the indoor (evaporator) coil: higher airflow helps, lower airflow hurts. In humid climates, the situation is more complex. At higher airflows, there will be less dehumidification, leading to high indoor humidities. If the airflow gets too low, however, the evaporator coil may freeze. This makes performance worse and can damage the compressor until it fails - leaving you with an expensive repair bill and no cooling!
WHAT THOSE FILTERS DO
Almost every air conditioning system has a filter upstream of the evaporator coil. This can be in the return grille or in special slots in the duct system and can be a fuzzy-looking or a folded paper filter. This filter removes particles from the air stream to both keep the air conditioning system clean and to remove particles from the air.
As the filter does its job, it gets loaded with more and more particles. This actually has the effect of making it more efficient, but it also increases resistance and reducing airflow. When this happens, it is time to change the filter. How long it will take to happen depends on how dirty the air is and how big the filter is.
If you don’t change the filter, the air flow will go down, and the system will not perform well. Not only that, but if the filter is too dirty, it starts to become a source or air pollution itself.
If you take the filter out completely, you would solve the low air flow problem, but this victory would be short lived. The particles that the filter would have taken out will now build up on your evaporator coil and eventually cause it to fail. A new filter is a lot cheaper.
When you do buy a new filter, ASHRAE recommends getting one with a Minimum Efficiency Rating Value of MERV 6 or higher.
MAINTAIN THE SYSTEM
Routine maintenance such as changing filters can be handled by most consumers, but others require professional service.
It’s a good idea to brush dirt and obstructions from the coils and the drains at the start of each cooling season. Depending on the system and the consumer, this may require a service call from a professional.
If the system is not producing as much cold air as is normal, it could also be an indication of a refrigerant charge or airflow problems. These problems may require servicing.
DUCTS MATTER - A LOT
Another reason systems may appear not to be producing enough cold air is because of duct leakage. Duct leakage can sap 20 to 40% of the energy out of even a well-operating air conditioner, if the ducts pass outside the cooled space (this includes attics, crawlspaces and garages). Ducts outside need to be well insulated. Various products exist specifically for insulating ducts that can be installed by a keen home owner or a professional contractor.
You might be able to get an extra half ton of air conditioner capacity for free, if you seal your leaky ducts. If the ducts are accessible, handy consumers can seal ducts with mastic—that white sticky stuff you can paint on the ducts. Otherwise you would need a professional to seal the ducts.
HOW TO INCREASE ENERGY EFFICIENCY
Sealing leaky ducts may be the biggest single thing you can do to improve efficiency, but a lot of the issues mentioned about will help as well: replace dirty filters, keep the right charge and airflow, clean the coils.
Another thing to do is to make sure the outdoor (condenser) unit is not so hidden from sight that its air flow is blocked or that leaves or other matter are not clogging it.
If you are replacing the air conditioner, look to buy high efficiency equipment. The most generally known efficiency rating is Seasonal Energy Efficiency Rating (SEER). SEER 13 is the minimum efficiency you should consider, but higher efficiencies are likely to be quite cost effective.
Depending on your climate, you may wish to consider other efficiency numbers as well. For example, in hot, dry climates you should look at the Energy Efficiency Rating (EER) which says how well the system will work at peak conditions. If you live in a hot, humid climate you need to consider how well the unit can dehumidify.
LIGHTEN YOUR LOAD
You can make your air conditioner work better by reducing the size of the job it has to do. You can do this by improving the building or reducing the internally generated loads that your air conditioner must deal with.
Improving the building “envelope” includes things such increasing insulation levels or shading windows or reducing air leakage. Such improvements will reduce energy spent on heating and cooling, but may require substantial time or investment. When putting in a new roof or new windows, it is usually cost effective to use high-efficiency products. “Cool” roofing, for example, can save half a ton of cooling and a lot of energy over the year.
Reducing internal loads can be simpler. Shut off unneeded electrical appliances, lights and equipment. Shift appliance use (such as washers and dryers) to cooler times of the day. Use local exhaust fans to remove heat and humidity from kitchens and baths. Buying Energy Star or similarly efficiency appliances helps as well.
In some climates other techniques can be used to reduce the load on the air conditioner. In dry climates evaporative air conditions (the modern version of what used to be called “swamp coolers”) can provide substantial cooling. In climates with large temperature swings, such as the hot, dry climates, you can reduce the load by bringing in large amounts of cool outdoor air. Such systems can be called “night cooling” “ventilative cooling” or “residential economizers”.
The previous points have focused on cooling, but the original definition of air conditioning contains more than that; an ideal air conditioner should heat, cool, clean, ventilate, humidify and dehumidify as needed to provide health and comfort. In fact the second most important objective of the original definition is to provide ventilation. Whether or not the piece of equipment we call an air conditioner provides it, ventilation is needed.
Without adequate ventilation, contaminants generated indoors will can lead to significant health and comfort problems. ASHRAE recommends that there be at least enough ventilation to exchange the air inside house once every four hours, depending on house design.
Older homes tend to have leakier walls and leakier ducts and mostly get sufficient ventilation through such leakage. Such leakage and infiltration may not be the most energy efficient approach to ventilation and is an opportunity for savings.
Most new homes and some existing homes are relatively tight and thus require mechanical ventilation to meet minimum ventilation requirements.
IT'S NOT THE HEAT, IT'S THE HUMIDITY
Humidity control was the problem that originally spurred the need for air conditioning. Lack of humidity control in hot, humid climates, in particular, can lead to mold growth and other moisture-related problems. High indoor humidities can lead to health and comfort problems.
Modern air conditioners dehumidify as they cool; you can see that by the water that drains away, but this dehumidification is incidental to their main job of controlling temperature. They cannot independently control both temperature and humidity.
In hot, humid climates the incidental dehumidification that occurs may not always be enough to keep the indoor humidity conditions acceptable. (ASHRAE recommends roughly a 60% relative humidity maximum at 78F.) The maximum dehumidification happens not at the hot times of the year—when the air conditioner is running a lot—but at mild times of the year when the air conditioner runs very little.
Although there are some leading edge air conditioning systems that promise to independently control humidity, conventional systems may not be able to sufficiently control the problem and can cause comfort or mold problems in certain situations. Some current high-end systems have enhanced dehumidification, but when the existing system cannot sufficiently dehumidify, it may be necessary to buy a stand-alone dehumidifier.
There are things that consumers can do to lessen the need for dehumidification:
Do not set your thermostat to the “fan on” position. In this position the fan blows air all the time whether your cooling system is running or not and one key impact is that a lot of the moisture your system just took out of the air, will be blown back into the house before it can drain way.
Use exhaust fans during moisture-producing activities. Cooking, bathing, washing, and similar activities produce a lot of moisture inside the home. Exhaust that moisture directly outdoors using a fan. Similarly, avoid drying clothes indoors except with a clothes dryer that is exhausted directly outdoors.
things you should do
Air conditioning is a specialty area of service and therefore is something that
most people know nothing about, but when summer hits it is important to be
knowledgable. You also want to feel confident that your money is being spent wisely and
that the work you’re receiving is needed. Well, the best way to feel more confident about
these things is to educate yourself. Here are 10 things you should know about the heating
and cooling system in your home:
1. It requires regular maintenance. Service calls are most often related to lack of
maintenance. The good part about the maintenance is a lot of it can be done yourself.
2. An air conditioning system is a sealed system that is to be extensively leak checked
upon installation. Once your HVAC system has been checked, it should not leak unless
something has impacted the unit. This means the thought that an air conditioning system
just needs recharged every so often is a myth.
3. The pressure and temperature relationship of an air conditioning system is very touchy.
Slight adjustments to either of these two factors can result in problems with the system.
4. Air conditioning repairs are often electrical. Three very common problems are: (1) blown
fuses in the service panel located outside near the condensing unit, (2) tripped breakers at
the main electrical panel and (3) blown capacitors.
5. Air conditioning will usually let you know something is wrong before there is a shut
down that is not electrically related. Routinely check the copper lines in your system for
frost or ice.
6. The condenser coil is where the process of the refrigerant returning from a gas to a
liquid begins. There is no mechanical function here. It is simple, the coils either contain
refrigerant or they don’t. If they don’t, you have a problem on your hands.
7. You may have noticed that lately, the air conditioners that people are having installed
are much larger than those they replaced. This is largely related to the fact that energy
regulations have commanded that the minimum SEER rating (efficiency rating) be
increased over the last few years.
8. It’s a good idea to brush dirt and obstructions from the coils and the drains of your
HVAC system at the start of each cooling season.
9. You can use ductless systems to create temperature zones in your home. A roomby-
room ductless system – sometimes called a multi split, with multiple inside air handlers –
allows you to fit your heating and cooling to your specific needs.
10. Changing your air filter regularly is important. If you don’t change the filter, the air flow
will go down, and the system will not perform well. Not only that, but if the filter is too dirty,
it starts to pollute your home’s air.
1 An electric radiant heater is more energy-efficient as a result of all the heat being focused on heating up the surface, which, in turn, reflects heat back. With a gas heater, some of the energy is used to heat up the surrounding air, and this energy just disappears.
2 An electric radiant heater is safer to run than a gas heater. This is because there is no handling of flammable gas bottles, which always involves some risk. There is also no open flame as in a gas heater.
3 The burning gas in a gas heater is also sensitive to draughts. Unlike an electric radiant heater, which can be installed even where it is exposed to wind and weather.
4 An electric radiant heater requires minimal maintenance, unlike gas heaters, where the gas supply runs out and must be replaced from time to time. Hoses and valves must also be cleaned regularly to ensure that the apparatus functions properly. This is not necessary with an electric radiant heater.
5 An electric radiant heater begins heating as soon as you press the button. You don’t have to wait for the bottled gas to heat up the system before you feel the result.
6 In some locations, such as glazed-in terraces and balconies, the oxygen supply may be too limited to allow use of a gas heater. As gas burns, it consumes oxygen to keep the fire going.
7 Burning bottled gas gives off carbon dioxide and contributes to the greenhouse effect. You avoid this with an electrically-powered radiant heater.
8 Modern electric radiant heaters are very efficient, even small ones. This makes positioning easy, and they won’t restrict space on the terrace.
9 There are also electric radiant heaters that can be sited directly under an awning or a parasol. This is impossible with a gas heater, as the open flame is hazardous in the vicinity of textiles or other flammable material.
10 Operating costs are also more favourable with electric radiant heaters. A standard-size gas bottle will generally be sufficient for up to half a day and must then be replaced. This can be compared with energy-efficient electric radiant heaters, which use minimal electricity in proportion to the heat given off.
Chimney liners provide a barrier between the components of your chimney and the surrounding wood or other building materials. This may seem like an extra layer of protection that isn’t really necessary, but it turns out that having a lining adds more than reassurance. There are some solid reasons you should seriously consider installing a chimney liner if you don’t have one already.
10 Things You Should Know About Chimney Liners
Acidic flue gasses can shorten the life of your chimney by eroding it from the inside out. Installing a liner can extend the life of your chimney while making it safer to use.
Chimney liners also protect the masonry materials in many chimneys, making your chimney a more reliable confinement area for heat and sparks.
Liners help maintain good air flow in the chimney, resulting in a more efficient fire. This will maximize the usefulness of your fuel and save you money.
Aluminum or stainless steel chimney liners in particular wear well, last a long time, and are safe to use.
Chimney liners discourage the back flow of gasses, like carbon monoxide, into your rooms.
Since chimney liners keep sooty air from seeping back into your rooms, your walls, carpeting and furniture will stay cleaner.
A chimney liner can reduce the presence of a smoky or sooty smell in your rooms, making your indoor environment healthier and more pleasant.
Chimney liners make maintenance easier because they naturally reduce creosote buildup. Less creosote means less maintenance and fewer costs for you.
Less creosote also means a furnace or fireplace that runs safer and more efficiently, with a reduced risk of fire.
Chimney liners can be made from many materials, like tile, aluminum, or concrete, making them an investment that can be retrofitted to your existing setup at a number of practical price points.
Chimney liners can enhance the safe operation of your furnace or fireplace, but only if you keep your furnace clean and have it inspected regularly. There’s no magic bullet that will allow you to avoid regular maintenance and periodic inspection of your chimneys, furnaces and fireplaces. To stay safe, schedule yearly inspections of all your chimneys, follow the safety directions on your appliances and equipment, and never leave an open flame unattended.
Adding a humidifier to your home especially during the dry winter months offers a host of benefits. When you live in a dry climate or have a cold and dry winter, you and the things in your home can suffer various ill effects from the dry air. Indoor air, especially in winter, can have humidity levels at around 10 percent, but the ideal humidity level for your home is about 30-40 percent. Here are the top ten benefits to humidified air:
Humidity allows tiny hairs in the nose to move and do their job of filtering out bacteria and viruses to prevent colds and flu. Added humidity can also help prevent bloody noses.
Air moistened with a humidifier can help soothe some symptoms of colds or flu, including irritation of nasal passages, the throat and bronchial tubes, helping you breath and sleep easier.
Wood furniture and flooring responds negatively to too much or too little moisture in the air. Too little moisture can cause wood to split and crack. Adding a humidifier to any room with wood furniture can help preserve the integrity of the wood.
Preserve Your Voice
Vocal cords need to be supple and well lubricated in order to vibrate and produce the best sounds. Dehydration, viruses and sometimes eating the wrong thing can cause you to lose your singing, and even your speaking, voice. Keeping the air moist, especially while you sleep, can help you get it back.
Moisturize Your Skin
The heat blasting through your home during the winter months can leave skin tight, dry and itchy, especially skin on your hands, which has fewer oil glands. Lips also seem to chap more often and more easily in winter. A humidifier can help keep them moist.
A humidifier will not only fight the dry skin that usually accompanies winter, it will also make your home feel warmer. The more moisture that is in the air, the warmer it will feel. Air with a temperature of 70 degrees Fahrenheit and 10 percent humidity will feel like 67 degrees, but with 50 percent humidity, it will feel like it is 69 degrees.
Low moisture levels in your nose and soft palate can increase snoring, so staying hydrated can be a big help. That includes drinking plenty of water, of course, but adding moisture to the air with a humidifier can also fight off dryness that can lead to snoring.
Control Static Electricity
One sure sign of winter is the first time you pet the cat and get a jarring jolt of static electricity, or when you find the latest missing sock stuck to someone's shirt or pants. Dealing with an entirely different hairstyle also is no picnic. A humidifier can lessen the potential for static electricity during the winter months.
Lessen Electronics Shock
Added static electricity in your home is annoying, and a little comical, but the very real danger to electronic equipment, including your computer, is decidedly unfunny. The chance of significant damage is minimal, unless you happen to have your computer open at the time to add RAM, a sound card, or any similar task. The risk is considerable in that case. You could end up with a dead board or other less obvious damage.
Hydrate Plant Life
Many species of indoor plants originally came from tropical climates with high humidity. Indoor air in many climates, especially in winter, does not offer adequate humidity for the plants to thrive. This will become apparent when leaves get brown at the tips or when they die altogether. Adding a humidifier to a room will make a difference for many plants.
Adding humidity to your home can have many positive impacts. It is a balancing act though. Too much moisture in the air can encourage the growth of organisms, including dust mites. Monitoring moisture levels and regular maintenance of your humidifier can ensure you get all of the benefits of moistened air without the risks.
During the winter months, as outside temperatures drop, so does the relative humidity (rh) inside a home. This “thirsty air” begins to absorb moisture from everything it touches, such as woodwork, furniture, paintings, wooden musical instruments, carpet, wood molding, kitchen cabinets, doors, and floors. Moisture is then pulled and absorbed from these hygroscopic, or moisture-retaining, materials, and damage can occur.
For example, cracks will appear in wood floors, leaving a dull finish. Furniture may warp and become loose at the joints. Rare paintings can be destroyed in only a few years as paint cracks and flakes from the canvas. Carpets can deteriorate quickly, and doors will seem to warp before the homeowner’s eyes. Contractors need to keep in mind the symptoms and dangers of poorly controlled humidity levels of indoor air for homes during the winter months.
10 basic things about humidification:
1 To foster healthy indoor living, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends keeping indoor humidity levels between 40 and 60 percent rh. Relative humidity is the ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air can hold at that temperature, expressed as a percentage.
- 2 - Humidity levels that are too low can aggravate symptoms of asthma, rhinitis, and respiratory infections.
- 3 - Proper humidity control can improve the health and comfort of people living in the home.
- 4 - Proper humidity levels decrease static electricity in the home, eliminating static shock and protecting valuable electronics.
- 5 - Bacteria, viruses, mites, and fungi are virtually inhabitable when a home maintains healthy indoor rh.
- 6 - Mold growth indoors is a serious issue for homes today. Molds are incapable of obtaining moisture directly from the air. Molds thrive indoors when the rh range is consistently from 60 to 99 percent at surface substrates.
This is why properly insulated walls and surfaces of a home are crucial to preventing high temperature differentials between the ambient air and an outer wall. The temperature of a surface at or below its dew point can cause water condensation on a given surface, allowing germination and mold growth regardless of ambient humidity.
- 7 - Proper humidity control can be significant to reducing energy consumption.
- 8 - Proper humidification will make one feel warmer and more comfortable.
A properly controlled whole-house humidifier is designed to decrease the rate of evaporation of moisture from the human body, leaving one feeling warmer at lower temperature settings, thus saving energy costs.
- 9 - Humidity levels that are too low will cause the air to become “thirsty.” This extremely dry air can warp furniture and door frames. Woodwork, paintings, and other valuables can be vulnerable to a low indoor moisture level as well, sometimes causing irreparable damage.
- 10 - Carpeting can also deteriorate quickly in a low-humidity home.
SOLUTIONS FOR HUMIDITY CONTROL
By stabilizing the humidity level indoors, hygroscopic materials - woodwork, furniture, and paintings, for example - will not absorb or give off moisture, protecting them and other valuables from irreparable damage.
When faced with a low-humidity situation, contractors need to understand the cause and possible solutions. One such solution is whole-house humidifiers, which connect directly to a furnace and work with the heating system to distribute moisture throughout the home. These humidifier types rely on furnace heating cycle temperatures to deliver the rated humidity capacity output.
An effective whole-house humidifier injects steam into the airstream with a specifically designed nozzle that allows the vapor gas to be efficiently absorbed at temperature as low as 70°. This type of humidifier is not dependent on the heating cycle to deliver humidity capacity, but only needs airflow as low as 800 cfm at 70°.
Both contractors and homeowners often misunderstand steam humidifiers. The common misperception is that steam humidifiers put water droplets into the air distribution system and cause unwanted pools of stagnant water and damage. This is not true.
Actually, steam humidifiers that use electrode technology to boil water in a renewable steam-generating cylinder are designed to inject pure, sterile steam vapor into the duct airstream, where it is designed to be completely absorbed quickly and efficiently. Meanwhile, electrode steam humidifiers are designed to deliver greater capacity outputs on demand to meet challenging humidity loads to maintain designed rh set points.
Controlling humidity can be a challenge for today’s heating contractor, especially during the winter months. By understanding humidity symptoms, problems, and possible solutions, contractors can better meet the needs of their homeowner customers.
types of air filters
There are many types of air filters on the market these days, but which one is best? We are often asked the question, do electrostatic air filters work? The real answer is, it depends. Electrostatic air filters are washable furnace filters that can be very useful for certain uses, but whether or not they should be used in your house is a much broader question. If someone in your home suffers from asthma or severe allergies then the answer will likely change. As a general rule, electrostatic air filters cannot even come close to the filtration power of a high quality anti-allergen filter from 3M or Honeywell, but that doesn’t mean you should rule them out altogether. Those of you who read our articles regularly, know that we are a small, U.S. Veteran-Owned HVAC company in Southern California, and pride ourselves in giving people honest, straight answers to their questions. In this article, we will discuss what an electrostatic air filter is, how it works, the pros and cons of using one and whether or not washable furnace filters would work for your home.
What is an Electrostatic Air Filter and How Does It Work?
Electrostatic air filters are washable air filters that theoretically never need to be replaced. I say ‘theoretically’ because I have a hard time believing that something that is subjected to dirt and debris regularly will work indefinitely, but that is the standard claim. The idea is that instead of replacing your electrostatic air filter at regular intervals like you would a conventional air filter, you take them out back and wash them off with a hose about once a month. This is a handy trick if you are sick of spending money on conventional air filters, but do electrostatic air filters work? They do work, but the question is do they work as well as a conventional air filter?For more information on conventional air filters and how often you should change them, take a look at: Air Conditioning Filter Change – How Often Should I Do It?
How Do Electrostatic Air Filters Work?
These washable furnace filters work by having multiple layers of vented metal which the air passes through. As the air passes through the first layer of filtration, the air molecules are positively charged by the friction between the air and the filter. The now positively charged air molecules attach themselves to the next few layers as they pass through the rest of the filter. Think about it as working kind of like walking across the carpet with your socks on and then touching a door knob – the process of walking across the carpet charges you with static electricity which is then released when you touch a grounded surface like a door knob. Only instead of your socks scooting across a carpet, it is the air scooting across your air filter that creates a charge and traps dust particles in the air filter. For more information on electrostatics, try this short vintage physics video – it’s worth a look: Electrostatics – How Electrostatic Air Filters Filter Air.
The Pros of Electrostatic Air Filters
One of the most attractive parts of washable air filters is the fact that you never have to buy a new one. This is definitely a plus, I mean who wants to buy a new air filter every few months? Even if you opt for the cheaper air filters that run you 50 cents each (which I do not recommend), you still have to go through the hassle of buying them and replacing them on a regular basis and who wants to deal with that?
The other appealing part about using electrostatic air filters is the price. If you are buying high quality air filters then you may be spending $15 every few months which adds up to around $60 each and every year. Now even though this might not break the bank, it can add up over time. Washable furnace filters cost around $50 to $60 each but never have to be replaced, meaning that they pay for themselves in the first year of their use. You can’t argue with the cost of these filters, so it may be an option to keep in mind.
The Cons of Electrostatic Air Filters
I have to say that the cons of an electrostatic air filter far outweigh the pros, in my opinion. There are several problems with a washable air filter, ranging from how effectively they filter your air to how often they have to be washed. Some of these problems are a matter of preference, but some can’t be argued with and should be kept in mind before making your decision:
Electrostatic air filters can only filter so much. One of the problems with electrostatic filtration is that it relies on static electricity to operate. What I mean by this is that static electricity is powerful enough to filter small, lighter dust particles out of the air but what about larger dust and dirt particles? Or mold spores? Unfortunately, this is one of the areas that electrostatic filtration falls short in. An electrostatic air filter will never be able to filter as well as a high quality HEPA filter or even a moderate 1200 MPR filter (micro particle performance rating). These filters are designed to filter out everything down to a certain specification size and are good at what they do. If you have someone in your house who suffers from asthma or bad allergies, then I’d definitely recommend you avoid washable furnace filters and instead opt for a high-filtration replaceable filter with at least a 1400 MPR. For more information on this, take a look at: How to Reduce Asthma Symptoms and How Your Air Conditioner Can Help.
Other problems with electrostatic air filters include:
An additional problem that you run into with inadequately filtered air is that your air conditioning coils get caked with any dust and debris that is not filtered out. Aside from this stuff polluting your air, it provides an organic substrate for mold and mildew to grow in over time. If enough of it collects, then you have a perfect recipe for what is called Dirty Sock Syndrome, a situation where your air conditioner starts to make your house smell like a gym or locker room. It isn’t pleasant.
do electrostatic air filters work - new filterWashable air filters also take time to clean. Unfortunately, it isn’t just a matter of spraying them down with the hose as they’d like you to believe. That would make the outside layer clean, but these filters have between eight and ten layers to them. You actually have to disassemble them and clean each layer separately to properly use them. This takes about 20 minutes every month or so to do, depending on how much dust is in your area.
Electrostatic air filters also block air flow more than conventional air filters. Although this may not seem like a big deal, it is to your HVAC system. If air flow is restricted by 50%, then your air conditioner has to work twice as hard to do the same amount of cooling. It is true that all air filters restrict air flow to some extent, but electrostatic air filters block more than any other type of air filter. In fact, we often get maintenance calls for units that use them. If your air conditioner is running twice as much, its components will wear out quicker.
Because this type of air filter uses static electricity to operate, any particles that make it through the filter are now likely to stick to the inside of your duct work which can promote mold growth and possibly force you to have your air ducts cleaned. What you will also notice with time is that black dust will start to accumulate around the walls of your house – this dust is difficult to clean sometimes because it is ionically charged and wants to stick to a surface (which is how an electrostatic air filter works).
Just food for thought before investing in a washable air filter. For information on how to prevent mold and whether or not you need to have your air ducts cleaned, take a look at these helpful articles:
Should I Have My Air Ducts Cleaned?
How Do You Prevent Mold?
Do Electrostatic Air Filters Work?
It depends on what you mean by ‘work.’ They do remove some dust particles from your air, but overall I do not recommend electrostatic air filters for home use. Electrostatic air filters are an interesting technology but they just won’t work as well as a 3M 1600 MPR and they never will. The nasty stuff that is in your air needs to be removed for the health of you, your family and your air conditioner. A disposable filter allows you to do this, then throw this nastiness into the garbage where it belongs. In the end, although they are a great idea in principle they just won’t filter your air as well as a conventional air filter will. If you add in the hassle of having to spend 20 minutes a month washing it, then you just aren’t coming out ahead in the long run,
Take a deep breath—if you can. Many of the things we do to keep energy costs down, such as fixing drafty doors and leaky windows, can also seal in pesky pollutants and irritants. Most people who buy air purifiers do so in hopes of easing asthma or allergies. But despite product claims, there's little definitive medical evidence that air purifiers help to relieve respiratory symptoms.
Improving indoor air quality starts with minimizing pollutant sources such as cigarette smoke or dust and pet hair. We test how well a room air purifier removes dust and smoke from an enclosed space, how it performs at high and low speeds, and how quiet it is. For whole-house filters, we test air-flow resistance, which measures how freely air flows through the filter.
The very best portable models we tested were effective at cleaning the air of dust, smoke, and pollen at their highest or lowest speed. For whole-house filters, our recommended models did best at filtering dust and pollen without impeding the airflow of forced-air heating and cooling systems. The worst models weren't terribly effective at any speed.
1 Breathe Easier
Before you resort to buying an air purifier, try some simple steps to reduce indoor air irritants, including:
Vacuum often and thoroughly with a vacuum with HEPA filtration.
Ban smoking indoors.
Maintain your heating equipment and change filters regularly.
Minimize use of candles and wood fires.
Use exhaust fans in kitchen, bath, and laundry areas.
Don't store chemicals, solvents, glues, or pesticides near your living quarters.
If pollen or related allergies keep you from opening windows, run your air conditioner or forced-air cooling system with a clean filter.
2 Types of Air Purifiers
The top selling air purifiers are portables; whole-home systems are the other option. We tested portable room models and filters for homes with forced-air heating and cooling systems.
Room Air Purifiers
These are an option for homes without forced-air heating or cooling.
They’re portable—most room air purifiers weigh from 10 to 20 pounds, have a handle, and stand on the floor or on a table, while heavier models might have wheels.
Some have a high-efficiency particulate air (HEPA) filter, which can capture ultrafine particles. Keep in mind: Most HEPA filters need to be replaced annually, an expense that might approach the cost of the air cleaner, but some models are now available with cleanable HEPA filters.
Room models that use either electrostatic-precipitator or ionizer technology could produce some ozone, a lung irritant.
Dedicated ozone generators, a subcategory of room models, produce large amounts of ozone by design. According to manufacturers, that is to reduce allergens such as dust, smoke, pollen, germs, and mold. Ozone, however, is a serious health concern, prompting the State of California to ban the sale of ozone generators (and other air purifiers that emit more than 50 parts per billion of ozone) from the general market.
Prices: Range from $50 to $850
Whole-House Air Filters
If you already have forced-air heating and cooling, popping in a specialized filter is an inexpensive alternative to a built-in home unit. Basically, it acts as a furnace or central A/C filter that you replace regularly.
It’s easy. You slip out the old filter and slide in the replacement. Some are conventional fiberglass filters; others are pleated or electrically charged to pick up particles. (Note that the electrically-charged versions are not actually electrically powered, even when they have names like Electroclean, and they don't produce ozone.)
Whole-house air filters generally include a range of standard sizes, with some that adapt to fit different-size filter-box or return-air openings.
For thicker filters to fit, you may possibly need to have your ductwork modified by a professional.
The filters must be replaced every one to three months.
Prices: From $20 to $80 per filter
Which air filters scored best in our Ratings?
3 Things to Consider
Many portable (aka room) models have annual operating costs of $150 to $200 for filter replacement and electricity (with the majority of that cost being for filters). Filter prices can range from around $10 each up to about $100 (with some priced well into the hundreds). Some units use a pre-filter to capture large airborne particles before they reach the HEPA filter, possibly extending its life and can range from around $10 to $35.
Depending on usage, you typically need to replace filters every 3 months. To cut costs, look for room models that are Energy Star qualified, meaning they are relatively energy-efficient compared to standard models. Some models have washable filters that can be reused. For whole-house filters, annual replacement costs are typically under $100.
Keep it Clean
Any type of air purifier won’t work well if the filter is clogged and dusty, and, if filter is full, it may stop working or even release dirt back into the air.
Noise level is important, especially if you run an air purifier in a room where you sleep or work. For the sake of efficiency (and quietness), we recommend picking a larger unit and running it on a lower speed, rather than cranking up a small one.
4 Room Air Purifier Features
Fan: Most room air cleaners use a fan to suck in air for filtration. Those without a fan (the air circulates naturally throughout your home) run more quietly, but those we tested without fans worked poorly.
Servicing indicator: A clogged air cleaner works inefficiently. This feature lets you know when the unit needs to be cleaned or the filter replaced.
Programmable timer: These controls allow you to set the purifier to run a few hours before you’ll be using a room, or turn it off automatically.
Carrying handle: Makes it easy to move unit from room to room.
Number of speeds: The unit adjusts to your air-cleaning needs—lower when you are sleeping or working and need quiet, higher when it’s prime pollen time.
Ionizer: If a unit has an ionizer (which attracts particles via an effect like static electricity), it’s important that it not produce ozone (it may say on the box or in an operation manual; you can also check our Ratings), a possible lung irritant.
Remote control: Lets you easily adjust settings from across the room.
Dirt sensor: In some room models, the unit automatically adjusts fan speed to the level of dirt or dust in the air.
Washable pre-filter: A washable—and re-usable—pre- filter collects large particles; if it’s washable, it can help cut overall costs. However, many of our higher-rated models did not have this option.
5 Clearing the Air
What They Do Well
The better air purifiers are especially good at filtering pollutant particles such as dust, smoke from candles or fireplaces, and pollen.
What’s Not So Great
Volatile organic compounds (VOCs) from adhesives, paints, and cleaning products, and other types of gaseous pollutants, however, are another matter. Some portable models with carbon pre-filters are claimed to filter VOCs, but the Environmental Protection Agency warns that such filters are specific to certain gaseous pollutants, not for others, and that no air purifier is expected to remove all gaseous pollutants found in the typical home. Carbon filters also must be replaced often, typically every 3 to 6 months, or they stop working.