Frequently Asked Questions
The outdoor unit of my heat pump puts off smoke from time to time. Also, it looks like it is frozen sometimes. Is this normal?
- If the “smoke” is white or very light gray, then yes!
- The reason is because of the way heat pumps work. In the winter, the outdoor coil gets cooler than the outside air in order to extract heat from the air. In fact, it can get as much as twenty degrees cooler than the outside air during normal operation. In this way it absorbs heat from the outside air, then the compressor “Pumps” it to the indoor coil. If the outdoor air is 45 degrees, then the heat pump coil can be 25 degrees. Any moisture in the outside air condenses on the outside coil when the air passes over it, and freezes instantly. The heat pump has a special “defrost” circuit that warms the outside coil and melts the ice off every 90 minutes. The defrost circuit is active whenever the outdoor coil is colder than 32 degrees. When this “defrost” occurs, it can look as though smoke is pouring off of it.
- As long as it thaws periodically, the thin frost buildup does not adversely affect normal heat pump operation. However during freezing rains, the defrost circuit may not be able to thaw the coil often enough. In that case you can often turn the heat pump off and thaw the coil yourself with water from a bucket or garden hose.
Why does my house or business seem to have plenty of cooling capacity, but it tends to feel clammy?
An oversized air conditioner makes your house feel clammy. A unit that’s too big can’t dehumidify the air effectively because it runs for only short periods at a time. The indoor coil never gets cold enough to do its job of removing moisture from the air. An oversized unit will leave your home cold and clammy, especially in South Carolina’s humid climate. It can also mean that you will have higher electric bills and possibly a noisy system.
How do I know where to buy the right size air conditioner?
Follow these tips for buying the right size air conditioner:
- Don’t use a contractor who wants to size your unit solely on the square footage of your house or building. Contractors should calculate how much cooling home or business needs according to guidelines such as the Air Conditioning Contactors of America’s manual J. To gather the information necessary, a contactor should spend about an hour poking around your house, taking measurements in each room, and asking questions. He or she needs to measure floors, ceilings and walls – including all the windows, – and check insulation in the attic, walls, and crawlspaces. Some other factors that go into the cooling load formula include indoor and outdoor temperatures, direction orientation, number of occupants, shading, siding, and roof color.
- Insist on getting a copy of the cooling load calculations (or computer printout). These can be useful in comparing bids from contractors. Question the contractor if the calculations do not include at least all the items mentioned above, or if they require and explanation.
- Don’t be tempted by the lowest bid. Be willing to pay for the time the contractor must spend to do the job right.
- Check for duct leaks. Be sure air flow is not restricted by ducts that are disconnected, crushed, or too small for the system. Ideally, the contractor should use diagnostic equipment to find leaks and then fix them with quality duct sealants (NOT DUCT TAPE!). It doesn’t make a lot of sense to buy a larger air conditioner to cool your attic or crawlspace!
What is happening with refrigerant in air conditioning systems?
There have been many reports regarding air conditioner refrigerants and their effect on the earth’s ozone layer. Refrigerant is the cooling agent used in air conditioning systems. Most all of the air conditioner and heat pump products sold today utilize one refrigerant known as R22, which is from the family of refrigerants called HCFCs. HCFCs have been used for decades in a safe and efficient manner; but government regulation will eventually phase them out of use. The United States congress, acting in response to an international treaty called the Montreal Protocol, provided new direction and authority to the Environmental Protection Agency (EPA).As a result, the EPA, through the Clean Air Act, is regulating the productions and use of refrigerants in air conditioning systems. These changes will eventually eliminate air conditioning refrigerants containing chlorine due to the concern about ozone depletion.
Should I hesitate to buy a new air conditioner or heat pump because of refrigerant phase-outs?
EPA regulations call for the eventual phase out of R22, which is the refrigerant used in current air conditioner and heat pump equipment. Products that use HCFC refrigerants, such as R22, must stop being produced by the year 2010. All production of R22 refrigerant will stop by 2020. Therefore, there is no need to hesitate buying current air conditioning or heat pump equipment. The air conditioning industry has worked closely with the EPA to coordinate the eventual HCFC phase-out so that consumers can have confidence that the products they purchase today will be capable of supplying their home or office heating and cooling needs for the full expected life-span of the air conditioner or heat pump. Sufficient quantity of R22 refrigerant will continue to be produced for any service needs that may arise until 2020. After 2020, recycled refrigerants will be available, for many years, which will safely fulfill all service need for products that use #R22.
When replacing the outdoor unit of an air conditioner or Heat Pump, should the indoor unit also be replaced?
- All air conditioner and heat pump outdoor units are specifically designed to work with matched indoor units for optimum efficiency and performance. The result of this matched system is a coordinated, top-performance team that ensues the dependability and high efficiency today’s applications require.
- Air conditioner and heat pump outdoor units may “work” with indoor units other than those for which they have been specifically designed…however, the result is a definite compromise in system performance.
- If an air conditioner or heat pump outdoor unit is ten years old and needs to be replaced, the indoor unit is just as old and has been subjected to the same amount of wear and tear. Replacing both units means you won’t have to replace the indoor unit in a short time…you’ll have years of service from both units. A new unit also gives you a new product warranty.
- At first glance, replacing only an air conditioner or heat pump outdoor unit may appear to be a bargain. But when you consider the lower cooling and heating efficiencies, decreased reliability and the high cost of ownership that results, it’s not such a bargain after all!
Is there really that much difference in air conditioner sound levels?
Until recently, noisy air conditioners and heat pumps were accepted as the norm. High noise levels were even associated with the “power” of HVAC systems. But today’s technology lets you choose a system that is not only efficient, but also very quiet. Most systems manufactured today are quieter than those made in past years. But there is still a great difference in the sound levels of models on the market today. Be sure to compare sound ratings when you shop for a new system.
What do all those Heat Pump and Air Conditioner ratings mean?
- It is easy to feel overwhelmed by the array of efficiency ratings, abbreviations and acronyms used to describe or explain the equipment. The following will give you what they mean and how you can use the knowledge gained to make a more informed choice on your comfort needs.
- EFFICIENCY RATINGS
- SEER – Seasonal Energy Efficiency Ratio. This is the rating for the efficiency of cooling equipment. It is calculated by dividing the cooling capacity of a continuously operating air conditioner by the electric power input. The higher the SEER, the less your unit will cost to operate.
- HSPF – Heating Seasonal Performance Factor. This measurement is similar to SEER, but it measure the efficiency of the heating portion of your heat pump. Like the SEER, HSPF industry minimums have risen in recent years. The current industry minimum is 6.80 HSPF.
- COP – Coefficient of Performance. This is a measurement of comparison of a heat pump’s heating capacity to the amount of electricity required to operate it. Since a heat pump is less efficient at lower outside temperatures, the COP falls as the temperature drops. To aid you in comparing efficiency, ARI provides the COP for two temperatures: 47° & 17°.
- SOUND RATINGS
- Db – Decibel. A term to describe the relative loudness of a sound. Typically, heat pumps and air conditioner are between the sound of a human voice (70 db) and a blender (88 db).
- SRN – Sound Rating Number. A unit based on ARI tests. Average sound ratings range from 74 to 80 db. The lower the SRN rating, the quieter the unit.
- GENERAL INDUSTRY TERMS
- HVAC – Heating, ventilating and air conditioning. This term applies both to the heating and cooling industry and to the products they manufacture.
- ARI – Air Conditioning and Refrigeration Institute. A non-profit, voluntary organization comprised of HVAC manufacturers. ARI publishes standards for testing and and rating heat pumps and air conditioners and ensures a level of quality within the industry.
- DOE – The Department of Energy. This is the federal agency that set the HVAC industry efficiency standards.
- BTU – British Thermal Unit. >This is the amount of heat that will raise or lower the temperature of one pound of water ;by one degree Fahrenheit.
- Btuh – British Thermal Units per Hour. A measure of heat transfer rate.
- Ton – A ton is 12,000 btus. A typical single family residence uses air conditioning of heat pumps ranging between two and five tons of capacity.
- Watt (W). A unit of electrical power.
- Kilowatt (kW). One thousand watts.
- Kwh – Kilowattt hour. A unit of electrical energy equal to the work done by one dilowatt acting for one hour.
- THE PRICE OF QUALITY – There is more to buying a heat pump or air conditioner than ratings. The quality of construction and materials used a s well as the reliability of the manufacturer and installing contractor can all affect your long-term satisfaction and comfort. Top quality, high efficiency equipment will cost more initially, but is will save you money on utility bills and service calls for years to come. Be sure to weigh all the factors before choosing you new system.
My crawl space is always damp. I know this promotes termites and rots wood. What can be done to help this situation?
Any home that has a crawlspace is in jeopardy or having problems if it is continuously moist. Following are items to consider.
- Add gutters and downspouts to your house to carry water away from the house. Pipe the downspouts as far away from your house as reasonably practical.
- Dig a hole in the lowest spot in your crawlspace and put a perforated five-gallon bucket (sump) in it. Dig trenches in the ground in the crawlspace and lay slotted drainage pipes in them, pitched down to the sump pit. Cover the pipes with the soil you took out to make the trenches. Put a sump pump into the bucket and pipe the discharge line well away from the house. Do this step only if the ground in your crawlspace is damp or if there is condensate forming on your ducts or floor joists.
- Lay plastic sheets in your crawlspace, covering the ground completely. This will reduce evaporation of water out of the ground. Use at least 4-mil plastic and overlap the joints by twelve inches. Cover the bottom inside wall of the crawlspace as far up as possible. We have found that water sometimes condenses in the crawlspace above the plastic. You can cut or poke small holes in the plastic sheeting at the low points to allow the water to drain into the ground below. This will not add significantly to the evaporation problem.
- Seal and insulate all of the ducts in the crawlspace. Or you can replace the ducts, making sure the new ones are sealed and insulated. Or you can move the duct system to the attic.
- Insulate your floor to reduce condensation on the wood.
- Close your crawlspace vents. Install a dehumidifier in the crawlspace and run the drain outside, piped as far away from the house as practical. If you installed a sump pump in the crawlspace, you can drain the dehumidifier into the sump pit.
- The ground should slope away from the foundation of the house so water does not puddle near the foundation when it rains. If your water table is high, you may want to install a French drain, as long as there is somewhere lower nearby where you can pipe the water to. Ventilating the crawlspace is only effective in the spring and fall when the absolute humidity of the air outside the crawlspace is lower than the absolute humidity of the air inside the crawlspace. In coastal areas of this country, that almost never happens in the summer. As a general rule, if it is above 75 degrees outside, there is more moisture in the outside air than in the 70 to 75 degree crawlspace air. Therefore if you ventilate the crawlspace, you are bringing more moisture into the crawlspace than you are removing. When it gets to 95 degrees outside, and that air is brought into the 75 degree crawlspace, the relative humidity (RH) doubles. If it is 60% RH outside, then the relative humidity in the crawlspace is at the dew point. At dew point conditions the water vapor turns back to a liquid. Therefore we do not recommend installing exhaust fans to ventilate the crawlspace. If you run exhaust fans in the crawlspace, you can also suck air-conditioned air out of the house into the crawlspace, making it colder in the crawlspace. This can cause even more condensation in the crawlspace, making the problem even worse. If you must use a fan to ventilate your crawlspace, install it in the attic and blow hot attic air into the crawlspace. By making the crawlspace warmer, the relative humidity level drops, because the air can hold more moisture at higher temperatures. This requires a space where you can run a duct from the attic to the crawlspace. Make sure you install a fan and duct large enough to warm the entire crawlspace. Remember that this will increase your air conditioning load slightly, as well as your power consumption.
- Make sure the condensate drain line from the air conditioner indoor unit does not drain into the crawlspace. Make sure the drain line is kept clear. If the condensate drains into the crawlspace, a sump pump or condensate pump should be installed. In some cases a new condensate drain line can be run with proper downward pitch all the way to the outside. The drain should terminate above grade outside so the line does not clog.
- The crawlspace should be at a higher level than the ground outside. Problems occur when the crawlspace is below the exterior grade. If there is standing water in the crawlspace, see the sections on sump pumps and dehumidifiers.
- If mold is growing on the wood in the crawlspace, even in spots, you have problems. If the mold is white, that is usually a surface mold that is a danger sign, but does not damage the wood. If the mold is black, wood rot is occurring. If you find something that looks like roots going from the ground into the wood, that is poria fungus. It is very bad and can completely destroy a house in a few months.
- Plumbing leaks can be a major source of crawlspace moisture. They should be fixed as soon as possible because they can cause the wood to soften making it easier for mold & rot to destroy the wood.
Is there anything I can do to help maintain my own heat pump?
On the Indoor unit: Check the air filter monthly. Change it whenever it gets dirty. The air filter is usually inside the indoor unit, if the indoor unit is installed in a closet. If the indoor unit is installed in an attic or crawl space, there is usually a return air filter grille low in the wall, or in the ceiling, with the filter in it. An all-in-one unit (package unit) usually has a low sidewall return air filter grille.
On the Outdoor unit: Rinse the outdoor coil in the spring, summer and fall with a garden hose. The outdoor unit is made to withstand a driving rain, so you cannot hurt it by rinsing it with a hose. Also, lubricate the outdoor fan motor every year, unless it is a sealed unit. It is best to have the Freon charge checked in the Spring when the outdoor temperature is above 70 degrees. Keep bushes, shrubs pampas grass and fences away from the unit. They can block airflow and reduce efficiency.They can also block service access, making it difficult and expensive to work on the unit.