AFUE (Gas or Oil Furnace) High Efficiency Furnace Payback SEER (Air Conditioner and Heat Pump) HSPF (Heat Pump Heating)

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1 AFUE (Gas or Oil Furnace) The measure of efficiency for furnaces is a rating known as AFUE (Annual Fuel Utilization Efficiency). It is a lot like your car s miles-per-gallon. AFUE tells you how efficiently the furnace converts fuel (gas or oil) into heat. An AFUE of 80% means you use this much fuel to heat your home, while 20% goes up the chimney. The National Energy Code mandates no manufacturer can build furnaces with an AFUE rating lower than 80%. In contrast, many furnaces manufactured before 1989 have an AFUE rating as low as 60%. They waste nearly ½ the fuel being bought! Furnaces with AFUE ratings of 78% to 80% are considered "minimum efficiency"; those with ratings of 90% or higher are known as "high efficiency." The maximum furnace efficiency available today is around 98%. In general, a higher efficiency furnace usually means you pay a higher price for the unit, but have a lower monthly operating cost. If you have an older furnace (with an AFUE of about 60%), you could reduce your heating bill up to 38% by replacing it with a new high efficiency furnace. You recover your cost to replace the old, inefficient furnace, by savings with lower utility bills. High Efficiency Furnace Payback If you live in a cold climate, you will see a payback in a few short years. If you live in a very moderate climate, it might make more sense to purchase a minimum efficiency furnace. Your Mendenhall Mechanical Services representative can use heating system data from your area to help you determine about how long it will take to recover the additional cost of a high-efficiency model. After the payback, you continue to save on your energy bills for the life of the furnace. SEER (Air Conditioner and Heat Pump) Cooling efficiency for air conditioners and heat pumps are indicated by SEER (Seasonal Energy Efficiency Ratio) rating which tells you how efficiently the device (air conditioner or heat pump) uses electricity through the season. The higher number offers greater efficiency. The typical SEER rating of units manufactured prior to 1989 is about 6.0. Now, the government mandated minimum is 13 SEER. High-efficiency units have a SEER of at least 15; the maximum SEER available now is around 24. You can expect Minimum SEER standards to change in the near future. HSPF (Heat Pump Heating) Heat pumps also have heating efficiency ratings, indicated by HSPF (Heating Seasonal Performance Factor). In general, the higher the HSPF rating, the less electricity the unit will use to heat your home. The government mandated minimum heating efficiency standards for new heat pumps to be 6.8 HSPF. Most heat pumps manufactured before 1989 have HSPF ratings below 5.0. An HSPF rating of 8.0 or higher is high-efficiency; the maximum available is High Efficiency Heat Pump and Air Conditioner Payback The higher efficiency of heat pumps and air conditioners usually mean greater system cost, but lower utility bills. If you live in a warm and/or humid climate, you will probably see the higher cost of a high-efficiency air conditioner or heat pump paid back through lower utility bills, in a few short years. Ask an MMSCorp Representative to help you determine about how long it would take you to recover the additional cost in energy savings. Of course, after the payback, you continue to save on your energy bills. What are the different types of heating systems? Heating systems come in all sizes, types, and fuels. In residential systems, there are two different distribution systems, forced air and radiation. One or more fuel sources are options. Oil, electricity, natural gas, propane, solar, wood, or wind can fuel these type systems. For most purposes, you can categorize home heating systems into two broad categories, furnaces and boilers. Furnaces (this also includes heat pump systems) heat air and use fan systems and ductwork to move air throughout a home. Boilers generate steam or heat water and use circulating pumps and piping to move heated water or steam throughout radiators, radiant tubing, or hydro-coils in the air duct. FAQ s Page 1

2 What are the different types of cooling systems? Residential cooling systems are generally forced air ducted systems, ductless mini-split systems, through-the-wall air conditioners (PTAC s), or window air conditioners. Most homes have forced air, ducted systems. These are generally air source or water source air conditioners and/or heat pump systems, which utilize ductwork to disperse the air throughout a home. One generally uses ductless mini-splits, PTAC s, or window units for individual room application where ductwork is difficult or impossible to install. People often use these units to supplement central air systems. These units are available with heat also. How much energy does my heating and cooling system use? About half of all energy used by households goes to heating and cooling the home. Over 7% of all homes, use heat pumps for heating and cooling and 24% of new homes use them. In 2008, about 77% of all new homes in the United States were built with central air conditioning. This is up from 43% in Almost 100% of new homes in the Southeastern States have central air conditioning! (these numbers include manufactured housing) Over 80% of all existing homes now have central air conditioning In 2008, manufactures shipped nearly 2 million heat pumps and almost 4 million central air conditioners, the most ever. By increasing the efficiency of new heat pump and air conditioning units, we can dramatically reduce the nation's energy consumption and resultant pollution. It will help utilities offset their peak loads and avoid having to construct costly new power plants. Equipment that is more efficient has the added benefit of helping consumers save money on their energy bills. What is the U.S. Environmental Protection Agency Doing About Energy Conservation? U.S. Environmental Protection Agency formed an Energy Star Program with most energy consuming product manufacturers. The Energy Star heat pump and air-conditioner program is a voluntary partnership between manufacturers and U.S. Environmental Protection Agency to stimulate the market for high-efficiency products. The Energy Star SM logo is a symbol that consumers can look for to identify heat pumps and air conditioners that save energy and prevent pollution. Energy Star air conditioners are 20 percent more efficient than the ones currently meeting the federal government minimum standard. Energy Star heat pumps and central air conditioners could save consumers over $350 million per year by the year 2010 in heating and air conditioning bills. Consumers will easily recognize the new, more efficient products. You indentify them by the U.S. Environmental Protection Agency Energy Star logo. How is my heating and cooling system sized? Each home and business will have different indoor comfort needs. An analysis of the structure should be done using Manual J Load Calculation to determine its heating and cooling needs. The Manual J takes into account the local weather data, occupancy load and orientation of the building, insulation levels, window, and door placement among other factors to determine the size system needed for each individual situation. What system is best for my home? To determine which heating and air conditioning system is best for your home, take into consideration factors such as your budget, your comfort expectations, physical factors (such as your current system) and other unique features of your home. Your geographical region is also an integral factor in choosing a central heating or air conditioning unit. You should consider the following as well. For the basics of heating or cooling temperature control, you have four system options. Listed below are these options, followed by the approximate percentage of U.S. homes using them. FAQ s Page 2

3 Gas or Oil Furnace/Air conditioner (60% of homes) Gas or Oil Furnace/Heat Pump (25% of homes) Gas/Electric Small Packaged System (5% of homes) Gas or Oil Boiler/Other (10% of homes) Accessories you may want to consider are an Air Purification System, Energy Recovery Ventilator, or a Whole House Humidification System. All are beneficial to your quality of life. System control is another factor when choosing home heating and central air conditioning. This involves being able to maintain a comfortable temperature, either manually or automatically. Quality temperature control (thermostats), keep your home consistently comfortable with changing physical or environmental fluctuations. To choose a heating and air conditioning system, you also must assess your current fuel source. The three most likely energy sources for your comfort system are electricity, gas, and fuel oil. Electricity: If gas or fuel oil is not an option, you will need to use an all-electric system. You would need to consider a heat pump or an air conditioner with an electric furnace. You may be able to have a gas line installed to your home, but that could be an additional cost. In some areas, electrical rates are so low; an all-electric system can be the best operation cost option even if gas or oil is available. Gas: When natural or propane gas is available, forced hot air systems and boiler systems become an option for you. If you choose to use a boiler, steam or circulating hot water radiant heat may be an option. Many people have a combination of forced air and boilers using hydro coils installed in the forced air system. You may decide a dual fuel or Hybrid system is a good choice. Oil: If oil is available, oil furnaces and boilers may be an option for you. You can apply all combinations used with gas, to oil Wood and Solar: Many people apply wood and solar devices to supplement their fuel choice. Everyone s home is different. Some are big and some are small. Older homes in general, are not air and vapor sealed as well new ones. That means efficiencies of older homes are not as great. The number and size of windows, the direction your home is facing, number of mature trees in the yard, and many more factors can affect your comfort. All may be an important part in deciding what type system is best for you. Your MMSCorp Service Specialist has the expertise to assess any unusual circumstances surrounding the specific needs for your home. What should I look for in a home comfort system? It is best to evaluate what makes you comfortable to determine the best heating and air conditioning system for your home. Heating and cooling are the foundation for your comfort; it is the second most expensive cost of building a house. It is a very important decision. You have a lot of flexibility to maintain comfortable temperature, air cleanliness, and humidity levels. For many people, temperature is a big factor. As the temperature outside changes, the temperature inside your home can fluctuate as well. Another factor in home comfort is cleanliness. Many allergy sufferers are sensitive to dusty or FAQ s Page 3

4 odorous homes. In today s, tightly sealed, well-insulated home, the air can become stale. Dust, pollen, pet dander, mold, skin flakes, chemical fumes, cigarette smoke, radon gas, or other things in the air can cause inhabitants and visitors to be uncomfortable. You may benefit from air duct cleaning. Humidity can be useful in cooler weather when the air is dry, but cause you to be uncomfortable in warmer weather when the outside air is humid. You may want to consider whole house humidity control. System control is what makes your home comfortable. You can adjust the heating or air conditioning to your liking. Many choices are available to give complete control, allowing you to set your comfort zone, which combines temperature and humidity control. Having total system control can divide a home into areas with individual control. Heating and air conditioning system designers should match equipment for optimum system efficiency. Heating codes requires indoor (evaporator coil) and outdoor units to match as tested by AHRI (Air Conditioning, Heating, and Refrigeration Institute). They are the independent testing agency that guarantee s the efficiency claims made by equipment manufacturers. To meet the intent of heating and energy codes, brand should match brand and SEER ratings should match SEER rating. For most manufacturers warranty to be in effect, these things must match. Will my new heating and cooling equipment qualify for federal tax credits? HVAC equipment will qualify for certain federal tax credit when it meets the requirements. You must purchase HVAC equipment, in the calendar years. The credit is for existing home replacement or newly installed units. Tax credit does not apply to new construction applications. The tax credit is for 30% of installed project cost with a cap of $1,500. Listed below are the energy efficiency requirements: A) Air-to-air heat pumps: must meet or exceed 15.0 SEER/12.5 EER/8.5 HSPF B) Air-to-air A/C units: must meet or exceed 16.0 SEER/13.0 EER C) Gas furnaces: must meet or exceed 95% AFUE* D) Oil fired furnaces: must meet or exceed 90% AFUE* E) Hot water boilers: must meet or exceed 90% AFUE (oil or gas) There is tax credit allowance for gas/oil furnaces with variable speed blowers that use no more than 2% of the energy used by the furnace, even if the AFUE ratings may not qualify known as advanced main air circulating fan. The exact way this credit is calculated is still unclear, however. You must purchase geothermal units in the calendar years. These are applicable for existing homes as well as new construction applications. The tax credit is for 30% of installed cost with no cap. Geothermal heat pumps: must meet or exceed 14.1 EER/3.3 C.O.P. on a closed loop system and 16.2 EER/3.6 C.O.P. on an open loop system. System must come with a de-superheater for domestic hot water production as well (hot water assist feature). For more information on tax credits, visit How can I save money on a heating or air conditioning system? Will the lowest priced heating and air conditioning system end up costing you money in the end with high operating costs or by needing to be replaced sooner? Will the lowest priced system provide the comfort you expect? Before you make your final decision, you should consider operating costs and efficiency ratings. Comparing energy efficiency of different brands of home heating and air conditioning units is relatively easy. There are three standardized rating systems used. Each rating is used for a specific type of product (in other words, all furnaces use the same system; heat pumps use a different system, and so on). How much money can my Energy Star furnace save? Over 10 years an Energy Star furnace could save: $1,700 relative to an old furnace* FAQ s Page 4

5 $920 relative to a new standard furnace* *Savings based on $732 average annual heating bill from a 1993 American Gas Association survey for the Middle Atlantic region. U.S. Environmental Protection Agency estimates for old furnace AFUE = 66%; standard furnace = 78%; and Energy Star = 92%. Actual savings for individual homeowners will vary based on geographical area of the country, local gas rates and the age and size of the home. For more information about Energy Star furnaces, please contact: Peter Banwell, Manager Energy Star Furnaces U.S. Environmental Protection Agency (6202J) 401 M Street, S.W. Washington, D.C Phone: (202) Fax: (202) U.S. Environmental Protection Agency Energy Star heat pumps and air conditioners can save you money by reducing electricity bills. Look for the Energy Star SM logo when purchasing a home heating system or central air conditioner to be sure of lowering your energy bill. This information courtesy of the U.S. Environmental Protection Agency. Can I troubleshoot my system before I call for a repair? Of course, you can! MMSCorp heating and air conditioning specialists encourage you to perform these simple procedures before calling us. Check the disconnected switches (indoors and outdoors if you have a split system). Make sure that circuit breakers are on or that fuses have not blown. Check for sufficient airflow. Make sure air filters are clean and that supply-air and return grills are open and unobstructed. Check the settings on your thermostat. On a thermostat that has a screen display, if the screen is blank, you may need a battery. If you want cooling, make sure the temperature control selector is set below room temperature and the SYSTEM switch at the COOL or AUTO position. If you want heat, make sure the temperature control selector is set above room temperature and the SYSTEM switch at HEAT or AUTO. The FAN switch should be set at ON for continuous blower operation or AUTO if you want the blower to function only while the home heating system or central air conditioning unit is operating. In addition to the routine maintenance you perform, properly trained service technicians should inspect your home comfort system seasonally. An MMSCorp Service Professional will help insure your heating and air conditioning systems operate safely and give you the best performance at the lowest cost. You may want information on an MMSCorp Service Agreement, which covers regular maintenance. How often should I change the air filter? Your home s air filters should be checked at least monthly. The type of filter you are using, as well as the indoor environment, will determine how frequently the filter needs to be changed. 1 disposable filters will likely need to be changed monthly or bi-monthly. Electronic air cleaner pre-filters should be cleaned or replaced monthly. 4 media filter or air purifier filters will likely need to be replaced once or twice a year. FAQ s Page 5

6 Should I cover my outdoor unit in the wintertime? It certainly is fine to cover an Air Conditioning unit in the wintertime when the unit will not be operating for long periods. This may make sense, especially in areas with lots of tree litter. Make sure you purchase an approved cover for your unit that will allow condensation to drain properly. Be sure to remove any covers before the spring cooling season begins. Outdoor units are designed to withstand the outdoor elements. Covering your outdoor unit is not necessary. DO NOT COVER HEAT PUMP UNITS AT ALL! What can I do to improve indoor air quality? Adding high efficiency air cleaners or air purifiers, UV lights, ERV air exchangers, or humidifiers will help improve indoor air quality in your home. Air cleaners, purifiers, and UV lights will help capture and kill indoor contaminates and keep HVAC systems clean. Do I really need to have my air ducts professionally cleaned? The duct system in your home is the pathway through which heated and cooled air follows throughout your home. If your ducts are dirty, dusty or contaminated with molds or fungi, then the air you breathe will contain these substances as well. Having your air ducts professionally cleaned can contribute to better health, a cleaner home environment, and better efficiency from your heating and cooling system. Even if you live in a new home, it may not be as clean as you think. During construction, your air duct system is open, allowing wood shavings, drywall dust, dirt, trash, carpet fibers, and all kinds of other things to settle, or be swept into your system. Cleaning the duct system is the only way to remove these contaminates. What kind of maintenance should I do annually? With the proper maintenance and care, your HVAC equipment will operate economically and dependably. You can do a few simple, routine maintenance operations. They will help ensure the best performance and comfort from your heating and air conditioning system. Safety First Before you perform any kind of maintenance, consider these important safety precautions. Disconnect all electrical power to the unit before removing access panels to perform maintenance. Please note that there may be more than one power connection switch. Although manufacturers take special care to prevent sharp edges in the construction of heating and air conditioning equipment and indoor air quality systems, it is best to be very careful when you handle parts or reach into units. Do-It-Yourself Heating and Air Conditioning Maintenance Check the air filter in your furnace or fan coil unit every three to four weeks. A dirty filter will cause excessive strain on your furnace, air conditioner, or heat pump. Replace the filter when necessary or clean it if you have the reusable type. (If you have a reusable filter, make sure it is completely dry before re-installing it.) The pre-filter and collection cells of an electronic air cleaner should be cleaned at least two or three times per year for optimal indoor air quality. Clean dust from the indoor coil. With a vacuum cleaner and soft-brush attachment, you can remove any dust from the top and underside of the coil. Make sure you do this after the condensate has dried from the coil. If you cannot get the coil clean this way, you may call your MMSCorp Service Professional for service. Keep your outdoor condensing unit free of debris. If you keep grass clippings, leaves, shrubbery, and debris away from your outdoor unit, it should only require minimal care to operate properly. Check the base pan (under the unit) occasionally and remove debris, to help the unit drain correctly. FAQ s Page 6

7 If the outdoor coil becomes dirty, use a brush or a vacuum cleaner with the soft brush attachment to clean the surface. To clean dirt that is deep in the coil, contact your MMSCorp Service Professional. Make sure your outdoor unit stays in a level position. If the support for your split-system outdoor unit shifts or settles and the unit is no longer level, re-level it promptly to make sure moisture drains from the unit. If you notice water collecting under the unit, arrange for it to drain away from the equipment. Inspect your furnace s combustion area and vent system before each heating season. If you find dirt, soot, or rust your system, may not operate properly or at peak efficiency. Do not operate the furnace until you have an MMSCorp Service Professional inspect and/or repair it. Other than general housekeeping, (dust and dirt removal, changing air filters, etc.) oil burner maintenance is not for the normal homeowner. Qualified oil burner technicians should inspect oil-fired boilers and furnaces annually. Contact your MMSCorp Service Professional for a thorough inspection of the unit s operation. This will help insure your oil heating system works at maximum efficiency for the winter season. Clean your humidifier at the beginning of every heating season. Review your owner s manual for the proper procedure to clean the external and internal components of your whole house humidifier. The evaporator pad may need replacing before each heating season. If the water in your area is hard or has high mineral content, you may need to clean or service your humidifier more frequently. Clean the core and air filters on an energy recovery ventilator at least every three months. You can vacuum the core of an energy recovery ventilator as long as it is dry and the outdoor temperature is between 60 0 F. (16 0 C.) and 75 0 F. (24 0 C.). Energy Recovery Ventilator cores can be soaked for three hours in a solution of warm water and mild soap, and then rinsed. The other ventilator filters are washable: just use a vacuum to remove the heaviest accumulation of dust and then wash them in lukewarm water. Reinstall them after they are completely dry. REMEMBER----You should change thermostat, carbon monoxide detector, and smoke detector batteries on a yearly schedule, it could save your life! Is annual maintenance on my HVAC system necessary? Annual maintenance inspections can often spot small problems before they become large and lead to expensive repairs or dangerous operating conditions. Annual maintenance inspections and service will help keep your HVAC system operating at peak efficiency, which will save you money in operating cost. How often should I have my HVAC system serviced? Most manufacturers recommend annual preventive maintenance. Proof of this may be required to receive any parts warranty. The best time is before the beginning of the heating and cooling season. Yearly service helps avoid costly breakdowns when you need the system most. It also helps extend the life of the system and keep it running efficiently. What should one do if they hear refrigerant hissing from their air conditioner? Turn your air conditioner off. Call the MMSCorp Service Professional immediately. When replacing the outdoor unit, do I need to replace the indoor unit as well? The answer is yes; here are some of the reasons why. FAQ s Page 7

8 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 these matched units is a coordinated, top-performance team that ensures dependability and efficiency. 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. In addition, through the years, indoor blower coil units have undergone numerous design advances especially in the areas of air handling performance, filtering efficiency, and operating sound levels. New indoor units include the latest design advances. While changing only the outdoor unit may result in improved efficiency compared to the old unit; it s SEER rating will be lower than advertized. Most air conditioning and heat pump systems have indoor units the same age or older than the outdoor units they are connected to. They have the same ware and tear. If they are older, they have more. Replacing both units gives you the assurance to expect years of service and comfort from both units. To receive manufacturer s warranty, you may need to prove the indoor and outdoor units were purchased at the same time. Many manufacturers require this now. Last, but not least; the indoor and outdoor units should be matched to meet requirements of the heating codes adopted by the State of North Carolina. At first glance, replacing only an air conditioner or heat pump outdoor unit may appear to be a bargain. When you consider the lower cooling and heating efficiencies, decreased reliability and high cost of ownership that result, it is not such a bargain. Replacing an entire system cost more, but by doing so, you get efficiency, reliability, and comfort. What is the average life expectancy of HVAC equipment? Life expectancy is one of those things that will vary widely from location to location based on usage, installation procedures, and type of system. For example, air source heat pumps can expect to achieve years while air conditioning units may last years. Ground source heat pumps could achieve an year life. Gas and oil furnace will likely have life expectancies of years. Boilers may range from 15 years to 30 plus years. In 2007, The National Association of Home Builders and Bank of America Home Equity conducted a study on the life expectancy of home components. View this document at The area units are installed (basements, crawl space, attic, etc.) will play a factor as well as the demand and usage placed on the equipment. The most important aspect to long life is the quality of installation when the equipment was new. What is zoning? Zoning is multiple thermostat controls installed on an HVAC or boiler systems for individual temperature control in different areas of a house. Zoning gives you more flexibility in temperature control from one area to another in your home and can lower overall system operating cost. How can I tell if the furnace s heat exchanger is leaking and what causes these leaks to occur? You likely will not be able to see a crack in the heat exchanger. Most cracks occur in areas not accessible to sight without unit disassembly. In the normal course of furnace operation, the heat exchanger experiences repeated heating and cooling, which causes a corresponding expansion and contraction in the metal of the heat exchanger. Cracks will tend to form in areas of the FAQ s Page 8

9 heat exchanger that are weak, such as factory welds. More weak spots and holes will form because of corrosion. Corrosion of the heat exchanger often signifies problems with exhaust venting. Corrosion is caused by water vapor in the exhaust of the furnace, which contains carbonic acid. It cools too quickly, condenses out; drains back down the chimney and onto the heat exchanger where the acid eats away at the metal. Another cause of heat exchanger failure is insufficient airflow through the system. This can come from a lack of return air, insufficient air supply ducting, or stopped up air filters. The poor airflow causes the system to overheat and put thermal stress on the heat exchanger. How much clearance do I need around the air conditioner or heat pump? This will depend upon the type and make of the outdoor unit. Generally, the outdoor unit should have 24 to 30 inches clearance around sides of the unit and at least four feet unobstructed area over top the unit, assuming the unit has topdischarge. I have noticed ice forming on the refrigerant lines that run to the furnace or air conditioner, what does this mean? Ice forming on the refrigerant line or the coil inside the furnace will usually be caused by a restriction in the airflow through the evaporator coil, restriction in the refrigerant circuit, or a lack of refrigerant in the system. If the problem is an airflow restriction, you may be able to correct the problem by replacing or cleaning the air filter. One or a combination of the following can cause restricted or reduced airflow: Air filter is very dirty and needs to be changed or cleaned Evaporator coil (indoor coil) is plugged with dirt and needs cleaning Condenser coil (outdoor unit coil) is plugged and needs cleaning Furnace fan or fan coil motor is not moving enough air. The fan motor may be burned or the fan belt broken. If your unit is low on refrigerant, it is because there is a leak in the system. Your MMSCorp Service Professional can make this correction. Before refrigerant is added, you should fix the leak. When it cools down outside during the cooling season, is it ok to turn off my air conditioner? There is no easy answer to this question. Many people like to turn off the air conditioner at night, or when it cools off for a day or two. This can cause the system to work harder and run longer to bring the temperature and humidity down to comfort levels. If the outdoor humidity is high, this can be a problem. The central air conditioning unit s first job is to remove the moisture or humidity from inside your home. This process can take days. Once the humidity has been removed, it is much easier for your unit to maintain comfort-temperature and humidity levels. If the outdoor relative humidity is higher than inside, turning off your unit and opening the windows will cause the humidity level to rise again inside the house. When the temperature rises again, your air conditioner will have to work harder to lower the level once again. If the humidity level outdoors is low, and the temperature drops a few degrees, then open the windows for a while and get some fresh air. What is the best temperature set point for my air conditioner or heat pump? The temperature at which you feel comfortable is the quick answer. However, we all have different needs and comfort level. Most people feel comfortable in the winter somewhere between 68 0 F. and 72 0 F. In the summer F. is common for many. When choosing an indoor set-point temperature, remember; your air conditioner should lower the relative humidity in the house making you feel more comfortable at higher temperature setting than the same temperature would feel in the winter. The important thing to remember is not to vary the temperature too much. Your air conditioner is constantly struggling to maintain the delicate balance of humidity and temperature. Every time you adjust the temperature, you can potentially upset this balance. Air conditioning systems are generally sized to maintain 20 0 F. difference between the indoor and outdoor temperature. It is important to remember that on really hot days, the system will likely run for long periods of time and may be FAQ s Page 9

10 unable to maintain settings below 75 0 F. (unless the system is oversized). In the cost cutting market today, many system designers will Value Engineer this temperature difference at 15 to 18 0 F. (It seems value engineering is the new catch phrase for cost cutting) What is the ideal humidity for my house? The humidity set point in a house will certainly vary throughout the year. The ideal humidity level is between 35% and 55% annually. Air Conditioning systems dehumidify naturally. You can add a whole house de-humidifier if the air conditioning units run time is not long enough to remove the humidity or is oversized. Humidifiers can be added to most central HVAC systems to provide additional humidity in the heating season. The most commonly used humidifiers are fan powered type, evaporative type, and steam injected type. A contractor told me my duct system needed to be replaced. Is this necessary? If an air duct system is located in, an unconditioned space such as an attic, un-heated basement, or crawl space the answer may be yes. One very good energy saver for forced air systems is sealed, insulated air distribution. Leaking air duct can suck in outside air or loose conditioned air to the outside. Sealed, insulated, air duct systems will help insure as much of your conditioned air gets into the living space as possible. There is a dark streak on my carpet about 4 wide on the outside walls only. What is it? Often negative air pressure inside your home causes this. It causes the carpet to act as an air filter. There can be many reasons for this negative pressure. Negative air pressure in your home can cause many safety, health, indoor air quality, comfort, and energy consumption issues. Consult your MMSCorp Service Professionals for solutions. Should I be concerned about carbon monoxide? Carbon monoxide, also known as the silent killer, can pose a serious threat in some instances and is yet another reason to have your furnace and water heater inspected by The HVAC Professionals at MMSCorp. Carbon monoxide and smoke detectors are wise investments that may save your life someday! Mendenhall Mechanical Services Corp. offers high quality products for both. Some Important Indoor Air Quality Facts You Should Know: The average 6-room house collects 40 pounds of dust a year (Discover Magazine) Air duct systems have more germs than a chicken coop (American Lung Association) The EPA claims indoor air has been found to be up to 70% more polluted than outdoor air Children and Senior Citizens are more likely than adults to be affected by polluted air (Dept. of Consumer Affairs) A build up of 0.42 inches of dirt on a heating or cooling coil can result in a decrease of efficiency by 21% (EPA) 9 out of 10 heating, ventilating, and air conditioning system failures are caused by dust and dirt (Louisiana Coop Extension Service [LCES]) The LCES also reports that clean systems restore capacity and reduces running time. This means saving on your monthly electric bill. Allergies and asthma run in my family. Can the indoor air quality be improved? Indoor air quality is a growing concern in our society today. Americans on average spend 70% of their time indoors. According to the American Lung Association, the quality of our indoor air can be up to FIVE TIMES dirtier than the outside air. That is a scary statistic! FAQ s Page 10

11 The HVAC Industry has been dealing with this issue for years and has a variety of products that will help you improve the quality of air you breathe in your home. Air Cleaners Air cleaners can improve your health by keeping your entire house cleaner; protect your furnishings, save you the time, and aggravation of continuous dusting and cleaning. A whole-house cleaner can help provide relief from irritants up to 40 times more efficiently than standard furnace filters. Air Purifiers An air purifier whole-house air filtration system is the most effective air cleaning system available. It thoroughly cleans and filters out 99.98% of airborne allergens that pass through the system. It is up to 100 times more effective than a standard 1" filter. Filters By changing your filters once a month, you can cut down on the amount of dust and pollutants in your home. Filters remove dust and other particles from the air such as pollen, bacteria, smoke, smog, pet dander, plant pollen, and mold spores. They also help to increase the energy efficiency and prolong the life of your heating and cooling system. Duct cleaning Whole-house duct cleaning dislodges dirt and debris in the airflow system; then is followed by thorough power vacuum cleaning. This cleaning will kill germs and bacteria, remove dust in your home, and improve the efficiency of your system. It makes your home smell clean and fresh. Most doctors and allergist recommend them. New construction homes can benefit from having the ductwork cleaned to remove drywall dust, sawdust, and debris from the construction process. UV Germicidal Lamps With an Ultraviolet (UV) Germicidal Lamp, you will not just remove airborne contaminants; you will destroy them. Mold and bacteria can easily grow on air conditioning coils because of normal condensation that takes place during the cooling process. UV Germicidal Lamps are designed to kill mold and bacteria by breaking down its DNA. The elimination of mold and bacteria will reduce your family s risk of allergic reactions and illnesses as well as get rid of foul odors. If you have respiratory problems, your Doctor may write you a prescription for these. If so, your Health Insurance may pay part of their cost or they may be tax deductable. Purchasing Energy Star Heat Pumps and Air Conditioners Utilities all over North America are promoting high-efficiency heat pumps and air conditioners. They help reduce peak demand, reducing the need to build more power plants. They provide higher customer satisfaction. Energy Star heat pumps and home central air conditioning systems also produce a variety of other benefits: Energy bills are dramatically reduced All high efficiency units come with better manufacturer's warranty Reduce pollution by being highly efficient. In addition to asking for Energy Star when purchasing heat pumps and air conditioners, consumers should consider the following: FAQ s Page 11

12 Quality conscious contractors make sure the systems he sells are properly sized and installed to ensure maximum comfort and efficiency. Their contractor should be well trained in the proper installation of heat pumps and central air conditioners as well as all products he sells. Your contractor should properly install the duct system. Improperly installed systems dramatically reduce efficiency. FAQ s Page 12