Home Air Conditioners: Unitary (window or portable)
Some home air conditioners provide cooling to only a portion of a home. These include
window air conditioners, through-the-wall, and ductless split-system air conditioners and heat
pumps. Wall air conditioners
and heat pumps are often called packaged terminal air conditioners. Unitary systems are frequently used where
ductwork is not present, installation difficulties exist, or where cooling is
desired in only a portion of the home.
The performance
rating for window and through-the-wall units is the Energy Efficiency Rating (EER). It is the ratio of the cooling capacity in
Btu's divided by the energy input in
watts. It is not a seasonal
performance rating but rather is determined at a
single outside condition. Room home air conditioners
generally range from 5,500 Btu per hour to
14,000 Btu per hour. National appliance standards require room air
conditioners built after January 1, 1990, to have an EER of 8.0 or greater. Select a room air conditioner with an EER of at least 9.0 if you live in a mild climate. If you
live in a hot climate, select one with an EER over 10. An Energy Guide
label will provide you with the rating for the unit being considered and the
range for that class of product.
Wall air conditioners and heat pumps are also rated in EER. Minimum EERs will range from 7.6 to 8.9 depending on size. With both window and through-the-wall units, higher EERs are available and should be considered.
One disadvantage of window and through-the-wall units is noise. The compressor and circulating fan are housed in the unit. Compressor noise is difficult to dampen. Some manufactures offer units with a low profile such that the compressor is located outside and below the window opening. This helps reduce but not eliminate noise.
Ductless split-system air conditioners and heat pumps are relatively new on the market. They use a remote condensing unit located outside, usually mounted at ground level. Inside the building is a small fan unit with the cooling coil. Only refrigerant lines connect the condensing unit with the fan and cooling coil. A small condensate line is required for draining condensate from the unit. If a direct path to the outside is not available for condensate drainage, a small condensate pump is used to discharge the water to a remote location. Because the compressor is located outside and not in contact with the building, the units tend to be very quiet.
The inside fan and coil can be wall or ceiling mounted. Often, they are equipped with a wireless remote for control. These units can be used to cool a single room or many manufacturers offer a dual-zone unit that will cool two rooms, each with independent control. SEER, as with conventional central air conditioners, is the rating for ductless split-systems.
Ductless Mini-Splits
Mini-split systems can be an attractive retrofit option for room additions and for houses using hydronic heat. Like conventional central air conditioners, mini splits use an outside compressor/condenser and indoor air handling units. The difference is that each room or zone to be cooled has its own air handler. Each indoor unit is connected to the outdoor unit via a conduit carrying the power, refrigerant and condensate lines.
The primary advantage is that, by providing dedicated units to each space, it is easier to meet the varying comfort needs of different rooms. By avoiding the use of duct work, mini-splits also avoid energy losses associated with central forced-air systems.
The primary disadvantage of mini-splits is cost. They can cost 30% more than a typical central air conditioner of the same size. But, when considering the cost and energy losses associated with installing new central duct work, buying a ductless mini-split may not be such a bad deal, especially considering the long-term energy savings. Talk with your contractor about what option would be most cost-effective for you.
Estimating cooling costs
Annual cost of cooling is affected by cost of electricity, efficiency of the cooling system, cooling requirements of the home, and the lifestyle of the occupants. The simple method described below will provide a rough estimate of annual cooling costs that can be used to compare the performance of different cooling systems. Because this is a simplified procedure based on average conditions and use, your actual cooling costs will vary from these estimates.
To determine your estimated cooling costs, contact a K. Kelly professional for a free estimate.
Wall air conditioners and heat pumps are also rated in EER. Minimum EERs will range from 7.6 to 8.9 depending on size. With both window and through-the-wall units, higher EERs are available and should be considered.
One disadvantage of window and through-the-wall units is noise. The compressor and circulating fan are housed in the unit. Compressor noise is difficult to dampen. Some manufactures offer units with a low profile such that the compressor is located outside and below the window opening. This helps reduce but not eliminate noise.
Ductless split-system air conditioners and heat pumps are relatively new on the market. They use a remote condensing unit located outside, usually mounted at ground level. Inside the building is a small fan unit with the cooling coil. Only refrigerant lines connect the condensing unit with the fan and cooling coil. A small condensate line is required for draining condensate from the unit. If a direct path to the outside is not available for condensate drainage, a small condensate pump is used to discharge the water to a remote location. Because the compressor is located outside and not in contact with the building, the units tend to be very quiet.
The inside fan and coil can be wall or ceiling mounted. Often, they are equipped with a wireless remote for control. These units can be used to cool a single room or many manufacturers offer a dual-zone unit that will cool two rooms, each with independent control. SEER, as with conventional central air conditioners, is the rating for ductless split-systems.
Ductless Mini-Splits
Mini-split systems can be an attractive retrofit option for room additions and for houses using hydronic heat. Like conventional central air conditioners, mini splits use an outside compressor/condenser and indoor air handling units. The difference is that each room or zone to be cooled has its own air handler. Each indoor unit is connected to the outdoor unit via a conduit carrying the power, refrigerant and condensate lines.
The primary advantage is that, by providing dedicated units to each space, it is easier to meet the varying comfort needs of different rooms. By avoiding the use of duct work, mini-splits also avoid energy losses associated with central forced-air systems.
The primary disadvantage of mini-splits is cost. They can cost 30% more than a typical central air conditioner of the same size. But, when considering the cost and energy losses associated with installing new central duct work, buying a ductless mini-split may not be such a bad deal, especially considering the long-term energy savings. Talk with your contractor about what option would be most cost-effective for you.
Estimating cooling costs
Annual cost of cooling is affected by cost of electricity, efficiency of the cooling system, cooling requirements of the home, and the lifestyle of the occupants. The simple method described below will provide a rough estimate of annual cooling costs that can be used to compare the performance of different cooling systems. Because this is a simplified procedure based on average conditions and use, your actual cooling costs will vary from these estimates.
To determine your estimated cooling costs, contact a K. Kelly professional for a free estimate.
Sizing Window Air Conditioners
Multiply the room height, room width, room length, exposure factor, and insulation factor together, and divide the results by 60. This gives the required capacity of the room air conditioner in British Thermal Units per hour (Btuh).
Exposure factor depends on orientation of the wall containing the most window area. If two or more walls have roughly the same area of glass, use the factor for the longest outside wall. The exposure factor for walls facing north is 16; east, 17; south, 18; and west, 20.
Insulation factor is a subjective judgment of the amount and quality of the room insulation. Good insulation equals 10 while poor insulation equals 18. Use a factor of 10 if the roof or attic is well insulated, or if there is another room above the one being cooled. Use a factor of 18 if the room has many windows or an uninsulated ceiling or roof. Values within this range can be used.
For example, the cooling load of a room 14 feet by 16 feet with an 8-foot ceiling, on the first floor of a two-story house (insulation factor 10), with the longest outside wall facing east (exposure factor 17), is computed as follows:
14 · 16 · 8 · 10 · 17 = 5,077 Btuh.
60
Need More Information on Cooling and Air Conditioning?
Cooling your home is an important aspect of your family life. To stay cool and comfortable all summer long you'll want to make sure you are choosing the right cooling and air conditioning system for your home and your budget. The air conditioning contractors at K. Kelly offer top of the line cooling and air conditioning systems at affordable prices from trusted brands such as Rheem, Buderus and Climatemaster and provides free air conditioning Price Quotes.
Whether you are considering a wall air conditioner, window air conditioner or other home air conditioning system, Call 920-469-3500 today to get your free cooling system quote or your home air conditioning questions answered from the Green Bay air conditioning experts at K. Kelly Inc.
