HVAC - Heating, ventilating and air conditioning refers to the indoor comfort industry.
Kilowatt (kW) - a kilowatt equals 1,000 Watts. A kilowatt hour (kWh) is the amount of kilowatts of electricity used in one hour of operation of any equipment.
BTU - British thermal unit is the amount of heat that will raise or lower one pound of water by one degree Fahrenheit. A Btuh is how many Btus are used per hour.
Ton - Heat pumps and air conditioners are generally sized in tons. Typical sizes for single family residences are between two and five tons. Each ton equals 12,000 Btuh.
It is important to note that actual capacity is not constant and will change based on outdoor or indoor temperatures. The published capacity rating of air conditioners and heat pumps is based on performance at the ARI standard temperature levels of 95 F outside, 80 F inside.
Efficiency
A rating on comfort equipment is similar to the miles per gallon rating on your car. The higher the rating number, the more efficient the system and the lower your fuel consumption will be.
You can save a lot of money with a high efficiency unit. Depending on your local climate, lifestyle and electricity rates, savings will vary.
SEER - Seasonal Energy Efficiency Ratio is the amount of cooling your equipment delivers per every dollar spent on electricity. SEER applies to air conditioners and heat pumps.
In the past, a unit with a SEER of 8.00 was considered standard efficiency, and a unit with a 10.00 SEER was considered high efficiency. After January 1, 1992, the minimum SEER required by the Department Of Energy is 10.00 and 15.00+ SEER is considered high efficiency. As of January 1, 2006 the minimum SEER rating allowed in residential application is 13 SEER.
HSPF - Heating Seasonal Performance Factor is similar to SEER, but it measures the efficiency of the heating portion of your heat pump. Like SEER, industry minimums have been raised recently, and the minimum is now 6.80 HSPF.
Sound Ratings
Although sound does not affect the efficiency of a unit, it will certainly affect your comfort. If your unit has a low sound level, you will hardly notice it is operating. But if it has a higher sound level, it may mean your good night's sleep is disturbed every time it runs.
Decibel (db) - a decibel describes the relative loudness of a sound. Some common sounds are fairly close to a typical air conditioner or heat pump's sound level: human voice, 7.0 decibels; blender, 8.8 decibels.
Sound Rating Number (SRN) - sound is measured in bels (a bel equals 10 decibels). The SRN of a unit is based on ARI test, performed at ARI standard rating conditions. Average sound rating range from 7.0 to 8.0 decibels. The lower the SRN rating, the quieter the unit.
Indoor Coils
A homes comfort system consist of two components: the outdoor unit (air conditioner or heat pump) and the indoor unit (coil or blower coil). Combinations of various units will result in vastly different efficiency ratings.
Unreasonably high efficiency ratings can be created by using unrealistic indoor and out door equipment combinations.
Value
There is more to buying a heat pump or air conditioner than ratings. The quality of equipment and materials used as well as the reliability of the installing contractor can all affect your long-term satisfaction and comfort. High quality, high efficiency equipment may cost more initially, but will save you money on utility bills and service calls for years to come. Weigh out all the factors before choosing your new system.