Frequently Asked Questions
Below are answers to some of the most common questions people have about their heating and cooling systems. Click on each question and the answer will expand below it…
Q: What size HVAC system should I have?
A: Contrary to popular belief there, is no rule of thumb for sizing a system to a home. Depending upon the construction of your home, a single ton of air conditioning can cool anywhere from 300 to 800 square feet of living space. The only way to insure that the size of the system you purchase will be large enough to cool your home (but not any larger than you need) is to have your home’s individual heating and cooling needs evaluated by a licensed professional.
Q: How is the size and capacity of a heating and cooling system measured?
A: Heating and cooling systems are sized according to their tonnage. A one (1) ton unit provides 12,000 BTU/H. Residential systems can range from 1 to 5 tons.
Q: How is the efficiency of a heating and cooling system measured?
A: The S.E.E.R. (seasonal energy efficiency ratio) is the amount of cooling your system will deliver per dollar spent on electricity. For example, a 3-ton unit may have a S.E.E.R. efficiency rating of 13, 14, or 15. The higher the S.E.E.R. the more efficient the system will be. The S.E.E.R. rating of any given unit can range anywhere from 13 to 17.
Q: Can I increase the efficiency and life of my home’s heating and cooling systems?
A: Absolutely, the most important thing you can do is to clean and replace your filters frequently. Also, a system heats and cools more evenly when the blower is in the “on” position. The blower provides constant air movement throughout the home, and allows for better filtration. Finally, shades, drapes, shutters, or screens should be installed on windows that are exposed to extreme sunlight.
Q: Is a larger capacity system better?
A: No. A larger system with more capacity delivers less comfort and costs more to operate. An air conditioner is at its least efficient when first turning on. A system with too much capacity will run in numerous short cycles, turning on and off repeatedly, therefore causing it to be less efficient. Also keep in mind that an air conditioner only removes humidity when it’s running, so a system with shorter run cycles doesn’t remove humidity from the air very well.
Q: How long should my system run in a cycle?
A: There is no exact answer for how long your system should run during each cooling or heating cycle. The average air conditioner is sized to remove the heat from your home as fast as it comes in (on a 110° day). Therefore, ideally, on days like these the system should be able to keep up with the incoming heat, but not gain on it and be able to turn off. The farther it is below 110°, the more the system will cycle on and off.
Q: Should I try to keep my system from running too much?
A: Every time your system starts up, it will use a lot of electricity and not produce much cooling. Usually a system that is too small to cool the home is more economical to run but delivers less comfort. Even though it runs nonstop, it will usually consume less power than a larger system that cycles on and off. As a rule of thumb, a unit that is either on or off is less expensive than one cycling on and off.
Q: What air temperature should my air conditioner produce?
A: The air temperature your system produces depends on the temperature of the air going into the system. Generally, the air produced should be 18°-20° below what enters the system. So if the air entering the system is 80°, the air exiting should be about 60°-62°. However, that only works on a system that has been running at least 15 minutes on a warm, dry day with a home that is about 80° inside. On a mild day, with an indoor temperature in the low 70′s, or during humid conditions, the air coming out may only be 15°-17° cooler than what enters.
Q: What temperature should I set my thermostat?
A: Obviously the time of year becomes a big factor for desired temperature settings. In the summer months the average temperature setting is 78°-80°, in the winter 70°-72° seems to be the most common setting for Phoenix area residents. Remember, when leaving your house; try to avoid drastic temperature changes. Do not set your temperature back more than 5°; this will cause your unit to work harder to achieve the desired temperature setting.
Q: Should I consider a programmable thermostat?
A: Programmable thermostats are now the standard in most homes and offer many different features. Because they are electronic, they are more accurate and efficient than older style thermostats that contain mercury. With programmable thermostats you can control the temperature in your home at different times of day without ever touching your thermostat (or even when you are away from your home!). Because everything is automatic, you will never forget to change the setting on your own.