An essential part of getting a new air conditioner is finding the right-size unit. We don’t mean the physical size of the air conditioner, but the size of its cooling power and its capacity. You want to ensure you have an air conditioner that’s big enough to cool your house, but which isn’t too big.
“Wait a minute,” you might think. “Why is it a problem if the AC’s too big? Isn’t it better to err on the side of too big rather than too small?”
You’re not the only one who has thought this when getting a new air conditioner. We’ll explain why bigger isn’t necessarily better with an air conditioner. In fact, it can often be a disaster!
How AC Sizing Works
The cooling capacity of an air conditioner is measured in units called tons. One ton equals 12,000 BTUs of heat removed from the house per hour. The reason this measurement is called a ton is because it’s the amount of heat necessary to melt 2,000 lbs (1 ton) of ice at 32°F over one day.
Most homes require a central air conditioning system between 1.5 to 5 tons. Although you can look up a basic measurement system that matches cooling tons to a home’s square footage, more needs to go into sizing an AC.
To accurately size a residential air conditioner requires a full load calculation that takes into account factors about the house such as heat-generating appliances, the amount of insulation, the number of people in the household, the number of windows and their facing, the lights, etc. It takes professionals to do this work.
When the AC Is Too Big
What happens if your home needs a 3-ton air conditioner, but because of a mistake (something amateur installers often make) a 5-ton system is put in its place? You can’t just “turn the AC down” to compensate because that’s not how thermostats or air conditioners work: the air conditioner either is on or off.
If the AC is too large for the house, it will blow out so much cold air that the thermostat will incorrectly register that it’s finished its job before it has. The AC will shut down, only to turn back on a short time later and start the process over.
The rapid starting and stopping is called short cycling. An oversized air conditioner may end up turning on and off 8-10 times per hour, but an accurately sized air conditioner will only need to turn on and off 3-5 times per hour.
Short-cycling puts an enormous amount of strain on the air conditioner because of how much power the compressor uses at start-up. You’ll see enormously high cooling costs because of this, plus the AC will wear down rapidly and need numerous repairs and an early replacement.
It takes skilled professionals to determine the correct tonnage for a new AC using a load calculation, so make sure you call us for your AC installation in Eden Prairie, MN. We’ll get it right the first time!
Residential Heating and Air Conditioning has served the Twin Cities Since 1991. Schedule AC installation with us today.