What Size AC Unit Should I Get?

Two Air Conditioning Units Outside in Michigan

Having the right sized air conditioner is a key component in cooling your space effectively. A unit that is too small has to run constantly, playing catch up all day trying to fill a space that it isn’t designed for. A unit that is too big will turn on, cool the space quickly and then shut off, which sounds good but the heat will come back in and the unit will click back on and then back off. This on, off, on, off uses a lot of energy and more energy equals more money. At Eller Services, we are in the business of keeping you cool and saving you money.

Air conditioners are measured by tons, but this isn’t the weight of your appliance in tons. The tonnage of an AC unit is based on how much the unit can cool. A 1 ton air conditioner = 12,000 BTUs.

A BTU or British Thermal Unit is the unit of energy that equals 1055 jules. One BTU is the amount of energy needed to cool 1 pound of water by 1 degree Fahrenheit. A one ton AC unit can cool 12,000 pounds of water by 1 degree, each hour.

Home units can be anything from a 1-5 ton unit and they increase by .5’s as they go up. Size matters, but bigger is not necessarily better, having an accurately sized unit is the way to go.

The old school equation to finding out the right size unit for you is as follows:

The square footage of your house multiplied by 25, divided by 12,000, then subtract .5.

Climate zones also make a difference in determining the correct unit for you, so you can follow the equation or contact us for more specifics.

We are happy to assist you in finding the right appliance for your home.

Call us today or request service online.

Call Us Today at 248-652-6650
– or –


Eller Services provides plumbing, heating and cooling services to Rochester, Rochester Hills, Oakland Township, Troy, Birmingham, Bloomfield Hills, Auburn Hills, Lake Orion and surrounding communities. Call 248-652-6650 or request service online today!

<script type="text/javascript"><!– –>(function(a,e,c,f,g,h,b,d){var k={ak:"864714775",cl:"b9spCOua73EQl4CqnAM",autoreplace:"248-652-6650"};a[c]=a[c]||function(){(a[c].q=a[c].q||[]).push(arguments)};a[g]||(a[g]=k.ak);b=e.createElement(h);b.async=1;b.src="//www.gstatic.com/wcm/loader.js";d=e.getElementsByTagName(h)[0];d.parentNode.insertBefore(b,d);a[f]=function(b,d,e){a[c](2,b,k,d,null,new Date,e)};a[f]()})(window,document,"_googWcmImpl","_googWcmGet","_googWcmAk","script");<!– –></script>

Need HVAC Service?

Contact the experts at Eller Services.

Call us at 248-652-6650!

Read More of Our Articles