Selecting the right size HVAC system for your home is a balancing act. If you go too small, you’ll wind up uncomfortable. If you go too big, you’ll waste money – and probably wind up uncomfortable.
Fortunately, choosing the correct heating and cooling systems for your home is easy. Ask an HVAC technician. An experienced one has already installed hundreds of furnaces and air conditioners at properties sized similarly to your own. They’ll spare you from making an egregious mistake that could wind up costing you thousands.
But just for the sake of argument, suppose you don’t want to contact a local HVAC contractor with this question. No worries! It’s actually really straightforward.
How to Choose the Right Size Cooling System
It’s not the size of the air conditioner that counts. It’s the cooling capacity: the amount of heat the system can remove from a finite amount of space over time.
Cooling capacity is measured in British thermal units (BTUs), where 1 BTU is roughly equal to the energy released by burning a single match. To calculate the number of BTUs your new air conditioner should be, just multiply the square footage of your home by 20. Here’s a table for reference:
| Square Footage | BTUs | Square Footage | BTUs |
| 500 | 10,000 | 2,300 | 46,000 |
| 700 | 14,000 | 2,500 | 50,000 |
| 900 | 18,000 | 2,700 | 54,000 |
| 1,100 | 22,000 | 2,900 | 58,000 |
| 1,300 | 26,000 | 3,100 | 62,000 |
| 1,500 | 30,000 | 3,300 | 66,000 |
| 1,700 | 34,000 | 3,500 | 70,000 |
| 1,900 | 38,000 | 3,700 | 74,000 |
| 2,100 | 42,000 | 3,900 | 78,000 |
Note: BTUs are also measured in “tons,” where 1 ton equals 12,000 BTUs. A 3,900 square-foot house therefore needs a “6-2/3 ton” cooling system (rounding up to 7 is safe in this circumstance).
Pretty convenient, isn’t it? And it only gets better, because selecting the right size furnace is also easy as pie.
How to Choose the Right Size Heating System
Estimating the correct size for your home’s next furnace is also a matter of multiplication: just multiply the square footage of your home by 30. Once again, this would have required doing math if we weren’t so thoughtful as to create a table.
| Square Footage | BTUs | Square Footage | BTUs |
| 500 | 15,000 | 2,300 | 69,000 |
| 700 | 21,000 | 2,500 | 75,000 |
| 900 | 27,000 | 2,700 | 81,000 |
| 1,100 | 33,000 | 2,900 | 87,000 |
| 1,300 | 39,000 | 3,100 | 93,000 |
| 1,500 | 45,000 | 3,300 | 99,000 |
| 1,700 | 51,000 | 3,500 | 105,000 |
| 1,900 | 57,000 | 3,700 | 110,000 |
| 2,100 | 63,000 | 3,900 | 117,000 |
How Do You Know How Many BTUs a Furnace or Air Conditioner Is?
Don’t worry. HVAC appliance manufacturers don’t keep that important information a secret. A sticker, data plate, manual, product description, or other piece of marketing materials should make the unit’s tonnage obvious.
Don’t forget to factor in a unit’s efficiency! For example, if a 10-ton (i.e. 120,000 BTU) furnace has an AFUE rating of 90%, then it is effectively a 9-ton furnace.
Call PrairieSons for the Right Size HVAC System
Figuring out the right size HVAC system for your home is relatively easy. Actually installing it, on the other hand, is not. If you live in the greater Sioux Falls, SD area and want your new heating or cooling system installed the right way, then PrairieSons is at your service. Reach out today for all your heating, AC and plumbing needs!