What Size Furnace Do I Need for a 1500 Square Foot Home?

Arcoire furnaceThe average home in Modesto is about 1500 sq. feet. As an HVAC company in Modesto, we at Irish Heating & Air frequently have customers ask what size furnace they need to heat their 1500 sq. foot home. It’s such a critical question that we’ve set out to answer it once and for all so you can be sure that your furnace will run efficiently and keep your home at your desired temperature without extra wear and tear.

The Importance of Furnace Size

Choosing the correctly sized furnace is a matter of long-term cost savings. If you choose a furnace that is too small for your home, it will run constantly. Not only is this an inefficient use of energy, but the furnace will break down much sooner than a properly sized furnace. Plus, your home will have cold spots.

The opposite problem occurs with a furnace that is too large. It will switch on and off frequently, which causes a different kind of wear on the appliance. It willalso use energy inefficiently, which translates to a higher utility bill for you.

Still, if you have to choose between a furnace that is slightly too large and a furnace that is slightly too small, pick the larger. It’s best to choose furnace that has the capacity to meet your needs. It may wear out sooner than a properly sized furnace, but at least it will maintain your home’s temperature, while a smaller furnace may never be able to accomplish that.

Calculating Your Furnace Needs

The size of furnace you need depends mainly on the size of your home. As mentioned, a typical home in Modesto is 1500 square feet. Generally in a Californian climate you will need 25-30 BTU per square foot. BTU is a measurement of a furnace’s heat output. 1500 sq feet by 25 BTU gives us a 37,500 BTU furnace.

The same calculation will not work for your friends or family in colder states, who need a more powerful furnace to counter-act their harsher winters. They could need 45 BTU per square foot, or more.

In fact, you may need more BTU per square foot than the 25 we used for the calculation above. If you live in a slightly colder area of California, or if you prefer to keep your home slightly warmer than average, you may need more like 30 BTU per square foot. This would give you an overall furnace size of 45,000 BTU.

A few other factors can affect your ideal furnace size. Homes with a lot of windows, or especially old insulation, may benefit from a higher furnace BTU. Similarly, homes designed with great insulation and few energy inefficient design features may get away with smaller furnaces.

If you have other questions about your furnace size, or any of your HVAC needs please reach out to us at Irish Heating & Air. We’re dedicated to answering your questions so you can make an informed decision about your HVAC appliances, including your furnace.