“What size furnace do I need for my home?” is a great question to ask. The square footage of your home is one of the many variables that come into play in determining furnace size. There are many others like the year it was built, where it is built and the type of construction, the direction it faces, how many windows and doors you have, how many people live in the home. Are just a few other things that should be taken into consideration. We highly recommend having a heat loss calculation completed to properly size your furnace. Although rules of thumb can get you close in some cases, missing one step or miscalculating the info can lead to reduced comfort, Higher energy bills and shorter life expectancy. Proceed with extreme caution.
Another thing to keep in mind is that there are many types of furnaces. Consulting with a heating professional is recommended to help with selecting the type of furnace that will best fit your family’s needs.
Furnaces are built with various heat output capacities which are measured in British Thermal Units (BTUs). Larger homes need furnaces with higher BTUs. You can find the square footage of your home on the real estate records from when you purchased the property. You should also measure the dimensions of every room and add them up to confirm the accuracy of those records. Once you have the correct square footage that should suffice for calculating what furnace size you will need.
Factors That Influence Furnace Size 
Although home size is the primary variable, important secondary issues are:
- Climate
- Insulation
- Furnace BTU/hr output
For heating purposes, the country is divided into climate zones. The Delaware Valley falls into Zone 3, but the region is on the border of the colder Zone 4. This means you might want to select a higher BTU furnace unless your home is well insulated. In Zone 3, a furnace should deliver 45 to 50 BTUs of heat output per square foot. Today’s highly insulated homes can be much less than 45 BTUs per square foot.
Insulation reduces heat loss from a building. A modern home with wall and attic insulation and modern windows places less strain on a furnace. You’ll be able to select a furnace at the lower end of the appropriate BTU range. With a well-insulated Zone 3 home, you would want 45 BTUs per square foot. An older home with little to no insulation will require a more powerful furnace. Minimal insulation and drafty windows require a furnace on the higher end of the appropriate BTU range. An older home without good insulation would need a furnace with 50 BTU per square foot.
Furnaces are rated with input and output capacity ratings, choose the unit based on the output rating.
How to Calculate Furnace Size For a 2000 Square Foot Home Steps
- Find out the square footage of your home.
- Examine your insulation, windows, and doors. A drafty, poorly insulated home needs a more powerful furnace.
- Multiple square footage by 45 or 50 BTUs depending on insulation status.
- This produces the BTU output that you need to heat your home efficiently.
- Choose a furnace that has an output rating at or above the calculated number.
Expert Guidance for Sizing a Furnace
Oliver Heating & Cooling has been keeping people’s homes warm throughout the Delaware Valley for 50 years. We fully understand the heating demands of this climate. We also know how to address the heating needs of an older home. We do a heat loss calculation on every project, Getting the BTU size of a furnace right is vital for comfort, safety, and control of utility bills. A furnace that is too small will run constantly but still fail to keep the home comfortable. All of the excessive run time can wear out the furnace faster too. If you select a system that is too large, then the furnace runs in short cycles. This creates excessive wear and tear and results in cold spots throughout the home. We can help you make an ideal furnace size choice and perform professional installation services you can count on. Contact Oliver about your furnace replacement today.
