How to Determine What Size Furnace I Need

Furnaces that are too large waste energy. Furnaces that are too small have a shorter lifespan, from overworking, and can result in cold spots. So, it is important to get exactly the right size furnace for your home. While an HVAC professional should be the one to confirm you’re looking at the right size furnace, it is useful for you to get a sense of the size of furnace you need prior to confirming with an HVAC professional. Here’s what you need to know to determine what size furnace you need. 

What are BTUs? 

Furnace size is measured in BTUs, so the first thing you need to understand is just what this measurement means. BTU stands for British Thermal Unit. One BTU is the amount of energy it takes the furnace to raise the temperature of one pound of water by one degree Fahrenheit. 

BTUs are not the same as energy efficiency, which is measured in AFUE, or Annual Fuel Utilization Efficiency. The more efficient the furnace, the more BTUs it actually delivers. Whatever percentage the AFUE is, you can expect to get that percentage of the furnace’s BTU output in the home. The rest of the heat is lost in exhaust. 

How Many BTUs Do I Need? 

The simple rule is that every square foot of home needs 25 – 30 BTUs. Therefore, a home that is 2,000 square feet needs between 50,000 and 60,000 BTUs. However, much more goes into a professional calculation than just this basic estimation. 

Factors Affect Furnace Size

Other Factors that Effect Furnace Size 

No two homes are exactly the same. Many other factors will affect what size furnace your specific home needs. Here are a few: 

  • Home layout: Open-concept homes are more efficient to heat as warmth moves through the building without the restriction of walls. 
  • Insulation: Of course, homes that have better insulation will retain more of their heat in the winter, which means they will need less heat output from the furnace. 
  • Windows: Windows can help with efficiency or reduce it greatly. It all depends on the direction they face and the quality of their glazing. 

Why Choose a Professional to Size Your Furnace? 

Coming up with a basic BTU estimation is a great way to start when you’re shopping for a furnace. However, in the end, you’ll want a professional to confirm your hunch. An under-sized or over-sized furnace is likely to cost you more money in the long run, so getting the size right is an important part of the process if you want to maximize your budget. 

To keep warm during the colder months, you need to have a correctly sized furnace. The experts at Advantage Airtech ClimateCare can help you determine the right furnace size for your needs. We carry high efficiency furnaces from well known brands including Lennox & ClimateCare  Contact us today! 

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