If this 1,900-square-foot home is in Washington, D.C., however, and the furnace you’re looking at has an 80 percent efficiency, the input rating should be 100,000 BTUs. Furnaces typically have around an 80 percent efficiency rating, although more expensive, high-energy models have at least a 93 percent efficiency rating.
If you're in Washington, D.C., in the 1,900-square-foot home, and the furnace you're considering has an efficiency of 80 percent, you'll want your input rating to be 100,000 BTUs. You can calculate this with any size home. Just substitute your own total square footage, and multiply it by your regional heating factor.
For this example, using an 80% efficient furnace, the 1900 square foot home above would require a 90,000 Btu input furnace that produces 72,000 Btu's of heating, which is close enough to the 76,000 Btu's required using the climate heating factor.
As you can see, the properly sized central air conditioner for a 1,900 square foot home in Montana is quite different from the required size in Santa Clarita, California. Hopefully, this section helped you get a quick idea of what size central air conditioner is right for your home.
In the example above, using an 80% efficient furnace, the 2000 square foot home above would require a 100,000 BTU input furnace which will produce the necessary 80,000 BTU's output of heat. Variables Let's talk about all of the variables that come into play when selecting a new air conditioner system or furnace.
The Carrier brand 35-45kW Air-Cooled Home Standby Generator, for example, outputs a running wattage of 26kW to power a 5,000-square-foot home. Generators this size are best used for either long periods of time or for large power needs.
A rule of thumb is to allow 25 to 30 BTU per square foot for moderate climates and up to 45 BTU per square foot in harsher climates. For a 2,000 square foot home, the ideal furnace size therefore varies from 60,000 to 90,000 BTU. Efficiency is an important consideration in selecting the correct size of furnace for a home.
For cooler climates, a very broad estimate of furnace sizing is to select one that generates 40 to 45 BTUs per square foot. At 40 to 45 BTUs per square foot, you'd need a 100,000 to 112,500 BTU ...
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.
BTU Charts Furnace Output and Air Conditioner size for a Bungalow Bungalow Area [sq ft]* Furnace Output [BTU/hr] Air Conditioner size [ton] Built after year 1980 Built before year 1980 Built after year 1980 Built before year 1980 up to … Readmore