How do I choose the right size furnace?

Calculating Your Basic Heating Needs You’ll want to multiply your home’s square footage by the recommended heating factor to obtain the furnace output rating you’ll need. For example: If your home is 2,400 square feet and you figure 35 BTUs per square foot, you’ll need a 84,000 BTUH-capacity furnace.

How is furnace size measured?

The size of a furnace is based on how much heat it can produce in an hour, as measured in BTUs, or British thermal units. A BTU is the energy required to heat a pound of water by one degree Fahrenheit. The higher the BTU rating a furnace has, the more warmth it can provide.

How do I calculate my furnace heat?

Heating Guide

1. Simply multiply the appropriate factor above by your home’s total heated square footage to arrive at your approximate required heating capacity.
2. Then, to calculate the output on a given gas furnace, multiply it’s efficiency rating by it’s listed input rating to determine the actual Btu output of heat.

Is it good to oversize a furnace?

Having a furnace that’s too big for your space is extremely inefficient. There are two simple signs that indicate that your furnace is most likely oversized: Your furnace runs for a short period of time before shutting off. Your home has uncomfortable hot and cold rooms.

Is it better to undersize or oversize a furnace?

An undersized furnace will work fine for the majority of the time, but every once in a while it won’t get the house quite as warm as desired. An over-sized furnace will keep the house warm no matter how cold it gets outside, but it does so at a cost.

How many square feet will a 60000 BTU furnace heat?

A standard that is used by heating and cooling equipment companies is to provide at least 25 to 30 Btu of heat per square feet in the home for a moderate to warm climate. A mid-sized home of 2,000 square feet would need approximately 50,000 to 60,000 Btu to heat it properly.

What is the correct size furnace for a 1500 square-foot house?

A 1,500-square-foot home will require between 45,000 to 90,000 BTUs. A 1,800-square-foot home will require between 55,000 to 110,000 BTUs. A 2,100-square-foot home will require between 65,000 to 125,000 BTUs.

How many square feet will a 75000 BTU furnace heat?

Heating a Poorly Insulated Room A 75,000 BTU heater can heat a room of between 1,900 and 3,700 square feet in a cold climate if there is little to no insulation. In more temperate climates the heater fares better, heating an uninsulated room of any size from 2,400 to 4,600 square feet.

What happens if furnace is too small?

When furnaces are too small, they’ll have to kick on often—or even non-stop—try to increase your indoor temp. They end up running and running, but without any real progress. This leads to excessively high energy bills, and not much help in making your home comfortable.

How many BTUs do I need to heat 1000 square feet?

18,000 BTUs
Calculating the number of BTUs needed to heat an area For example, a 300 square foot room typically requires 7,000 BTUs to maintain a comfortable temperature, while a 1,000 square foot room requires 18,000 BTUs.