Estimating Furnace Size Based on Square Footage The general rule of thumb is that you need between 30 and 60 BTUs per square foot, depending on your climate. Climate zones can help you determine how many BTUs per square foot you need.

How do I determine what size furnace I need?

Below are the furnace BTUs required for homes of certain sizes.

  1. Furnace for 1,200-square-foot house: 36,000 to 72,000 BTUs.
  2. Furnace for 1,500-square-foot house: 45,000 to 90,000 BTUs.
  3. Furnace for 1,800-square-foot house: 54,000 to 108,000 BTUs.
  4. Furnace for 2,100-square-foot house: 63,000 to 126,000 BTUs.

How can I maximize my furnace efficiency?





These seven simple tips will ensure your furnace isn’t using too much energy — which will save you cash.

  1. Change the air filter. …
  2. Check and clean the vents. …
  3. Clean out the furnace. …
  4. Rethink the thermostat. …
  5. Put a sweater on. …
  6. Get a tune-up. …
  7. Upgrade your equipment.

What size furnace do I need for 2000 square feet?

Rough Estimates
A mid-sized home of 2,000 square feet would need approximately 50,000 to 60,000 Btu to heat it properly. With a less efficient furnace operating at 80 percent efficiency this would require a 60,000- to 72,000-Btu furnace.

Is it better to undersize or oversize a furnace?

It’s better to be a little undersized than oversized, You’ll get a little longer run time, but it’s better than shortcycling.

What happens if my furnace is too big?





Oversized Furnace
The problem with a furnace that’s too large is that it puts out too much heat for the space, which causes the thermostat to shut the system down early. This places extreme stress on the furnace, which will eventually cause the system to break down.

What size furnace is needed for a 1500 square foot house?

between 45,000 to 90,000 BTUs

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 efficient is my 40 year old furnace?

How efficient is the average 35-40 year old furnace? 80% at best. Likely lower if it is indeed close to 40 yes old. A lot of savings to be had with a new furnace 95% with a ecm blower motor.

Do high efficiency furnaces run more often?



Contrary to what you may initially think, high efficiency furnaces run more often. However, this does not mean that they use more energy. By running more often, they can ensure that your home is kept at a more even temperature without having to work as hard.

How many hours should my furnace run per day?

How Often & Long Should You Run a Furnace? Generally speaking, a healthy furnace runs for 15 minutes per cycle, two to three times per hour. The amount of these cycles will vary and depend on the time of year and how high you have set your thermostat.

How many square feet does a 3 ton furnace cover?

1,800 sq ft.



Estimated square footage: 1,800 sq ft. 4-Zone Mini Split ACs: About 3 Tons or 36,000 BTU. Estimated square footage: 1,800 sq ft.

Is a 95% furnace worth the extra money?

An 80% furnace with two stages of heat will usually be better for your energy bills than a 95% furnace with just one stage. Some 95% furnaces even come with a fully modulating gas valve. It’s similar to having two stages of heat, only better!

How do I know if my 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.

Is it a good idea to undersize a furnace?

An undersized furnace will work harder – and longer – to keep your home warm. In fact, a furnace that is too-small may run almost constantly, especially in colder weather. In the worst cases, an undersized furnace may not be able to reach the temperature you’ve set on your thermostat.

How many square feet will a 80000 BTU furnace heat?



80 X 1,000 square feet = 80,000 BTUs.

How big of a house will a 100000 BTU furnace heat?

In colder climates, you’ll want a furnace that generates 40 to 45 BTUs per square foot. At this amount, you’ll need 100,000-112,500 BTU furnace to heat a home of 2,500 square feet. A more accurate way to estimate furnace size is through heat degree day calculation.

How many square feet will a 80 000 BTU furnace heat?

1,000 square feet

80 X 1,000 square feet = 80,000 BTUs.

How big of a furnace do I need for a 1000 sq ft house?



Chart For Furnace Tonnages And BTUs For 500 – 3,000 Sq Ft Houses

House Size (Sq Ft): Furnace Size (in BTUs):
800 sq ft home 36,000 BTU furnace
900 sq ft home 40,500 BTU furnace
1000 sq ft home 45,000 BTU furnace
1100 sq ft home 49,500 BTU furnace

What size furnace do I need for 1600 sq ft house?

Table of Furnace Sizing by Square Footage

Home Size Hot Climate Moderate Climate
1,600 sq ft 54,000 BTU 67,000 BTU
1,800 sq ft 61,000 BTU 75,000 BTU
2,000 sq ft 68,000 BTU 83,000 BTU
2,200 sq ft 75,000 BTU 92,000 BTU

How many sq feet will 24000 BTU cool?

BTU Sizing Chart for Mini Split Systems

Area To Be Cooled Capacity Needed (BTUs Per Hour)
700 to 1,000 square feet 18,000 BTUs
1,000 to 1,200 square feet 21,000 BTUs
1,200 to 1,400 square feet 23,000 BTUs
Up to 1,500 square feet 24,000 BTUs

How many seers do I need for 2000 square feet?

MrCool 3-ton DIY mini split with 20 SEER rating is an affordable unit for 2,000 sq ft homes in colder climates and with good insulation.

How many square feet will a 3-ton AC cool?

How many square feet does a 3-ton air conditioner cover is quite easy to answer as well. 3-ton is equal to 36,000 BTU. If you apply the 20 BTU per sq ft rule of thumb, you can see that a 3-ton air conditioner cools about 1,800 square feet spaces.

How many BTU do I need furnace?

In most areas with cold winters, a home furnace will need to generate between 40 to 45 BTUs per square foot. Using this information, you can get a rough estimate of your required furnace size based on your home’s square footage.

Is higher BTU better for furnace?

A heater with a higher BTU rating is more powerful — that is, it has a higher heat output — than one with a low BTU rating. It can do more to raise the temperature in your room each hour, so you can either heat a room more quickly or heat a larger space.

What size furnace do I need for 1700 sq ft house?

A 100- to 200 square-foot room, such as a small home office, will have an average recommendation of 4,000 to 8,000 BTUs. For a space of 800 to 900 square feet, such as a small home or two-bedroom townhouse, the recommendation is between 30,000 and 45,000 BTUs.