what size heat pump do i need

What Size Heat Pump Do I Need? How To Calculate?

It’s roughly 1,000 BTU per 100 square feet for an air conditioner or heat pump. Accordingly, your heat pump would be about 12,000 BTU for a 1,000–1,200 square foot space.

If there is not enough room, the power can be decreased to 9,000 BTU for the same area. Continue reading, you will learn more facts about heat pumps for the right size.

How to Rough Calculate the Right Heat Pump?

Numerous factors, as previously mentioned, determine which heat pump you should buy. You can choose the approximate power you require by using some general rules of thumb, though.

General Rules for a Rough Calculation

It’s roughly 1,000 BTU per 100 square feet for a heat pump or wall-mounted air conditioner. Your heat pump would therefore be approximately 12,000 BTU for a 1,000–1,200 square foot space.

If there isn’t enough room, the power can be decreased to 9,000 BTU for the same area. However, if the area is open, has lots of windows, or has high ceilings, the power can be increased to 15,000 BTU.

Homes with an open floor plan benefit greatly from the single-split wall-mounted heat pump, which has just one indoor unit in the main room. The typical range is 9,000 to 18,000 BTU.

For homes with multiple floors or enclosed rooms, the multi-zone wall-mounted heat pump with multiple indoor units is advised. Between 18,000 and 36,000 BTUs is typically it’s rating.

One cooling ton, or 12,000 BTU, is used to measure central heat pumps. For every 750 square feet, this equates to about one ton. So, for a 1,500-square-foot home, ft. (excluding the basement and garage), you need a heat pump of at least 2 tons, and maybe even 2.5 tons if there are many windows or poor insulation.

Homes with existing air ducts are typically where central heat pumps are installed. Between 24,000 and 60,000 BTU is their typical size range.

Sk Specialized Contractors

The best course of action is to consult experts to make sure that the heat pump you have is adequate for meeting your cooling and heating needs because there are so many variables that can affect your choice of unit.

These knowledgeable contractors can assess the heating and cooling requirements for your home.

what size heat pump do i need

The size of your house, the number of floors, the height of the ceilings, and the amount of insulation will all be assessed by MST’s technicians during the initial visit. These elements enable us to assist you in making an informed decision by advising you on the best unit for your home.

When you work with MST, you’ll receive a high-quality heat pump that is customized to your needs and installed in accordance with the exacting manufacturer’s specifications. The end result is that your heat pump will last a long time and perform at its best, giving you comfort and peace of mind.

Check to See If Your Unit is Eligible for a Grant

For the acquisition and installation of heat pumps that qualify, some government programs provide grants.

Your heat pump’s size will determine the grants that are available. You get $50 in financial aid for every thousand BTUs of heating at -8°C. As a result, you get $500 for a 10,000 BTU/hr heat pump at -8°C and $1,000 for a 20,000 BTU/hr unit.

Both Transition Énergétique Québec’s Rénoclimat program and Hydro Québec’s Efficient Heat Pump program offer these subsidies. In addition, when an eligible heat pump is installed, the Novoclimat program provides a grant to the initial owner of a newly constructed Novoclimat-certified home.

Why You Should Have the Correct BTU?

One of the most crucial steps in the installation process is sizing a heat pump due to the peculiar way they operate. However, a lot of homeowners and even knowledgeable installers make mistakes.

A heat pump can have some serious issues if it is sized incorrectly.

The problem with undersized

If your heat pump is too small, it won’t be able to keep your house warm on the coldest days. Your home will stay warm if you have backup electric resistance heat, also known as heating strips, but you may incur significant electricity costs.

However, make no mistake: a heat pump that is the right size functions in cold climates.

The problem with oversizing

Since we discussed heat pumps vs. According to the AC article, most heat pumps have variable speed motors, which means they change the amount of heating or cooling they offer in response to the outside temperature. Heat pumps with variable speeds can maintain a comfortable temperature rather than turning on and off frequently. But if you oversize your unit, even a variable speed model will kick on and off frequently, as its lowest speed might still overheat your home.

Because heat pumps also serve as dehumidifiers, this is a problem in humid areas of the nation. If the system is the right size, it will continuously remove moisture from the air, keeping your home mold-free and you comfortable. An oversized system will spend most of its time off, allowing moisture to build up.

But even if you live in a dry climate, a large system will make your house less comfortable. A heat pump needs more time to circulate warm or cool air throughout your house the more often it runs. If it’s constantly kicking on and off, you’ll end up with hot and cold spots instead of a steady temperature throughout your home.

what size heat pump do i need

There are financial expenses associated with oversized heat pumps. Besides the higher upfront cost, an oversized unit will need to be replaced sooner than a properly sized unit, since kicking on and off constantly leads to more wear and tear.

How to Approach Heat Pump Sizing on Your Own?

Some of Manual J’s factors cancel one another out. You can have a home that is inadequately insulated, has few windows, and a number of appliances that are 1,000W or more.

The key determinant of how big a heat pump you need is how big your house is. You need a larger heat pump the bigger the house, right?

We can roughly reduce all the variables to a single rule of thumb. When you want to accurately determine the size of the heat pump you need, this general rule of thumb is very helpful.

Here’s the 1 rule of thumb:

30 BTU of heating output per 1 sq ft of living space.

It’s not too difficult to apply this heat pump sizing rule. It roughly incorporates the averages from the Manual J rules. This rule applies to both the heating BTU calculator and the EPA’s general guideline for sizing air conditioners.

A heating output of about 30 BTU is required for every square foot of living space. It follows that, for instance, a 30,000 BTU heat pump (or a 2.5-ton heat pump), would be needed for a 1,000-square-foot home.

How to Determine the Power of Your Unit?

In Canada, cooling needs outweigh heating needs. You must determine your BTU needs based on your cooling needs in order to avoid purchasing a unit that is too powerful and unable to dehumidify the air in the summer. Additionally, it wouldn’t be cost-effective to use a heat pump to fulfill all of your heating requirements because its efficiency declines as the outside temperature drops.

According to Natural Resources Canada, the capacity of your heat pump can be calculated by assuming that it can meet 125% of your cooling requirements. Accordingly, if you determine that your home requires 20,000 BTUs to cool, installing a 25,000 BTU heat pump will satisfy your cooling requirements while reducing the heating load to between 80% and 90%. Electric baseboard heaters or another type of heating system can compensate for the difference. The performance and price are the best they can be.

Also according to Natural Resources Canada (NRCan), the CSA-F280-FM90 standard: Determination of the Required Capacity of Residential Heating and Cooling Appliances should be consulted in order to determine the necessary heat pump capacity.

According to this standard, a number of factors are taken into account to determine how much heat the building loses in the winter and how much heat it gains in the summer. Floor area, level of insulation, amount of sunlight, and air leakage are just a few of these variables.

what size heat pump do i need

Why You Shouldn’t Trust Rules of Thumb?

If you Google “heat pump calculator,” you’ll probably find a rule of thumb like this: “For every square foot of living space that you want to heat or cool, you need 30 BTUs of heat.”

This generalization suggests that you require a 60,000 BTU heat pump if your home is 2,000 square feet.

It’s likely that you will hear something similar if you call a contractor. For many years, most contractors have calculated the size of HVAC systems, such as heat pumps, by multiplying the total square footage of a home by 500 to determine the approximate number of tons of heat that space requires.

According to this general rule, a 4-ton system would be appropriate for a 2,000-square-foot home. One “ton” in heating-speak is equal to 12,000 BTUs, which means that according to this contractor’s rule of thumb, we require 48,000 BTUs.

The Massachusetts Clean Energy Center has been releasing information on the heating loads of state homes for the past few years. The state mandates Manual J and blower door tests, which we’ll explain below, making it an excellent dataset. I made the decision to compare these actual heating load data to the guidelines I previously mentioned using this data.

I performed the calculation for each residence in the dataset using the aforementioned general guidelines. For instance, the first rule of thumb would recommend a 30,000 BTU heat pump for a 1,000-square-foot home, while the second rule of thumb would recommend a two-ton (24,000 BTU) heat pump. After that, I contrasted those two figures with the actual heating load of the house as determined by the Manual J test, a standard industry test that I’ll explain in more detail in the following section.

What Impacts is Heat Pump Sizing the Most?

Insulation and Sealing

Insulation and air sealing in homes are additional important factors.

Some homes are terrible at keeping warm in the winter and cool in the summer, as anyone who has lived in a drafty home can attest to. On the other hand, the most advanced “passive homes” are so airtight that turning on the oven will increase their temperature noticeably.

Older homes typically have poor insulation and air leaks. Their heating loads are higher as a result.

Use of Space

Your home’s heating and cooling requirements are influenced by how you use it, how many people are expected to live there, and the appliances you have.

A larger household will require more cooling in the summer and less heating in the winter, depending on how many people live there and how many heat-generating appliances they use (such as dryers, refrigerators, and ovens).

Windows and Doors

In America, leaky windows and doors are as common as leaky ducts. Your home will likely have a high heating and cooling load if it has single-pane windows or doors with gaping cracks.

what size heat pump do i need

Shade and Sunlight

Your home receives more free thermal energy the more sunlight enters it. This results in less heating during the winter. It entails a greater cooling load in the summer.

Duct Efficiency

Ductwork typically loses effectiveness as it gets older. In other words, your home receives less of the warm air your heating system produces and the cool air your cooling system creates.

According to Energy Star, “In a typical home, leaks, holes, and improperly connected ducts cause 20 to 30 percent of the air that is moved through the duct system to be lost.”


Your local climate is the main determinant of heat pump size. You need more cooling in hotter, more humid climates, and more heating in colder, more humid climates.

To determine which climate zone you are in, use the map below, which was created by the Pacific Northwest National Laboratory.

Conclusion on Right Size Heat Pump

It Might Seem Like the Size of Your Heat Pump Isn’t That Important. Having a Heat Pump That’s Either Too Small Or Too Large Can Result in You Wasting Money.

When it comes to energy savings and maintaining the ideal temperature in your home during the winter and summer, choosing the appropriate heat pump size for your residence is essential. While initially appearing challenging, sizing your heat pump is actually quite straightforward. And fortunately, there are many heat pump sizing calculators online that can further simplify the process. Finding the ideal heat pump should be simple once you know what size you require.