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What Size Heat Pump Do I Need? Factors, Cycles & FAQs

heat pump outside the house

A heat pump can be a great alternative to traditional heating systems and can dramatically reduce the strain on your furnace. However, since these devices are relatively new, you might be confused about what size you need. The short answer is that most people will need a 3- to a 5-ton heat pump, but there are several things to consider before you make a purchase, so keep reading as we look at the different factors in play.

divider 7 How Do Experts Determine What Size Heat Pump Is Needed?

HVAC experts in North America follow the Manual J and Manual S procedures to determine the best heating or cooling unit to use in a given property. Manual J helps determine relative humidity, floor area, total heat loss, total heat gain, and number of occupants, while the Manual S focuses on thermostats, air handlers, and ductwork. You can usually hire a company to do a Manual J and Manual S audit on your home for a small fee, usually between $100 and $300, to get the most accurate determination of what size heat pump you need.

Two heat pumps outside the house
Image By: Nimur, Shutterstock

Factors That Affect Heat Pump Size

Square Footage

A primary factor that will determine what heat pump you need is the square footage of your home. Naturally, a large area will require a large heater to maintain an even temperature and keep your living environment comfortable.


Another thing to consider before purchasing a heat pump is the climate where you live. For example, people living in zone 1 or 2 environments will require a larger heater than those living in zones four or five.

white and gray heat pump
Image Credit: Carlos Lindner, Unsplash

What Size Heat Pump Do I Need?

Understanding what size heat pump you need requires you to understand the terms BTU and ton. A BTU, or British Thermal Unit, measures how much heat you need to raise the temperature of 1 pound of water by 1 degree. According to Manual J and Manual S procedures, 1,000-square-foot homes need a 30,000-BTU heat pump. One ton equals 12,000 BTUs, so you will need at least a 2.5-ton heat pump for a 1,000-square-foot home.

Heat Pump Size in Tons Zone 1–2 Square Footage Zone 3 Square Footage Zone 4–5 Square Footage
1.5 600–800 700–1,000 800–1,100
2 800–1,000 1,000–1,200 1,100–1,500
2.5 1,000–1,300 1,200–1,500 1,500–1,800
3.5 1,600–1,800 1,800–2,000 2,000–2,500
4 1,800–2,000 2,000–2,400 2,500–3,000
5 2,000–3,000 2,700–3,000 3,300–3,700

divider 7

Other Factors to Consider

Blower Motor

Blower motors help move the air from one location to the other. You will usually see single, double, and multispeed motors, and in our experience, multispeed motors use the least power.


There are several types of compressors, including single stage, two stage, and variable speed. Single-stage compressors work at full capacity, so they may not last as long as the others, but they are the least expensive and most common. Dual-stage compressors can operate at about 70% capacity, while the variable speed can increment through several changes.


The location of your heat pump can dramatically affect how it works, so you will need to take the time to determine the best place to put it in your home.

Heat pump on a residential home
Image Credit: Palatinate Stock, Shutterstock

What if I Purchase a Pump That Is the Wrong Size?

A heat pump that is too small for your home will run continuously because it is struggling to maintain the ideal temperature. This constant running will likely increase your electric bill more than expected. It can also cause your machine to wear out faster than it ordinarily would, leading to expensive repairs or replacements. If the machine that you purchase is too large, it will only run in short increments, which is hard on the engine. These short cycles can also lead to improper heating, encouraging mold growth and other problems in your home.

divider 7 Summary

Most people in America will need a 3- or 4-ton heat pump to maintain a comfortable and even temperature in their home. If you live in an especially large home, you may need to go up to a 5 ton, and if you live in a mobile home, you can likely get away with something smaller. The best option is to hire a professional to come out and do a Manual J and Manual S audit on your home, so you know that you are getting the right sized unit. This audit will prevent you from getting the wrong size, which will break down faster and won’t provide you with a comfortable environment.

Featured Image Credit: HarmvdB, Pixabay


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