How Big Is A Heating Pump And What Size Do I Need?

How big is a heating pump and what size do I need

Charlie Hardcastle

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Are you thinking about getting a heating pump installed in your home or professional space?

Unsure what size you may need and how much space this would require?

How big is a heating pump and what size do I need

This guide will help you to understand what you need to consider when buying a heating pump to ensure you get the best size for your space.

What Is A Heating Pump?

A heating pump is both a heating and cooling system that pumps air from the outdoors through an indoor space as a way to cool the space in the summer and heat it in the wintertime. 

Whether this appliance is being used to cool or heat a space the physics remains the same.

When cooling a space the outside coil on the heat pump is a condenser and the inside coil on the appliance acts as an evaporator.

When heating the home the function of the coils switches so that cold air is now brought in and heated before being distributed through the indoor space. 

As heating pumps rely on the air there are particular temperatures where these versatile appliances do not work as efficiently as desired.

When temperatures drop to less than 40 degrees Fahrenheit many heating pumps are affected and become more costly to use. 

How To Know What Size You Need

Below we look at everything you need to know to understand what size heating pump you need.

Manual J Inspection 

The Manual J is a method of sizing heating pumps used by the HVAC industry.

It was created by the Air Conditioning Contractors of America and it is a number of calculations that are done to decide how much hot or cold air is needed for rooms in a home throughout the year.

There are 8 different factors that are considered during a Manual J Inspection, these are:

  • Local climate
  • Your home’s shape and square footage
  • Number and location of windows
  • Total air filtration that occurs
  • Insulation in the home
  • Number of residents
  • Temperature preference of residents
  • Additional appliances used to heat the home

How To Find The Square Footage Of Your Home 

The square footage of a home is first calculated. The length and width of each room are multiplied and then the footage squares of each room give the total square footage of a home.


Factors that affect insulation in the home are next considered, these are the exposure to the sun, airtightness, and windows. These are measured in British Thermal Units or BTUs. 

100 BTUS is added for each resident, and 1,000 extra BTUs are added for each window and also for each exterior door.

Use of Spaces 

How each room is used and the number of people it is used by are also considered. 

How To Calculate The Size Of The Heat Pump Needed

Below is an example of the formula used to calculate the size of the heat pump you need.

This example is calculated for a home with 2,000 square feet, a ceiling height of 10 feet, 10 windows, 4 residents, and 2 exterior doors. 

  • 2000 x 10 = 20,000 base BTU
  • 2 (exterior doors) x 1,000 = 2,000
  • 10 (windows) x 1,000 = 10,000
  • 4 (residents) x 100 = 400
  • 20,000 + 2,000 + 10,000 + 400 = 32,400 BTU 

This is the final calculation used in a Manual J inspection to give the HVAC load, which in this case is 32,400 BTUs.


If you live in a cold climate, buying a larger heating pump (see also ‘What Is A Heat Pump And How Does It Work?‘) will not give you a better operating appliance as all heating pumps, regardless of size, are affected by climate.

If you live in an area where the climate can be under 40 degrees Fahrenheit in the cooler months you should expect that your heating pump (thermostats) operations will be affected.

IF you live in a climate where temperatures frequently fall below 25 degrees Fahrenheit a heating pump would not be suitable for you. 

SEER Ratings

SEER Ratings are Seasonal Energy Efficiency Ratios and they are used to determine the efficiency of a heating pump.

It takes the cooling efficiency for ductless and air-source systems and divides the result by the amount of energy used in watt-hours.

Higher ratings are a sign of an efficient heating pump and these tend to be 15 and higher.

Star-rated products often have SEER ratings of anywhere between 18 to 27.5. High SEER rated products are expensive but they will help save you money in the long run. 


A 2-ton heating pump is rated at a capacity of 24,000 BTUs and so it is capable of heating and cooling a space that is less than 1,000 square feet, depending on the heat and insulation loss in this space.  

A 3-ton heating pump is rated at 36,000 BTUs per hour and so it has the capacity to heat or cool a space of up to 1,500 square feet, again this depends on the heat and insulation loss in this space. 

A 4-ton pump with up to 40,400 BTUs should be enough to heat or cool a 2,500-square-foot home that has 12 windows, 3 exterior doors, and a ceiling height of 10 feet.

If this home had more than 4 residents a unit with a higher BTU would be necessary. 

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How Much Space Does A Heating Pump Require? 

When looking at how much space a heating pump would require it is important to remember that the majority of this space will be outdoors and so it is more important to consider how much outdoor rather than indoor space you have.

Air-source heat pumps (see also ‘Heat Pump Vs Air Conditioner‘) and ground-source heat pumps require different amounts of space.

Air-Source Heating Pump

An air-source heating pump takes up very little space and is usually smaller than a washing machine.

You can place this type of heating pump anywhere on your private land as long as the appliance will have access to enough fresh air with no obstructions that could affect this.

When considering an air-source heating pump, think about how much space you want to heat, this will influence the power output you would need, which would be between 5 to 13 kilowatts.

1 kilowatt can generally heat 10 meters square of an indoor space in peak temperatures but this is subject to heat and insulation loss in the space.

Ground-Source Heating Pump

This type of heating pump (see also ‘Heat Pump Water Heater vs. Gas‘) is more complex than air-source heating pumps. Pipes are laid in the ground and you would need approximately 50 to 80 meters of pipework to produce 1 kilowatt.

The pipes are laid up to 1.2 meters deep in the ground is porous. Gardens typically need to be remodeled after this pipework has been laid which is another cost to consider. 

Where Should A Heating Pump Be Installed? 

When deciding where to place your heating pump consider the below 6 factors to find the best location.

1. Accessibility

As maintenance will be required it is imp[ortant that your heating pump is installed in an area that will be easy to access should repair work need to be done.

A technician should be able to get full access to every part of the appliance. 

2. Weather

The heating pump should not be installed in an area where it will have direct sunlight.

Direct sunlight will impact the operations of the appliance and cause it to work harder than necessary which can prevent it from working efficiently.

Install your heating pump in a shaded area and also ensure it is not somewhere that snowdrifts can affect it. 

3. Ventilation 

The heating pump should be placed in an area where it will have access to a lot of fresh air. These units should not be installed in enclosed spaces as they will run out of air to utilize when powered on. 

Heating pumps should be installed at least one to three feet away from walls and should be elevated between 4 to 8 inches above the ground to ensure the appliance can drain properly and stay above snow level. 

4. Surrounding Vegetation 

Vegetation can affect the airflow and so there should be no surrounding vegetation within 18 inches of the appliance.

Make sure you keep any vegetation nearby trimmed and pruned to prevent your heating pump from not working effectively. 

Also prevent installing a heating pump near roads or driveways as these tend to create dust which can clog the fans and vents of the heating pump, ultimately leading to more maintenance work and reduced operation capabilities of the heating pump. 

5. Sea Salt Exposure 

Sea salt is another thing that can affect the operations of a heating pump as this can lead to corrosion. Air-source heating pumps should be avoided in coastal areas and ground-source heating pumps should be used. 

Applying an anti-corrosive agent to the coils during installation can prevent damage to your unit as a result of the sea salt.

6. Neighbors and Home Occupants

While heating pumps are very quiet they should be installed away from bedrooms to prevent any disturbances. If you have close neighbors, install a fence so that any sounds from the heating pump will be absorbed and muffled.

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The Benefits and Disadvantages of Heating Pumps

As with all appliances, there are several benefits and disadvantages associated with heating pumps. These are explained below.

Benefits of Heating Pumps 

Using a heating pump is a very green way of heating and cooling your home.

These appliances work efficiently to maintain an optimal temperature in your home or professional space without leading to extortionate energy bills.

Other more traditional heaters and coolers can be very expensive to operate and not work as efficiently. 

The air quality in your indoor space also benefits from this appliance as heating pumps also have humidity control so you don’t need to worry about breathing in dry air or having to operate a dehumidifier to remove excess moisture in your home.

Many heating and cooling appliances can be extremely noisy which can affect the quality of sleep you may have.

Heating pumps are generally very quiet, allowing you to heat and cool your home at any time without causing disturbances or affecting sleep.

Another reason heating pumps are popular and seen to be beneficial is that they are safe. In the case of gas heating systems or furnaces, they can cause household fires, gas leaks, or explosions.

With air conditioners, many require refrigerant which can be a highly toxic chemical that can cause medical issues when ingested. 

Disadvantages of Heating Pumps

Installing a heating pump can be very expensive but do remember that this appliance will enable you to save money in the long run, view this cost as an investment.

These appliances are quite large and require a lot of space in comparison to other appliances. It is because of their size that many people find that this appliance would not be suitable for their home.

When installing a heating pump you will also claim back space in your home as previous appliances will no longer be needed.

Another disadvantage associated with heating pumps is that they are less efficient when temperatures drop below 40 degrees Fahrenheit and so it is important to really understand the weather you experience each year to ensure the heating pump can do its job effectively in your local climate. 

The last disadvantage is that heating pumps (see also ‘Solved: Heat Pump Constantly Running‘) require frequent maintenance to keep the appliance running at its best.

There are a lot of mechanical parts within the internal system of a heating pump and so these require frequent attention to prevent any dust or dirt build-ups that can affect the operating efficiency of the appliance. 

Final Thoughts

We hope that this guide has answered any questions you may have had so that you will be able to find a suitable heating pump for you and your home. Need any help? don’t hesitate too contact Peco Air.

Heating pumps (see also ‘Do Heat Pumps Work Below Freezing?) are an effective and green way of cooling and heating your home as long as your home meets the certain criteria mentioned in this piece. 

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