How To Choose The Right Size Heater

To get the most out of your heat pump, choose the right size heater and use a professional heat pump installer.

If the heat pump is too small for your house, expect to pay more in utility bills because it runs longer to provide enough heat. Likewise, if the heat pump is too big, it emits too much heat, resulting in waste.

Therefore, knowing how to size a heat pump saves your money and ensures your home stays warm and comfortable.

This post focuses on how to choose the right size heater. We simplify how to calculate what size heat pump you need for your home.

How Do I Calculate What Size Heater I Need?

Before you learn how to size a residential heat pump, it helps if you understand the unit used for heater sizing.

Heat pump size depends on how much heat it produces per hour. British thermal unit (BTU) is the amount of energy required to heat a pound of water by one degree Fahrenheit.

Therefore, the higher the BTU rating, the more warmth you get from the heat pump.

Before purchasing a heat pump, calculate how many BTUs you need to heat the house.

According to HVAC experts, you should install one ton (12,000 BTUs) of air conditioning capacity for every 500 square feet of conditioned floor area.

Here is a chart to help you size the heat pump for your space based on square meters.

Home size (in square feet) Heat pump size (in tons) Heat pump size (in BTUs)
500 square feet 1 ton 12,000 BTUs
1,000 square feet 2 tons 24,000 BTUs
1,500 square feet 3 tons 36,000 BTUs
2,000 square feet 4 tons 48,000 BTUs
2,500 square feet 5 tons 60,000 BTUs
3,000 square feet 6 tons 72,000 BTUs


How HVAC Experts Calculate Heat Pump Size Using Manual J

HVAC experts follow a standard heat pump sizing formula, referred to as Manual J. The standards require that you go room-by-room to determine the correct heat pump size.

Manual J looks at eight factors to develop the appropriate heat pump size for your home.

They are:

  1. The local climate and how many days a year you need active heating and cooling
  2. The building’s layout, such as square footage and the shape
  3. The number and location of windows
  4. Amount of air infiltration in the house
  5. Your current insulation and whether the insulation meets the region’s efficiency rating
  6.  The number of people occupying the building.
  7.  How residents use the home and their temperature preferences
  8. Other appliances used to generate heat

While we have the formula and the guide for calculating heat pump size, it is still an overwhelming task. That is why you should talk to a professional about correct heat pump sizing.

Is a Heat Pump Better Than a Furnace?

Ideally, heat pumps use the outside air to heat a home in winter and cool it in summer. Therefore, the heat pump extracts heat from outdoor air or ground and distributes it into the home in winter. On the other hand, a furnace converts fuel (gas) into cozy heat and then distributes it throughout your home.

Compared to furnaces, heat pumps offer an energy-efficient alternative.

How Do I Calculate How Much Heat I Need For My Home?

Follow these steps:

  1. Determine the size of your home in square feet
  2. Multiply the square feet by a factor of six for BTUs/by 0.0606 for KW
  3. You will find the minimum heat output you need to keep the room heated

How Many BTUs Do I Need For a 1,700 SQ Foot House?

For every 500-square-foot house, you need 12,000 BTUs. Therefore for a 1,700 SQ Foot house, you need approximately 36,000 to 48,000 BTUs.


Now you understand how to size a heat pump for your home. If you live around the Coachella Valley area – Indio, Indian Wells, Palm Desert, or La Quinta – a reputable heating and air conditioning repair company is nearby.


Let Anthem Heating & Air help you with all your air conditioning and heating questions and needs! Visit us at or call now at (760) 895-2621.

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