Heat pump calculator

Use this tool to estimate if your home is ready for a heat pump and what the potential benefits could be. This calculator provides a high-level estimate; a professional survey is always required for accurate sizing.

What you’ll need

To get the most accurate estimate, it helps to have the following information ready:

  • Property age and type: e.g., 1930s semi-detached.
  • Annual energy usage: Look at your gas or oil bills for the last 12 months (in kWh).
  • Insulation details: Do you have cavity wall insulation? How deep is your loft insulation?
  • Radiator sizes: Are your current radiators “standard” or have they been upgraded?

Key outputs

The calculator will provide estimates for:

  1. System size: The required capacity of the heat pump in kilowatts (kW).
  2. Running costs: Comparison of annual electricity costs vs your current fuel costs.
  3. Carbon savings: How many tonnes of CO2 you will save per year.
  4. Grant eligibility: Direct links to apply for the £7,500 Boiler Upgrade Scheme grant.

Methodology

Our calculations are based on the MCS Heat Emitter Guide and standard UK degree day data. We assume a Seasonal Coefficient of Performance (SCOP) of 3.0 to 3.5 for air source heat pumps, depending on the age of your property.

Important: This tool is for guidance only. An MCS-certified installer must perform a room-by-room heat loss calculation before any installation to ensure the system is sized correctly.

Interactive Calculator

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Insulation and glazing
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