Energy & Sustainability

Heat Pump Calculators & Efficiency Guides

Efficiency → energy → cost → payback. Start with your heat demand and a performance figure for your equipment.

Use this hub to decide which performance figure to read, how much electricity heating may need and whether a replacement pays back. Start with the COP/SCOP guide if the efficiency input is unclear; use the savings calculator once you have heat demand and tariffs.

What do you want to work out?

Which efficiency figure belongs in my estimate?

Inputs to gather

Manufacturer performance data, rated climate and heating-water temperature.

Read COP and SCOP

COP describes an operating point; SCOP covers a defined heating season. Use a rating matching your equipment and conditions, not a universal multiplier.

What could my annual heating cost and payback be?

Inputs to gather

Annual useful heat demand, current heating efficiency, seasonal heat-pump performance, fuel and electricity tariffs, and net installation cost.

Compare heat-pump running cost and payback

Compare the same heat delivered by both systems. A positive annual saving is not the same as recovering the installation cost. Replace generic defaults with your own evidence.

Understand heat-pump savings and payback

Guides behind the calculations

Modern heat pump unit installed outside a home for efficient heating

Heat Pump Efficiency Guide: Understanding COP and SCOP

Choose a performance input from the equipment rating and understand its conditions.

Air-source heat pump installed beside a Scandinavian home in winter

How to Calculate Heat Pump Savings and Payback

Turn heat demand, seasonal performance and tariffs into cost and payback.

Convert inputs when needed

  • MJ → kWh

    Put heating energy recorded in MJ on the same kWh basis as electricity.

  • thm → kWh

    Convert US therms from an energy bill; check which therm your supplier uses.

  • BTU/h → W

    Compare heat-output power ratings. This is power, not annual energy use.

Before choosing a calculation

Do I need COP or SCOP before comparing annual costs?

Use seasonal performance appropriate to your equipment and conditions for an annual estimate. A COP at one test point is not an annual efficiency assumption. The COP/SCOP guide explains how to read the rating.

Can this hub tell me what size heat pump to install?

No. The savings calculator compares energy and cost; it does not replace a property-specific heat-loss assessment. Obtain that assessment before selecting equipment.

Can savings be negative?

Yes. Tariffs, heat demand and seasonal performance can make the heat pump more expensive to run. Compare both systems using the same useful heat demand before estimating payback.

Your next decision

Measure your home-energy baseline

If heat demand is uncertain, start from bills and measurements before comparing a heating replacement.

Assess solar output and payback

Evaluate generation separately using when you consume electricity, rather than assuming solar makes heating free.

Check calculator methods and assumptions