How to Calculate Heat Pump vs Gas Boiler Running Costs in the UK: Step-by-Step Guide

Introduction

Energy and home improvement costs are easier to control once you can put a number on them. A few minutes with a calculator can stop you over-buying materials or guessing at bills.

This guide explains how to calculate heat Pump vs Gas Boiler Running Costs in the UK, step by step. Compare the yearly running cost of an air source heat pump with a gas boiler. You'll see the formula, a fully worked example and practical tips for UK readers.

What this calculation covers

Compare the yearly running cost of an air source heat pump with a gas boiler.

Unit rates, standing charges and waste allowances all add up. Calculating properly helps you compare tariffs, plan projects and judge whether an upgrade will pay for itself.

The method and formula

Boiler cost is heat demand ÷ efficiency × gas price. Heat pump cost is heat demand ÷ SCOP × electricity price. A SCOP of 3 means 3 kWh of heat per kWh of electricity.

Every figure on our heat Pump vs Gas Boiler Calculator follows this method, so you can check the working yourself.

Worked example

Here's a typical example using these figures:

Running them through the method gives:

The headline figure is yearly difference (boiler − heat pump): -£185.20. Change any input and the result will move with it.

How to use the calculator

1. Enter or choose yearly heat demand (kWh).
2. Enter or choose boiler efficiency (%).
3. Enter or choose gas price (p/kWh).
4. Enter or choose heat pump SCOP.
5. Enter or choose electricity price (p/kWh).
6. Read your results. The main figure is shown at the top, with a breakdown underneath.
7. Try different values to compare scenarios side by side.

Tips for UK readers

• Find your unit rates and standing charges on your latest bill or in your supplier's app.
• Standing charges are paid every day regardless of usage.
• Always buy materials from the same batch and add a waste allowance for cuts.
• Smart meter data shows your real usage, which is more accurate than estimates.

Frequently asked questions

What's the quickest way to work out heat Pump vs Gas Boiler Running Costs?

Use our free heat Pump vs Gas Boiler Calculator. It applies this method automatically: Boiler cost is heat demand ÷ efficiency × gas price. Heat pump cost is heat demand ÷ SCOP × electricity price. A SCOP of 3 means 3 kWh of heat per kWh of electricity.

Where do the default energy prices come from?

They are typical UK price-cap level figures used as a starting point. Replace them with the rates on your own bill for an accurate result.

Do the DIY calculators include waste?

Most include an adjustable waste allowance. 10% is typical; complex layouts may need 15%.

Are the results exact?

They are estimates. Real usage, weather and installation details will change actual costs.

Summary

To work out heat Pump vs Gas Boiler Running Costs, follow the method above: Boiler cost is heat demand ÷ efficiency × gas price. For a quick, accurate answer with your own figures, use the calculator.

Next, read Heat Pump vs Gas Boiler Running Costs: Common Mistakes, Tips and FAQs.