One budget, two upgrades. Here is how UK households prioritise when they cannot do both immediately.
They solve different bills
Solar reduces electricity purchased from the grid and may export surplus. Air-source heat pumps replace gas or oil heating with efficient electric heat — often raising electricity demand while cutting gas. Together they can synergise; alone each targets a different line on your energy statement.
Fabric first still applies
Solar on a poorly insulated home still works, but heat demand remains high. Loft insulation, draught-proofing, and upgraded glazing reduce the size of heat pump required and improve comfort. BUS grant eligibility and EPC ratings often assume reasonable fabric — check current GOV.UK rules.
Solar without insulation is like filling a bucket with holes. Fabric first is boring advice because it works.
A simple priority matrix
| Your situation | Consider first |
|---|---|
| High daytime electricity use, gas boiler fine | Solar |
| Poor EPC, expensive gas heat | Insulation + heat pump |
| Time-of-use EV charging at home | Solar (+ battery if budget allows) |
| Rented property | Neither without landlord agreement |
Running costs in plain numbers
A heat pump might deliver three units of heat per unit of electricity at mild temperatures — efficiency drops in cold snaps. Solar offsets daytime electricity including heat pump use in spring and autumn. Winter evenings still draw grid power unless you have storage sized for heating loads, which is uncommon domestically.
Grants and sequencing
The Boiler Upgrade Scheme offers grants toward qualifying heat pump installations — rules and amounts change. Solar has no equivalent nationwide grant in 2026, but zero-rate VAT may apply. Many owners install solar first for visible bill reduction, then fund a heat pump with BUS where eligible.
Sequencing both over five years
Modelling annual kWh before and after heat pump installation prevents undersized solar arrays. If you plan both, ask installers to size PV against projected electricity demand post-retrofit.
Boiler Upgrade Scheme rules change — check GOV.UK before quoting grants.
