Why heat pump savings claims can be misleading
Common reasons headline heat pump savings look better than real life: tariffs, boiler comparisons, grants and missing install costs.
A quote can look fine and still compare badly
You might see one line: save £900 a year. Behind it are usually:
- How much heat the house needs (kWh)
- Assumed heat pump efficiency (SPF/SCOP) and flow temperature
- Electricity price (often a special tariff)
- What you are compared against (old boiler vs new gas)
- What install costs are left out (radiators, loan repayments, disruption)
If any of those is optimistic, the headline saving shrinks. That does not mean heat pumps never work. It means the quote should make each assumption clear.
Claim to check on the paperwork
“Save X% on heating bills”. Ask: per cent of what bill, which tariff, and does the price include loan repayments and upgrades?
Tariff dependency
A tariff saving is not the same thing as a heating-system saving. If the quote assumes a heat-pump or time-of-use rate you might not keep, ask for the annual cost on the tariff you pay today.
Old boiler only
Is the heat pump being compared with your old boiler only? A new condensing gas boiler may cost less to install and still heat the house. The quote should show that comparison, not hide it.
Grants and loans
A grant reduces upfront price. It does not automatically make the system cheaper to run each year. Loan repayments can eat into cash flow even when running cost looks lower.
Solar and battery offsets
Are solar and battery savings being counted as heat pump savings? Ask for a heating-only running cost without those offsets.
What to do next
Use your bills, ask for written assumptions, and try the Heat Pump Quote Reality Checker with the figures on the estimate.
Common questions
Is a large percentage saving always a red flag?
Not always, but it usually means you should read the assumptions. Big percentages often come from an old boiler baseline or a cheap tariff in the spreadsheet.
Should I trust a printed estimate?
Use it as a list of figures to check, not as proof the saving will match your bills. Then test those figures against your own usage and tariffs.
Related guides
Are air source heat pumps really cheaper than gas?
Sometimes yes on running costs. Often the answer depends on tariffs, SCOP and what boiler you compare against.
Read more →Heat pumps, solar panels, deposits and cancellation rights
Distance and off-premises home-energy contracts usually carry a 14-day cancellation right. A survey or system design does not automatically remove it.
Read more →How to read your heat pump estimate before using the calculator
Layouts differ. Look for labels, not page numbers.
Read more →Why comparing a heat pump to an old boiler can distort the figures
If your boiler is old, almost any upgrade looks good. That does not show a heat pump beats a new gas boiler.
Read more →What to ask if a quote relies on a special energy tariff
Tariff-dependent savings are not wrong by default. You need the saving without that tariff too.
Read more →