Grants, loans and tariffs: know the difference
Why government grants, installer finance, and special energy tariffs change quotes in different ways, and how to compare fairly.
What to check first on any quote
Split the paperwork into three buckets before you trust a headline saving:
Capital: price of kit and install, minus any grant you have actually confirmed you can claim.
Borrowing: loan amount, years, APR and annual repayment (cash leaving your account).
Running cost: kWh and unit rates assumed, including whether a special tariff is required.
A quote that blends all three into “you’ll save £X a year” is hard to challenge unless you unpack it.
Grants
A grant reduces upfront price. It does not automatically make the system cheaper to run each year. Marketing sometimes talks as if grant money cuts your bill. Usually it only cuts the install invoice.
Loans
Are loan repayments missing from the headline annual cost? A lower running cost plus a loan repayment can still strain monthly cash flow. Total cost over the loan term matters.
Tariffs
A tariff saving is not the same thing as a heating-system saving. If the heat pump figure needs a named tariff, ask for the running cost on the tariff you have today.
Fair comparison sequence
- Gross install (itemised)
- Minus confirmed grant → net capital
- Plus annual running cost on a conservative tariff
- Plus loan repayment per year if financed
- Repeat for the alternative you would really consider (new boiler, delay, solar-only, etc.)
Scotland and England/Wales schemes differ. Check official eligibility for your address; do not rely on a sales summary alone.
Common questions
Does a grant prove the system is good value?
No. It helps affordability. Running cost, quality and fit for your home still matter.
Related guides
How to spot misleading solar panel grant claims
A grant changes upfront price. It does not by itself prove payback or eligibility.
Read more →Why heat pump savings claims can be misleading
Headline savings are model outputs. The assumptions behind them are what you need in writing.
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 →