What does the retrofit pay back?
Your bill, your BER band now, the band you are aiming at. Free, no account, and the method is written underneath so you can argue with it.
Electricity, gas, oil and solid fuel combined.
Before any grant. Quotes are the only reliable source.
On your BER certificate. No certificate? An assessment is about €150–€300.
B2 is the target for a One Stop Shop deep retrofit.
Not sure? The grant checker works it out by measure.
How this is worked out
- Each BER band is a range of primary energy use in kWh per m² per year. We take the midpoint of the band you are in and of the band you are aiming at, and treat the proportional drop between them as the proportional drop in your bills.
- Using your own bill rather than a modelled fuel price avoids guessing at your tariff, your fuel mix or how warm you keep the house.
- Payback is net cost divided by annual saving. It does not discount future money, assume energy prices rise, or count the resale value of a better BER — all three would flatter the result.
- An estimate, not an assessment. A registered BER assessor and a contractor's quote are what turn this into a decision.