EPC upgrade cost calculator
Start from your current SAP score and see the cheapest order to do the work in, with the cost of each step and the score it leaves you on.
The number on the certificate, 1 to 100.
Size changes the cost, not the points a measure earns.
£745 to £2,300
Score 58 → 74, target band C
Cheapest route, in order
| Measure | Cost | Score after |
|---|---|---|
| Hot water cylinder insulation | £20–£60 | 60 |
| Loft insulation to 270 mm | £100–£350 | 64 |
| Low energy lighting throughout | £25–£90 | 65 |
| Cavity wall insulation | £600–£1,800 | 74 |
Indicative installed costs from EPC recommendation reports for England & Wales, scaled for property size. Real quotes vary by region and by the state of the property.
Getting the work done
Prices here are indicative ranges from EPC recommendation reports, not quotations. Get at least two quotes before committing, and check whether you qualify for help under ECO4.
We may earn a commission from bookings. This does not change the price you pay.
Cost per SAP point
The calculator takes measures in this order: cheapest per point first, until the target band is reached. That is usually the cheapest route, though not always the one that saves most on energy bills.
| Measure | SAP points | Installed cost | Per point |
|---|---|---|---|
| Hot water cylinder insulation | +2 | £20–£60 | £20 |
| Loft insulation to 270 mm | +4 | £100–£350 | £56 |
| Low energy lighting throughout | +1 | £25–£90 | £58 |
| Cavity wall insulation | +9 | £600–£1,800 | £133 |
| Heating controls and TRVs | +3 | £350–£900 | £208 |
| Condensing gas boiler | +8 | £2,200–£3,600 | £363 |
| Solar PV, 3 kWp | +11 | £5,000–£8,000 | £591 |
| Internal solid wall insulation | +12 | £4,000–£14,000 | £750 |
| Double glazing throughout | +3 | £3,300–£6,500 | £1,633 |
| Air source heat pump | +6 | £9,000–£14,000 | £1,917 |
Indicative installed costs from EPC recommendation reports for England & Wales, for an average sized property.
Common questions
Will the work show up on my EPC automatically?
No. The certificate only changes when a new assessment is lodged. Keep the paperwork — an assessor who cannot see the insulation may assume it is not there.
Are grants available?
Some households qualify for help with insulation and heating under ECO4, which is funded by energy suppliers and aimed at homes in bands D to G.
Is the cheapest route the best route?
Not always. Fabric first — insulation and draughts before heating — usually cuts bills more per pound spent, even when it earns fewer SAP points.