EPC recommendations explained
The recommendation report is generated by software from what the assessor recorded. The costs are national indicative ranges, and the potential rating assumes every measure is installed.
Last reviewed 24/09/2026
Every EPC comes in two halves. The first is the rating: a letter band, the SAP score behind it, and a potential rating. The second is the recommendation report — a list of measures, an indicative cost range for each, the typical saving, and the rating the property would reach if they were all carried out.
People treat the second half as a survey of their house. It is not. It is output from approved software, driven entirely by the data the assessor entered. Nobody priced your particular property, and nobody judged whether the work is practical.
Where the numbers come from
The cost ranges are national indicative figures attached to each measure. A mid-terrace in Hull and a detached house in Surrey can be shown the same £100 to £350 range for loft insulation, because the range describes the measure and not the building.
The savings are modelled, not metered. They assume a standard occupancy, a standard heating pattern and standard fuel prices, none of which match any real household exactly. Two identical houses with different families in them will have very different bills and the same EPC.
How to read the potential rating
The potential rating is a ceiling: it assumes every listed measure is installed. It is not a forecast of what will happen if you do some of them, and the points are not evenly spread across the list.
The measures at the top usually earn the most points, because the report is ordered by impact rather than by value. That is the opposite of the order most households want, which is cheapest first.
What the report leaves out
- Draught proofing, which cuts bills noticeably but earns almost nothing in SAP.
- Anything the assessor could not see. Insulation hidden inside a wall is often assumed absent, and the recommendation to install it may already be done.
- Whether the work is practical. Solid wall insulation is recommended without regard to whether you can lose 80 mm from every room.
- Grants. Costs are shown at full retail, with no ECO4 or other funding applied.
- Sequencing. Some measures are cheaper done together — scaffolding for solar and for roof insulation, for instance.
The measures you will see most often
| Recommendation | Typical points | Indicative cost |
|---|---|---|
| Loft insulation to 270 mm | +4 | £100–£350 |
| Cavity wall insulation | +9 | £600–£1,800 |
| Hot water cylinder insulation | +2 | £20–£60 |
| Low energy lighting | +1 | £25–£90 |
| Heating controls and TRVs | +3 | £350–£900 |
| Condensing gas boiler | +8 | £2,200–£3,600 |
| Internal solid wall insulation | +12 | £4,000–£14,000 |
| Solar PV, 3 kWp | +11 | £5,000–£8,000 |
Indicative installed costs from EPC recommendation reports for England & Wales.
Using the report to plan work
Treat it as a shopping list rather than an order of service. Work out the cost per SAP point for each measure — divide the middle of the cost range by the points — then start at the cheapest and stop when you reach the band you need.
For most band D properties that means four cheap measures and no more. The £4,000 solid wall recommendation sitting at the top of the report is frequently irrelevant, because the property reaches band C long before you get to it.
If the property is let, the order matters more, because spending counts against the £10,000 cap that applies to the band C standard from 1 October 2030.
When the report is simply wrong
It happens, and it is almost always a data problem rather than a software problem. The commonest case is a recommendation to install something that is already there, because the assessor could not verify it and the software assumed the default.
If that has happened, the fix is not to argue with the report. It is to gather evidence — installer certificates, guarantees, photographs from the installation — and have a new assessment lodged. The existing certificate cannot be edited; it can only be replaced.