How much does it cost to upgrade an EPC from D to C?

Last updated 6 July 2026·Prices are typical England & Wales ranges

For most D-rated homes, reaching a C costs between £1,000 and £8,000 — far less than the £10,000 cost cap the 2030 rental rules allow for. Where your property lands in that range depends almost entirely on its walls and its heating. Here's how to price the gap before asking anyone for a quote.

Start with the points, not the products

An EPC rating is a score out of 100: band D covers 55–68 points and band C starts at 69. A property at D-68 might need one cheap measure to cross the line; a property at D-55 needs a plan. Your current certificate's "recommendations" section lists measures with estimated costs and the rating each would achieve — it's conservative, but it's the right starting point, and checking it costs nothing.

Typical costs by measure

Measure	Typical cost	Impact on score
Loft insulation (top-up to 270mm+)	£500–£1,000	Small–medium; cheap points if yours is thin
Cavity wall insulation	£1,000–£3,500	Medium–large; often the single best £-per-point
Heating controls (room stat, TRVs, smart controls)	£150–£600	Small; quick win alongside other works
Condensing boiler replacement	£2,000–£4,000	Medium–large if the current boiler is old
Double glazing (whole house)	£3,000–£8,000	Smaller than most people expect
Solar PV	£5,000–£8,000	Large on today's cost-based score
Air source heat pump	£8,000–£14,000 before grant	Large; £7,500 Boiler Upgrade Scheme grant available
Internal/external solid wall insulation	£7,500–£15,000+	Large, but often the expensive last resort

Ranges are indicative 2026 figures for an average three-bed house; get multiple quotes for anything structural. Older, solid-wall properties sit at the expensive end — which is exactly the scenario the cost-cap exemption exists for.

Three rules that change the maths

Grants first. The Boiler Upgrade Scheme currently offers £7,500 towards a heat pump in England and Wales, and ECO4 / the Great British Insulation Scheme can fund insulation for qualifying tenants and properties. Check eligibility before pricing anything privately.
Spend from October 2025 counts. For landlords, qualifying improvement spend from 1 October 2025 counts towards the 2030 rule's £10,000 cap — except spending on fossil-fuel heating. Keep every invoice.
Fabric first beats gadgets. EPCs are moving to new metrics (from around 2027) where fabric performance — insulation, airtightness — is the headline measure a rented home must reach C on. Solar PV flatters today's score but won't move the fabric metric, so insulation is the safer long-term spend. Details in our EPC C by 2030 guide.

A realistic worked example

A 1930s three-bed semi at D-62 with unfilled cavity walls, 100mm of loft insulation and an ageing boiler: cavity wall insulation (~£1,800) plus a loft top-up (~£600) and a room thermostat with TRVs (~£350) will typically clear 69 points comfortably — around £2,750 all-in. The same house with solid walls could need £8,000–£12,000, and that's when the exemption route and grant funding become the real conversation.