EPC rating D explained

D is the most common EPC rating in the UK, representing around 40% of homes.

What is a D rating?

EPC ratings run from A (best, 92-100 points) to G (worst, 1-20 points). D sits in the middle: 55 to 68 SAP points. The SAP (Standard Assessment Procedure) score is calculated from the property's physical features (insulation, heating, windows, floor area) and estimates how much energy it takes to heat and light the home per square metre per year.¹

A property at the bottom of the D band (55 points) is close to slipping into E. A property at the top (68 points) is close to C. Small improvements can make a big difference to which side of the boundary you land on.

Typical D-rated properties

Based on analysis of 24 million EPCs in England, the English Housing Survey found that D-rated homes make up around 40% of the housing stock.² Common characteristics:

• Age: mostly built 1980s-2000s, but older homes (1950s-1970s) can be D if they've had some upgrades
• Loft insulation: 100-200mm (not the recommended 270mm)
• Walls: cavity walls, often filled, or solid walls with no insulation
• Windows: double glazing in most rooms, possibly some single glazing remaining
• Heating: gas central heating with a boiler that's 5-15 years old (reasonably efficient but not the latest model)
• Controls: basic programmer and room thermostat, maybe thermostatic radiator valves (TRVs)
• Renewables: rarely any (solar panels, heat pump)

Energy costs for rating D

The EPC certificate shows an estimate of annual energy costs based on standard assumptions (average occupancy, typical heating pattern, fuel prices from the date of assessment). For a D-rated property in June 2026:

Typical annual energy cost (D rating)

£1,400 to £1,800

Approximate monthly cost

£115 to £150

For comparison: C rating

£900 to £1,200 per year (£200-£600 less than D)

For comparison: E rating

£2,000 to £2,400 per year (£200-£600 more than D)

These figures assume gas central heating (most common in the UK) and Ofgem price cap rates as of June 2026. If you heat with electricity, oil, or LPG, costs will be different. If energy prices change, so will the cost difference between bands.

Your actual bills depend on how you use the property. A D-rated home kept at 18°C and occupied by one person will cost far less to run than the same home kept at 22°C and occupied by a family of four. The EPC estimate is for a standardised household, not your household specifically.

D vs C: what's the difference?

The boundary between D and C is 69 SAP points. A property scoring 68 is a D. A property scoring 69 is a C. Here's what typically separates them:³

The gap from D to C is usually 1 to 12 SAP points. For many homes, one or two targeted improvements (topping up loft insulation, filling cavity walls) will close that gap.

How to upgrade from D to C

The cheapest route from D to C depends on what your property already has. Check your EPC certificate (find it at find-energy-certificate.service.gov.uk) and look at the "Recommendations" section. It will list improvements ranked by cost-effectiveness.

For most D-rated homes, the best value improvements are:

1. Top up loft insulation (£300-£600)

If your loft has less than 250mm of insulation, adding more is cheap and effective. Topping up from 100mm to 270mm typically adds 6-10 SAP points. This alone can push a mid-D to a low C.

2. Fill cavity walls (£500-£1,500)

If you have unfilled cavity walls (check your EPC), filling them adds 8-12 points. Combined with loft insulation, this almost always lifts a D to a C.

3. Upgrade the boiler (£2,000-£3,500)

If your boiler is over 12 years old, replacing it with a modern condensing boiler adds 4-8 points. This is more expensive than insulation, so it makes sense if the boiler is failing anyway.

4. Improve heating controls (£150-£400)

Adding a programmable thermostat and thermostatic radiator valves (TRVs) on all radiators adds 2-4 points. Low cost, modest impact, but useful if you're close to the C boundary.

See our full guide: How to improve your EPC rating.

D rating for landlords

If you're renting out a property with a D rating, you're comfortably above the legal minimum. Since April 2020, the Minimum Energy Efficiency Standard (MEES) requires rental properties in England and Wales to be at least an E.⁴

However, the government has proposed raising the minimum to C by 2030 for all new tenancies (2028 proposal, not yet law). If this goes ahead, D-rated properties will need upgrades before they can be re-let. The proposed rules include a cap on landlord spending (£10,000 per property), meaning you only need to do cost-effective improvements up to that limit.

Even if the C target is delayed or dropped, improving from D to C often pays for itself through lower void periods (easier to let), higher rents (tenants value lower bills), and reduced maintenance (better insulation prevents damp and condensation issues).