What Is
EPC Rating D?

What EPC D means in practical terms

EPC D is the most common UK rating plus often described as average or below average. It sits in the middle of the A to G scale plus reflects the bulk of UK pre-1990 housing stock that has had some but not all energy efficiency improvements.

The SAP score reality of D. EPC D covers SAP 55 to 68. By comparison: A is 92+, B is 81 to 91, C is 69 to 80, E is 39 to 54, F is 21 to 38 plus G is 1 to 20. A D-rated home is below modern new-build standard but well above the legal rental minimum.

Common features of UK D-rated properties:

• Pre-1990 cavity wall or solid wall construction.
• Loft insulation but possibly less than the modern 270mm standard.
• Cavity wall insulation may be present or may be missing.
• Older condensing boiler (post-2005) or pre-2005 non-condensing boiler.
• Basic programmable thermostat without zone control.
• Double glazing throughout (often first or second-generation).
• Mix of LED plus halogen lighting.
• Hot water cylinder with basic insulation.

Annual energy bills at D rating. Bills depend on usage but UK averages give a useful guide:

• Typical 1-bed flat at D: £850 to £1,150 per year.
• Typical 2-bed terrace at D: £1,400 to £1,800.
• Typical 3-bed semi at D: £1,800 to £2,300.
• Typical 4-bed detached at D: £2,400 to £2,900.

What D means for selling. D-rated properties are common plus generally sell without significant EPC-related issues. Some buy-to-let mortgage products are starting to exclude properties below C plus this trend is increasing. A D-rating versus a C-rating typically affects offers by £500 to £2,000 for similar properties.

What D means for renting. Currently legal as the rental minimum is E. From 1 October 2030 EPC C becomes the rental minimum under the Warm Homes Plan. Landlords with D-rated properties have until then to upgrade or register an exemption. The £10,000 cost cap protects against unlimited spend.

What D means for owner-occupiers. Energy bills run £300 to £500 per year more than equivalent C-rated property. Across 10 years that is £3,000 to £5,000 in additional energy costs. Most D-rated homes can reach C for £2,000 to £7,000 of upgrades, with payback typically 5 to 10 years through bill savings.

How to reach C from D. The gap is 5 to 15 SAP points. Common path:

• Loft insulation top-up to 270mm if not already done. £300 to £1,000. Adds 5 to 15 points.
• Cavity wall insulation if missing. £500 to £1,500. Adds 5 to 12 points.
• Modern A-rated boiler if pre-2005. £2,000 to £4,000. Adds 3 to 8 points.
• Smart heating controls. £150 to £500. Adds 1 to 3 points.
• LED lighting throughout. £50 to £300. Adds 1 to 3 points.

Total typical cost £2,000 to £7,000. SAP gain 8 to 25 points. Most D-rated homes reach low to mid C.

Solid wall D-rated homes. Pre-1920 properties with solid walls require internal or external wall insulation to reach C. This adds £8,000 to £25,000 to the upgrade cost. Total typical cost to reach C from D in solid wall properties: £12,000 to £20,000. The £10,000 landlord cost cap may be exceeded, in which case exemption registration is possible.

UK property mix context. D is the largest UK EPC band. Around 35 to 40 percent of UK properties currently rate D. Most D-rated properties are pre-1990 housing without comprehensive retrofit work. Newer mid-2000s properties typically rate C. Pre-2000 homes that have had partial improvements (some insulation, modern boiler) often plateau at D without further work.

EPC D is the UK's most common rating plus the priority improvement target ahead of 2030 rental rules. Our full EPC Ratings hub covers Energy Performance Certificates plus MEES regulations across UK homes plus rental properties.