EPC rating F explained

F-rated properties have poor energy efficiency, with SAP scores between 21 and 38 points.

What is an F rating?

An F rating on an Energy Performance Certificate indicates poor energy efficiency. Properties with SAP (Standard Assessment Procedure) scores between 21 and 38 points receive an F rating. This places them near the bottom of the A-G scale, with only the very worst G-rated properties scoring lower.¹

F-rated properties have severe heat loss through walls, roof, and windows, often combined with very old or absent heating systems. They are extremely expensive to heat and are frequently associated with fuel poverty and poor living conditions. Most F-rated properties require substantial investment to become habitable to modern standards.

How common are F ratings?

According to the 2024 English Housing Survey, approximately 5% of homes in England have an EPC rating of F. This proportion has declined sharply from around 10% in 2012, as many F-rated properties have been upgraded to meet the minimum E rating requirement for rental properties.²

F ratings are most common in:

• Pre-1900s properties with solid walls, no insulation, and very old or absent heating systems
• Rural cottages with stone or cob construction, single glazing, and reliance on solid fuel or old oil heating
• Properties off the gas grid with inefficient electric storage heaters or direct electric heating
• Vacant or derelict properties that have not been maintained or upgraded
• Listed buildings where planning restrictions prevent insulation or double glazing

Around 1% of UK homes have the even lower G rating. The remaining 94% of homes are rated E or above.

Energy costs for F-rated homes

Typical annual energy costs for an F-rated property are £2,400 or more, depending on property size, heating fuel, and how much the occupants heat the property. This is more than double the cost of heating a C-rated home of similar size.³

A three-bedroom terraced house with an F rating might cost around £2,600 per year to heat and power, while the same house with a C rating would cost approximately £1,100. Many occupants of F-rated properties cannot afford to heat them adequately, leading to cold indoor temperatures and associated health risks.

Properties heated by electricity (storage heaters, panel heaters, or electric radiators) often have the highest costs, particularly if electricity is charged at standard rates rather than Economy 7 overnight rates. Oil heating in poorly-insulated F-rated properties is also very expensive, with annual oil bills often exceeding £2,500 for larger homes.

Typical features of an F-rated property

Most F-rated properties have multiple severe deficiencies:¹

Walls

Uninsulated solid walls (stone, brick, or cob). Significant heat loss and often visible damp or condensation. No cavity to fill.

Roof

No loft insulation, or very thin insulation (less than 50mm). Poorly-sealed roof space with major draughts. Some F-rated properties have thatched or slate roofs with no insulation.

Windows and doors

Full single glazing throughout, often in poor condition with gaps and draughts. Doors may be solid wood with no insulation or weather seals.

Heating

Very old heating system (20+ years), inefficient electric heating, or no central heating at all (reliance on open fires or portable heaters). Boiler efficiency below 70% if present.

Hot water

Uninsulated hot water cylinder or immersion heater. No thermostat or timer. Significant heat loss from pipes and tank.

Floors

Uninsulated suspended timber floors or solid floors with no damp-proof membrane. Major draughts around skirting boards and through floorboards.

Many F-rated properties also suffer from damp, mould, and structural issues that make energy efficiency improvements difficult without addressing underlying building defects first.

Why F-rated properties cannot be rented

Since 1 April 2020, landlords in England and Wales cannot let properties with an EPC rating below E (including F and G ratings) unless they have a valid exemption registered on the national PRS Exemptions Register.⁴

Key points about the F rating prohibition:

• Legal ban: Letting an F or G-rated property without an exemption is a breach of the Minimum Energy Efficiency Standard (MEES) regulations
• Penalties: Fines of up to £5,000 per property for non-compliance
• Existing tenancies: The ban applies to all tenancies, including those that started before April 2020. Landlords must upgrade or end the tenancy when it comes up for renewal.
• Spending cap: Landlords must spend up to £3,500 (including VAT) on improvements, even if this does not achieve an E rating
• Exemptions: Available if improvements are not cost-effective, not technically feasible, or would devalue the property by more than 5%. Exemptions last 5 years and must be registered.

Options for landlords with F-rated properties

If you are a landlord with an F-rated property, you must:

1. Upgrade to at least E before continuing to rent the property
2. Apply for a 5-year exemption if improvements are not feasible (must be registered and evidenced)
3. Stop renting the property until it is upgraded
4. Sell the property (EPCs are required for sale, but there is no minimum rating for selling)

Most F-rated properties can be upgraded to E for under £3,500 by adding basic insulation and heating improvements.

How to improve from F to E

Moving from an F rating (21-38 SAP points) to an E rating (39-54 points) typically requires gaining 10-20 SAP points. The most cost-effective improvements depend on the property's specific deficiencies, but common upgrades include:⁵

Install loft insulation

Cost: £500-£900 for 270mm insulation in a typical loft. Gain: 8-12 SAP points if upgrading from nothing. One of the highest-impact, lowest-cost measures.

Install central heating

Cost: £3,000-£5,000 for a full system (boiler, radiators, pipework) in a property with no heating. Gain: 15-25 SAP points. Transforms habitability but expensive. May need to combine with exemption if cost exceeds £3,500.

Replace old storage heaters

Cost: £1,500-£3,000 for modern high-retention storage heaters throughout a house. Gain: 8-12 SAP points if replacing 1980s/90s models. Cheaper than installing gas central heating.

Cavity wall insulation

Cost: £700-£1,200. Gain: 12-18 SAP points if walls are currently uninsulated. Only applicable if property has cavity walls (most post-1920s properties).

Install double glazing

Cost: £4,000-£8,000 for a whole house. Gain: 10-15 SAP points if replacing single glazing. High cost, but also improves comfort and reduces draughts significantly.

Insulate hot water cylinder

Cost: £20-£50 for an insulating jacket. Gain: 2-4 SAP points. Very low cost, but modest impact. Should be done alongside other measures.

Many F-rated properties can reach E with just one or two major measures. For example, installing loft insulation (10 points) and upgrading to modern storage heaters (10 points) would move a 30-point F-rated flat to a 50-point E-rated flat for under £3,500.

For properties with cavity walls and loft space, adding cavity wall insulation and loft insulation together (20-25 points gain) is often enough to reach E, even without upgrading the heating system.

Landlords should obtain quotes from accredited installers and ensure all work is certified. After improvements are completed, book a new EPC assessment to confirm the property has reached at least E before advertising for new tenants.