How to Improve EPC Rating: Cost-Effective Upgrades for Landlords

Improving your property's EPC rating is no longer optional—it's a regulatory requirement and an increasingly important factor in tenant demand and property values. This guide prioritizes cost-effective improvements ranked by impact per pound spent.

Understanding EPC assessments

Before undertaking improvements, understand how EPC ratings work. The assessment considers:

• Heating system type and efficiency
• Insulation levels (loft, walls, floors)
• Window glazing type
• Lighting (percentage of low-energy bulbs)
• Hot water system
• Building fabric (construction type, thermal mass)

Each property receives a score from 1-100+, which maps to a rating band (A-G). The calculation uses standardized assumptions, not actual energy usage.

Start with your EPC recommendations

Every EPC includes specific recommendations for that property. These are prioritized by the assessor and include estimated costs and point improvements. Always start here—these recommendations are tailored to your property's actual construction.

High-impact improvements

These upgrades deliver the best EPC point improvement per pound spent:

1. Loft insulation (highest priority)

Loft insulation delivers exceptional value. UK building regulations recommend 270mm depth. Most older properties have 100mm or less. Topping up to 270mm is cheap and highly effective.

Practical tip: Ensure proper ventilation when insulating. Compressed or damp insulation loses effectiveness. Don't insulate over electrical cables without protective covers.

2. Cavity wall insulation

Cavity wall insulation (CWI) is highly cost-effective for properties with unfilled cavity walls (typically 1920s-1980s construction). Foam, beads, or mineral wool are injected into the wall cavity.

Important: Not all properties have cavity walls. Solid wall properties (pre-1920s, many Victorian terraces) require external or internal wall insulation, which is far more expensive.

3. Heating controls and thermostats

Installing thermostatic radiator valves (TRVs) on all radiators except the room with the main thermostat, plus a programmable room thermostat, delivers good point gains for modest cost.

Modern smart thermostats (Nest, Hive, etc.) may provide additional EPC points depending on features and certification.

4. LED lighting

Replace all light bulbs and fixed fittings with LED equivalents. The EPC assessment counts the percentage of low-energy lighting outlets. Cheap and simple, but modest point gains.

Medium-impact improvements

5. Boiler replacement (condensing boiler)

Replacing an old non-condensing boiler (pre-2005) with a modern A-rated condensing boiler delivers significant point gains. This is often the single largest upgrade cost, but may be unavoidable for properties with very old heating systems.

Strategic note: If the boiler is less than 10 years old and condensing, replacement won't improve EPC significantly. Focus on insulation instead.

6. Double glazing

Double glazing is expensive and delivers moderate EPC gains relative to cost. However, it's often necessary for tenant appeal and may be unavoidable in properties with failing single-glazed windows.

Secondary glazing (adding internal panes) is cheaper (£200-£400 per window) but provides lower EPC improvement than replacement double glazing.

7. Hot water cylinder insulation

If your property has a hot water cylinder (not a combi boiler), ensure it has an 80mm insulation jacket. Cheap and simple. Replacing an old uninsulated copper cylinder with a modern pre-insulated model delivers better gains but at higher cost.

Lower-impact (but sometimes necessary) improvements

8. Floor insulation

Floor insulation is disruptive and moderately expensive relative to EPC gains. However, it may be required to reach EPC C in properties that have already addressed loft, walls, and heating.

9. External or internal wall insulation (solid walls)

For solid wall properties (no cavity), wall insulation is the only option and is extremely expensive. External wall insulation (EWI) requires planning permission in many cases and changes the property's appearance. Internal wall insulation (IWI) reduces room sizes.

Investment decision: Many solid wall properties cannot economically reach EPC C. Landlords face a choice: sell the property, or invest £10,000+ in wall insulation. This is why solid wall Victorian terraces are trading at significant discounts.

10. Solar panels (PV)

Solar PV panels generate electricity and improve EPC ratings. However, in rental properties, the tenant benefits from reduced electricity bills, not the landlord. This makes the investment economics unfavorable unless required to reach EPC C.

Solar thermal (for hot water) is cheaper but delivers lower EPC gains than PV.

Strategic upgrade planning

Approach EPC upgrades systematically to maximise impact per pound spent:

Step 1: Obtain current EPC and review recommendations

If your property doesn't have a recent EPC, commission one. The recommendations section lists specific improvements for your property with estimated costs and point gains.

Step 2: Prioritize by cost-effectiveness

Work through improvements in this order:

1. LED lighting (cheap, immediate)
2. Loft insulation top-up (if needed)
3. Cavity wall insulation (if applicable)
4. Heating controls and TRVs
5. Hot water cylinder jacket
6. Boiler replacement (if old and inefficient)
7. Double glazing (if single glazed)
8. Floor insulation (if other measures exhausted)
9. Solid wall insulation (last resort, very expensive)

Step 3: Get new EPC after works

After completing improvements, commission a new EPC to confirm the upgraded rating. Don't assume the improvements worked—verify with a new assessment.

Cost vs benefit: Reaching EPC C

Not all properties can economically reach EPC C. Understanding upgrade costs versus property value is critical:

For solid wall properties requiring £15,000+ investment to reach EPC C, many landlords will choose to sell rather than upgrade. This is creating a two-tier market: compliant properties command premiums, while non-compliant properties face discounts.

Frequently asked questions