How to Improve EPC Rating from E to C

You open the EPC and see an E. Then comes the real problem: a long list of upgrades, vague cost ranges and no clear answer on what will actually move the property to Band C. Loft insulation, new glazing, heating controls, solar panels or a replacement boiler could all help, but choosing the wrong one may mean spending thousands and still missing the target.

Many landlords respond by fixing whatever looks easiest or following the certificate line by line. But two E-rated properties can have completely different weaknesses. One may need only 15 extra points, while another may need 30. The real enemy is not the letter E itself.

It is making expensive improvements without knowing which problem is holding the score back.

For most private rented homes in England, Band E is the current legal minimum unless an exemption applies. The government intends to raise the minimum to Band C or equivalent from 1 October 2030, subject to legislation.

This guide helps you cut through that uncertainty, identify the property’s weakest area and prioritise the most cost-effective route to Band C.

Check your current EPC before making improvements

Do not look only at the letter E. Review the full certificate, including your current score, potential score and recommended improvements.

Then check how it describes your insulation, glazing, boiler, heating controls, hot-water system and renewable technology.

An EPC is valid for 10 years. But it will not automatically reflect insulation, solar panels or heating upgrades completed after the assessment.

Before installing anything new, make sure the certificate accurately describes what your home already has.

Which EPC Improvement Should You Investigate First?

Start with the problem that wastes the most energy, not the upgrade that sounds most impressive.

Use the signs below to identify which part of your property should be checked first.

Once you have identified the likely problem, speak to an accredited energy assessor before committing to expensive work.

Use the official GOV.UK assessor service and check that the assessor belongs to a government-approved accreditation scheme.

A domestic EPC assessment typically costs £60–£120, although fees vary by assessor, location and property size.

Improve insulation to keep heat inside

Your boiler may work perfectly well, but that will not help if warmth escapes soon after the heating switches off.

In a typical uninsulated home, around 25% of heat is lost through the roof, 33% through the walls and 10–20% through the floor.

Check the loft or roof

Look for thin, compressed or uneven insulation, particularly around the loft hatch and in hard-to-reach corners. Roof rooms may also have poorly insulated walls or ceilings.

Insulation should retain warmth without blocking the ventilation needed to control moisture. Signs of condensation or damp should be investigated before adding more material.

Check the walls

The correct solution depends on whether the property has cavity walls, solid walls or traditional construction.

A recommendation on an EPC is useful, but it is not a bespoke retrofit design. Older or unusual homes may need specialist advice before wall insulation is installed.

Consider floors and hot water

Suspended timber floors can allow cold air into ground-floor rooms. An under-insulated hot-water cylinder and exposed pipework can also lose useful heat.

The aim is simple: help the home stay warm for longer so the heating system does not need to work as hard.

Improve Heating Controls and Reduce Wasted Energy

Sometimes the boiler is not the problem. It works—but it may still heat spare rooms all afternoon or keep running after the home is already comfortable.

Thermostatic radiator valves, timers, thermostats and heating zones give you more control over where and when warmth is used. That can reduce unnecessary heating without leaving the rooms you use feeling cold.

The challenge is knowing whether those changes are actually lowering energy use without affecting comfort.

EnergieBee brings heating and household energy information into one dashboard, so you can compare usage before and after adjusting schedules, controls or insulation.

Upgrade the heating system when it is genuinely inefficient

Replacing the heating system may make sense when it is old, unreliable, inefficient or poorly matched to the property. New domestic gas boilers installed in England must meet a minimum efficiency rating of 92% ErP, although actual performance still depends on correct installation, controls and flow temperatures.

But a new boiler cannot stop heat escaping through an under-insulated roof. Improve the building and its controls before assuming the heating system must go. A well-designed heat pump can provide around three units of heat for every unit of electricity used.

However, heat pumps commonly send water to radiators at around 35–45°C, so the property may need larger radiators, better insulation or longer heating periods. Arrange a room-by-room heat-loss assessment before installing one.

Reduce draughts and improve poor glazing

Cold air around doors, windows and unused chimneys can make a room feel uncomfortable even when the heating is running. Around 18% of the heat lost from an uninsulated home can escape through its windows, so poor glazing and gaps are worth checking.

Draught-proof uncontrolled gaps and consider replacing particularly poor single glazing. But do not block trickle vents, air bricks or other designed ventilation. Draughts are unwanted; ventilation is necessary.

Smaller improvements that add useful EPC points 

Lighting accounts for around 5% of an average home’s total energy bill. LED bulbs use about 80% less electricity than halogen bulbs and can last up to 20 times longer, making them a simple improvement where older lighting remains.

Check the hot-water cylinder too. If it is uninsulated, fitting an 80mm British Standard jacket can reduce heat loss suggested by Bracknell Forest Council. Insulating exposed hot-water pipes can also help the water stay warmer for longer.

Consider solar after reducing energy waste

Solar panels can reduce grid electricity use and support progress towards EPC C.

But solar cannot stop warmth escaping. Therefore, reduce heat loss and improve heating control first, then consider how solar can support the home’s remaining electricity demand.

EnergieBee tracks live solar generation and uses weather-based forecasts to identify peak production windows.

It can then suggest better times to run high-energy appliances or charge a battery, helping you use more of your own solar and rely less on grid electricity.

How much could EPC improvements cost?

EPC improvements can range from small changes costing under £100 to major building work costing several thousand pounds. The table below gives indicative government figures, but your actual cost will depend on the property, access and the amount of work required.

These are indicative ranges published in the government’s landlord guidance, not fixed market prices. Your EPC may recommend only one or two of these measures, so check the property’s score and speak to an assessor before budgeting for a full package.

Keep evidence of every completed improvement

Keep invoices, installation certificates, product details and commissioning documents. Photograph insulation before it is hidden behind walls, floors or ceilings.

Without suitable evidence, concealed insulation may not be included in the next EPC assessment. The expert guidance also recommends keeping clear photographic proof and records of completed work.

Step-by-Step Plan to Move from EPC E to C

1. Check your exact EPC score and certificate details.

2. Consult with an energy assessor before committing to expensive work.

3. Identify the biggest source of energy loss.

4. Improve insulation and heating control first.

5. Add heating, glazing or solar upgrades where suitable.

6. Keep evidence and arrange a new EPC.

Looking ahead: EPCs are changing

From the second half of 2027, the Home Energy Model (HEM) is expected to replace SAP and RdSAP for new EPCs in England and Wales. It will use more detailed property data and half-hourly calculations to assess heat loss, heating performance and smart-energy technology more accurately.

EnergieBee brings your heating, solar and household energy data into one dashboard, helping you understand how these parts of your home work together as EPC assessments become more detailed.

Frequently Asked Questions (FAQs)

How many EPC points do I need to move from E to C?

Check the current score shown on your EPC and subtract it from 69, where Band C begins. For example, a property scoring 52 would need at least 17 additional points, although an assessor should confirm which improvements are likely to achieve them.

Which improvement has the biggest effect on an EPC rating?

There is no single best improvement for every home. Insulation may have the greatest impact where heat escapes quickly, while an inefficient heating system may be the main issue in another property. Start with the weakest part of your home.

Can insulation alone improve an EPC rating from E to C?

It can in some properties, particularly where loft, wall or floor insulation is missing. However, homes near the bottom of band E may also need heating controls, glazing, a heating-system upgrade or solar panels.

Does a new boiler or solar panels improve an EPC rating?

Both can improve an EPC score, but only when they suit the property. A new boiler may help if the existing system is old and inefficient. Solar panels can reduce grid electricity use, but they will not solve poor insulation or uncontrolled heating.

Do I need a new EPC after completing the improvements?

Yes. Your current certificate will not update automatically. After completing the work, arrange a new assessment and provide the assessor with invoices, certificates and photographs of any hidden improvements.

Can EnergieBee improve my EPC rating?

EnergieBee helps you spot wasted energy, optimise heating schedules and understand how insulation, controls and solar affect your home’s performance.

By showing heating, solar and household energy use in one dashboard, it gives you the clarity to make smarter improvements and track the results; while a new EPC assessment confirms your official rating.