If your electric-heated flat is stuck below band C, the fix is almost always the same one: swap the old storage or panel heaters for modern high heat retention (HHR) storage heaters, put the flat on an Economy 7 dual-rate meter so they charge on cheap overnight electricity, and fund it through ECO4 while the scheme is still open. The heating system is the single biggest score lever for this type of flat. Get it right and you usually move the rating materially, often decisively.
This guide is the how-to for that specific fix. For the wider picture of why flats behave differently and where leasehold rules bite, see our purpose-built flat EPC overview and the flat landlord EPC compliance guide. Here we stay on the heating.
Why do electric-heated flats score so badly?
Electric-heated flats are the hardest common archetype to get to band C, and the reason is baked into the way EPCs are calculated.
The RdSAP methodology behind every EPC does not just measure how much energy your flat uses. It weights that energy by cost and carbon. Mains electricity carries a much higher cost and CO2 factor per kWh than mains gas. So an all-electric flat scores worse than a gas one even when the heating itself is perfectly efficient. You are penalised for the fuel, not just the fittings.
On top of that, the heaters found in these flats tend to be the worst-scoring kind. Old-style storage heaters, panel heaters, and direct-acting electric convectors all score poorly in RdSAP. They either waste stored heat, offer little control, or run entirely on the expensive daytime rate. If your flat has any of these, the assessment is working against you from the start.
That is why the heating system, not the insulation, is usually where the points are hiding in an electric flat. A typical below-C property needs roughly 9 to 14 SAP points to reach band C, and for this archetype the heating swap is the lever most likely to deliver a big chunk of that in one move.
What are high heat retention storage heaters, and why do they score better?
A high heat retention storage heater is a modern, heavily insulated version of the old night-storage heater. It charges up on cheap off-peak electricity overnight, holds that heat far better than an old unit thanks to improved insulation, and releases it slowly and controllably through the day, with a fan and thermostatic controls to top up when you need it.
RdSAP recognises HHR heaters as a distinct, better-scoring category. It does not lump them in with the old storage heaters or with direct-acting panel heaters. Two things drive the improvement:
- Off-peak charging. They use cheaper, lower-carbon overnight electricity, which the calculation rewards.
- Better retention and control. Improved insulation means less heat is wasted, and proper controls mean the SAP model credits you for room-by-room and time control, which it values heavily.
The practical upshot: replacing tired storage or panel heaters with HHR units is frequently the most effective single change you can make to an all-electric flat. It does not turn electricity into gas, so it will not close every gap on its own, but it lifts the score materially and is often the measure that tips a flat over the line.
Modern HHR heaters typically cost a few hundred pounds each to buy, and under the right grant route that cost is often fully covered. You can get a property-specific projection first using our EPC predictor tool.
Why you need an Economy 7 (dual-rate) meter
HHR storage heaters only make sense, and only score as intended, if the flat can buy cheap overnight electricity. That means a dual-rate meter, usually Economy 7, which charges a lower rate for around seven hours at night.
Without it, the heaters would charge on the full daytime rate, which is expensive for the tenant and undermines the point of storage heating entirely. The SAP calculation assumes the off-peak tariff is in place for this kind of heater, so the meter is not optional if you want the score you are paying for.
The good news: the meter change itself is usually free from the energy supplier. The catch is that it can take some arranging, so start the conversation with the supplier early rather than discovering the delay on install day. Sort the meter and the tariff alongside the heater order, not after it.
How ECO4 pays for it, and how to qualify
The reason this fix is attractive is that you often do not pay for it. Replacing inefficient electric heating with HHR storage heaters is an ECO4-fundable measure. ECO4 is the government's Energy Company Obligation scheme, funded by the large energy suppliers, and it is aimed squarely at improving the least efficient homes by at least two bands.
The important part is timing. ECO4 installs run until 31 December 2026, and the scheme is winding down: it is not accepting new applications indefinitely, so treat it as ending soon and move now. If you leave it, you risk losing the funding entirely and paying out of pocket.
To qualify, two things generally need to be true:
- The property is EPC band D to G. ECO4 targets the worst performers, which is exactly where electric-heated flats tend to sit.
- There is a qualifying route. This usually means the tenant receives certain benefits, or the flat qualifies through Local Authority Flex, a route that lets councils widen eligibility beyond the standard benefit list.
Check your position before committing to anything. Our grant checker tool walks through eligibility, and two guides go deeper: the ECO4 grants landlord guide for the scheme mechanics, and the ECO4 LA Flex route for landlords if the standard benefit test does not fit your tenant.
The supporting cheap wins
The heating swap does the heavy lifting, but a handful of low-cost measures stack on top and can be the difference between just missing C and clearing it comfortably. None of these need freeholder consent, so they are yours to do inside your own front door.
- Hot water: an insulated cylinder and better water-heating controls reduce wasted heat and pick up SAP points cheaply.
- LED lighting: swapping every fitting to LED is a small cost with a reliable, if modest, score bump.
- Draught-proofing: sealing gaps around doors and windows cuts heat loss for very little money.
- Insulation where possible: loft insulation for a top-floor flat, or any accessible fabric improvement, helps, though options are often limited in a flat.
These are ranked by cost per SAP point in our cheapest ways to improve EPC rating guide. Do them at the same time as the heater install so a single assessor visit captures everything.
Will this actually get me to band C?
Honest answer: usually a big step, sometimes the whole way, not guaranteed on its own.
HHR storage heaters plus an Economy 7 meter will typically lift an electric flat's score materially, and for a flat starting at band D and only a few points short, that is often enough to reach C by itself. For a flat starting lower, at E, F, or G, the heaters do the most work but you will likely need the supporting measures stacked on top to close the gap.
What the heaters cannot do is escape the fuel penalty entirely. Electricity still carries a higher cost and carbon weighting than gas in the calculation, so an all-electric flat has a lower ceiling than a gas one. That is why the honest framing is "the decisive measure, not a magic bullet." The final result depends on the whole property: its fabric, its floor level, its glazing, and its starting score. Model it before you commit using our EPC cost calculator.
What to do if you are still short
If the heaters and the cheap wins still leave you below C, you have not run out of road.
First, check what else the EPC recommends. Glazing, fabric insulation, or a communal system upgrade may be on the report, though several of these need freeholder consent in a flat and can be slow. Our flat cost breakdown sets out what those bigger measures cost and where leasehold rules change the maths.
Second, keep every receipt. Qualifying spend counts toward the £10,000 cost cap, and if you have genuinely done what you reasonably can and the flat still will not reach C, an exemption route may apply. The flat compliance guides linked above cover the exemption framework in full.
The practical order of play: get a current EPC, confirm ECO4 eligibility through the grant checker, arrange the Economy 7 meter, install HHR heaters, and layer the cheap wins on top before the reassessment. Do it now while ECO4 is still funding it.
Frequently Asked Questions
Do high heat retention storage heaters improve an EPC rating?
Yes. RdSAP treats high heat retention storage heaters as a distinct, better-scoring category than old storage heaters or panel heaters, because they use cheaper off-peak electricity and hold heat far more efficiently with proper controls. For an electric-heated flat they are usually the single most effective measure, often lifting the score enough to reach band C on their own or with a few cheap supporting measures. They will not eliminate the fuel penalty electricity carries in the calculation, so the final result depends on the whole property.
Do I need an Economy 7 meter for storage heaters?
Effectively yes. Storage heaters are designed to charge on cheap overnight electricity, and the SAP calculation assumes a dual-rate tariff such as Economy 7 is in place for this kind of heating. Without it, the heaters would run on the expensive daytime rate, which is costly for the tenant and undermines both the running cost and the EPC score. The meter change is usually free from the supplier, but it can take time to arrange, so start early.
Can I get a grant for storage heaters as a landlord?
Often, yes. Replacing inefficient electric heating with high heat retention storage heaters is an ECO4-fundable measure, and the cost is frequently covered in full. The flat generally needs to be EPC band D to G, and you need a qualifying route such as the tenant receiving certain benefits or the property qualifying through Local Authority Flex. ECO4 installs run until 31 December 2026 and the scheme is winding down, so check eligibility and act now.
Why does my electric-heated flat score lower than a gas one?
Because EPCs weight energy by cost and carbon, not just by how much you use. Mains electricity carries a much higher cost and CO2 factor per kWh than mains gas in the RdSAP methodology, so an all-electric flat scores worse even when its heating is efficient. That fuel penalty is why electric-heated flats are the hardest common flat type to get to band C, and why the heating system is usually where the points are hidden.
Is ECO4 still available in 2026?
For now, but not for long. ECO4 installs run until 31 December 2026, and the scheme is no longer accepting applications indefinitely, so you should treat it as ending soon. If your flat is band D to G and you have a qualifying tenant or a Local Authority Flex route, apply now rather than risk losing the funding and paying for the heaters yourself. Use the grant checker to confirm your position before you commit.
This article was last updated on 19 July 2026. EPCGuide's analysis covers the full domestic EPC register for England and Wales. For methodology and interactive data, visit the EPCGuide Research Hub.