Experts: EPC ratings need rethinking to encourage switch away from gas boilers

The way Energy Performance Certificate (EPC) ratings are calculated should be re-evaluated to incentivise landlords to switch away from using carbon energy like gas boilers, experts say.

Energy company EDF Energy, as well as the Heat Pump Association, are both in agreement that the way EPCs are calculated is inherently flawed.

It’s both cheaper and easier for homeowners to achieve an EPC rating of C when using gas boilers rather than ‘greener’ heat pumps, which take heat from either the ground or the air.

Air source heat pumps

In fact, people using heat pumps tend to be penalised on the score because of the higher running costs involved, while carbon emissions aren’t taken into account.

Subject to government consultation landlords could be expected to get their property EPC ratings to C by 2025, while new builds will no longer be allowed to install new gas boilers from 2025.

EDF Energy

An EDF Energy spokeswoman said: “EPC ratings are based on the estimated costs of heating a property rather than the carbon emissions associated with the heating system installed.

“As such there is no credit given in the EPC rating system for installation of efficient electric heat pumps, which provide substantial carbon savings compared to gas boilers.

“We are encouraging policymakers to take action to rebalance these policy costs, and that the environmental benefits offered by heat pumps are recognised in EPC ratings, so that homeowners are encouraged to switch away from gas boilers.

“We hope that the government’s upcoming Heat and Buildings Strategy will begin the process of bringing forward these policy changes.”

The government’s Heat and Buildings Strategy entails increasing heat pump installations, phasing out gas boilers, as well as introducing new incentives and schemes.

EDF’s views are expanded on in its research, ‘Public First – Options for Energy Bill Reform’.

Heat Pump Association

When approached, the Heat Pump Association’s views seemed to largely echo EDF Energy’s.

The association agreed that EPCs need to reflect the government’s target of reaching zero net carbon emissions by 2050.

As it stands it seems there’s a lack of incentives in place to make this happen.

The representative said that gas boilers typically have lower running costs than heat pumps, which means owners with gas boilers get a better EPC rating compared to if they use the low-carbon alternative.

EPCs don’t take all building performance factors into consideration that are essential to decarbonisation, such as the ability to heat at low flow temperatures.

As it stands the system assesses running costs based on the Energy Efficiency Rating (EER), measuring the performance and efficiency of things like lighting and heating.

While carbon emissions are detailed in the Environmental Impact Rating (EIR), which sits alongside the EPC rating, the banding system isn’t used in government targets.

The Heat Pump Association made some recommendations on how the government can incentivise the adoption of heat pumps over gas.

It said there should be a firm end date to using fossil fuels to heat homes, following advice from the Climate Change Committee.

When replacing or installing new heating systems there should be a requirement to install radiators with a higher surface area or underfloor heating, while having either in place should be reflected by EPC ratings.

Older radiators don’t work well with heat pumps, because they operate at lower temperatures than gas boilers.

National Residential Landlords Association

Alan Ward, non-executive director of the National Residential Landlords Association, responded to the push towards heat pump adoption.

He said: “Heat pumps have to be economical compared to the cost of boilers – at the moment they are roughly six times the cost and then radiators have to be replaced.

“Landlords shouldn’t be forced to do switch – we should be persuaded.

“Landlords aren’t going to do it if it costs an arm and a leg unless there’s a reason, like a tax break or an allowance.

“If little help is given and landlords are forced then ultimately rents will go up to pay for the works.”

Ward also raised the issue of legionnaires’ disease.

Because heat pumps operate at a lower temperature than gas boilers there are fears that bacteria can more easily multiply without being killed off.


The Heat Pump Association was probed on the issue of cost, a factor that’s putting off most landlords from switching how they heat their homes.

Currently heat pumps are expensive, costing between £6,000 and £8,000 for air-based pumps and £10,000 to £18,000 for ground-based pumps.

The association predicted that a more competitive market for products, installation, maintenance and other services such as finance will likely combine to bring down costs for consumers.

Increased demand for heat pumps will likely encourage new entrants, while delivery services and contractors will benefit from increased scale.

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