EPC vs ErP – What’s The Difference?

If you’re a UK homeowner reviewing new heating systems for your property, you may have come across two similar-sounding terms:

EPC and ErP.

While they may seem indistinguishable at first glance, these terms are entirely different.

Let’s break down what these terms are in plain English.

What is an EPC?

An EPC (Energy Performance Certificate) is all about your property and assesses how efficiently your home uses energy.

By law, you need to have a valid EPC when:

• Selling,
• Renting,
• Or building a property in the UK.

The EPC is a legal document compiled by an accredited Domestic Energy Assessor, who will provide a report rating your property’s energy efficiency from A (the most efficient, with the lowest running costs) to G (the least efficient, with the highest running costs).

Prices for an assessment usually range between £60 and £120, depending on the property size and location.

When you receive your certificate, your ratings mean the following:

An EPC is valid for 10 years. If you can’t locate your property’s certificate, you can look it up on UK.gov.

When awarding your home a rating, the accredited Domestic Energy Assessor will be inspecting:

• If there is sufficient insulation in your walls, loft, or roof.
• Whether your heating systems, such as your boilers, radiators, and controls, are operating efficiently.
• Checking if your property’s windows and doors are single, double, or triple-glazed, as well as not allowing excessive draughts.
• And lighting, which checks if energy is wasted through older bulbs compared to LEDs.

What Does An EPC Show You?

Your EPC shows more than just a rating. In the EPC report, the assessor will include:

• Your property’s current energy rating.
• The potential rating it could achieve with improvements.
• Estimated costs for heating, hot water, and lighting.
• Recommendations to boost efficiency.

Why Does An EPC Matter?

An EPC is so much more than just paperwork. Homes with higher EPC ratings are more attractive to potential buyers and tenants, as this indicates that the property is more energy-efficient and less expensive to heat.

As mentioned, a good EPC rating will mean that you will spend less money a month.

Additionally, for homeowners seeking assistance with installing improved heating systems and help from a government grant, an EPC with a poor rating is a requirement for applicants.

Government grants, such as the Energy Company Obligation (ECO4) scheme or the Boiler Upgrade Scheme (BUS), use your EPC rating to check eligibility.

But what can homeowners expect when applying for these grants?

ECO4 (Energy Company Obligation)

The ECO4 scheme is the latest phase of the UK government’s long-running Energy Company Obligation and will run until March 2026.

Its main aim is simple: to help low-income households, families in fuel poverty, and homes with inefficient heating systems reduce their bills and energy waste.

Your EPC rating plays a key role here. To qualify, your property typically requires an EPC rating between E and G, with lower ratings (E, F, or G) prioritised because these homes consume the most energy and incur the highest heating costs.

Through ECO4, you could receive free or heavily subsidised upgrades, including:

• Boiler replacements.
• Loft, cavity wall, or underfloor insulation.
• Renewable heating options, such as heat pumps.

To access ECO4 support, you generally need to be a homeowner or tenant receiving means-tested benefits (such as Universal Credit, Pension Credit, or Child Tax Credit).

Boiler Upgrade Scheme (BUS)

While ECO4 focuses on households in need, the BUS (boiler Upgrade Scheme aims to drive the UK towards low-carbon heating.

The scheme offers grants to replace old fossil-fuel boilers with more environmentally friendly alternatives, such as heat pumps or biomass systems.

To qualify, you’ll need a valid EPC that shows no outstanding recommendations for loft or cavity wall insulation (these need to be addressed first).

The EPC also helps guide what improvements are best for your home.

Instead of discounts, BUS provides cash grants towards the installation cost:

• £7,500 for an air source or ground source heat pump.
• £5,000 for a biomass boiler (in rural, off-gas areas).

BUS is open to both domestic and small non-domestic properties.

And here’s the critical bit: as the homeowner, you don’t apply directly.

An MCS-certified installer prepares your quote on your behalf.

An EPC is a snapshot of how much energy your home uses and how much you could save with upgrades like insulation, a new boiler, or renewable systems.

So, what is an ErP?

What is ErP?

The Energy-related Products (ErP) Directive, also known as the EU Ecodesign Directive, is a European Union rating system that measures the energy efficiency of products such as boilers, heat pumps, and water heaters.

Under this directive, all boilers must meet a minimum efficiency of 92% (thanks to the Boiler Plus 2018 rules).

The goal behind the directive is straightforward: when manufacturers design appliances, energy efficiency and reduced environmental impact must be a priority, not an afterthought.

Manufacturers label their products with an efficiency band (A+++ down to G), similar to how EPCs label properties.

Products are labelled on a clear, colour-coded scale:

• A+++ (dark green) = the most efficient.
• G (red) = the least efficient.

This labelling system means homeowners know exactly how efficient a new boiler is when shopping, so they can make an informed decision before making a purchase.

By setting minimum standards, the ErP Directive helps ensure products use less energy, produce fewer emissions, and consume fewer resources.

This ties into the EU’s broader sustainability goals of:

• Cutting greenhouse gas emissions by 20% compared to 1990 levels.
• Improving appliance efficiency across the board by 20%.
• Increasing energy from renewable sources by 20%.

How the ErP Rating is Calculated

When deciding on a product’s rating, the ErP Directive looks at several key factors:

Energy Efficiency

For boilers, this means measuring the amount of energy required to generate heat.

The higher the efficiency ratio, the more of your fuel is converted into usable energy rather than wasted.

Even idle (standby) consumption is assessed, so waste is minimised across all operations.

Environmental Impact

Emissions, such as CO₂, are factored into the score. The lower the output, the higher the rating.

The sustainability of materials used in manufacturing is also considered, along with how long the product is expected to last.

Longer-lasting, more sustainable appliances are rated more favourably.

Other Performance Metrics

Other elements that are included and tested in the ErP rating include:

• Noise levels,
• Functionality,
• And overall performance.

Once all the metrics are tested, they are included in the overall rating.

The Key Difference Between EPC And ErP

If you’re looking for the shortest answer, the key differences between EPC and ErP are as follows:

• EPC = Focuses on your property’s overall energy performance.
• ErP = Focuses on the efficiency of the products installed in your property.

Together, these two ratings give homeowners a complete picture of how energy-efficient their property is.

While these two systems are great, it can be confusing for individuals just looking for a boiler replacement.

Luckily, WarmZilla makes finding the best, most energy-efficient boiler for your home easy.

Get The Boiler With The Right ErP For Your Home’s EPC!

For those still unsure about what boiler to choose, you can always take WarmZilla’s quick online survey.

It takes less than 2 minutes, and when you’re done, our algorithm will match you with the perfect boiler and brand for your home.