Heat pump and EPC score: what real impact does it have on your certificate?

You are wondering whether a heat pump will significantly improve your EPC score before putting your property on the market? The short answer is yes, but with some important nuances. The impact depends on several factors specific to your home, and it is worth understanding them before investing several thousand euros.

How is the EPC score calculated in Belgium?

The EPC certificate (Energy Performance of Buildings) measures a property's primary energy consumption, expressed in kWh per square metre per year. The lower the figure, the better the class, ranging from A+ down to G. In Wallonia, Flanders and Brussels, the calculation follows the same basic logic, but the software and class thresholds can vary slightly.

The final score incorporates several elements: the insulation of the building envelope (roof, walls, floors, glazing), the heating system, domestic hot water production, ventilation and any renewable energy installations. The heating system accounts for a considerable share of the score - often between 30 and 50% of the total calculated consumption. This is precisely where the heat pump comes into play.

Why does a heat pump influence the EPC?

A heat pump does not directly consume fossil fuel. It uses electricity to extract heat energy from outdoor air, the ground or groundwater, and delivers it as heat inside your home. Its efficiency is measured by the coefficient of performance (COP): a COP of 3 means that for every 1 kWh of electricity consumed, you get 3 kWh of heat.

In the EPC calculation, primary energy accounts for conversion and energy transport losses. In Belgium, the primary energy factor for electricity is set at 2.5 (in Wallonia and Brussels) or a similar value in Flanders. In practical terms, even if you consume less final energy, electricity is still penalised compared to natural gas in this calculation. This means that a heat pump with a modest COP will improve your EPC score less than is sometimes assumed.

On the other hand, a high-performing air-to-water or ground-to-water heat pump, with a seasonal COP (SCOP) above 3.5 or 4, can reduce primary energy consumption significantly and gain one or two EPC classes depending on the building's starting point.

How many EPC classes can you realistically gain?

It all depends on the starting point. If your property is currently in class D or E with an old oil boiler, replacing it with a modern air-to-water heat pump can move your property to class C, or even B in some favourable cases. The gain is more limited if you are already starting from a recent condensing gas boiler.

Some approximate figures observed in practice for a four-facade house of 150 m² in Wallonia:

• Old oil boiler to air-to-water heat pump: possible gain of 1 to 2 EPC classes.
• Condensing gas boiler to air-to-water heat pump: possible gain of 0 to 1 EPC class.
• Heat pump combined with photovoltaic panels: additional gain of 0.5 to 1 class.

These figures are indicative. A certified EPC assessor can provide you with a precise simulation before any works are carried out, which is strongly recommended before making any investment.

Insulation remains the priority for the EPC score

A common mistake is to rely solely on the heat pump to improve the EPC, while neglecting the building envelope. The EPC calculation heavily penalises heat loss. A poorly insulated home with a heat pump will achieve a worse score than a well-insulated home with a standard boiler.

If your roof is not insulated, your walls are solid brick with no insulation and you have single glazing, investing in insulation first will deliver a greater improvement to your EPC score than installing a heat pump alone. The combination of both remains ideal, but if the budget is limited, insulation is generally the priority.

For sellers, this is an important point: a poor EPC score caused by a weak building envelope cannot easily be masked by a good heating system.

Impact on the resale value of your property

In 2026, the impact of the EPC score on sale prices is well documented on the Belgian market. According to recent analyses by notaries and property institutes, a property in class A or B sells on average 5 to 15% more than a comparable property in class D or E in the same municipality. This gap has been widening since the introduction of renovation obligations in Flanders and the new regulations expected in Wallonia.

A property with an installed heat pump and a good EPC score reassures buyers about future energy costs. It is a concrete selling point, especially in a context where energy prices remain volatile.

If you are considering selling your property, it may be useful to obtain a free valuation of your property to gauge the impact of your renovation works on market value.

What to check before installing a heat pump

Before making a decision, a few points deserve your attention:

• Sizing: an undersized heat pump will perform poorly and its real-world SCOP will be disappointing. Use a certified installer.
• The type of heat emitters: low-temperature heat pumps work best with underfloor heating or large radiators. Traditional radiators may need to be replaced.
• Available grants: in 2026, regional grants remain accessible in Wallonia (Primes Habitation), in Flanders (Mijn VerbouwPremie) and in Brussels (Primes Renolution), subject to income conditions and the type of works carried out.
• Planning permission: some outdoor units require a declaration or a permit depending on the municipality.

If you plan to sell within two to three years, calculate the return on investment taking into account the potential gain in sale price and the grants received. A local estate agent with a good understanding of the energy market can help you assess whether the investment makes sense in your situation.

To find a professional who knows the realities of your local market, you can compare accredited IPI estate agents near you for free via IMV.

Heat pump and EPC: the key takeaways

A heat pump can improve your EPC score significantly, provided your home is already properly insulated and the heat pump is correctly sized with a high COP. The gain is real but not automatic. In the context of a property sale, a better EPC score translates into a higher property value and a solid commercial argument for buyers.

To maximise the impact of your works on the sale price, the best approach is to consult an experienced estate agent who knows what buyers in your municipality expect. Compare certified local IPI agents for free and make the right decisions before putting your property on the market.

Frequently asked questions

Is a heat pump alone enough to reach class B or A?

In general, no. The EPC class depends above all on the insulation of the building envelope. A high-performing heat pump can gain one or two classes, but reaching class A or B almost always requires thorough insulation of the roof, walls and glazing at the same time.

Which type of heat pump is most favourable for the EPC?

Ground-to-water heat pumps (geothermal) generally achieve the highest SCOPs, around 4 to 5, which is favourable in the EPC calculation. Air-to-water heat pumps are less expensive to install and remain very attractive if their SCOP exceeds 3.5. Air-to-air heat pumps are less advantageous as they do not always cover domestic hot water production.

Does the EPC score really influence the sale price in Belgium?

Yes. Belgian market data for 2026 confirms that properties rated A or B sell at noticeably higher prices than equivalent properties in class D or E. The gap varies by region and municipality, but it is now well documented and taken into account by buyers and banks when granting mortgages.

Do you need a new EPC certificate after installing a heat pump?

Yes, if you want the new system to be recognised in the certificate presented at the time of sale. A certified EPC assessor must draw up a new certificate based on the updated data for the property. This certificate is valid for 10 years in Belgium.