Electrification of Heating in Belgium: When Heat Pumps, PV and Battery Storage Make Financial Sense

Executive summary. Electrifying heating can materially reduce fossil-fuel consumption and operating costs in Belgian buildings, but only when the building, electrical connection, tariff structure and operating profile are assessed together. A heat pump is not a like-for-like boiler replacement: its value depends on seasonal efficiency, required flow temperatures, peak electrical demand and the interaction with on-site solar generation.

What European policy actually changes

The revised EU Energy Performance of Buildings Directive establishes a pathway towards a zero-emission building stock by 2050. It requires zero-emission performance for new public buildings from 2028 and for all new buildings from 2030. It also ends financial incentives for new stand-alone fossil-fuel boilers from 2025, subject to limited exceptions.

This is a clear direction of travel, but it is not an immediate EU-wide ban on every existing gas boiler. Requirements for existing buildings are implemented through national and regional measures. Owners should therefore plan for tighter carbon and efficiency requirements without assuming that every asset must follow the same timetable.

The economic question

The correct question is not simply whether a heat pump has a high coefficient of performance. It is whether the complete heating system can deliver lower whole-life cost and acceptable resilience under the building’s actual conditions.

Our assessment compares the current gas and electricity bills with an hourly or representative-load model of the proposed system. We test seasonal coefficient of performance, design temperatures, distribution losses, electrical capacity, tariff exposure, maintenance and replacement costs. This produces a decision case rather than a technology sales calculation.

Why Belgian tariffs require careful modelling

Belgian energy bills combine commodity prices, network charges, taxes and region-specific tariff structures. A heat pump can convert one unit of electricity into several units of useful heat, making the electricity-to-gas price ratio more favourable than a simple comparison of headline prices suggests. However, poorly controlled peak demand can erode part of that advantage.

The model must therefore consider annual consumption and peak capacity. A good seasonal performance figure is valuable only if the building can operate at suitable flow temperatures and the electrical infrastructure can support winter demand.

The role of on-site solar generation

Photovoltaic generation can improve the economics by supplying part of the heat pump’s electrical demand. The match is not perfect: heating demand is highest in winter while solar production peaks in summer. Daytime domestic hot-water production, thermal storage and intelligent controls can nevertheless increase self-consumption.

The credible approach is to model the hourly overlap between generation and demand, not to subtract annual PV production from annual electricity consumption.

Does the project need battery storage?

A battery may help shift daytime solar production, reduce short-duration peaks and support tariff optimisation. It does not provide seasonal storage and should not be added automatically. Its value depends on the load profile, connection limits, market access, control strategy, cycling assumptions and replacement cost.

In some projects, thermal storage or improved heat-pump control offers better value. In others, a battery becomes compelling because it serves several uses: PV self-consumption, peak management, flexibility and operational resilience.

Full, hybrid or staged electrification

Three pathways are commonly appropriate. Full electrification can suit well-insulated buildings with low-temperature distribution and sufficient electrical capacity. Hybrid systems can retain a boiler for extreme temperatures or critical redundancy. A staged approach can begin with controls, metering, envelope improvements and electrical upgrades before major plant replacement.

Common mistakes

• Sizing from boiler capacity rather than measured heat demand.
• Using a catalogue COP instead of seasonal performance at required temperatures.
• Ignoring electrical connection and peak-capacity costs.
• Treating annual PV production as if it coincided with winter heating demand.
• Adding a battery without a defined operational use case.
• Comparing only energy prices and omitting maintenance, replacement and financing.

Information required

• Gas and electricity invoices and interval data where available.
• Heating plant, controls and distribution-system information.
• Building use, occupancy and comfort requirements.
• Electrical single-line diagram and connection capacity.
• Existing or planned PV, battery and energy-management systems.
• Planned renovations and investment horizon.

The Altair assessment

We assess the decision through four lenses: technical feasibility, financial value, operational practicality and long-term strategic fit. The result is an independent roadmap that defines what to implement, what to defer and what evidence suppliers must provide.

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Policy references: Directive (EU) 2024/1275 and the European Commission EPBD overview.