Home Battery vs Heat Pump Boiler: Which is Smarter?

Two ways to store solar energy

A heat pump boiler and a home battery solve the same problem: they store surplus solar energy during the day for use when the sun isn't shining. But they do so in a fundamentally different way, with different advantages and disadvantages.

In this article, we compare both technologies fairly and help you make the best choice for your situation.

How does a heat pump boiler work?

A heat pump boiler uses surplus solar electricity to heat water (up to 65°C) with an efficiency of 300-400% (COP 3-4). The stored thermal energy is used later for showering and heating. A heat pump boiler is relatively affordable (€1,500 to €3,000 including installation) and has a short payback period.

The disadvantage of a heat pump boiler is that the stored energy is exclusively available as heat. You cannot power electrical appliances with it, charge a car, or absorb electricity peaks.

Direct comparison: home battery vs heat pump boiler

A direct comparison on the most important criteria.

After the comparison, it's clear: a home battery is more versatile but more expensive, while a heat pump boiler is cheaper but limited in application.

When should you choose a home battery?

A home battery is the better choice if you want to reduce high electricity costs, have little or no hot water consumption, want to charge an electric car with solar power, want backup power during outages, or want maximum flexibility for future applications.

• You have high electricity costs beyond hot water
• You want to charge an electric car with your own solar power
• You want backup power during outages
• You already have a modern central heating boiler or district heating for hot water

When should you choose a heat pump boiler?

Choose a heat pump boiler if you primarily want to save on hot water costs, have a limited budget, use more hot water than average (large family), and if your household has relatively low electricity consumption.

• Your primary cost is hot water (showers, baths)
• Your budget is limited and payback period is a priority
• You have a large family with high hot water consumption
• You have relatively low electricity consumption (no EV, no heat pump)

The best choice: combine both

The optimal solution is a combination of both: a heat pump boiler takes care of thermal storage (hot water), while the home battery stores the electrical surplus. Together, you maximise self-consumption and minimise the energy bill.

The cost of the combination is higher, but the payback period can still be attractive thanks to the ISDE subsidy that applies to heat pump boilers in combination with solar panels.