Batería doméstica vs Heat Pump Boiler: Which is Smarter?

Two ways to store energía solar

A bomba de calor boiler and a batería doméstica solve the same problem: they store surplus energía solar 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 bomba de calor boiler work?

A bomba de calor 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 bomba de calor boiler is relatively affordable (€1,500 to €3,000 including installation) and has a short payback period.

The disadvantage of a bomba de calor 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: batería doméstica vs bomba de calor boiler

A direct comparison on the most important criteria.

After the comparison, it's clear: a batería doméstica is more versatile but more expensive, while a bomba de calor boiler is cheaper but limited in application.

When should you choose a batería doméstica?

A batería doméstica is the better choice if you want to reduce high electricity costs, have little or no hot water consumption, want to charge an coche eléctrico with solar power, want alimentación de respaldo during outages, or want maximum flexibility for future applications.

• You have high electricity costs beyond hot water
• You want to charge an coche eléctrico with your own solar power
• You want alimentación de respaldo during outages
• You already have a modern central heating boiler or district heating for hot water

When should you choose a bomba de calor boiler?

Choose a bomba de calor 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 hogar 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 bomba de calor)

The best choice: combine both

The optimal solution is a combination of both: a bomba de calor boiler takes care of thermal storage (hot water), while the batería doméstica stores the electrical surplus. Together, you maximise autoconsumo and minimise the factura energética.

The cost of the combination is higher, but the payback period can still be attractive thanks to the ISDE subvención that applies to bomba de calor boilers in combination with paneles solares.