Solar PV, Battery Storage and Heat Pumps: Designing a More Efficient All-Electric Home

As more homes move away from fossil fuels, it's becoming increasingly common to see several low-carbon technologies installed at the same property.

Solar PV, battery storage, heat pumps and EV chargers can all form part of an efficient all-electric home. The trouble is, these technologies are often installed at different times, by different companies, without anyone really considering how they'll eventually work together.

From our experience across hundreds of heat pump installations, planning these technologies as part of one overall energy system can make a real difference. You don't need to install everything at once. But if solar panels, battery storage, a heat pump or an EV charger are likely to appear at some point down the line, it makes sense to think about them from the start.

Solar PV and Heat Pumps Can Work Brilliantly Together

Solar PV and heat pumps are a natural pairing.

A heat pump runs on electricity rather than burning a fossil fuel directly, so generating some of that electricity on site can reduce how much needs to be imported from the grid.

One area we particularly like this combination for is domestic hot water during the warmer months. If a property has solar PV but no battery storage, the heat pump's hot-water schedule can, where practical, be set to run during the middle of the day. Heating the cylinder between roughly 10am and 3pm, for example, increases the chance of using electricity the panels are already generating rather than exporting it and buying it back later to heat the water.

The exact schedule depends on the household's hot-water needs, the system design and the amount of solar generation available, but the underlying principle is simple: where possible, run electrical loads when renewable electricity is actually available on site.

Don't Design a Heat Pump Assuming Solar Will Power It Through Winter

This is where expectations sometimes need managing.

Heat pump demand is highest during the colder months, which is exactly when UK solar generation tends to be at its lowest compared with spring and summer.

How much an individual PV system generates depends on things like array size, orientation, shading, location and weather. But homeowners shouldn't assume that having solar panels means those panels will cover the heat pump's demand during the coldest parts of winter.

Solar can still make a meaningful contribution to the property's annual electricity use, but the heat pump itself needs to be designed, and its running costs discussed, without relying on large amounts of solar generation being available exactly when outdoor temperatures are at their lowest. This matters a lot when it comes to setting homeowners' expectations around running costs.

Why We Like Battery Storage With Heat Pumps

Battery storage can be an excellent partner for a heat pump, particularly alongside a suitable time-of-use electricity tariff.

Rather than depending solely on solar generation, a battery lets a homeowner buy electricity from the grid during cheaper off-peak periods, store it, and use it later when grid prices are higher. Where the battery has enough usable storage relative to the property's consumption, this can cover a meaningful chunk of the heat pump's electricity use outside the cheapest tariff periods.

The battery can also store any surplus solar generation, so electricity produced during the day doesn't go to waste and can be used later instead.

That means battery storage can potentially add value across more of the year, rather than only when sunshine happens to line up with the property's electrical demand. For that reason, if a homeowner asked us to choose between adding solar PV or battery storage alongside a new heat pump, we'd generally lean towards battery storage first, provided the property, tariff and expected consumption make the numbers work. Ideally, a well-designed property ends up with both.

Plan the Heat Pump First

When several technologies are on the table, our preference is to start by properly designing the heat pump system.

A room-by-room heat loss calculation should establish the property's heating requirement. From there, the heat pump, radiators or underfloor heating, hot-water needs and proposed operating temperatures can all be worked out. The electrical requirements of the proposed heat pump then feed into the wider electrical assessment of the property.

This is one reason an independent heat pump pre-installation review can be so useful before committing to a proposed system, especially where other electrical technologies are already installed or planned. Once the heat pump's requirements are properly understood, it's far easier to work out how battery storage, solar PV, EV charging and other significant loads fit around it.

Think About the Incoming Electrical Supply

One thing that's easy to overlook when technologies are installed separately is the electrical supply into the property itself.

A home might start out with fairly conventional electrical demand. Solar and a battery go in first. A heat pump gets added later, followed eventually by an EV charger. Each installation can make sense on its own, but somebody still needs to look at the property as a whole.

The rating of the incoming supply, the main fuse, the consumer unit arrangement and the expected electrical demand all need considering as new loads are planned. Depending on the equipment involved and local network requirements, the Distribution Network Operator may also need to be notified or consulted before certain equipment is connected. It's another reason thinking a few years ahead can genuinely pay off.

Planning for a Future EV Charger

Electric vehicles are a good example of this.

A homeowner might have no plans to buy one today but expect to within the next few years. If a heat pump, solar PV and battery system are already being planned, it's worth factoring that future charger in now.

That doesn't mean paying for an EV charger immediately. It might just mean checking the incoming supply, considering future electrical demand, leaving appropriate space within or around the consumer unit, and thinking ahead about where equipment and cable routes could eventually go. A small amount of planning at the first installation can save considerably more work later on.

Equipment Positioning Matters

Electrical capacity isn't the only thing to think about.

Modern low-carbon homes can end up with a surprising amount of equipment: an outdoor heat pump, hot-water cylinder, controls, battery modules, an inverter, consumer unit equipment, solar components, and potentially an EV charger too. Space disappears quickly.

Planning equipment locations together helps stop one installation taking the ideal spot another technology will need later. The same goes for cable routes, plumbing routes, maintenance access and future replacement. Again, the homeowner doesn't need to buy everything at once, they just need a plan.

Design the Home as One Energy System

Solar PV, battery storage, heat pumps and electric vehicles tend to get discussed as separate technologies. Increasingly, we think it makes more sense to treat them as different parts of the same home energy system.

The heat pump should be properly designed around the building's heating requirements first. Its electrical requirements can then be considered alongside the existing supply and any future loads. Battery storage can make use of cheaper off-peak electricity and surplus solar generation. Solar PV contributes renewable electricity throughout the year and works particularly well with planned daytime loads like domestic hot-water production in the warmer months. An EV charger can then slot into the longer-term electrical strategy, rather than turning up as an unexpected extra load several years down the line.

The result should be a home where these technologies complement each other, not just sit alongside one another.

You don't have to install your heat pump, solar panels, battery and EV charger on the same day. But if you expect to have them eventually, planning them together from the beginning can lead to a simpler, more efficient, and potentially cheaper, all-electric home.