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30–60%Heating Bill ReductionTypical range for homeowners replacing gas or oil with a solar-powered heat pump. Where your home lands depends on insulation, efficiency, and location.
5×Make Your Electricity Work moreA modern heat pump delivers up to 5 kWh of heat for every 1 kWh of electricity it uses. That's what makes solar coverage realistic — and gas look expensive.
40–60%Annual HP Electricity from SolarThe honest annual figure — not a cherry-picked summer number. Winter requires grid top-up, but spring, summer, and autumn more than compensate over a full year.
No BatteryYour Home Stores the HeatPre-heating during solar peak hours stores energy as warmth in your walls and water tank — no expensive battery required for the heat pump itself.
30 to 60% Off Your Heating Bill With a Solar-Powered Heat Pump — But Not for Every Home
Households replacing gas or oil heating with a solar-powered heat pump typically reduce their annual heating bill by 30 to 60%. That's a wide range — because no two homes are the same.
Your insulation, your heat pump model, and your location all shape where you land. A well-insulated house with a modern heat pump in a sun-rich location sits at the upper end. An older, draughty house with an ageing unit sits closer to the lower end. Both benefit — but by very different amounts.
Most people coming from gas or oil have no idea how much electricity a heat pump actually uses. The good news: far less than you'd expect. A modern heat pump doesn't just convert electricity into heat — it multiplies it. For every 1 unit of electricity it consumes, it delivers 3 to 5 units of warmth. That's what makes solar coverage realistic in the first place.
Whether your home is closer to 30% or 60% — that's exactly what this page helps you work out.
The Obvious Concern — and the Honest Answer
You've probably already thought of it: heat pumps run hardest in winter, and winter is exactly when solar produces the least. That's true — and worth taking seriously.
In the coldest months, a south-facing roof produces a fraction of what it generates in summer. You will not get 60% solar coverage in January. Nobody should tell you otherwise.
What makes the annual picture work is the balance. The warmer months generate far more solar energy than your heat pump needs. That surplus compensates for the winter shortfall. Over a full year, the 30–60% savings range holds.
On clear winter days there's also a practical strategy worth knowing: running the heat pump slightly harder during the midday solar window pre-heats the house and the hot water tank. The house then coasts through the evening on stored warmth — without drawing from the grid. No battery required. Your home's walls and water tank do the storing.
Three Things That Determine Where Your Home Lands
No calculator can give you your number without knowing these three things about your home.
1
How Well Your Home Holds Heat
Better insulation means your home needs less heating to begin with — and holds pre-heated warmth longer into the evening. In a well-insulated house, midday solar-powered pre-heating carries the home comfortably through the evening. In a draughty house, that warmth leaks out within hours and the system has to run again before sunset. Insulation quality is the single biggest multiplier on coverage — more impactful than adding extra panels.
✓ Less heat loss = less electricity needed
✓ Pre-heated warmth lasts longer into the evening
✓ Modelled for your insulation level
2
How Efficiently Your Heat Pump Converts Electricity
A heat pump's efficiency is measured by its COP — Coefficient of Performance. A COP 3 unit delivers 3 kWh of heat per 1 kWh of electricity. A COP 5 unit delivers 5 kWh from the same input. Same home, same heating demand — but the COP 5 unit needs 40% less electricity to do the job. That directly shrinks the solar system required to cover it. Modern air-source heat pumps typically achieve COP 4–5 in mild weather; older or cheaper units sit closer to COP 2.5–3.
✓ Higher efficiency = less electricity needed
✓ Same solar system covers a larger share
✓ Newer models outperform older units significantly
3
When You Run Your Heat Pump
Scheduling your heat pump to run during peak solar hours — rather than evening — changes how much of its electricity comes from your roof. The strategy is simple: run slightly harder at midday using free solar electricity, then let the home coast on stored warmth through the evening. Most modern heat pumps and smart thermostats can automate this entirely. It costs nothing extra and meaningfully shifts your coverage figure.
✓ Midday operation captures free solar electricity
✓ No extra hardware — smart thermostat is enough
✓ Automatable on most modern systems
Calculate Your Solar Heat Pump Savings in 3 Steps
1
Enter Your Address and ConsumptionPV Freund automatically pulls your roof geometry and local solar irradiance from satellite data — no manual measurements needed.
2
Add Your Heat Pump DetailsEnter your heat pump's electricity consumption (or house size and insulation class for an estimate) and whether you have a buffer tank. The tool builds a pre-heating schedule around your solar window.
3
See Your Personal Coverage and SavingsYou get the percentage of your heat pump's electricity covered by solar, annual savings, recommended system size, and payback — with a monthly breakdown showing exactly where solar covers the load and where the grid fills in.
Frequently Asked Questions about Solar and Heat Pumps
Does solar make sense with a heat pump given winter is when I need both most?
Yes — with realistic expectations. In winter, solar output drops to 15–25% of peak summer levels in most climates, so grid top-up in the coldest months is normal and expected. What makes the combination worthwhile is the annual balance: strong solar coverage in spring, summer, and autumn offsets the winter shortfall. Over a full year, a well-sized system covers 40–60% of your heat pump's electricity. The winter months require grid draw, but the summer months more than compensate. PV Freund shows you the honest monthly breakdown so you can judge the trade-off yourself.
What COP should I look for to maximise solar coverage?
Aim for COP 4 or higher under typical heating conditions (not the peak rated value on the spec sheet, which is usually measured at ideal conditions). Air-source heat pumps typically achieve COP 3–4 in heating mode in temperate climates; ground-source units reach COP 4–5. Each point of COP improvement reduces the electricity you need — and therefore the solar capacity required — by roughly 20–25%. If you're choosing between heat pump models, a higher-COP unit shrinks the solar system you need and improves the combined payback.
Do I need a battery with solar + heat pump?
For heat pump operation specifically, no — a thermal buffer tank replaces the electrical battery. The buffer tank stores hot water heated during peak solar hours, releasing it gradually through the evening. A 200–300 litre buffer tank costs a fraction of a lithium battery and lasts decades without degradation. An electrical battery only makes financial sense if you have significant evening household loads (appliances, EV charging) beyond what the heat pump covers. PV Freund calculates both configurations and shows you the payback comparison.
Can solar cover my hot water too?
Yes, and this is one of the most financially efficient uses of surplus solar. In summer, your heat pump running in domestic hot water mode can produce all your hot water needs from solar electricity at effectively zero cost. Many heat pumps include a hot water mode, or you can add a separate heat pump water heater. PV Freund's calculation includes domestic hot water demand alongside space heating so the coverage figure reflects your full thermal energy picture, not just the heating system.
Is it worth switching from gas now or waiting for better technology?
The honest answer: the economics favour switching now for most homeowners. Heat pump efficiency (COP) has improved significantly in recent years and is approaching a plateau — the step-change improvements happened between 2015 and 2022. Solar panel prices have also largely bottomed out. Waiting for a technology step-change is unlikely to produce significantly better economics than what's available today. Meanwhile, gas prices remain unpredictable, and many European countries are introducing stricter regulations on new gas boiler installations. The case for switching is strongest for homeowners who also have a roof suitable for solar — the combination pays back faster than either system alone.
