Can Solar Panels Heat Radiators in Ireland? 4 Methods Compared (2026)

Yes, solar panels can power radiators in Ireland — but not by connecting panels directly to radiators. You need either solar PV panels paired with a heat pump or electric boiler, or a solar diverter that sends excess solar power to your immersion heater. Here’s how each approach works, what it costs in Ireland in 2026, and which option delivers the best return on investment for your home.

This question comes up constantly because Irish homeowners are looking for ways to cut heating bills — and with good reason. The average Irish household spends €1,800–€2,500 per year on heating alone. Solar panels can realistically offset 30–50% of that cost when set up correctly. But the “correctly” part matters enormously. Let’s break down every option.

4 Ways Solar Can Heat Your Radiators (And Hot Water)

There are four distinct approaches, each suited to different budgets and situations:

Method	How It Works	Cost (Ireland 2026)	Best For
Solar PV + Heat Pump	PV panels generate electricity that powers a heat pump, which heats water for radiators	€6,000–€9,000 (PV) + €8,000–€14,000 (heat pump)	Whole-home heating, maximum efficiency
Solar PV + Diverter	A diverter sends surplus solar electricity to your immersion heater to heat water	€6,000–€9,000 (PV) + €300–€600 (diverter)	Hot water heating, maximising solar self-use
Solar PV + Electric Boiler	PV panels power an electric boiler that heats water for radiators	€6,000–€9,000 (PV) + €1,500–€3,000 (boiler)	Simpler setup, lower upfront cost
Solar Thermal	Thermal collectors heat water directly using sunlight	€3,000–€6,000	Hot water only (limited for radiators)

Option 1: Solar PV + Heat Pump (Best Overall)

This is the gold standard for heating radiators with solar energy in Ireland. A heat pump combined with solar panels is the most efficient combination available:

• Solar PV panels generate free electricity during the day
• The heat pump uses that electricity to extract heat from the outside air (even in Irish winters at 0–5°C)
• For every 1 kWh of electricity consumed, a heat pump produces 3–4 kWh of heat
• The heated water is circulated through your existing radiator system

Let’s put real numbers on this. A 5 kW solar PV system in Ireland generates roughly 4,500 kWh per year. If your heat pump has a COP (Coefficient of Performance) of 3.5, that solar electricity effectively produces 15,750 kWh of heat. The average Irish home needs 10,000–15,000 kWh of heat per year, so solar + heat pump can theoretically cover your entire heating demand on paper.

The catch? Timing. Heating demand peaks in winter when solar output is lowest. A 5 kW system generates 25 kWh/day in June but just 5–8 kWh/day in December. This is why you still need grid electricity as backup, and why adding a battery to store daytime solar for evening heating improves the economics further.

Costs and grants

Component	Cost	SEAI Grant	Net Cost
5 kW Solar PV system	€6,500–€9,000	€1,800	€4,700–€7,200
Air-to-water heat pump	€8,000–€14,000	€3,500	€4,500–€10,500
Total	€14,500–€23,000	€5,300	€9,200–€17,700

The combined SEAI grants of €5,300 make a significant dent. With 0% VAT on solar installations and heating bill savings of €1,200–€1,800 per year, the payback period is typically 6–10 years.

Option 2: Solar PV + Diverter (Most Popular Add-On)

A solar diverter (also called an immersion diverter or power diverter) is the most popular and affordable way to use solar energy for heating water in Ireland. It does not heat radiators directly, but it heats your hot water cylinder using surplus solar electricity — which reduces the load on your boiler or heat pump.

Here’s how it works:

1. Your solar panels generate electricity during the day
2. Your home uses what it needs for appliances, lights, etc.
3. Instead of exporting the surplus to the grid, the diverter redirects it to your immersion heater
4. Your hot water cylinder heats up for free
5. Your boiler or heat pump does not need to run for hot water, saving gas or electricity

Popular diverter brands in Ireland include the Eddi by myenergi (around €450–€550 installed), the iBoost+ (around €350–€450 installed), and the SolarEdge Home Smart Energy Manager.

A diverter typically saves €200–€400 per year on hot water costs. With the unit costing €300–€600 installed, it pays for itself in 1–2 years — making it one of the best-value solar accessories you can buy.

Option 3: Solar PV + Electric Boiler

If you don’t want the expense of a heat pump, you can use solar PV panels to power an electric boiler that heats water for radiators. This is simpler but less efficient — an electric boiler converts electricity to heat at roughly 1:1 (compared to 1:3.5 for a heat pump).

This approach works best if:

• You already have an electric boiler installed
• You want a lower upfront cost than a heat pump
• Your heating demand is relatively modest (well-insulated home)
• You have a large solar array (8–10 kW) generating plenty of surplus

The main drawback: your solar panels alone won’t generate enough electricity to fully heat your home via an electric boiler, especially during winter when solar output drops to 5–8 kWh/day. You will still draw heavily from the grid for heating in the darker months.

Option 4: Solar Thermal Panels

Solar thermal panels are different from solar PV — they use sunlight to heat water directly rather than generating electricity. There are two types:

• Flat plate collectors — metal-framed panels with a dark absorber surface, more affordable (€2,500–€4,000)
• Evacuated tube collectors — glass tubes with a vacuum seal, more efficient in cloudy Irish weather (€3,500–€6,000)

Solar thermal can reach efficiencies of up to 70–80% (vs 20–22% for PV panels), but the heated water is typically only hot enough for domestic hot water, not for powering a full radiator system. In Ireland’s climate, solar thermal realistically provides 50–70% of your hot water needs but cannot be relied upon as your primary heating source.

For a full comparison of solar PV vs solar thermal, see our detailed guide.

Which Option Should You Choose?

Your Situation	Best Option	Why
Want maximum heating savings	Solar PV + heat pump	3.5x efficiency multiplier, €5,300 in grants
Already have solar panels	Add a diverter	€300–€600 for free hot water, 1–2 year payback
Limited budget	Solar PV + diverter	Lowest cost way to heat water with solar
Only need hot water (not radiator heating)	Solar thermal or PV + diverter	Both work well; PV + diverter is more versatile
Have an existing electric boiler	Solar PV + diverter or direct connection	Use free solar electricity to offset boiler running costs

Will Solar Panels Fully Replace Your Heating System?

In Ireland, the honest answer is no — not entirely. Here’s the reality:

• Heating demand peaks in winter when solar output is at its lowest
• An average Irish home needs 10,000–15,000 kWh of heat per year
• A 5 kW solar system generates roughly 4,500 kWh per year — and only about 30% of that falls in the October–March heating season
• Solar panels can realistically offset 30–50% of your heating costs when paired with a heat pump

Solar is best used as part of a hybrid system — supplementing your existing heating rather than replacing it entirely. The combination of solar PV, a heat pump, and a battery gives you the most independence from the grid.

Frequently Asked Questions

Can I connect solar panels directly to my radiators?

No. Solar PV panels produce electricity (DC current), while radiators need heated water. You need an intermediary device — either a heat pump, electric boiler, or immersion heater/diverter — to convert that electricity into heat for your water-based radiator system.

How much can I save on heating with solar panels?

With solar PV + a heat pump, typical Irish homes save €1,200–€1,800 per year on combined heating and hot water costs. With solar PV + a diverter (hot water only), savings are €200–€400 per year. Your actual savings depend on your system size, insulation level, and heating habits.

Do solar panels work for heating in Irish winters?

They work, but at reduced capacity. A 5 kW system generates about 5–8 kWh/day in December (vs 25 kWh/day in June). This is why solar is best combined with a heat pump — the heat pump’s 3.5x efficiency multiplier stretches every kWh of solar generation much further. A battery can also store daytime solar for evening heating.

Is solar thermal or solar PV better for heating?

For radiator heating, solar PV is better. Solar PV is more versatile (it powers everything, not just heating), qualifies for a larger SEAI grant (€1,800 vs €1,200 for solar thermal), and pairs far more effectively with a heat pump. Solar thermal is only better if you specifically want hot water and nothing else. Read our full PV vs thermal comparison.

What size solar system do I need to heat my home?

To make a meaningful impact on heating costs when paired with a heat pump, you need at least a 4–5 kW solar PV system. For a larger home or higher heating demand, a 6–10 kW system is better. Use our solar calculator to estimate the right size for your home.

The Bottom Line

Solar panels can heat radiators, but they need a heat pump, electric boiler, or diverter as an intermediary. The most cost-effective approach for Irish homes in 2026 is solar PV panels + an air-to-water heat pump, with SEAI grants covering up to €5,300 of the combined cost. If that is too expensive, adding a €300–€600 diverter to existing solar panels is the best-value way to start using solar for heating.

Start with our solar and heat pump guide or use our solar calculator to estimate your system size and savings.