Solar Panels and Electric Heating: Reducing Bills in NI Homes

Northern Ireland’s Heating Challenge

Northern Ireland has a unique heating profile compared to the rest of the United Kingdom. While the vast majority of homes in England, Scotland, and Wales are connected to the mains gas network and use gas boilers, the picture in NI is very different.

Approximately 68% of NI homes rely on home heating oil as their primary heat source. Around 10% use electric heating (primarily storage heaters on Economy 7 tariffs), and a smaller but growing number use heat pumps, LPG, or solid fuel. Mains gas coverage in Northern Ireland sits at only around 25% of homes, concentrated in the greater Belfast area and a few other towns.

This means a significant proportion of NI homeowners either buy oil at volatile prices or pay premium electricity rates to heat their homes. Both groups stand to benefit substantially from solar panels, but the opportunity is especially strong for homes with electric heating.

If your home runs on electric storage heaters, panel heaters, or an electric boiler, this guide explains exactly how solar panels can help, what system size you need, and the best combinations of technology to maximise your savings.

Why Electrically Heated Homes Benefit Most from Solar

The simple economics make the case. If your home uses electricity for heating, your annual electricity consumption is significantly higher than the national average.

A typical NI home using gas or oil for heating consumes around 3,500 to 4,500 kWh of electricity per year (for lighting, cooking, appliances, and hot water). A home with electric heating can easily consume 7,000 to 12,000 kWh per year, because the heating system draws heavily from the grid.

Every unit of electricity your solar panels generate displaces a unit you would otherwise buy from the grid. At current NI electricity prices of 24p to 28p per kWh (and significantly higher on daytime Economy 7 rates), the value of each solar unit is substantial. The more electricity you consume, the more you save by generating your own.

Here is how the numbers compare:

Heating Type	Typical Annual Electricity Use	Solar Self-Consumption Potential	Estimated Annual Solar Savings (4kW system)
Gas/oil heating	3,500-4,500 kWh	30-50% of generation	£350-£550
Electric storage heaters	7,000-10,000 kWh	40-60% of generation	£500-£800
Electric panel heaters	8,000-12,000 kWh	45-65% of generation	£550-£900
Heat pump	5,000-7,000 kWh	35-55% of generation	£400-£700

These figures assume a 4kW system without battery storage. Adding a battery pushes self-consumption rates significantly higher and increases savings accordingly, as we will cover later in this guide.

Understanding Economy 7 and Solar Panels

Many NI homes with electric heating are on Economy 7 tariffs (or similar time-of-use tariffs). Understanding how these interact with solar panels is essential for maximising savings.

How Economy 7 Works

Economy 7 gives you two electricity rates:

• Off-peak rate (7 hours overnight, typically 1am to 8am): Around 12 to 14p per kWh
• Peak rate (remaining 17 hours): Around 28 to 32p per kWh

The logic is straightforward: your storage heaters charge overnight using cheap electricity, storing heat in ceramic bricks. They then release that heat gradually throughout the day. Your immersion heater also typically runs on a timer overnight, heating a full tank of water using the cheaper rate.

Where Solar Fits In

Solar panels generate electricity during daylight hours, which falls entirely within the expensive peak rate period. This is actually excellent news, because every unit of solar electricity you use during the day displaces the most expensive electricity on your tariff.

Consider the maths:

• If you are on a flat-rate tariff at 26p/kWh, each solar unit saves you 26p
• If you are on Economy 7 with a daytime rate of 30p/kWh, each solar unit used during the day saves you 30p

Solar panels are therefore even more valuable for Economy 7 customers than for those on flat-rate tariffs, because the electricity they displace is the premium daytime rate.

The Timing Mismatch

The challenge with Economy 7 and solar is timing. Your storage heaters charge overnight when there is no solar generation. Your solar panels generate during the day when your storage heaters are discharging (not drawing electricity). So the solar electricity and the heating demand do not naturally overlap.

This means that without a battery or alternative strategy, your solar panels will mainly offset your daytime electricity use (lighting, cooking, appliances, entertainment) rather than your heating costs directly. You still save money, but you are not directly powering your heating with solar.

There are several solutions to this timing problem, which we cover in the following sections.

Solution 1: Battery Storage

Adding a battery to your solar system is the most effective way to use solar electricity for overnight heating needs. During the day, surplus solar electricity charges the battery instead of being exported to the grid. In the evening and overnight, the battery discharges to power your home, including your heating system.

How It Works With Storage Heaters

With a sufficiently large battery (10 kWh or more), you can store a meaningful amount of daytime solar electricity and use it to offset the overnight charging of your storage heaters. The battery discharges during the evening and early night, reducing what you draw from the grid. When the Economy 7 off-peak period starts (typically 1am), the battery will likely be depleted, and your storage heaters switch to drawing cheap off-peak electricity from the grid.

The result is a two-pronged saving:

1. Solar electricity offsets expensive daytime usage directly
2. Battery-stored solar electricity offsets some evening and early overnight usage
3. Storage heaters still benefit from the cheapest overnight rates for the bulk of their charging

Battery + Economy 7: The Smart Strategy

Some hybrid inverters (such as GivEnergy and Huawei) allow you to charge your battery from the grid during off-peak hours. This opens up an additional saving strategy:

1. During the day: Solar panels power your home and charge the battery with any surplus
2. Evening (peak rate): Battery discharges to power your home, avoiding expensive grid electricity
3. Overnight (off-peak): Battery recharges from the cheap grid rate alongside your storage heaters
4. Next morning: Battery discharges again during the expensive morning peak

This cycle maximises savings by ensuring you rarely buy electricity at the full peak rate. For a detailed look at battery options and costs, see our solar battery storage guide.

Battery Sizing for Electrically Heated Homes

Homes with electric heating use more electricity and therefore benefit from a larger battery than the standard recommendation. Here is a rough guide:

Battery Capacity	Best For	Typical Cost
5 kWh	Small home, supplementary heating only	£3,500-£4,500
10 kWh	Medium home with storage heaters	£5,000-£7,000
13-15 kWh	Larger home, high heating demand	£6,500-£9,000

A 10 kWh battery is a sensible starting point for most electrically heated NI homes. It stores enough solar electricity to meaningfully offset evening and early overnight usage without being oversized for the solar system’s daily generation capacity.

Solution 2: Solar Diverters for Immersion Heaters

If your home has an immersion heater for hot water (which most electrically heated homes do), a solar diverter is one of the simplest and most cost-effective additions to a solar panel system.

What Is a Solar Diverter?

A solar diverter (also called a solar PV diverter or power diverter) is a device that automatically detects when your solar panels are generating more electricity than your home is using at that moment. Instead of exporting that surplus to the grid (where you receive little or nothing for it), the diverter sends it to your immersion heater to heat your hot water.

The most popular solar diverter in the UK market is the myenergi Eddi. Other options include the iBoost+ and the Marlec Solar iBoost.

How It Saves Money

Without a diverter, you typically heat your hot water using:

• Economy 7 overnight electricity (12-14p/kWh), or
• Peak-rate daytime electricity (28-32p/kWh), or
• A combination of both

With a solar diverter, your surplus solar electricity heats the water instead. Since that electricity would otherwise have been exported for little return, you are effectively getting free hot water during sunny periods.

For a typical household, a solar diverter can save £100 to £200 per year on water heating costs.

Cost and Payback

Item	Cost
myenergi Eddi (unit only)	£300-£400
Installation	£100-£200
Total installed cost	£400-£600
Annual savings	£100-£200
Payback period	2-4 years

A solar diverter is one of the fastest payback investments in the solar energy space. If you have an immersion heater and solar panels, it is almost always worth adding one.

Diverter vs Battery

A common question is whether to install a diverter or a battery. The answer depends on your priorities:

• Diverter: Cheaper, faster payback, but only heats water. Does not help with overnight electricity usage.
• Battery: More expensive, slower payback, but more versatile. Stores electricity for any use, not just hot water.
• Both: The ideal combination. The diverter handles surplus on sunny days when the battery is already full, ensuring no solar electricity is wasted.

Solution 3: Modern Smart Storage Heaters

If your current storage heaters are old (pre-2015), replacing them with modern smart storage heaters can dramatically improve how well they work with solar panels.

The Problem With Old Storage Heaters

Traditional storage heaters are simple devices. They charge overnight on a timer and release heat throughout the day, whether you need it or not. They have limited controls (usually just an input dial and an output dial), no connectivity, and no ability to respond to solar generation.

How Smart Storage Heaters Differ

Modern smart storage heaters (such as Dimplex Quantum or Elnur Ecombi) offer several advantages:

• Programmable charging. They can be set to charge at specific times, not just during the Economy 7 window. This means they can charge during the day when your solar panels are generating.
• Room-by-room control. Each heater can be controlled independently, with its own schedule and temperature target.
• Weather compensation. Smart heaters adjust their charge level based on weather forecasts, storing more heat before cold spells and less before mild days.
• Wi-Fi connectivity. Control and monitor via an app. Some models integrate with smart home systems.

Solar + Smart Storage Heaters

The key benefit for solar owners is the ability to charge storage heaters during the day using solar electricity, rather than being locked into overnight charging. If your solar panels are generating a surplus between 10am and 3pm, a smart storage heater can absorb that electricity as heat, storing it for release during the evening.

This approach works best in spring and autumn, when heating is still needed but solar generation is reasonably strong. In the depths of winter, solar generation is too low to meaningfully charge storage heaters, and you will still rely on overnight grid electricity.

Cost of upgrading: Modern smart storage heaters cost £400 to £800 per unit, depending on size and brand. For a three-bedroom home with four to five heaters, the upgrade cost is roughly £2,000 to £4,000. This is a significant outlay, but the improved comfort and ability to use solar electricity for heating can deliver substantial savings over the heaters’ 15 to 20 year lifespan.

Solution 4: Solar Panels + Heat Pump

The combination of solar panels and a heat pump is arguably the most effective long-term solution for heating a Northern Ireland home electrically. A heat pump extracts warmth from the outside air (or ground) and uses electricity to amplify it, delivering 2.5 to 3.5 units of heat for every unit of electricity consumed.

Why This Combination Works

Solar panels generate electricity. Heat pumps consume electricity to produce heat. The two work together naturally:

• During the day, your solar panels power the heat pump directly, giving you free heating
• The heat pump’s electricity consumption is offset by solar generation
• In summer, when heating demand is low but solar generation is high, the surplus charges your battery or heats your hot water
• The heat pump replaces storage heaters entirely, giving you a more controllable, efficient heating system

Cost of Solar + Heat Pump

Component	Typical Cost
5kW solar panel system	£7,500-£10,500
Air source heat pump	£8,000-£14,000
Battery storage (10 kWh)	£5,000-£7,000
Total	£20,500-£31,500

This is a significant investment, but the savings are substantial for a home currently spending £1,500 to £2,500 per year on electric heating. Annual running costs for a solar-powered heat pump system can be as low as £300 to £600, meaning the combined system could save £1,000 to £2,000 per year compared to storage heaters.

For a full comparison of these two technologies, see our solar panels vs heat pumps guide.

The Practical Approach: Solar First, Heat Pump Later

Most homeowners cannot afford to install solar panels, a heat pump, and battery storage all at once. The most practical sequence is:

1. Year one: Install solar panels (£6,000-£10,000). Start saving immediately on daytime electricity.
2. Year two or three: Add battery storage (£3,500-£7,000). Increase self-consumption and offset evening usage.
3. Year four or five: Add a heat pump (£8,000-£14,000). Replace storage heaters with a more efficient system powered largely by your solar panels.

Each step delivers its own savings, and each step makes the next more cost-effective. By the time you install the heat pump, your solar panels and battery are already reducing your electricity costs, so the heat pump’s running costs are even lower.

Sizing a Solar System for Electric Heating

Homes with electric heating need a larger solar system than homes with gas or oil heating. This is simply because you consume more electricity, so there is more to offset.

Recommended System Sizes

Home Type	Heating System	Recommended Solar Size	Estimated Cost
2-bed apartment/terrace	Storage heaters	3-4 kW (8-10 panels)	£5,000-£8,000
3-bed semi-detached	Storage heaters	4-5 kW (10-14 panels)	£6,000-£10,500
4-bed detached	Storage heaters	5-6 kW (14-16 panels)	£7,500-£12,000
3-bed semi-detached	Heat pump	4-5 kW (10-14 panels)	£6,000-£10,500
4-bed detached	Heat pump	5-6 kW (14-16 panels)	£7,500-£12,000

These are general guidelines. Your installer will size the system based on your actual electricity consumption, roof space, orientation, and shading. If you are unsure what size you need, getting quotes from local NI installers is the best starting point, as they will assess your property and usage.

Why Bigger Is Often Better for Electric Heating

For homes with gas or oil heating, a solar system is typically sized to match daytime electricity usage (3-4 kW for most homes). Surplus generation beyond daytime needs has limited value without a battery.

For electrically heated homes, the calculus is different:

• Your total electricity consumption is much higher, so there is more to offset
• A larger system generates more surplus, which can charge a battery for evening and overnight use
• Solar diverters can absorb surplus by heating water, even when the battery is full
• The payback period for a larger system is often shorter for electrically heated homes because the savings per unit are higher (especially on Economy 7 peak rates)

The main constraint is usually roof space. A 6kW system requires roughly 24 to 30 square metres of south-facing roof, which is achievable on most detached and many semi-detached homes.

Cost Savings Calculations for Different Heating Types

Let us work through some realistic savings scenarios for different heating configurations in a typical three-bedroom NI home.

Scenario 1: Storage Heaters, No Solar

• Annual electricity consumption: 8,500 kWh
• Economy 7 split: 4,000 kWh off-peak at 13p, 4,500 kWh peak at 30p
• Annual electricity cost: £520 (off-peak) + £1,350 (peak) = £1,870

Scenario 2: Storage Heaters + 5kW Solar (No Battery)

• Solar generation: 4,250 kWh per year
• Self-consumption (40%): 1,700 kWh used directly during peak hours
• Remaining peak consumption: 2,800 kWh at 30p = £840
• Off-peak consumption unchanged: 4,000 kWh at 13p = £520
• Export income (2,550 kWh at 5p): £128
• Annual electricity cost: £840 + £520 - £128 = £1,232
• Annual saving: £638

Scenario 3: Storage Heaters + 5kW Solar + 10kWh Battery

• Solar generation: 4,250 kWh per year
• Self-consumption (75%): 3,190 kWh used directly or via battery
• Battery also charges overnight at off-peak rate for evening use
• Remaining peak consumption: 1,310 kWh at 30p = £393
• Off-peak consumption (reduced by battery strategy): 3,200 kWh at 13p = £416
• Export income (1,060 kWh at 5p): £53
• Annual electricity cost: £393 + £416 - £53 = £756
• Annual saving: £1,114

Scenario 4: Heat Pump + 5kW Solar + 10kWh Battery

• Annual electricity consumption: 5,500 kWh (heat pump is more efficient than storage heaters)
• Solar generation: 4,250 kWh per year
• Self-consumption (70%): 2,975 kWh
• Remaining grid consumption: 2,525 kWh at 26p (flat rate, no Economy 7 needed) = £657
• Export income (1,275 kWh at 5p): £64
• Annual electricity cost: £657 - £64 = £593
• Annual saving vs storage heaters: £1,277

These scenarios illustrate the progression from basic solar to a fully optimised system. Each step delivers meaningful savings, with the solar + battery + heat pump combination cutting annual heating and electricity costs by roughly two-thirds compared to the starting position.

Why NI Homes Benefit More Than GB Homes

Northern Ireland homeowners with electric heating are in a particularly strong position to benefit from solar panels, for several reasons:

Higher Electricity Prices

NI electricity prices have historically been higher than the GB average. In 2026, NI domestic electricity costs 24 to 28p per kWh on standard tariffs, and up to 30 to 32p per kWh on Economy 7 peak rates. This is 5 to 15% higher than typical English and Welsh rates. Higher electricity prices mean every unit of solar generation is worth more.

Greater Oil Dependence Creates an Opportunity

The 68% of NI homes on oil heating are increasingly exposed to volatile oil prices. Many of these homeowners are considering switching to electric heating (via heat pumps) as part of the UK’s decarbonisation drive. Solar panels make this transition much more affordable by reducing the electricity costs of running a heat pump.

Fewer Mains Gas Connections

Only about 25% of NI homes have mains gas. In GB, the figure is around 85%. This means NI homeowners have fewer cheap heating alternatives. Solar panels, combined with efficient electric heating, offer a path to lower and more predictable energy costs that does not rely on a gas grid connection.

Good Solar Resource

Despite the perception that NI is too cloudy for solar, the reality is that Northern Ireland receives enough solar irradiance for excellent returns. A 4kW system typically generates 3,400 to 3,800 kWh per year, which is ample for meaningful bill savings. The combination of decent solar resource and high electricity prices creates a strong economic case.

Practical Steps to Get Started

If you have electric heating and are considering solar panels, here is a practical roadmap:

1. Gather your electricity bills. You need to know your annual consumption and, if you are on Economy 7, the split between peak and off-peak usage. This data helps your installer size the system correctly.

2. Check your roof. South-facing is ideal, but east or west orientations still work well. You need approximately 20 to 30 square metres of unshaded roof space for a 4-6kW system. Our guide to solar panel costs in Northern Ireland covers pricing by system size.

3. Get multiple quotes. Compare quotes from MCS-certified NI installers to get competitive pricing. When requesting quotes, mention that you have electric heating, as this affects the system design and sizing.

4. Discuss battery storage and diverters. Ask each installer about adding a battery and/or solar diverter. Some installers include these as standard options; others offer them as add-ons.

5. Consider your long-term plan. If you plan to switch to a heat pump in the future, mention this to your installer. They can recommend a hybrid inverter that is “battery-ready” and “heat pump-ready,” saving you the cost of upgrading later.

6. Check grant eligibility. If you receive means-tested benefits or your property has a low EPC rating, you may qualify for funding through the Warm Homes Plan or ECO scheme. Check before committing to a purchase, as you could get a significant discount or even a free installation.

Summary

Solar panels and electric heating are a natural fit, particularly in Northern Ireland where electricity prices are high and many homes rely on electric or oil-based heating. The key points:

• Homes with electric heating consume more electricity and therefore save more per unit of solar generation
• Economy 7 customers benefit especially, as solar displaces the expensive daytime rate
• Battery storage bridges the gap between daytime solar generation and overnight heating demand
• Solar diverters offer a low-cost way to heat water with surplus solar electricity
• Smart storage heaters can charge during the day using solar, unlike traditional models
• The solar + heat pump combination is the long-term ideal, delivering the lowest running costs
• NI homes benefit more than GB homes due to higher electricity prices and less access to mains gas
• A larger system (5-6kW) is typically recommended for electrically heated homes

The transition from expensive electric heating to solar-supported heating does not need to happen all at once. Starting with solar panels, then adding a battery and eventually a heat pump, allows you to spread the investment over several years while benefiting from savings at each stage.