Can solar panels heat my hot water on the Isle of Man?
The short answer
Yes, in two ways. Spare electricity from solar panels can run an immersion heater, or solar thermal panels can heat water directly.
A hardwired solar system can send electricity it would otherwise export for 9.7p a unit to your hot water instead. Homes heated only by electricity can also use Manx Utilities’ Comfy Heat tariff, with 8 cheaper hours a day.
Heating and hot water are where most homes use the most energy, so it is worth knowing how they fit with solar. This guide covers using solar electricity for hot water, solar water heating panels, Manx Utilities’ tariff for electric heating, and the rules for the electrical work.
Using spare solar electricity for hot water
On a sunny day a solar system often makes more electricity than the home is using. A hardwired system sends that surplus to the grid, and Manx Utilities pays 9.7p a unit for it under the Sustainable Generation tariff. A device usually called a solar diverter can send that surplus to an electric immersion heater in your hot water cylinder instead, so the water is heated with your own electricity.
Whether that is worth more than exporting depends on how you would otherwise heat the water. If you would heat it with electricity at Manx Utilities’ standard 29.5p a unit, each unit diverted saves more than the 9.7p it would have earned. If your water is heated by gas, oil or cheaper off-peak electricity, the gain is smaller. A diverter is a hardwired electrical installation, so it needs a Part P registered electrician, and ask Manx Utilities whether it changes anything about your connection.
Solar water heating panels
Solar thermal panels heat water directly rather than making electricity. For planning, the island treats them like solar electric panels: Class 42 of the Permitted Development Order 2025 covers solar photovoltaic or solar thermal equipment on a roof, with the same conditions. They must sit within 200mm of the roof slope, stay below the highest part of the roof, and not be on a horizontal roof. A conservation area or a registered building needs a planning application. Our planning guide covers the details.
Solar thermal panels do not generate electricity, so the Sustainable Generation export tariff does not apply to them.
Planning from the Town and Country Planning (Permitted Development) Order 2025, SD No. 2025/0027, Class 42, read in full on 28 September 2026. Tariff rates from Manx Utilities’ domestic tariffs page.
The Comfy Heat tariff for electric heating
Manx Utilities’ Comfy Heat tariff is a two-rate tariff for homes that use electric heating and electric water heating. It gives 8 hours of cheaper electricity every day, from midnight to 6am and 2pm to 4pm (1am to 7am and 3pm to 5pm in British Summer Time). The peak rate is 29.5p a unit with a 25.5p daily standing charge.
It is only for homes whose sole source of heating and hot water is electricity. Manx Utilities lists gas heating, oil heating and a hybrid heat pump system as making a home ineligible. There is a minimum charge to switch tariff. Ask Manx Utilities whether your home qualifies.
From Manx Utilities’ domestic tariffs page, read on 16 October 2026.
The rules for the electrical work
Planning and Building Control lists electric ceiling or floor heating, power or control wiring for a new central heating system, and new circuits for heating or a shower as notifiable work under Part P of the Building Regulations. Use a business registered with NICEIC Domestic Installer or NAPIT Part P CPS, which can certify the work, or get Building Control’s approval before work starts. Our guide to choosing an installer explains how to check.
From Planning and Building Control’s page on electrical installations in homes, read on 16 October 2026.
Help with the cost
The Heat Wise Home scheme, approved by Tynwald on 23 July 2026 and not yet open when we checked, lists hot water tank jackets, pipe insulation, smart heating controls and radiator valves among the smaller measures it supports, alongside heat pumps and insulation. It does not cover solar. See our guides to heat pump grants and solar grants.
Common questions
What is a solar diverter?
A device that sends spare electricity from your solar panels to an immersion heater in your hot water cylinder, instead of exporting it to the grid. It is a hardwired installation, so it needs a Part P registered electrician.
Do I need planning permission for solar water heating panels?
Usually not on a pitched roof. Class 42 of the Permitted Development Order 2025 covers solar thermal equipment on the same terms as solar electric panels. A flat roof, a conservation area or a registered building needs an application.
What is the Comfy Heat tariff?
Manx Utilities’ two-rate tariff for homes heated only by electricity, with 8 cheaper hours a day. Gas, oil and hybrid heat pump systems make a home ineligible.