Heat Pump Service Cost UK 2026: Prices, What's Checked and Your Warranty

What a Heat Pump Service Costs

From each company's own website on 23 October 2026, except Mitsubishi's, which are as we read them on 11 October 2026 (its site wasn't reachable when we rechecked). Octopus's prices include VAT. British Gas says an air source service takes two to three hours. Ask your installer for their price too: they fitted the system, so they know it. A ground source service also covers the ground loop (see Kensa's checklist below).

For comparison, a repair visit without a plan isn't cheap: Mitsubishi charged £309 for an Ecodan engineer visit (diagnosis, plus a 12-month guarantee on the work), then £68 an hour for any further visits.

Does Your Warranty Need a Service?

If your warranty asks for it, yes, and in our view that matters more than anything else about servicing. Vaillant's guarantee and Kensa's longer warranties both ask for one every year. A missed service can void the warranty on a system that typically costs about £12,900 to fit (the DESNZ median for air source, before the grant; ground source costs more).

• Vaillant: the guarantee terms say the heat pump "should be serviced annually" by Vaillant or a suitably qualified engineer, and that if it isn't, the guarantee "will become invalid". You also have to register it within 30 days of installation, or the guarantee drops to 12 months. The standard aroTHERM plus guarantee is two years, extendable to seven through a Platinum or Renewable Partner installer.
• Mitsubishi Ecodan: the warranty length depends on who fitted it: up to 3 years from a standard installer, 5 from an accredited one and 7 from a Business Solutions Partner. Mitsubishi sells its service plans as the way to help maintain the warranty.
• Kensa (ground source): for pumps sold after 1 February 2026, one year out of the box, four years free if you register within 30 days of commissioning, or eight years on Kensa's extended warranty. Both of the longer warranties need an annual system check, done in the 60 days before it's due and sent to Kensa within 30 days.
• Octopus Cosy: eight years, and on Cosy Care Octopus monitors the pump remotely and says it doesn't need an annual visit to keep the warranty valid. That's unusual. The catch is that if its data spots a problem and you keep ignoring or cancelling the visit it books, Octopus says the warranty could be voided.

Whatever you've got, find the warranty certificate now and check two things: whether it's registered, and what it says about servicing. Your installer should have registered it for you, but "should have" is doing a lot of work in that sentence.

What Gets Checked

Air source

British Gas lists its service as: checking the heat pump and controls are safe, checking for corrosion and leaks, cleaning the system filter and other parts where needed, checking radiators and visible pipework for leaks, and leaving you a safety checklist. If you're booking someone else, ask what their service covers and compare it with that list.

One thing to ask about: glycol. Some systems use antifreeze in the water to protect the outdoor unit. British Gas will service glycol systems but won't include them in its repair cover, because glycol needs regular checks.

Ground source

Kensa's technical team says well-designed ground source systems need very little maintenance, but recommends checking:

• the pressure of the ground and heating circuits (Kensa recommends above 2 bar)
• the gas charge in the expansion vessel
• antifreeze concentration and condition in the ground loop
• inhibitor levels in the heating water, for corrosion
• filters, valves, actuators, thermostats and programmers

What You Can Do Yourself

None of this replaces a service, but it can catch problems early:

1. Keep the outdoor unit clear. Leaves, snow, overgrown plants and bins pushed up against it all choke the airflow. Clear the grille and the area around it, and never cover it.
2. Glance at the pressure gauge once a month, if your system has one. If it keeps dropping, tell your installer rather than topping up blindly.
3. Check the pipe lagging outside. If the insulation on the pipes between the unit and the house is cracked or missing, get it replaced: those pipes carry the heating water outdoors. Our pipe insulation guide has UV-resistant options.
4. Bleed the radiators if the tops are cold (see how to bleed a radiator).
5. Don't panic about steam or ice in winter. An air source unit defrosts itself, which can look alarming. Ice that builds up and doesn't clear for hours is worth a call.

Signs It Needs Looking At

• Running costs rising with no change in the weather or your settings (compare month by month in the app, if it has one)
• Radiators or underfloor heating not reaching temperature
• New noises from the outdoor unit: rattling, grinding or a much louder fan
• An error code on the controller, or the backup immersion heater running a lot
• Water dripping inside, or the pressure dropping week after week

If the bills are creeping up, check the settings before assuming a fault. Our heat pump running costs guide covers flow temperature, weather compensation and the tariffs that make the biggest difference.

Is a Service Plan Worth It?

We'd treat a plan as insurance. It pays off in the year something breaks out of warranty, or if you'd rather never think about it, so it comes down to how you feel about a repair bill that started at £309 for a single Mitsubishi visit when we checked.

For Vaillant, a one-off service each year keeps the guarantee valid for £189 a year with British Gas, less than British Gas's service-and-repairs cover. Mitsubishi sells its plans as the way to help maintain its warranty (its service-only plan is £237 a year), and Kensa wants its own annual system check, so check those certificates.

The strongest case for a plan is once the manufacturer's warranty runs out. Inside the warranty, the manufacturer should be fixing faults anyway (check whether yours covers labour as well as parts), so you're mainly paying for the service you'd need regardless.

What You Don't Need

• A Gas Safe engineer. There's no gas. You need someone qualified on heat pumps, ideally your installer or the manufacturer's own service team.
• More than one service a year. Once a year is what the warranties ask for.
• Chemical "efficiency boosters". If the inhibitor needs topping up, the engineer will do it with the right product during the service.

Still choosing a heat pump? The service terms are worth comparing alongside the price: see the best heat pumps in the UK and how to compare heat pump quotes.