Last year we replaced our (methane) gas boiler with an air-source heat pump. We’re a few months into the heating season, so time for an update on how it’s going.
Big Fan
First impressions are that it is fantastic. It keeps the house warm, even in sub-zero temperatures, and is cheaper to run than the gas heating. It was very cold at the start of the year, and while it had to work harder, it comfortably kept the house cosy. More data later in this post.
We have a Daikin Altherma heat pump installed by Octopus Energy (get a £100 Visa cash card if you get a heat pump or solar with this referral link).
It’s easy to use and has local controls/displays. There is also an app and a nice official developer API to integrate with Home Assistant etc.
I really like that the app/API is not the only way to control it. I try to limit time on my phone and don’t want to have to use it for a simple task only to be sucked into something else when noticing some notifications.
If we have guests (or babysitters) and they are too hot (or cold) then it’s good that they can adjust the set point and not need to freeze or open a window, wasting energy. Staying somewhere that you can’t control the heating isn’t very pleasant. It’s polite to let people be in control.
Super Ecosy
Most houses are different but our costs should give you a bit of an idea of what to expect.
Make Install
Our heat pump cost around £10k installed, before any government grants and bank cashback. Costs will vary based on the complexity so this is a rough guide. We had most (7) of our radiators swapped for new bigger ones and a new hot water tank installed.
There is lots of support to pay for a heat pump. Between the £7,500 grant and a couple of grand from your mortgage provider, most of the costs are covered. LLoyds even had a short offer last year for a free heat pump.
This often makes it cheaper than a new methane boiler and far cheaper than installing a wood-burner. Plus it’s actually eco-friendly and won’t wreak your health (unlike burning wood).
Cosy Runnings
Running costs are much lower than gas for us. We have solar PV panels and a home battery but the heat pump eats the battery for breakfast when it’s sub-zero outside.
In October 2025 we spent about £60 on electricity (including standing charge), in November this was about £105, roughly £110 in December and £150 in January 2026. This may look like a lot but this also includes all of our local motoring (within about 100 miles from home).
It’s difficult to compare year-on-year but in December and January a year earlier we would spend about £70 a month on electricity, so it is a significant increase. However, in December 2024 we spent about £100 on gas and £120 in January 2025 (including standing charge).
As we don’t pay anything for gas now (it’s removed so no standing charge) this represents a decent saving. We’re on an intelligent smart tariff, where the price varies by the time of usage, which makes a big difference. A good reason to get a smart meter.
If you are on a flat rate than it would probably be a similar running cost to gas. Electricity does need to get cheaper but it’s still cheaper than wood and doesn’t ruin the air quality (inside and outside your home).
Top of the SCOPs
Things are even more pronounced when you compare the energy rather than the cost. I get the energy values from the Daikin API using a Home Assistant integration or from the app. I also have a CT clamp on the heat pump tails feeding into Open Energy Monitor running on an emonPi (with voltage and hence accurate power sensing) also forwarded to Home Assistant.
In October 2025 the heat pump used about 170 kWh of electricity (110 kWh for space heating, the remainder for hot water), in November this was about 390 kWh (310 kWh heating), roughly 440 kWh (350 kWh heating) in December and 630 kWh (540 kWh heating) in January 2026. This appears high in isolation until you compare it to the gas.
In December 2024 we used about 1500 kWh of gas and around 1800 kWh in January 2025. This is roughly three times more energy for a similar amount of heating!
Using the total values for electricity and heat from the heat pump controller gives a SCOP of 3.3. This means that for every unit of electricity in we got 3.3 units of heat out. A gas boiler will give much less than 1.
This isn’t bad but is actually fairly low for a heat pump. It was very cold at the start of January and the heat pump had to work hard. The backup heater was used for about 6 hours according to the stats on the controller. The booster heater (hot water tank immersion) has been used for about 21 hours (around half an hour a week for the sterilisation cycle).
Some heat pumps get SCOPs of 4 or higher but ours runs overnight a lot when it is colder outside but energy is cheaper and greener. HeatpumpMonitor.org lists some of the best but we don’t have proper heat metering to accurately compare.
Cosiness Without the Mess
In summary, it’s clean cheap heating and the upfront costs are mostly paid for. What’s not to like?
You can run it on a timer or by remote control, there is nothing to clean or chop, and it doesn’t destroy the planet and your respiratory health. It’s a no-brainer.
You can still get that cosy stove vibe with a bio-ethanol burner or conversion, or even an electric fireplace. A conversion is very simple and then no more ash to clear out. You can even get smart voice-assistant activated versions!
Save the thousands you’d spend on a wood-burner and get solar PV panels to reduce your energy costs instead. Your children will thank you.
There is currently an open consultation on solid fuel burning - taking action to reduce fine particulate matter and smoke emissions. Lets hope for, and take, bold action to improve public health, reduce suffering and costs for the NHS, and protect the planet for our future.
Update
Mums For Lungs have some guidance on how to respond to the Defra wood burning consultation. It closes on Thursday the 19th of March 2026.
This BBC article shows how air pollution particles can be seen on red blood cells and the linked RCP report talks about solid fuel sources:
…in some urban areas this is currently going backwards due to the popularity of wood burners.
This smoke is smoke article shows that wood burning is the modern passive smoking:
Both wood smoke and cigarette smoke are the products of burning plant material, which is also sometimes referred to as biomass. Wood smoke has most of the same carcinogens, mutagens and teratogens (substances linked to birth defects) that are in tobacco smoke, but in much greater quantities. Virtually all of the adverse health effects that have been associated with secondhand cigarette smoke have also been linked with exposure to wood smoke.
Things are so much better and healthier since smoking was banned in public places a couple of decades ago. It used to be terrible.
Let’s not put up with the same thing on our streets and in our homes.