Wondering whether a heat pump could be right for you? In June 2025 Severn Wye energy assessor Neil Towler replaced his gas combi boiler with a Daikin heat pump, to provide heat and hot water for his family. This Net Zero Week 2025, 5-11 July, Neil reflects on his experience and gives some valuable tips on things to bear in mind.
First impressions
All good so far!
The system is very easy to set up and control using the app (and yes, I am geekily spending far too long optimising programming for the hot water), though as there is no need for space heating in July it’ll be a while before we’ll know if the pump is keeping us as warm as we’re used to over the winter. It will also take me a while to confirm and compare the running costs with the gas boiler.
Overall though, so far it feels like it’s been the right decision to get an air source heat pump. But where did the journey begin?
Should it stay or should it go?
Barely a day goes by when I’m not talking about the virtue of heat pumps to my clients, and I’d been pondering for a while whether one would be a good solution for my home.
Our gas combi boiler was about ten years old but we’d had it serviced regularly and it was running fine in our Victorian semi-detached house. It could continue to do so for another five years – but perhaps just another couple of years – who knows?
A new gas combi would probably cost just a little less than the online quotes I’d had for a heat pump solution, but as the heat pump installation costs included new radiators and new digital controls it seemed like a better deal. And I didn’t want to risk waiting for the gas boiler to break down mid-winter to decide.
At time of writing the UK government is offering a grant scheme towards the replacement of fossil-fuel based heating systems – the Boiler Upgrade Scheme. This meant I’d be eligible for £7,500 towards a heat pump – a huge incentive.
Under the circumstances, I decided it made sense for us to push on now.
After comparing several online quotes and heating solutions I decided to go with my current supplier, who quoted £2,700 after the incentive.
Pros and cons
It’s worth saying here that running a heat pump is more efficient than other electric heating systems but while electricity prices in the UK remain high, it may not come in cheaper than a gas boiler system. In the long term though, as more renewable energy sources are connected to the grid, electricity prices should come down. What’s true right now though is that a heat pump future proofs your heating system, and if you can combine it with solar PV – maybe even batteries – you’ll have your own energy supply for part of the year so at these times it will be free to run.
Most homes should be suitable for a heat pump, particularly if they’re well-insulated. Heat pumps can be trickier to specify currently in smaller properties and flats which might struggle to accommodate a water cylinder and bigger radiators, or in larger, older homes with high heat demands. In the latter case, improvements to the fabric of the building to prevent excess heat might be recommended first.
In our house, the main issues were to check there was room outside for the main heat pump unit and inside for the water cylinder (which we hadn’t needed with our combi boiler). In our case, it made sense to put the cylinder in the space the combi boiler would vacate (below).
An installation assessor first came out to survey the house, highlight any potential issues, and check a heat pump was a good solution for us. Everything came back OK, but there were a few things we needed to attend to.
The first was to update our old EPC – energy performance certificate. I did this myself, but it’s an inexpensive process available through many suppliers – see our Home Energy Surveys page for more info.
The second was to arrange an asbestos check for a bedroom wall that had been highlighted as a risk in our site survey and had to be signed off by a specialist. Happily, our installers agreed to cover this cost but it’s worth budgeting for the unexpected.
Location, location …
We had an ideal space for the external pump unit at the back of the house (right), tucked away but open enough to get good air flow. Incidentally the legal requirement for heat pumps to be at least one metre from a neighbour’s boundary have recently been dropped by the government to promote uptake. The restriction was to do with potential noise which could have been an issue with some earlier pumps. (I can report that my heat pump is quieter than our old gas boiler.)
Boxes ticked
I had to remove some of the concrete here and gravel the space to allow for drainage of the condensation produced by the pump. This would have been an extra cost, but I did it myself using a friend’s pneumatic drill.
When it came to the pipework needed for the new hall radiator caused, there had been a suggestion that the installers would cover this cost and I was perhaps over-optimistic in assuming this would be the case. But in the event I had to get it done myself – something I hadn’t budgeted for.
The installation
The whole process took nearly a week, starting on Monday morning and all done by lunchtime on Friday.
The first day mainly involved preparation of the area for the external unit, removing the current radiators, and adding some of the electrics. The gas boiler was removed on the Tuesday when the gas was disconnected, and once that was out the water cylinder could go in. This stage did mean a night without hot water which we knew about.
Once the new radiators went in and everything was connected, with new controls fitted, the system was tested and all the rubbish cleared away. The lead engineer spent some time with me going through the controls and use of the app to programme the heating and hot water and monitor how much energy the system is using.
Tips for your own heat pump installation
Overall the installation went well, but there were a few things I would advice people to look out for based on our experience.
I knew the new radiators would be a bit bigger than our old ones, but the replacement in our dining room turned out to be a vertical radiator 1.6m high. This meant moving a picture – not a huge deal perhaps but the new rad isn’t the most aesthetically pleasing replacement.
TIP: Check the specification of any replacement radiators with your installers and if necessary ask if you have the option to specify (for a bit more money) exactly what you want.
The slight differences in dimensions and locations of some of the other new radiators have also revealed undecorated areas which I’ll have to see to!
Another thing I hadn’t fully considered was the need for new electrical components. There simply wasn’t room for the additions in the small electrical services void in our kitchen so the new consumer unit for the pump is a visually intrusive black box which we’ll need to get boxed in.
TIP: Ask your installer to highlighted ‘extra’ considerations like electrics (right) and give you some options for location of new boxes and connections.
The water cylinder has taken a bit more room in our small utility than I had expected, mainly because a small volumiser was added to make the system a bit more efficient.
TIP: Check the system design in detail and make sure you’re happy with the impact the technology will have on your available space.
How’s it going so far?
Well, great! The system is easy to use and the pump is quieter than our old gas boiler so no issues there.
Once we need to ramp up the heat in the colder months we’ll have a fuller picture of how it’s going. Heat pumps work differently from conventional boilers, providing a steady supply of heat to keep living spaces at a comfortable temperature, rather than sudden bursts of energy that heat up a cold house quickly to higher temperatures. It’s a much more efficient way of heating a home, but it will be something else to get used to.
Meanwhile I’m weighing up the benefits of different electricity tariffs – some suppliers offer deals specifically for heat pump users that have several periods during the day of cheap electricity with higher peak rates. The benefits of this will depend on your lifestyle. For example, Octopus’s ‘Cosy Octopus’ tariff currently offers three periods during the day of cheap electricity which would be ideal for heating the water cylinder. But peak rate is 41.88p per kWh – a big difference, and it runs from 4pm to 7pm – just when my boys get home, power up devices and all want dinner. So, for us, shifting our patterns of demand right now is difficult – but I’ll be monitoring our use over the next few months to figure out whether we can make a heat pump tariff cost effective.
And finally
When funds allow, I’m considering solar panels on the roof and batteries (with or without solar) so we can benefit from periods of free clean energy to mitigate our increased electricity demand.
This musing, monitoring and learning is a big part of what I do as an energy adviser and I can now use personal experience to help advise people in future. Because there is little doubt that most of us will have heat pumps in the next five to ten years, and it’s important people are confident they can ditch gas boilers, cut carbon, and still enjoy warm, comfortable homes that are affordable to heat.
Want to know more?
You can learn more about how heat pumps work (and many other aspects of energy efficiency) on the Resources page of our website.
If you’d like to find out whether a heat pump would be a good solution for you, you can find out about our services and use the contact form on our Home Energy Services pages.
Neil Towler has been an energy efficiency expert with Severn Wye for 16 years. He and his family live in an extended Victorian semi in Stroud, Gloucestershire.
