First, the honest disclosure
LMB is a domestic gas business. Lloyd is Gas Safe registered, City & Guilds qualified and a Baxi Approved Installer. He does not fit heat pumps, and if your home genuinely suits one he will tell you so and point you toward an MCS certified heat pump installer, because that is who is allowed to claim the government grant on your behalf. What follows is professional opinion from someone who stands in South Wales boiler cupboards every working day, not a sales pitch in either direction.
The technology is good. The housing stock is the problem.
A modern air source heat pump is a genuinely impressive machine, and in the right house it works beautifully. The catch is in the words "the right house".
Wales has the oldest housing stock in the UK, with over a quarter of homes built before 1919, according to the Welsh Housing Conditions Survey. Around here that means street after street of solid-wall stone and brick terraces, built for coal fires, with no cavity to insulate. Plenty of them were retrofitted decades ago with narrow microbore pipework and radiators sized for a boiler running hot.
That matters because a heat pump heats differently. A gas boiler can push water out at 70 degrees and brute-force a draughty house warm. A heat pump runs at much lower flow temperatures, and it earns its efficiency by running low and slow. In a well-insulated home that is perfect. In a leaky pre-1919 terrace with original single-skin walls, the heat escapes faster than a low-temperature system can comfortably replace it. The usual fix is insulation first, then larger radiators, and often replacement of the old narrow pipework. None of that is impossible. All of it is disruption and cost on top of the heat pump itself.
The grant is real. So is the gap.
The Boiler Upgrade Scheme gives £7,500 toward an air source or ground source heat pump in England and Wales, and it runs until April 2028. That is a serious amount of government money and nobody should sneer at it. The application is made for you by an MCS certified installer, so you never handle the paperwork.
But the grant covers the heat pump installation, not the house. For a home that needs insulation, bigger radiators and new pipework before a heat pump can do its job, the total project cost is usually well beyond what the grant covers, and quotes vary a lot between installers and between houses. Anyone who tells you a single national average figure for your terrace is guessing.
Running costs deserve the same honesty. Electricity costs several times more per unit than gas in the UK, so a heat pump only undercuts a gas boiler on running cost when its efficiency advantage outruns that price gap. In a well-insulated house running at low temperatures, it can. In a poorly insulated house where the heat pump has to work flat out, the promised savings can shrink to very little. The house decides, not the brochure.
When a heat pump IS the right call
Fair is fair, so here is the other side. A heat pump is a strong choice if your home is a well-insulated newer build with decent radiators or underfloor heating. It is often the obvious choice if you are off the gas grid and heating with oil or LPG, where the running cost comparison swings hard in the heat pump’s favour, and the government has even announced a temporarily larger grant for eligible off-grid homes from late July 2026. And if you are doing a full whole-house renovation anyway, with walls open and floors up, that is exactly the moment to design the house around low-temperature heating.
If that describes your home, Lloyd will say so to your face, even though it means no work for him. Ask the customers in his reviews how he handles advice.
What to do meanwhile
For most owners of older South Wales homes the practical sequence looks like this. First, if your boiler is old and inefficient, replacing it with a modern A-rated combi cuts gas use immediately, and LMB fits them from £1,900. Second, insulate in the cheap-first order: loft, then draughtproofing, then whatever your walls allow. Every pound spent there helps the current boiler now and makes the house more heat-pump-ready later. Third, reassess in a few years. Electricity pricing, heat pump costs and the grant landscape are all moving, and a decision that is marginal today may be obvious by the time your next boiler reaches the end of its life.
That is not anti heat pump. It is pro doing things in the right order.
