Know what you are working with
Most older terraces around Bridgend, the Valleys and the coast share the same DNA: solid walls with no cavity, a slate roof, a back kitchen extension, and a heating system that has been modernised in layers over decades. Wales has the oldest housing stock in the UK, with over a quarter of homes built before 1919, so if this is your house, you are in the majority, not the exception.
That construction is the single biggest factor in this decision. A heat pump runs at low flow temperatures and rewards a house that holds its heat. A solid-wall terrace with original windows and an uninsulated loft loses heat quickly, which is precisely the condition a heat pump finds hardest and a gas boiler shrugs off.
The four questions that decide it
One: how insulated is the house, really? An insulated loft, decent windows and draughtproofing move you toward heat pump territory. Bare solid walls and single glazing move you away, or at least put insulation ahead of any heating decision.
Two: what size are your radiators and pipes? Low-temperature heating needs more radiator surface area. Many terraces also have narrow microbore pipework from older refits, which often needs replacing for a heat pump system to flow properly. Bigger radiators plus new pipework is a real, disruptive job in a small house.
Three: where would everything go? A heat pump needs an outdoor unit, usually a hot water cylinder too. In a mid-terrace with a small yard and no airing cupboard left, finding that space honestly matters. A combi boiler needs a kitchen cupboard.
Four: what is your budget and appetite for disruption? The £7,500 Boiler Upgrade Scheme grant is real and helps a lot with the heat pump itself, but it does not pay for insulation, radiators or pipework. A straight boiler swap is typically a one-day job. A full terrace retrofit is a project.
The honest answer for most terraces today
If your terrace is already well insulated, you have space for the kit, and you are ready for the upheaval, a heat pump from a good MCS installer is a genuine option and Lloyd will tell you so. For the larger group of terraces that are not there yet, the sensible sequence is the boring one: replace a failing boiler with an efficient A-rated combi from £1,900 fitted, insulate in cheap-first order while it runs, and make the heat pump decision properly at the next boiler change, when your house and the market will both be more ready.
For the full reasoning on costs, grants and running costs, read the longer piece: Heat pumps in South Wales, an honest take.
