Air source heat pumps are fast becoming the heating system of choice for new builds, renovations and retrofits across the UK – MCS data shows retrofit heat pump installations rose 7% in 2025 alone, with air source units accounting for the vast majority of new installs.
So is underfloor heating a must if you’re one of the growing number of homeowners considering one? Not technically – ASHPs can be paired with radiators – but if you want the maximum long-term benefit from your heat pump, in efficiency, running costs and comfort, underfloor heating is very hard to beat as its partner.
At Cozia, we don’t install air source heat pumps ourselves, but we work alongside renewable heating installers on a huge number of projects where the two go hand in hand – and it’s easy to see why once you understand what a heat pump actually needs to run well.
It Comes Down to Temperature
Traditional radiators are designed to heat a room quickly by running hot, often 65-75°C. Heat pumps work best running much cooler, so pairing one with existing radiators nearly always means upsizing them to compensate, adding cost and disruption to a project that may not be welcome (not to mention an aesthetic that most homeowners wouldn’t appreciate!).
Underfloor heating sidesteps that problem entirely. Because it distributes heat across the entire floor area rather than through a handful of panels, it needs a much lower flow temperature (typically 30-45°C) to heat a room to the same comfortable level. That’s exactly the range in which heat pumps are designed to run most efficiently, which is why the two make such a natural pairing.
Better Efficiency, Lower Running Costs
To simplify a highly technical area, a heat pump’s efficiency is measured by its Coefficient of Performance (COP) – essentially, how many units of heat it produces for every unit of electricity it consumes. That COP isn’t fixed; it changes depending on the flow temperature that the system is asked to deliver.
Run a heat pump at a high flow temperature to satisfy radiators, and the COP drops, electricity use climbs, and much of the potential saving over gas is eaten away. Run the same heat pump at the lower flow temperatures that underfloor heating requires, and the COP improves significantly, often making a genuine difference to a household’s running costs over a year.
In other words, pairing an ASHP with underfloor heating isn’t just a comfort upgrade; it’s often the difference between a heat pump that performs as promised and one that quietly underdelivers.
A More Even, More Comfortable Heat
Beyond the numbers, there’s a comfort argument too. Underfloor heating warms a room from the ground up, distributing heat evenly across the whole floor area rather than in pockets around a radiator. Combined with a heat pump’s tendency to run for longer periods at a gentle, steady output – rather than the short, intense bursts typical of a gas boiler – the result is a more consistent, even temperature throughout the day, without the hot-then-cold swings that some households notice with radiator-based systems.
Getting the Design Right
None of this happens automatically. It comes down to correct design and installation of both the ASHP itself and the underfloor heating system. A few things we always consider when a project involves an ASHP:
Pipe centres and heat outputs – rooms with higher heat loss (large glazing, exposed walls) may need tighter pipe spacing to deliver enough output at a low flow temperature.
Screed depth and floor build-up – enough thermal mass to store and release heat evenly, without working against the heat pump’s steady, lower-temperature output.
Zoning and controls – rooms and zones set up to work with the heat pump’s own controls and weather compensation, rather than fighting against them.
Manifold design and settings – ensuring good flow rates and minimum run times so the heat pump isn’t cycling on and off inefficiently.
Get these details wrong, and even a well-specified heat pump can underperform. Get them right, and the two systems work together almost invisibly, quietly delivering an even, efficient heat throughout the home.
Working Alongside Your Renewable Installer
Because we don’t supply heat pumps ourselves, we’re able to work impartially alongside whichever ASHP installer a project is using, bringing our underfloor heating design expertise to make sure the two systems are specified to complement each other from the outset, rather than being designed in isolation and hoping they align.
For homeowners, that collaborative approach matters. A heat pump and an underfloor heating system designed together, by specialists in each, tend to perform far better and more efficiently than the same two systems bolted together as an afterthought.
If you’re planning a renovation, extension or new build around an air source heat pump, it’s worth bringing underfloor heating design into the conversation early.
Get in touch with our team on 01283 759085 to discuss your project or Request a Quote.
