The quiet, even comfort renovators wish they'd specified five years earlier.

Wet UFH circulates warm water (typically 35–45°C) through pipes laid in screed or a low-profile panel. Slower to respond, dramatically cheaper to run, and compatible with any heat source; gas, heat pump, district heating. This is the system for whole-house and main living areas.

Electric UFH is a thin mat of resistance wire under tile or stone. Fast to respond, expensive per kWh to run, perfect for bathrooms and ensuites where you want warm tiles in the morning and not much more. Whole-house electric UFH is almost always a regret purchase.

Retrofit UFH is sensible when you're doing one of three things: a full kitchen/extension build, a ground-floor renovation that's pulling up the existing floor anyway, or a screed-replacement project. Add it in those moments and the marginal cost is a few thousand pounds rather than ten.

It is not sensible when the only reason to do it is the UFH itself. The cost of removing existing floors, lowering or raising thresholds, moving services, and re-laying everything will dwarf the comfort benefit. In those cases, larger radiators paired with a low-flow-temperature system get you 80% of the comfort at 20% of the cost.

The exception is overlay systems; low-profile panels 15–22mm thick that sit on the existing floor. Done well, they unlock retrofit without floor excavation. Done badly, they sound hollow and lose half their output to the floor below.

Heat pumps lose efficiency every degree they have to heat the water above ambient. At 35°C flow temperature a heat pump is genuinely 4x more efficient than direct electric. At 55°C; the temperature traditional radiators were sized for; it's closer to 2.5x. The difference is hundreds of pounds a year.

UFH runs natively at 35–45°C because it spreads heat across the entire floor area instead of a small radiator panel. That's why every Passivhaus and every premium new-build specifies it; not for the comfort, but for the system efficiency it unlocks.

Radiator-based heat pump installs are entirely possible and increasingly common, but they require radiators 2–3x larger than the gas-boiler ones they replace. Worth knowing before you commit either way.

Each UFH loop in your home needs its own actuator on the manifold and its own thermostat in the room it serves. Skip the per-room thermostats and the whole system runs to the warmest zone; meaning the spare room is 22°C while you're in the kitchen.

Good manifolds (Uponor, Polypipe, Roth) are visibly engineered, with flow meters per circuit you can read at a glance. Cheap manifolds save £400 on a £6,000 install and cost you 10% efficiency for the life of the system. Specify upwards.