Underfloor Heating in London Properties: Wet vs Electric, Costs and Whether It Is Worth It
A practical look at wet and electric underfloor heating for London homes, including installation costs, running costs by system type, and which property types benefit most.
The Two Types of Underfloor Heating
Underfloor heating (UFH) divides into two fundamentally different systems: wet (hydronic) and electric. Wet systems circulate warm water through pipes embedded in or laid on top of the floor structure. Electric systems use resistive heating cables or mats beneath the floor covering. The right choice depends heavily on the London property type, existing heat source, and how the system will be used.
Wet Underfloor Heating
Wet UFH connects to your boiler or heat pump and distributes heat via a manifold to multiple zones. It operates at lower flow temperatures than radiators — typically 35 to 45 degrees Celsius — making it exceptionally well-matched to heat pumps, which also operate most efficiently at lower flow temperatures. For London properties moving toward a heat pump, installing wet UFH alongside it makes strong engineering sense.
The installation challenge in London is floor construction. New builds and ground-floor extensions with beam-and-block or concrete slab floors are ideal: pipes are embedded in a screed overlay. Retrofitting wet UFH into existing suspended timber floors — common in Victorian and Edwardian London terraces — requires either lifting the floorboards to install between joists from below (a disruptive but effective approach) or using low-profile overlay systems that raise the finished floor level by 15 to 22mm.
Wet UFH costs for a 50 square metre ground floor typically range from £4,000 to £7,000 installed, excluding boiler or heat pump work.
Electric Underfloor Heating
Electric systems are far simpler to install, particularly in bathrooms and kitchens where they are most commonly used in London properties. A heating mat rolls out beneath tiles, connects to a thermostat, and is ready for use within a day. No manifold, no pipework, no hydraulic balancing.
The trade-off is running cost. Electricity costs approximately four times more per kilowatt-hour than gas (and more than a heat pump operating at its rated efficiency). Electric UFH in a bathroom used for warmth on cold mornings is affordable; electric UFH as the primary heat source for an open-plan living area is expensive to run.
For a standard bathroom installation, electric mat systems cost £500 to £1,200 installed.
Running Costs in London
With electricity at current rates, a 150-watt-per-square-metre electric mat in a 6 square metre bathroom running for two hours each morning costs roughly 25 to 35 pence per day. Wet UFH running from a modern condensing boiler in a well-insulated property is more efficient per unit area but involves higher installation cost and maintenance.
Heat pump-driven wet UFH can achieve a coefficient of performance (COP) of 3.0 or higher, meaning each unit of electrical energy delivers three or more units of heat, significantly reducing running costs over a standard boiler.
Which London Properties Benefit Most
Ground-floor extensions on period London properties are the clearest win — a new concrete slab accommodates wet UFH during construction at modest incremental cost. Basement conversions similarly offer the ideal substrate. Top-floor flats and upper floors of Victorian terraces are harder cases: heat loss upward into the floor above is wasteful, and floor height constraints can rule out practical overlay systems.
Properties with excellent insulation (cavity wall fill, loft insulation, double glazing) extract the most benefit from UFH because the system can run at lower temperatures consistently rather than cycling to compensate for heat loss.