Radiant Heating near you

Paragraph 5.10 of Approved Document L Volume 1 applies where a wet heating system is either newly installed or fully replaced in an existing building, including the heating appliance, emitters and associated pipework. In those cases all parts of the system, including pipework and emitters, should be sized to allow the space heating system to operate effectively and in a manner that meets the heating needs of the dwelling at a maximum flow temperature of 55°C or lower.

The escape clause is written into the same paragraph and it is often misquoted. Where it is not feasible to install a system that can operate at that temperature — the examples given are insufficient space for larger radiators, or an existing distribution system supplied with higher temperature heat from a low carbon district heat network — the system should be designed to the lowest design temperature possible that will still meet the heating needs of the dwelling. That is not permission to default to 75°C; it is an instruction to get as low as the house allows and to be able to say why.

A note to the same section points readers at the Building Research Establishment's FB 59, Design of Low-temperature Domestic Heating Systems, and confirms the low temperature requirement applies to space heating only, not to domestic hot water. This is England's guidance; Scotland handles the equivalent ground through section 6 of its technical handbooks under the building warrant system, and Northern Ireland through its own technical booklets, so confirm the position where you live.

The honest comparison is not radiant against convective, because a panel radiator does both. It is a question of surface area and temperature. A large surface at a low temperature gives steady comfort, works well with weather compensation and suits a heat pump, but responds slowly and takes up either wall, floor or ceiling. A small surface at a high temperature responds quickly, suits intermittent occupancy and a gas boiler, and is cheap to install, but it is exactly what Approved Document L is steering new and fully replaced systems away from.

Room use decides more than people expect. A living room occupied all evening rewards a slow, even radiant surface. A spare bedroom used twice a month does not, and a large heated floor there is an expensive way to warm an empty room. A bathroom wants fast heat for half an hour twice a day, which is why electric underfloor heating survives there despite electricity being the expensive fuel.

The building fabric sets the ceiling on all of it. A draughty, poorly insulated room has a high heat loss, and a low-temperature emitter large enough to meet it may simply not fit. That is the point at which insulation and draught-proofing do more for comfort than any change of emitter, and a good designer will say so before quoting for more surface area.

Emitters are rarely the expensive part. What moves a quotation is how much pipework has to change to feed a larger emitter, whether floors have to come up, how many rooms are being converted at once, whether the heat source itself is being replaced in the same visit, whether a proper room-by-room heat loss calculation is included, and how much making good, decorating and joinery follows. A design that reuses the existing distribution pipework is a different job from one that reruns it.

LokalMatch exists to make the introduction and nothing more. Set out the job once with your postcode — which rooms, what heat source you have or plan, and whether floors can be lifted — and heating firms covering your area come back to you. There is no charge to homeowners; pros pay for the requests they receive. LokalMatch does not carry out work, does not set prices and does not vet, rank or recommend anyone who replies, so comparing what each quotation includes by way of heat loss calculation and commissioning is worth your time.