Will My Existing Heat Pump Cope?
Adding a substantial extension increases your home’s heat demand. Whether your existing heat pump can handle the additional load depends on: the current heat pump’s capacity vs. original design heat demand, the extension’s heat loss (insulation quality and size), and the heating emitter chosen for the new space.
New Heat Loss Survey
Before extending, commission an updated heat loss survey that includes the extension. This determines whether your existing heat pump has spare capacity or needs upgrading.
Underfloor Heating in Extensions
Single storey extensions almost always have newly poured concrete floor slabs — the ideal substrate for underfloor heating. Installing UFH in the extension while keeping radiators elsewhere is straightforward with a mixing valve and manifold.
Pipework Planning
Plan the heating pipework route before the extension walls are built. Burying pipework in the floor slab is neater than surface-running pipes. Consult your heat pump engineer before construction begins.
Sources: Planning Portal and MCS standards.
