The radiator on your wall was sized for hot boiler water; a heat pump asks it to do the same job with gentler heat for longer. Some radiators shrug and serve; some genuinely cannot. Knowing which is which, room by room, is the emitter audit, and it is the compatibility check's beating heart.
Home Comfort Assured Renewables audits emitters across Watford homes as part of every compatibility check, and this is how the verdicts are reached.
Why flow temperature changes everything
A radiator's output falls as its water cools: the same panel that dominated a room at boiler temperatures delivers a fraction of that heat at heat pump flow. The physics is unavoidable; the response is design, larger surfaces, better emitters, or lower room losses, chosen per room.
That is why no honest answer exists at house level: 'will my radiators work' decomposes into every room's demand against every radiator's output at the new temperature. The audit does exactly that arithmetic.
- Cooler water means less output per panel.
- The response is sizing, not hope.
- Room-level arithmetic, not house-level slogans.
How the audit walks the house
Each room gets measured for its heat demand, dimensions, glazing, external walls, and its emitters logged for type and size: the first-fix copper and fresh panel in the photograph is the kind of detail recorded. Output at heat pump temperatures is then compared with the room's need.
The result is a per-room verdict list: serves as-is, serves with a modest upsize, or wants rethinking. Most houses return a mixed list, and the mix is the plan.
- Demand measured per room, not guessed.
- Every emitter logged for type and size.
- Output at new temperatures versus need.
Keep, upsize, change: what each verdict means
Keep is common: rooms with generous radiators or modest losses pass untouched. Upsize is routine: a deeper or taller panel in the same position, often done opportunistically during decoration. Change covers the genuinely undersized spots, where doubled panels, modern high-output emitters or underfloor circuits earn their place.
Underfloor deserves its own note: where it exists or can be added, its huge surface loves low temperatures, and rooms with it usually anchor the conversion. Home Comfort Assured Renewables sequences these verdicts into a sensible order so upgrades ride along with ordinary household works.
The audit as a planning tool
The finished audit is a document a household can act on gradually: which rooms are ready today, which upgrades to fold into upcoming refits, and what remains for conversion week itself. It converts a vague worry into a shopping list with sequence.
It also keeps quotes honest: an installation priced against an audited emitter list contains no radiator surprises, because the surprises were retired at survey. That is compatibility checking doing its actual job, making the later steps boring.
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Questions customers ask
Will all my radiators need replacing for a heat pump?
Almost never all: the audit typically returns a mix of keep, modest upsize and a few changes. The exact list is the point of checking room by room.
What makes a radiator suitable for heat pump temperatures?
Enough emitting surface for the room's demand at lower flow: bigger panels, doubles and modern high-output designs all achieve it. Suitability is arithmetic, not brand.
Is underfloor heating better with a heat pump?
Its large surface suits low temperatures superbly, so where it exists it anchors the system. It is an advantage, not a requirement: audited radiators serve most rooms well.
Room by room, output versus need, verdicts you can act on in any order: the emitter audit turns the radiator question from anxiety into a list.
Home Comfort Assured Renewables runs it across Watford as part of every compatibility check. The contact page books yours.
