Why the radiators that were fine on a boiler leave the house cold — and whether the pipe can carry it at all
Two things decide whether a heat pump retrofit works, and a calculator gives you neither. The radiators: a 1000 W panel gives about 350 W at heat-pump temperatures, so the pack has the correction at six real system temperatures and the badge figure you must actually buy. The pipework: a heat pump moves four times a boiler's water for the same heat, so the pack works out whether what is already in your floor carries it, what it does to the pump head, and what it costs when it does not. 10 pages, printable, with a fill-in room-by-room schedule to hold a quote against.
What’s inside
Radiator output correction for six real system temperatures
Why a 1000 W radiator gives about 350 W on a heat pump
The radiator you must BUY for a given room load, at every flow temperature
The same room on a boiler and on a heat pump, side by side
Whether your existing pipework carries a heat pump — by load and flow temperature
Why a modern condensing boiler is KINDER to pipework than the old one it replaced
The 22 mm primary that runs at 1.49 m/s on a 10 kW heat pump, against a limit of 1.5
Microbore tails: fine on a boiler, hopeless on a heat pump, and buried in your floor
The pump head the circuit demands, to hold a heat pump's own curve against
Five ways to fix a short room, cheapest and least disruptive first
The honest fallback nobody sells you: raise the flow temperature
Fabric measures that come before sizing anything, and which are poor value
Seven sizing rules, including why a boiler's size tells you nothing
Where heating work stops being a homeowner's job — and what is yours
The question that tells you whether an installer has actually sized the job
The order of work, and three things to settle before getting quotes
Fill-in room-by-room radiator schedule
Plus a second PDF, worked out for you
Run one of the free calculators first and buy from that page, and this sheet is computed from your own figures. Buy from here and the pack still arrives complete — the sheet simply has no numbers of yours to work from yet.
14-day refund, no questions asked. If the pack is not what you needed, email support@graburl.com and we refund you in full — you do not have to justify it or delete the file. Full policy.
$19.00 including any taxes · PDF, 10 pages · instant download, link valid 7 days and 5 downloads. Sold by GrabURL. The charge appears on your statement as GrabURL. Refund policy · Terms of sale · support@graburl.com
