The heat pump world is full of half-truths — some honest confusion, some from people trying to sell you more than you need. Here's what's actually true, so you can walk into any quote knowing more than the person quoting it.
Am I being told I need to replace all my radiators and pipework?
Often you don't. Heat pumps run cooler than a gas boiler, so some radiators may need upsizing — but rarely all of them, and your existing pipework is frequently fine. The only way to know is a proper room-by-room heat-loss survey. If someone tells you to rip everything out without measuring your home first, be very cautious: that's a sales estimate, not an engineering one.
Do heat pumps actually work in cold weather?
Yes. They're the standard heating across Norway, Sweden and Finland and keep working well below freezing. Output dips a little on the very coldest days, which is exactly why correct sizing matters — but 'they don't work when it's cold' is simply wrong.
Do they work in old or draughty houses?
They can. A heat pump just needs enough radiator surface to warm your home at a lower water temperature. Older homes may need a few radiators upsized or some insulation — but 'your house is too old' is usually a cop-out, not a fact. A good installer designs around your home's actual heat loss.
Are heat pumps expensive to run?
It depends almost entirely on how well the system is designed and commissioned — and on your electricity tariff. A properly set-up heat pump on a heat-pump tariff can cost about the same as, or less than, gas. A badly set-up one costs more. The kit matters far less than the person who installs it.
Do I need underfloor heating?
No. Radiators work fine with heat pumps — sometimes a few need to be larger. Underfloor heating is a nice-to-have, not a requirement, and anyone insisting you must have it is complicating your job (and their invoice).
Will it heat my hot water too?
Yes — through a hot-water cylinder. If you've got a combi boiler and no cylinder, you'll need space for one. That's a genuine thing to plan for, not a dealbreaker.
Are they noisy?
Modern units are quiet — roughly the hum of a fridge from a few metres away. They have to meet strict noise limits to qualify for permitted development. If someone's warned you it'll sound like a jet engine, they're wrong.
Do I need planning permission?
Usually not — most installations fall under permitted development if they meet the size, siting and noise limits. Your installer should confirm it for your property, and the rules differ slightly across the UK nations.
What's the grant, and is it actually real?
It's real. In England and Wales the Boiler Upgrade Scheme takes up to £7,500 off an air-source heat pump; Scotland has Home Energy Scotland grants and loans. It only applies through an MCS-certified installer — which is exactly who this directory lists.
How do I avoid getting ripped off?
Three rules. One: insist on a proper heat-loss survey before any quote — a good installer measures your home room by room, they don't eyeball it from the doorstep. Two: check they're MCS-certified; your grant depends on it. Three: walk away from pressure. A heat pump is an engineering job, not a doorstep sale — if it feels like you're being sold to by someone who was fitting conservatories last year, trust that instinct.