Heat pump replacement and upgrades in Darlington
Swapping a worn-out or badly specified heat pump in Darlington costs £6,000 to £10,000 where the cylinder and primary pipework can stay. Replacement units do not attract the £7,500 grant, so the case rests on running costs, reliability and correcting whatever the original design got wrong.
Two very different reasons for replacing
Machines that have simply reached the end of a working life are the simpler case: fifteen to twenty years is a reasonable expectation, compressors eventually tire, and spare parts for discontinued models become an argument nobody wins. The other case is more common in this area than people expect, because the early wave of installations across the eastern estates and the newer developments included some genuinely poor design work. Undersized emitters, a system running at 55 degrees because that was easier than sizing radiators, controls left on factory defaults. Those houses are not suffering from a faulty heat pump. They are suffering from a heating system nobody finished.
What a replacement usually keeps
Most of the expensive parts of the original job stay put. A sound unvented cylinder with a decent coil area carries on. Primary pipework, if it was sized properly, is reused. Radiators that were upsized correctly stay on the wall. What changes is the outdoor unit, the controls, and any emitters the original design skipped. That is why the band sits below a fresh installation: you are buying the machine and the design work, not the whole system a second time.
Before replacing, rule out the cheap fixes
An underperforming system is worth diagnosing properly first, because a surprising share of complaints resolve for a few hundred pounds rather than several thousand. Weather compensation switched off or curved wrongly is the single most common finding. After that: a clogged strainer, air trapped in the primary circuit, low refrigerant charge, a diverter valve that never fully closes, or a thermostat programmed as though it were still driving a gas boiler. A competent diagnostic visit costs a fraction of a replacement and quite often removes the need for one.
The grant question, answered directly
The Boiler Upgrade Scheme does not fund heat pump to heat pump replacements. It exists to move properties off fossil fuel and direct electric heating, so a house already running a heat pump has done what the scheme wanted. That makes the numbers here plainer than on a first installation: you are weighing £6,000 to £10,000 against the annual saving from a modern, correctly designed system, plus the value of not spending winters chasing faults. Where the old machine still works but works badly, an upgrade to the emitters and controls alone sometimes captures most of the benefit for a quarter of the money, and an honest survey will say so.
What the quote should show
A fresh measured heat loss calculation, not the figures from the original install. A statement of which existing components are being retained and why. The new design flow temperature. And a running cost comparison between what you have now and what is proposed, using your own recent electricity consumption rather than a manufacturer's laboratory figure.