Why is a home “after subsidies” sometimes harder to maintain than an old one?
It sounds paradoxical, but our advisors see it regularly: a family replaces an old coal boiler with a modern heat pump, receives a generous subsidy – and a year later their bills are higher than before. The neighbours, still burning cheap coal, shake their heads and say the technology does not work. But the technology usually works fine. The project was built in the wrong order.
Reason one: the building was not prepared
A heat pump is not a furnace – it is a low-temperature, high-efficiency system. Its economics depend entirely on the temperature it has to deliver. In a leaky, uninsulated house, the water in the radiators must be hot, and a heat pump producing hot water loses precisely the efficiency advantage it was bought for. It runs at maximum power all winter, and electricity at maximum power is expensive.
The house needed insulation first; the heat pump should have been step two, not step one. Every degree you cut from the required water temperature improves the heat pump's efficiency measurably – which is why insulating 15 centimetres of attic can do more for your bill than any brand of heat pump.
Reason two: the device was oversized or badly configured
An installer who sells equipment has an incentive to sell a bigger unit. But an oversized heat pump short-cycles: it switches on, satisfies the house in minutes, switches off, and repeats. Each start wastes energy, wears the compressor, and never reaches the steady, efficient operating state a heat pump is designed for. Proper sizing comes from a heat-loss calculation in an energy audit – not from a rule of thumb based on the house's floor area.
Configuration matters just as much. A unit left on factory settings may run a fixed high-temperature curve all season, while a correctly set weather-compensated curve quietly saves a fifth of the electricity. We have visited “expensive” heat pump homes where the fix was a forty-minute settings review, not new equipment.
Reason three: nobody taught the family how to run it
A heat pump is not a fire-and-forget stove. It rewards small habits: not blocking the outdoor unit with pallets or snow, keeping a stable daytime temperature instead of deep nightly setbacks the unit struggles to recover from, using the cheap tariff wisely, and understanding what the display is actually telling you. None of this is complicated – but none of it is obvious either, and a fifteen-minute handover is not training.
The right order of works
The lesson is not “avoid subsidies” – it is “do the project in the right order”:
- Audit first. Measure the building's real heat loss and get a ranked list of what to do.
- Insulate and seal. Attic, walls, windows where needed – the works that shrink the demand itself.
- Fix ventilation. A tightened house needs controlled ventilation with heat recovery, or you will trade heat loss for damp rooms.
- Only then choose the heat source, sized by the audit rather than by a salesman's estimate.
That is exactly the sequence we follow with every household we advise, and it is why our projects deliver the savings the brochures promise. The subsidy programmes themselves reward this order – higher funding tiers are available for projects that combine a heat source upgrade with proper insulation work.
A subsidy pays for equipment. An audit decides whether that equipment will ever pay for itself.