Air source heat pumps get talked up as the future of home heating, but most of the housing stock around Diss, South Norfolk and north Suffolk was built long before anyone thought about airtightness. The honest answer is that a heat pump can work very well in an older house, but only if the property and the system are prepared properly. Here is what actually decides it.
A heat pump runs most efficiently when it heats water to around 35 to 45 degrees, far cooler than the 60 to 70 degrees a gas or oil boiler typically sends to radiators. Modern, well insulated homes hold heat well enough for that low temperature to keep rooms comfortable. A draughty Victorian terrace or a 1930s semi with solid walls loses heat faster, so the same radiators need hotter water or bigger surface areas to keep up.
That does not rule heat pumps out. It means the starting point is a proper room by room heat loss calculation, not a guess based on floor area. Many older homes in this part of East Anglia have already had loft insulation topped up and cavity walls filled where cavities exist, and that alone can bring heat loss down to a level a sensibly sized heat pump handles comfortably.
In most older properties we look at, the house itself needs less work than people fear, but the heating system needs more. Microbore pipework, undersized radiators and old single panel convectors are the usual sticking points, because they were sized for high temperature boiler water.
A realistic conversion often includes some of the following, and the survey tells you which apply to your house:
A typical air source heat pump installation on an older house tends to land somewhere between £8,000 and £15,000 before support, depending on the size of the unit, cylinder location and how many radiators need changing. The Boiler Upgrade Scheme currently offers £7,500 off an eligible installation in England, which brings many projects close to the cost of a like for like oil boiler swap.
Running costs are where honesty matters. Electricity costs roughly four times as much per unit as mains gas, so a heat pump needs to run at an efficiency of around 300 to 400 per cent, which a well designed system achieves, just to match gas bills. Against oil or LPG, which heat a large share of rural homes around Diss, Harleston and Eye, the comparison is usually more favourable, and a heat pump paired with a time of use electricity tariff can undercut oil noticeably.
If a house has solid walls, original single glazing throughout and no realistic way to add insulation, the heat loss figures sometimes show the property would need very hot radiator water on the coldest days. A high temperature heat pump can do this, but efficiency drops and running costs rise, and in a few cases a modern oil or gas boiler remains the sensible choice for now.
The good news is that the survey costs you nothing but time, and the fabric improvements it recommends, insulation, draught proofing, a radiator or two, make the house cheaper to heat whatever fuel you stick with. Doing those first and fitting the heat pump when the boiler is due for replacement is often the smartest sequence for an older property.
Yes, provided the system is sized from a proper heat loss survey rather than rules of thumb. Heat pumps work differently, running steadily at lower temperatures rather than blasting heat in short bursts, so the house stays at an even temperature even on frosty days.
Rarely all of them. In most older homes a handful of radiators need upgrading to larger or double panel versions, and the heat loss calculation identifies exactly which rooms are affected before any work starts.
Often, yes. Oil heated homes are common in rural Suffolk and Norfolk, and because oil is dearer than mains gas, a well designed heat pump usually costs a similar amount or less to run, with the £7,500 Boiler Upgrade Scheme grant reducing the upfront gap.