A few years ago, when the price of oil was soaring and looked set to continue, many people with oil-fired heating systems began to think anxiously about their fuel bills for the coming winter. Among them was Peter, who lives near Eccleshall. He looked at the possible alternatives, and decided on an air source heat pump.
The unit sits on a slab against an exterior wall. Peter cautioned that the fan makes a bit of noise, and you probably wouldn't want it underneath your bedroom window. So choose the site with care.
The cost of the unit and installation by a supplier can run to anywhere between £7000 and £12,000. But Peter looked on eBay and found one listed by Wharf Plumbing and Heating in Stoke on Trent for just £1100. He bid for it and bought it at this price. Including changes to the pipework and control systems, he reckons the whole unit has set him back just £1500. And so far he's been very pleased with it, even given the plunge in oil prices.
"It's worked out well" he said. "It was fairly easy to install; I'm an engineer by profession, but any competent plumber could do the job. It now heats the house and produces all our hot water. We also have a Clearview log-burning stove in the living room; the stove is lit later in the day and helps out with the heating."
Indoors, the heat is stored in a Nu-Heat heat store, effectively a large (210 litre) lagged water tank. The relatively lower temperatures achieved by a heat pump, compared with a conventional boiler, suit the underfloor heating system in the house. The house is divided into thermostatically controlled heat zones, generally maintained at a background temperature of 18-20 celsius, although the temperature of each zone can be altered as required. There is also a recirculating ventilation system, so the house, built in 1999, can be kept fully insulated without the problem of condensation. The ventilation system also helps to circulate any heat within the house, and a heat exchanger incorporated in the system warms the incoming air using heat from the air being expelled.
The system delivers hot water at about 50 celsius, on demand, and Peter reckons that the water could be hotter without any ancillary heater. The oil-fired boiler is retained as a back-up, although it's seldom been required except for recent cold spells.
It's still early days to make accurate comparisons of running costs, but Peter reckons that for hot water alone, last summer the oil-fired system was costing £7/week compared with £2.70/week after the switch to the heat pump. Even with the fall in oil prices, the heat pump still works out cheaper to run. And it produces less carbon emissions. "The only glitch so far was when a sensor failed and the collector iced up. The supplier soon fixed it. Otherwise it's worked out well!"
The Nu-Heat heat store supplies the underfloor heating and provides instant hot water