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Ground Source Heat Pump
Published by Matt Polaine | Filed under Cottage, Matthew's wishlist
I am trying to work out if we can use, install, and afford a ground source heat pump (GSHP). We are looking at around £10,000 for the installation, although the government provides a £1,500 grant. The technology saves about 50-70% of heating costs compared to mains gas. See case studies. The problem is it works best with always on underfloor heating and a well insulated room and home. We don’t have that, although we are building a part of the house from scratch (if we get the Planning Permission). I will most definately get a site survey done, because radiators are possible. As homes are going to be rated in the future on their energy effeciency, this is the time to get it sorted out, especially before gas and oil costs sky rocket.
November 23rd, 2007
November 23rd, 2007 at 2:22 pm
Case study running costs:
The total annual energy consumption for this case study house is calculated at 32,400 kWh. This is based on a heat requirement of 45w/m sq. This is the energy required for central heating and domestic hot water.
The cost for satisfying this heating load using oil-fired or gas-fired boiler, assuming the cost of domestic heating oil at 3.57p/kWh, the cost of gas at 2p/kWh and a boiler efficiency of 75% will be:
Total energy cost (oil): 32,400 x 0.0357 x 1.25 = £1,446 per year
Total energy cost (gas): 32,400 x 0.02 x 1.25 = £810 per year
The cost for satisfying this heat load using Ice Energy heat pump, assuming electricity cost of 5p/kWh:
Electrical consumption for heat pump: 7,500kWh
Electrical consumption for additional heater: 620kWh
Total running cost (GSHP): 8,120 x 0.05 = £406 per year
The life expectancy of the heat pump is 25 years. During this time minimal maintenance will be required and there will be no reduction in the operating efficiency. The oil/gas boiler will require an annual service and has a life expectancy of 12 years. During this time the boiler efficiency may diminish.
25-year running cost for heat pump:25 x 406 = £10,150 (average £406/year)**
25-year running cost for oil-fired boiler: £1,446 x 25 + (25 x 100) + 2400 = £41,050 (average £1,642/year)**
25-year running cost for gas-fired boiler: £810 X 25 + (25 X 100) + 2400 = £25,150 (average £1,006/year)**
Source: Sept 05 - British Gas (gas) and Boilerjuice.com (oil)
*Assuming oil/gas boiler annual service cost at £100 and boiler replacement cost of £1200. Assuming NO increase in oil, gas and electricity prices. Assuming no decline in boiler efficiency.