Sustainability: Heat pumps | Features

Comparable efficiencies of low-energy and renewable technologies
Renewable technology	Candidate buildings	Annual saving per £100,000 cost
		kWh	kg CO2
Tower-mounted wind	Industrial, distribution	90,000	39,000*
Building-mounted	Most types of building	36,000	15,500*
Photovoltaic panels or roof	Most types of building	11,500	4,800*
Photovoltaic rain screen or glass	Prestige offices or retail	8,000	3,450*
Passive solar water heating	Residential, commercial, hotels and leisure	45,000	8,500**
Ground-source heat pump	Most types of building	36,000	6,850**
Borehole cooling	Offices, hotel, leisure	11,000	4,650*
Biomass boilers	Most types of building	90,000	17,000**
Biomass CHP	Industrial, hotel,	26,000	10,800*
	leisure, hospital	57,000	10,800**

* compared with electricity
** compared with gas

Indicative capital costs of ground source heat pumps and conventional heating and cooling plant
	Small (4 kWh) (£)	Medium (50 kWh) (£)	Large (400 kWh) (£)
Condensing boiler and flue	1,200	4,200	17,000
Air-cooled chiller	1,000	6,000	50,000
Heat pump	3,500-4,500	30,000-40,000	140,000-170,000
Horizontal “Slinky” collector	3,000-4,000	40,000-50,000	360,000-390,000
Vertical borehole collector	2,000-3,000	50,000-70,000	360,000-390,000
Costs exclude distribution pipework from the collection network to the heat pump and plant room
installations. Main contractors’ preliminaries, overheads and profit are also excluded.