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Read our policy.

Lifetime costs
Capital
cost £/m2
Energy
cost £/m2
Maintenance cost £/m2Net present value £/m2 (60-year life)Service life
(years)
Centralised air system
Ventilation and heating (no air-conditioning)1001.91.519020
Constant volume (single zone)16031.528625
Variable air volume 1802.42.532020
Dual duct2103.41.536120
Partially centralised air/water system
Centralised air with re-heat2003.12.533625
Unitary heat pumps1303.22.531412
Fan coil units1703.2336015
Local systems
Heat and local ventilation (no air-conditioning)901.10.814125
Split package units853.52.522515
Variable refrigerant flow rate1302.82.528415
Costs are based on £/m2 of treated floor area (gross areas less plant rooms and other non-heated areas).
Capital costs include supply and installation and the removal and replacement at the end of its service life.
Replacement costs are 80% of original supply and installation cost.
Maintenance and component replacement include: ductwork inspection and cleaning; filter replacement; cleaning fan coil units; maintenance of heating and cooling plant and controls to Heating and Ventilation Contractors’ Association standard maintenance specification.
Costs are discounted to net present values at a discount rate of 6%.
Energy and maintenance costs are annual figures.