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Technical Reference

Energy Sources

Energy consumption is commonly measured and costed in UNITS. 

1 Unit of energy is consumed by an appliance with a power output of 1kw running for 1 hour.

 FuelQuantity used per hourCost
£
Energy Used per hour Unit EquivalenceApproximate Cost per Unit
£
 Electricity 1 kW 0.1316 3600kJ 1 unit 0.1316
 Gas 1 m3 0.43 40100kJ 11.139 units 0.0387
 Oil 1 Litre 0.5818 43200kJ 11.94 units 0.049

Source: Department of Energy and Climate Change, June 2012 Quarterly Energy Prices

Unit costs are the average retail value of direct debit tariffs for UK suppliers.

Air Change Rates

 Room Rate (ChangesperHour)
 Living room 3 - 6
 Bathroom 6 - 10
 Kitchen 15 - 20

Heating Season


The figures below are suggested usage of a domestic central heating system for the purpose of calculations. Actual figures for individual households will vary considerably and probably be significantly greater.

Central Heating in Use Sept (part), Oct, Nov, Dec, Jan, Feb, Mar, Apl, May(part) 240 days approx
Hours of use 7 - 8:30, 4:30 - 10 7 hours
Total Hours  1680 hours


 Month Min Temp
deg C
Sep 9.5
Oct         6.5
Nov 3.5
Dec 1.3
Jan 1
Dec 1.8
Mar 2.4
Apl 3.7
May 6.5
Average 4

Radiator Heat Output

Chart 1


Chart 2