OffPEAK STORAGE HEATER RUNNING COST CALCULATION:
A basic calculation can be made by multiplying the hourly off-peak tariff rate by the overnight 7-hour charge, then multiplying that total by the kW rating of your heater (i.e., 4.0 cents x 7 = 28.0 x 3.4 kW = 95 cents per day). However, this calculation assumes that the heater has accepted maximum charge which may not be the case on every occasion. If the heater does not require the maximum charge, your running costs will be significantly lower.
CALCULATING HEATER SIZE:
Generally speaking, the standard area that can be kept at 20°C in a room with average furnishings and an insulated 2.4 m ceiling, is 8 m2 for every kW.
The standard area kept at 18°C in the same circumstances is 10 m² for every kW. Heating similar size areas may vary depending upon window area and furnishings, wall type, floor coverings, house aspect, and microclimate conditions.
For more accurate calculations please contact your electrical provider.