500W Heater

Shoie

I have a 500W electric heater in a Kelly Shed I use as a dog kennel in the garden, it is to prevent frost i.e. keeps the shed just above zero and is set to its lowest setting. The shed has been insulated with 4 inch fibreglass and plasterboarded on the inside. The heater is on for an average of 8 hours per night but during the recent cold spell it was on for 12 hours a night.

They have only been in the shed for two months but the bill has jumped astronomically. On the night rate the extra use is 700 units, to me this seems an awful lot. There is extra usage on the day rate of 1200 but some of that can be explained by building work being done in the house during the day.

Is this a lot for a smaal heater? Just wondering if anyone can explain how to calculate the useage of the heater and advise is the 700 units for two months is right?

Thanks

FarmerGreen

1 Unit=1Kw/h
A 500 watt heater would use 1 unit for every 2 hours it is actually giving out heat.
700 units = 1400 hours of use.
60 nights x 12 hours x 0.5Kw = 360 units (assuming its heating all the time)

If you are reading the meter, the last digit is tenths on mine.
If its only 70 not 700, that would mean the heater is on about 20% of the time

Shoie

FarmerGreen thanks for the reply and the calculation. It is actual 700 full units as charged on the bill. The bill period was 69 days.

69 nights * 12 hours * 0.5 KW = 414 units. This is the heater running all the time everynight but appart from the cold nights I can not imagine it running non-stop.

Does the heater use 1 unit every 2 hours even if it is set low? or is it on a percentage basis?

FarmerGreen

>>Does the heater use 1 unit every 2 hours even if it is set low?

Its only using electricity when there is heat coming out of it.
If its only working 10% of the time, then thats 1 unit in 20 hours.
Maybe they made a mistake with the bill, its not likely your dog heater cost that much.