Any maths or science whizz to help me with a conclusion of my experiment please?

Question

My mum's electricity bill is through the roof. She's paying £400 per quarter... and she's a pensioner, but she's active and out of the house most days anyway.

She doesn't have any fancy heaters draining electricity... gas bill is fine.

So I did an experiment... I unplugged or switched off ALL electrical devices in the house.... fridge/freezer, cooker, computer, router, television, kettle... the lot until the electricity meter stopped turning entirely.

Then I switch on just one house-light... an energy saving Osram Deluxe light at 20W.

I timed the amount of time that bulb took to use electricity via the meter. 1/10th = 42minutes... thus (10/10ths), or 1Kwh of electricity = 420 minutes.

However I'm not sure what conclusion to draw from my experiment? Can it be expressed another way... and does it sound expensive?

Thanks.

Answer 1

You might want to check to see if you're reading the meter properly, or perhaps have the utility company inspect the meter for accuracy.  A 20 W light bulb shouldn't consume 1 kwh of electricity in 7 hours.  By definition, 1 kwh of energy should power a 20 W light bulb for 50 hours.  

Something is wrong, I should think...

Answer 2

best way to do this is get back to the electricity board and ask them for a check of the meter!!

All you've worked out is that it takes 420 mins to use 1 unit!! the most electrical draining appliances are the microwave, electric kettle and silly things like that! You may want to make sure everything is turned off at night!! TV etc and check your bills!!

Remember also, the cost of energy is going up stupidly!! Good luck

Answer 3

That's a good experiment with a strange result.

The bulb uses 20W (0.02 kW)

Switched on for 42 minutes (0.7 hours) you'd expect it to use 0.02 kW * 0.7 h = 0.014 kWh.

But, if you read your meter correctly, it appeared to record 0.1 kWh in that time. This is over 7 times the power consumption it should have been!

If my reasoning is correct, the quarterly bills should be more like £55-£60, not £400

Alternatively, it's possible that the light bulb is faulty. Try a few more times with different appliances. Find one of 1kW if you can and leave it for an hour. You should get 1kWh.

If it still over-reads, get someone in the check the meter.

Answer 4

OK Joe, you've done the right thing in checking against one appliance - at least the meter stops when everything is disconnected - so next door haven't tapped into her supply!, but to confirm your findings you need to double check with at least one more item - a 1 kilowatt appliance would be easiest. This will give you the ammunition to fire at your utility supplier. The meters are supposed to be checked or replaced around every 10 years anyway so a faulty one needs to be reported and replaced and a refund demanded.