im trying to calculate what the different in costs would be, or in fact how to work out , heating a 3Kw water heater, which is kept running 24 hrs a day, against installing a timeclock to run for 12 hrs. it may seem a obvious answer but i trying to factor in high initial power consumption, heating water up to temperature against heater cutting in and out on the stat. the boilers capacity is 2 gallons, thanks to anyone who can help
power costing
- Thread starter duncan64
- Start date
depends how well insulated it is i suppose. you could try timing the interval between the element kicking in, then time how long it kicks in for and take your calcs from there. when it is not being used obviously. if it's 1 minute in 30 then that's 24 minutes x 3kw = 1.2kw - whats that? 12p ish? about 1p an hour?
that's a vague guess obviously
that's a vague guess obviously
You need to know the losses, which depend on the insulation quality, so you'll have to experiment.
Use no water for 28 hours and measure the number of kWh consumed over 24 (i.e. excluding the first 4 hours to make sure any heat lost to water consumption before the start is fully recovered). That is the 24-hour heat loss.
Now do the same experiment but switch off after 4 hours and on again 12 hours later, measuring the 24 hour consumption.
The difference between the two results is the minimum saving you could make per day using a time clock. Don't think that that gives you a return on your investment; you might make a greater saving by spending the same amount of money on fitting better insulation.
Use no water for 28 hours and measure the number of kWh consumed over 24 (i.e. excluding the first 4 hours to make sure any heat lost to water consumption before the start is fully recovered). That is the 24-hour heat loss.
Now do the same experiment but switch off after 4 hours and on again 12 hours later, measuring the 24 hour consumption.
The difference between the two results is the minimum saving you could make per day using a time clock. Don't think that that gives you a return on your investment; you might make a greater saving by spending the same amount of money on fitting better insulation.
I tried this on a water heater.
I do some maintenence work at the local scouts and guides hut, and we had one of these energy saving busy bodies came round.
She was horified to see that the water heater was left switched permanantly on, and reckoned we would save about 120kWh a week by fitting a time switch.
It is a modern well insulated ~50l water heater with a 3kW immersion element in it. The building is in use every week night for between 1 and 4 meetings per night.
We installed a kWh to the circuit and left if for 6 weeks recording the reading every week.
We then installed a time switch which is set to power the heater for an average of 4 hours per week day, and 2 hours on a sunday for the cleaner, and took the same readings from the same meter.
We saved an average of 10kWh per week. It won't exactly save you a fortune, but it is worth doing.
I do some maintenence work at the local scouts and guides hut, and we had one of these energy saving busy bodies came round.
She was horified to see that the water heater was left switched permanantly on, and reckoned we would save about 120kWh a week by fitting a time switch.
It is a modern well insulated ~50l water heater with a 3kW immersion element in it. The building is in use every week night for between 1 and 4 meetings per night.
We installed a kWh to the circuit and left if for 6 weeks recording the reading every week.
We then installed a time switch which is set to power the heater for an average of 4 hours per week day, and 2 hours on a sunday for the cleaner, and took the same readings from the same meter.
We saved an average of 10kWh per week. It won't exactly save you a fortune, but it is worth doing.
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