How to reduce the electricity bill by 70%

refusnik

If you want to reduce your electricity bill it is very important to identify what you need to concentrate your efforts on.

There are many electrical appliances around the house and they contribute differently towards the cost of electricity bill.

You don't have to be a scientist to grasp the basics of it but without doing simple estimations most of the efforts will be wasted and quite possibly you won't even see the results.

OK, let's start from the grassroots level.

We need some measurement of consumed electricity we are going to pay for. Suppliers call these chunks of electricity "units" or "kilowatt-hours" (kWh.) Each appliance is rated by how quickly it can consume the electrical energy when turned on. This is typically expressed in Watts (W) or kilowatts (kW). One kilowatt is one thousand Watts: 1kW = 1000W.

Now if you did not grasp it straight away you have to concentrate a little because this is important. A chunk of energy is a "unit" or "kilowatt-hour" (kWh). The speed (rate) of consumption is "watt" (W) or "kilowatt" (kW). If you are just about to throw up from this boring stuff, try to think about energy (kilowatt-hour) as a distance and power (kilowatt) as speed. Your energy supplier is a bus driver. You pay them for the distance (kWh), not the speed at which the bus travelled (kW) or time it took to get there (hours).

We understand now that we are paying for energy (=distance) as a product of two things: power (=speed) and time.
You are fully equipped now to do some basic estimation of where the cost might come from and where to concentrate your savings on. It is very useful to be able to practice the calculations in a spreadsheet program like Excel but it just as well can be done on a napkin.

It will be very useful if you now pull out your bill or contract and see how much you are paying for one unit (kWh) of electricity. I will use my figures (npower) for illustration:

daytime rate for the initial 728 units a year: 18.16p
daytime rate after that: 9.41p
nighttime rate (midnight till 7AM): 2.82p

These include VAT. You can see that during the daytime electricity is much more expensive (nearly 7 times) than during the night. Also daytime rate is very steep to a specific point (728 units which would cost £132.16) and then gets almost twice cheaper. For simplicity I will use initial daytime rate in my examples.

Let's look at some real life examples of what we are paying for:

Q: 60W bulb left turned on for one hour.
A: 60W * 1hour = 60 watt-hours = 0.06 kilowatt-hours = 0.06 units.
Cost: 1p during the day and 0.17p during the night.
Result: it is not the end of the world to forget to switch it off.

Q: 60W bulb used for 4 hours every day (7PM-11PM) during one month.
A: 60W * 4hours * 30 days = 7200 watt-hours = 7.2 kilowatt-hours = 7.2 units.
Cost: £1.31 (remember to use daytime rate)
Result: Replace it with 11W energy-saving bulb and you can save more than a pound each month.

Q: 40W bulb permanently turned on for one month
A: 40W * 24hours * 30days = 28800 watt-hours = 28.8 kilowatt-hours = 28.8 units.
Cost: Since we cover both day and night rates let's calculate them separately:
Daytime cost = 40W * 17hours * 30days = 20.4 units -> £3.70
Nighttime cost = 40W * 7hours * 30days = 8.4 units -> 24p
Result: £3.94 , well... decide yourself

Q: Same as above but for 11W energy-saving bulb
Cost: £1.08p, well these energy saving bulbs can be had for £1.99 so it will pay back in less than a month.

Q: Cooker with 1kW hob used for an hour
A: 1kW * 1h = 1 unit -> 18p

Now here is very interesting one. Heating stuff up. You can time it and see how long does it take to boil a kettle and then calculate the energy used but I am going to approach it as a real nerd. Physicists have figured out how much energy does it take to heat up different things by one degree. Leave alone that huge book, I am going to tell you! If you take 1 litre of water and heat it by one degree C, you have consumed 0.0012 units of energy (electrical or not). This is only one degree so to boil one litre of cold water you have to bring its temperature from about 20C room temperature to boiling 100C that is 80 times the initial figure so in total about 0.1 units. Now to boil 10 litres you need to use up 10 times more or 1 unit and so on. You get the idea...

Q: Make two cups of tea?
A: 0.5L * 80C * 0.0012 = 0.05 units
Cost: 0.8p during the day and 0.1p during the night. Fill the kettle to the top (2L) and it will become 3.4p - if you make only two cups, you've wasted 3p!

Q: Heat up the full contents of the boiler
A: I have 125 litres boiler and I have it set up to keep water at 60C. Cold water is coming straight from the pipe so it is a bit cooler than a room temperature, say 10C:
125L * (60-10)C * 0.0012 = 7.3 units
Cost: £1.32 during the day and only 21p during the night! Wow!

Let me go back a step if you have just missed it altogether. You have just had a shower or a bath and drained the full boiler so that it filled up with cold water again. It is 11pm. Do you care if the boiler will remain cold until midnight or 1am? If you don't than you have just saved yourself £1.11. All you need to do is:

1. Switch the boiler's power off.
2. Use the shower or fill up the bath
3. Wait until night rate starts (midnight or 1am) and switch the boiler back on.

You can do it yourself if you are desperate or get a powerful timer thingy and set it up to automatically switch the boiler off at say 9pm just before you normally have a bath and then switch it back on during the night (1am or 5am - does not matter.) The only thing is the timer should be quite powerful as the boiler can take a lot of energy - mine is 3kW.

Believe it or not I have identified the hot water boiler as the biggest energy drain in my electricity bill.

Even more I have found that I can have a shower in the morning and a shower after work using the same energy that boiler accumulates overnight.
So basically I switch the boiler on during the night, have a shower in the morning, turn the boiler off at 7am, get back from work, have a shower in the afternoon (water is still hot!), switch boiler back on at 1am and so on.

By changing its operation so that it heats up during the night rate time I was able to drop my monthly bill from 35 pounds to below 10! This is three times, guys! Now this will not apply so easily to people who pay the same flat rate day or night or to those who uses gas to heat the building and water up. But what I am saying is it is important to concentrate on a few biggest problems and solve them first. Don't spread the efforts! In my case it was not bulbs or PCs or wall power-bricks that helped me cut costs but shifting the boiler operation so that it accumulates major amount of heat during the night at 1/6th of original daily costs!

Hope this helps (or at least entertains) :rotfl:

Queenie

:hello: Welcome to MSE refusnik .....

.... and for an informative, interesting (and amusing!) first post

Pink.

Helpful and entertaining........welcome to MSE refusnik

margaret_3

This was VERY useful. Thanks.
Margaret

pre-reg

excellent, electricity usage is one of these things that ones forgets about when trying to make financial savings. I think initial post illustrates a crucial point here...everything little thing add ups!!

Cardew

I hate to pour cold water(pun intended) on a most useful post but your figures have a glaring error that make your calculations of savings completely wrong!
You are using a rate of 18+p a unit for all your daytime electricity calculations.

You state that 728 units per year are at that rate - that is in effect the extra instead of a standing charge - 182 units a quarter. Well you are going to use all of those units very quickly.

Your N power daytime rates are extremely high anyway. Even the much derided Britsh gas dual fuel electricity rates are much lower than yours. Using their off peak prices their daytime rates are approx 7p to 8p per hour including VAT
( East midlands is 6.474p + VAT = 6.8p)

Sorry!!

So taking some of your examples:

60W bulb used for 4 hours every day (7PM-11PM) during one month.

You give a figure of £1.31 where even use your high Npower rates the figure should be £0.68p and using BG would be £0.49p

"Q: Heat up the full contents of the boiler
A: I have 125 litres boiler and I have it set up to keep water at 60C. Cold water is coming straight from the pipe so it is a bit cooler than a room temperature, say 10C:
125L * (60-10)C * 0.0012 = 7.3 units
Cost: £1.32 during the day and only 21p during the night! Wow!"

Even taking that unrealistic example your figures are wildly out.

You say £1.32 it should be £0.69p using N Power and £0.49p using BG

Whilst I agree with the principles of using night-time electricity where possible, and low energy bulbs, the savings you give are totally unrepresentative.

loon_2

pre-reg wrote:

excellent, electricity usage is one of these things that ones forgets about when trying to make financial savings. I think initial post illustrates a crucial point here...everything little thing add ups!!

I do not mean to offend but...

Electricity usage ie CONSUMPTION should not be one of the things that people forget... it should be the only thing you base your comparisons on. If this is the case, no wonder so many people find it hard to compare companies.

refusnik

Cardew wrote:

I hate to pour cold water(pun intended) on a most useful post but your figures have a glaring error that make your calculations of savings completely wrong!
You are using a rate of 18+p a unit for all your daytime electricity calculations.

Cardew, I have MSc degree in theoretical physics and would have never published this without doublecheking it somehow. I was reading electricity counter figures twice a day and graphing it in Excel for a real world check.

My average consumption before I started to look at the figures was 8.9 units a day. Yes, it was taking me to a lower daytime rate within just one quarter. However after I started to look after pennies my day consumption has dropped to about 2 units a day, shifting those extra 7 units to a night rate.

You state that 728 units per year are at that rate - that is in effect the extra instead of a standing charge - 182 units a quarter. Well you are going to use all of those units very quickly.

There is no standing charge - simply first 728 daytime units each year are charged at higher rate than the rest. This is to prevent people switching too often and that is why I don't switch now until the year is finished.

I have used up more than 3500 daytime units in 2004. I am planning to use only 720 in 2005. During entire year.

Your N power daytime rates are extremely high anyway. Even the much derided Britsh gas dual fuel electricity rates are much lower than yours. Using their off peak prices their daytime rates are approx 7p to 8p per hour including VAT
( East midlands is 6.474p + VAT = 6.8p)

Unfortunately I don't have gas...

http://www.npower.co.uk/At_home/Electricity_and_gas/Prices_and_discounts/Prices_in_your_area.html
My area is Teesside:

Tariff  	 Rate excl. VAT  	 Rate incl 5% VAT
Economy 7
day rate:
first 728 units per year 	17.290p per unit 	18.15p per unit
additional units per year 	8.960p per unit 	9.41p per unit
night rate:
units 	2.690p per unit 	2.82p per unit

Even taking that unrealistic example your figures are wildly out.

You say £1.32 it should be £0.69p using N Power and £0.49p using BG

Whilst I agree with the principles of using night-time electricity where possible, and low energy bulbs, the savings you give are totally unrepresentative.

Even though I have said I am using higher rate for simplicity I shall stress it again: I am planning (and do) to save so much that I am going to stay within higher daytime rate for the whole year.

If you want, recalculate everything for the lower daily rate. You will end up saving half less or having twice longer payback. It is still huge saving...

I think you have missed the point of my post: identify the problem before making efforts. If I was paying 6p per unit flat rate all 24 hours a day obviously I'd put my efforts elsewhere. I also don't feel so nervous anymore about forgetting to switch lights off or using cooker after I know how much exactly they cost per hour of operation. :j

refusnik

loon wrote:

it should be the only thing you base your comparisons on. If this is the case, no wonder so many people find it hard to compare companies.

I think the problem is double-sided. If you reduce your energy consumtion you WILL reduce your bill on top of reducing it by switching the companies around. Due to few reasons I cannot switch supplier now. Of course comparing suppliers only makes sense under individual consumption pattern!

MarkyMarkD

Refusenik,

It's a very useful and informative post. But the point about using the "including standing charge" pence per unit still stands. Even if you succeed in reducing your consumption to 720 units per year, the MARGINAL saving on the units from 3,500 down to 728 is only at the lower pence per unit price i.e. 9.41p.

And 9.41p for daytime units is a pathetic price - as well as spending time and effort reducing consumption (which is in itself a laudable aim) people should spend less time and effort switching away from their incumbent supplier who is ALWAYS the most expensive.

All the above said, I am very impressed with your money-saving efforts (from a consumption reduction point of view). There are only 2 of us in our house but we struggle to get daytime consumption below 2,400 units per year (and night time is around 1,000) - and that's with gas central heating, everything possible running on timers overnight, and lots of low energy bulbs.

refusnik

MarkyMarkD wrote:

Even if you succeed in reducing your consumption to 720 units per year, the MARGINAL saving on the units from 3,500 down to 728 is only at the lower pence per unit price i.e. 9.41p.

Mark, it is still 260 pounds! I can't let this money go.

MarkyMarkD wrote:

All the above said, I am very impressed with your money-saving efforts (from a consumption reduction point of view). There are only 2 of us in our house but we struggle to get daytime consumption below 2,400 units per year (and night time is around 1,000) - and that's with gas central heating, everything possible running on timers overnight, and lots of low energy bulbs.

I live on my own in the apartment so can get as tight as I need to or comfortable to be. This is more of the experimental nature I suppose.

By the way I had a walk today and done a mental excercise of estimating energy consumption of us, humans. At 2000 kilocalories a day it is only 2.3 units daily or just 6 pence at my current night rate (if you recharge yourself when you asleep.) Could be even lower with gas!

Now, don't you think food is a bit overpriced here? :rotfl: