solar heated water costs/benefits

[dedee]

I'd thought I'd start a new thread specific to my own solar heated water project. Today I've studied the costs.

Our hot water is heated at night on a nighttime tariff. I think in two years I have only ever run out of water 2 or 3 times and had to heat water in the daytime.

Last year our nighttime electricity costs were €133. A proportion of this cost is for heating water for washing machine ( 4-5 times a week), dishwasher (7 times a week), fridge and freezer and appliances on standby. I'll have to check the meter one night when the dishwasher and washing machine are not on to get a better idea of much electricity the water heater does use.

Solar heating options:-
A) Replace the existing water heater for one with a solar exchanger and electric heating. Cost c/w solar panels, pump, expansion vessel, temperature controller etc - €1800 + pipe work
B) Add a new cylinder with exchanger to preheat the water and buy solar panels - €1,100
C) Add a new cylinder with exchanger to preheat water and DIY a solar panel - €900
I have not included installation costs as I would like to think I could do this myself - maybe.

If we were to recover the whole €133 cost recover would take more than :- 13 years option A, 8 years option B, 7 years option C

We would, of course,not recover all of the €133 but electricity prices would increase and the solar running costs would not.

Is it worth it?
Because of the extra efficiency of the purpose built solar panels I think option B may be worth pursuing if I can keep the costs down. I need convincing though.

cheers

Andy

 

[MikeG.]

I'm not going to pick apart your figures, but instead will suggest another way of looking at them. Instead of considering, as you did, that you will be using capital to cost this project, you could make a useful comparison by assuming you are borrowing the money.

Thus, the equation is annual interest vs annual saving. £1000 borrowed at 5% is £50 per annum. If your savings are, say, £100 per annum, then clearly there is a good financial argument for doing the project.

Mike

 

[cambournepete]

...you could make a useful comparison by assuming you are borrowing the money...

Or, you already have the cash and then compare the savings with the interest you might earn...

 

[Waka]

Andy

Not going to question your options or figures, but my advice would be go for the option that best suits, you will make a saving.

I had mine installed about 4 years ago and have to say that I'm more than pleased, even on a day like today with the outside temp approximately 5 degrees C, the sun is shining and heating up my water.

As for installing it yourself, it's not rocket science. I didn't install mine but my neighbour who at the time was 71 installed the same system that I had, he managed to save himself £1200 in the process.

 

[Waka]

Andy

Not going to question your options or figures, but my advice would be go for the option that best suits, you will make a saving.

I had mine installed about 4 years ago and have to say that I'm more than pleased, even on a day like today with the outside temp approximately 5 degrees C, the sun is shining and heating up my water.

As for installing it yourself, it's not rocket science. I didn't install mine but my neighbour who at the time was 71 installed the same system that I had, he managed to save himself £1200 in the process.

 

[dedee]

Thanks for the comments and encouragement.

There are a number of ways to justify the accounting and it will be an interesting project and give me something to do and think about and I will get that inner glow for knowing that I am ding my bit. So I will probably give this a go.

What shocked though was how cheap electrically heated water is, €0.0519 per kWh (overnght tariif) daytime is €0.0839. Most of which comes from exploding atoms of course and not fossil fuels.

How does this compare to the UK these days/

cheers

Andy

 

[RogerS]

..... A proportion of this cost is for heating water for washing machine ( 4-5 times a week), dishwasher (7 times a week),......

Andy

Another way to look at it might be to buy more crockery and turn your underwear inside out :wink: