when is the best time to turn on my themostat (have solar panels)

mymerrywidow

please bare with me, i am new to solar power.

i have had solar panels installed (feb21st 2012) i am on ecomomy 7 electric so have always heated up my water at night, but i was hoping one of you guys could tell me if it would be cheaper to heat the water up in the daytime.

any other tips about making the most of the new panels would be greatly recieved.

whasup

No. The tiny gain you might make in ideal conditions would be immediately swallowed up if a cloud came over. There are automatic controls available to switch the power supply in optimum conditions but at the moment they are too expensive to be worthwhile.

HappyMJ

It doesn't normally cost that much to heat water at night anyway. If you were heating water during the day you could potentially be using much more expensive power form the grid swallowing up all your savings.

To make the most from solar panels you need to be at home. Watching the telly...doing washing, anything but only if it sunny.

mymerrywidow

many thanks

Kernel_Sanders

mymerrywidow wrote: »

many thanks

Your thanks for this post are unwarranted:

whasup wrote: »

No. The tiny gain you might make in ideal conditions would be immediately swallowed up if a cloud came over.

Say your immersion heater is rated at 3kw. When your generation exceeds what you are using by at least 3000watts, you can switch it on; everything you use will be free. So, say at lunchtime you are only using the immersion, and the display is showing you are generating 3010 watts, but then a cloud comes over and it plummets to 1480 watts. Only 1520 watts will be charged at the full daytime rate, so you are only paying slightly more than the night rate on Economy7. Even if there was twice as much cloudy as sunny intervals, it would still be cheaper to use the solar+peak rate.

ian.birdman

:cool: We are also new to solar (1 month) and are getting quite anal about watching the meter! We are impressed that our small (2kw) installation still produces on cloudy winter days. Our water is heated by LPG which I believe is made from pulped £20 pound notes and we are contemplating using the immersion heater during the day when the summer months arrive but it would have to be on a timer for the best time of day. We already have changed our habits and run the washing machine and dishwasher during daylight hours. Any comments?
We are also interested in other peoples experience with various panels' output for the general good.

whasup

Economy 7 tarif is less than standard at night but more than standard during the day. In fact some E7 providers charge more than twice the normal during the day. At those rates you would very quickly lose any gain. Without an auto regulating switch or sitting next to the tank turning it on and off as the sun shines (or not) it's a non starter. And don't forget it's not just a hot water tank burning juice during the day. A lot of modern houses use 500 or 600 watts/hr just sitting still.

Martyn1981

whasup wrote: »

Economy 7 tarif is less than standard at night but more than standard during the day. In fact some E7 providers charge more than twice the normal during the day. At those rates you would very quickly lose any gain. Without an auto regulating switch or sitting next to the tank turning it on and off as the sun shines (or not) it's a non starter. And don't forget it's not just a hot water tank burning juice during the day. A lot of modern houses use 500 or 600 watts/hr just sitting still.

Not arguing per se, but every house is different. Mine (and wifey's) uses about 150Watts standing still. I don't think we do anything particularly good or bad. Fridge and freezer, lots of little lights on stuff, clocks, displays, standby's etc.

Normally, I can use the computer, or the telly and PBR, plus a 400W rad, just to keep one room topped up (rather than GCH), and still have the little solid light on my import showing export at 700Watts of generation.

Regarding immersion heaters during the day, this seems like a minefield, unless you have a smaller element, such as a 1kW for use when PV is good. And even then .....

Mart.

KevinG

whasup wrote: »

Economy 7 tarif is less than standard at night but more than standard during the day. In fact some E7 providers charge more than twice the normal during the day

Really? I'd be amazed if anyone could make it pay at that rate. I pay a little bit more for daytime units but use relatively little during the day anyway with the solar panels. Economy 7 is easily worth it for me as we normally run washing machine, dishwasher and water heating (during warmer weather when the LPG boiler isn't doing it) on the low rate.

The_Green_Hornet

I have come across this company's web site which is claiming that they can redirect excess solar power generation to your immersion heater to heat up your hot water.

http://www.engensa.com/solar24/

I will leave it up to the reader to decide whether it is fact or fiction.

EricMears

The_Green_Hornet wrote: »

I have come across this company's web site which is claiming that they can redirect excess solar power generation to your immersion heater to heat up your hot water.

http://www.engensa.com/solar24/

I will leave it up to the reader to decide whether it is fact or fiction.

Such a system is eminently possible and would indeed be ideal for anyone relying on electricity for water heating but not able to sit at home watching generation & consumption meters.

Price is quoted at from £250 (i.e. absolute minimum anyone would pay is £250 but no indication of actual cost to you) and if it was possible to get it at anywhere near that cost and installed at a reasonable extra cost it should have a pretty good ROI.

Emboldened words make it impossible to quantify without seeking a full quotation.