Gurtie, well, thanks for the info to help me make the decision!  Yes, we have 2 inverters, so get different readings for each. I am sure I will not be able to generate data as beautifully as you, and I have yet to see how accurate the data from the Wattson will be. I can download it, but I think it gives a 5 min average. My neighbour has the same set up, but all in one string, all south facing, and I suspect he will get 20% more than me.  It will be interesting, if frustrating to compare over a glass of wine each month

I will get overall readings though, and so hopefully will be able to give you a sense of the performance.

Rich, it makes my buttocks clench to post that in public.  It was rather expensive. .......£14.5K.  If the sun shines though, it should payback faster than any other investment I have, and with a 25 year Guarantee on income (if that is possible) will take me well into retirement   (if that is possible!!)


On if anyone is interested, the best GU10 halogen replacements I have found are from tp24. They are 50 watt equivalent. Dealtime do several, but none of the ones I have bought quite do it, as I said.

Bought a load of stuff from tp24. One downside is they have some unusual bulb fittings so you have to buy from them.

I would suggest you look at done if the latest led gu10. They are pretty close to the magic 35 watt equivalent light at only a few watts. 10-30£. Worth a look. I found some 7 watt compact fluorescent that were ok but still a bit dim and none of the 50 I used lasted anywhere near the 7 years.

Quote from: Rupert on April 14, 2011, 06:51:28 AM

On if anyone is interested, the best GU10 halogen replacements I have found are from tp24. They are 50 watt equivalent. Dealtime do several, but none of the ones I have bought quite do it, as I said.

About a year ago I was looking for these.  I couldn't find any that did 50w at the time so I settled for these http://specialistlightingonline.com/shop/article_151/Philips-MasterLED-3w-GU10-Perfect-Fit.html?pse=coa which only gave me 35w but it was fine as I had 7 in the rather small kitchen so the light is fine.  They were a bit more expensive then, I paid £19.99 each from B&Q but it cut that switch down from 350w to 21w.  Don't know how long it will take me to make up the £140 for the bulbs though.

Cool, I will check those out.  Sounds a similar issue of not enough lumens. 50W halogen is I think about 900 to 1000 lumens.

For a base costing, I work on 1w on all year is approx £1 at present. 

So if you use them for 8 hours a day ( we have lights on during the day in this house) Or 1/3 of the time

Then 330 watt reduction is going to save £110 per year.  So Not a bad payback

I think that right any way. Halogens cost the earth to run.

Eurotrash,
Great site, thanks for that.  Spotted this:

http://specialistlightingonline.com/shop/article_154/Philips-MasterLED-10w-Dimmable-MR16.html?shop_param=cid%3D6%26aid%3D154%26

That would take my 700 Watt to 70 watt, saving £210 pa. or a 2 year payback. I think I will wait a year to see how the solar settles down, and how the prices come down.

Trouble is I am becoming an energy bore!!!!

lol - I obsessed for the first few months of solar.  You do really start to watch the meters to see whats happening!

In terms of pure financial savings, once you manage to cut back, especially with solar, the best saving you can make imho is to switch to an energy deal with no standing charge - we pay a higher charge for the first 56 units a month rather than a standing charge, but mid feb - mid march we only imported 60 units, so by May we're using well under 56 and every unit under effectively saves money on a standing charge. 

When I was a kid, my dad made a solar panel to put on the side of the house to heat the basement.  It was a simple system, really, just a large shallow box with soda cans cut in half screwed to the bottom.  We painted the entire thing black and then put a cloudy plastic piece over the top to hide the hideous looking cans.

Then, a simple fan mounted to the bottom pulled air from the solar panel into the basement.

We used it for years.

Gurtie, so you heat with Gas?
What about cooking? Do you eat out?            thats only 2kw hrs per day!

Grnidone....   fantastic!  I met a lady on Sunday who has had solar for 29 years...   


...'cos of course you dads set up can only have been 15 years ago, if you remember it   

What is normal charge per kwh in the UK?

11-13p, according to this http://www.energy.eu/#Domestic


Rupert - we do use the electric oven probably 4 nights a week, and the gas range the rest of the time. We do run 2 freezers, 2 fridges, too many computers and a variety of lamps and lights in a house which only only has windows on one side, and I work from home half the week, so we do have a lot switched on.

I think it was just a combination of better rated appliances, the solar generation and swapping the electric shower over to gas once we got a proper boiler.

We don't have a 10 year old in the house though

Gurtie, sounds like you have it very well managed

Bob, over here Gas costs 3.5p per KWhr, and as Gurtie says, elec is about 13p.

We looked at ground source heat pumps, but as we heat with gas, the 75% efficiency saving just kept the bills the same.

You guys might find this interesting:

http://www.cracked.com/article_19133_6-ways-nature-cleans-up-our-messes-better-than-we-do.html

>elec is about 13p

Natural (piped-in) gas is just coming back in our region of the state but only available in a few downtown areas or significant installations (schools, hospitals). LP (bottled) gas is much more prevalent.  I don't know their costs as I'm all electric.  I pay 6p (GBX) per kwh ...thats after a 5% 'super-efficient home' discount.

>energy bore

Yeah, it comes with the package.


I enjoy trying to get off the grid but, so far, have only opted for passive or (nearly passive in the case of geothermal) methods.  The problem now is one of diminishing returns.  My power bill averaged $200 per month last year.  To trim anything substantial off that, I'd have to get into active systems and the ROI -even for DIY systems- is poor.  Add the maintenance burden and they're downright unattractive.  So I may be done.

Related for US readers: Home solar panel kits come to Costco
http://www.earthtechling.com/2011/04/home-solar-panel-kits-come-to-costco/

Ok, so first 3 months, I have produced 1338 kw hrs. It is the height of summer, so will have to see how the rest of the year goes.

But that's a check of £565 coming my way, when my contract is finally sorted out.  Also saved £200 on the elec bill this quarter compared to last year.  Part using what we make, and part  by being more sensible with usage.


very pleased so far. See how the next 10 years pan out!