That is only under optimum test conditions, £/W is the best gauge as it is cheap to put an extra panel in.

Posted By: fostertomWhy should you, unless short of roof space?

In the old days no one worried about vehicle fuel efficiency, now it helps sell cars. Thought the same approach could help sell solar! Maybe I'm wrong.

fuel efficiency does not directly equate to solar cell efficiency though . Fuel efficiency in effect saves you fuel every journey.
solar cell efficiency is of academic interest unless you are constrained on space, as with less efficient cells you just use more of them.

However the improvement in technology is absolutely to be applauded though - if the improvements filter down to mainstream and costs eventually decrease then it's a good thing - it's just not likely relevant to 95+% of the customers at this point

For my roof, since I could only fit 6 panels I went for Sanyo HITs - I paid a large premium for them and are very happy, but I only got these because I needed 1.4kWp to meet building regs - if I had more roof I would have used more, less efficient but cheaper panels with a higher output overall.

of course if more efficient panels were available at a price than enhanced the overall payback, then it's a no-brainer

-Steve

Posted By: Viking HouseHi Steve, how much were they per m2?

No idea, the quote was from some advertising blurb about their R&D efforts, not even sure they are in production yet!

hard to say per m2 , the quote wasn't itemised

6 (total 7.4m2) of panels cost us £8K so you could say >£1000/m2 - however the biggest part of that figure would be for installer's inflated profit margin under the old FIT regime. Less efficient panels would not have cost me much less

it was 1 man bob so he probably made the lot - however my choices at the time were limited to bob hope, or no hope... I don't begrudge him it, it was the market price at the time.

I could probably have got the job done for half price a week later - that was the market price then... (who says that subsidies don't distort the market)

-Steve

Solar Cell/panel efficiency is only a factor if your tight for space, or would like to have a few less panels on your roof for aesthetic reasons. If you have a small roof and require a higher efficiency panel you will be paying more, Panasonic are one of the best panels but you get much better £/w value for LG's higher efficiency panels. Ranging from 265watt -300watt panels (top 18.3% Module efficiency) compared to an average 250watt panel (14.93%) efficiency.

Remember that the panasonic efficiency is for the cell not the module efficiency which will be less.

I have a brief guide on some points to look at on our website;
http://green-uk.com/solar-pv/choosing-right-panels

Ultimately though the system will only perform if designed and installed well.