GRP/Fibreglass info needed

[GEOFFREY]

Its not.... you still get suction... but it will reduce it...

Not even sure that is true Irving. Obviously it depends on wind direction and strength, but according to Bernouli, (can't remember spelling) wind blowing between the surfaces will cause a reduction of pressure on the underside, so in some instances will actually create negative lift (downforce). Anyway that is all academic - try to pass all responsibilty on to the installer!!! Good luck. G.

[irving2008]

There's a proprietary product that claims to need only 1/10 of the ballast by directing the airflow to create negative lift, but none of the pics I've found give enough detail to see how its done :(

Tried the installer route... one suggested standard ballasted approach until I asked about loading then he wanted £700 up front for structural engineers report before he'd discuss further. Two others said they couldn't help....

Anyway, I don't want an installer, my sparky will do it, installers want to load the kit by 25% margin and charge £1500 for a days work roughly! Just so I can get the pointlessly low feed in rates that the gov now gives. Makes the ROI go from 3y to 8y...

Not even sure that is true Irving. Obviously it depends on wind direction and strength, but according to Bernouli, (can't remember spelling) wind blowing between the surfaces will cause a reduction of pressure on the underside, so in some instances will actually create negative lift (downforce). Anyway that is all academic - try to pass all responsibilty on to the installer!!! Good luck. G.

[GEOFFREY]

I suspect that the system you refer to will attempt to direct as much airflow as possible under the roof panel to create negative lift, and have some kind of spoiler to the perimeter of the upper surface to disrupt the airflow and form eddy currents(sorry eddy!!)and therefore prevent laminar flow or suction. Sorry to hear the installers don't want to play ball, but I do understand your wish to get a local sparky to fit, however I understand that to get the FIT benefits the panels and installer need to be MGCS (or whatever) registered. When I looked into it about a year ago I came to the conclusion that payback would be about 6 years and as I was 70, could not decide if it was worth it!!! G.

[irving2008]

I came to the conclusion that payback would be about 6 years and as I was 70, could not decide if it was worth it!!! G.

that's exactly my issue, the kit is cheap and installation only a day at most, but knowing the savings you're going to make the MCS registered installers load the install costs. My 14 panel system kit cost is £3500, the quotes are £7500. With FIT that's about 7y ROI, but just saving on usage without FIT with £500 for the sparky to install gives me a 2.5y ROI.