Solar Panel - have a east west roof - will it generate much? 11 October 2012 at 6:59PM in Green & Ethical MoneySaving 6 replies 12.6K views

swift1_2

Hi,

apologies if this has been discussed before (I've tried to have a look through there is so many threads but can't find info on east-west roof)

I've got a detached house with an east-west roof with a chimney on the east side.

I've had 3 sales people out - typically saying I can install 16 panels - 8 each side - will be a 4kwp system but saying it would generate a conservative 2450kwh.

system cost I've been quoted around the £5,500 -£6,500 mark.

Are there people who've had panels installed on east-west roof and does it generate a decent amount?

I live in Nottingham, and elec gets used during the day. Last year we used 8100 units!:eek:
october deadline looming, wondering whether to take the plunge! its a big investment!

Martyn1981

Hiya, just been chatting about E/W roof splits, the last few days on here, post 1344 onwards.

http://forums.moneysavingexpert.com/showthread.php?t=3853851&page=68

You should get about 80% of a due south roof. Earnings and savings will be greater if you have high daytime use. Any help?

Mart.

Martyn1981

swift1 wrote: »

I've had 3 sales people out - typically saying I can install 16 panels - 8 each side - will be a 4kwp system but saying it would generate a conservative 2450kwh.

Quick check on PVGIS (climate) for center of Nottingham, 4kWp (all East) gave 2,790 estimate.

http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#

Give it a try, 2kWp East and west should be similar. Some instructions here, post 1, section 5:

http://forums.moneysavingexpert.com/showthread.php?t=3872445

Mart.

1echidna

Yes as indicated above I have East and West facing roof. Too early for me to comment on actual performance of my new system though.

Hobbo2006

I have an East/West split system. Hopefully my system details will be in the signature.Although the total amount of kWh's is obviously less than a due south facing roof, there is a benefit to having a split system. We tend to get a flatter, wider generation graph. So rather than having a high peak of generation we start generating early and finish very late. As the generation is spread further across the solar day, I think we are able to use more of the electricity that we generate.

Having only had the system since Feb 21st I'm still missing the winter generation figures but have found that spring and autumn have substancially exceeded the figures we were quoted, whilst the summer months were pretty much as quoted.

Our chimney is on the East side too and creates shade, which is why we went with only 5 panels on the East side.

These guys will help you with the latest tariffs which you can use to calculate payback. I personally did a money transfer off a credit card with the aim to pay all the FIT money off the card as it comes in. It's working well so far and aiming to have paid off the card within 5.5 years and then have almost 20 years of FIT payments. Why use your own money when you can use other people's money?

Martyn1981

Hobbo2006 wrote: »

These guys will help you with the latest tariffs which you can use to calculate payback.

@ Swift1, Hobbo's right, should have slapped some numbers together too.

If that generation figure of approx 2,800kWh's pa is reasonable, then income and savings will be approx:
FITs 2,[email protected] = £448
Export (deemed 50%) 1,[email protected] = £63
Leccy savings modest guess = £100
Total approx £600pa.

As you said you have very high consumption and daytime use, then (depends on your tariff) but if you managed to use 50% at 12p, then total would be nearer £700pa.

Prices for 4kWp, I'd say you are spot on at around £6k.

Next tariff change is 1/11/12, but don't rush if you're not ready as the FIT rate will only be reduced by 3.5% to 15.44p and winter generation on an E/W system will be a little lower, so you might be better off researching more and haggling the price down say 5%+ over the autumn before the next tariff review date 1/2/13.

Best of luck.

Mart.

ViksB

We have a 4KW system installed entirely on a 1 degree off West roof. We are based in East Yorkshire and in 11 months (system installed in Nov) we have generated 2981 units, which was higher than both the PVGIS predictions and the solar company. We are very pleased with ours.