North Facing Install?

[mark da spark]

We have just been to quote for a customer who wants their panels on the North facing roof at the back of the property?
He does not want people pulling up outside the front of his house and looking at the panels.... Don't ask!

Has anyone ever installed on a north facing roof? And would you take on a north facing job?

The customer has been shown the difference in expected yield between a north and south facing roof and still happy with putting it on the north.

 

[BruceB]

At first sight it seems barking.
But if you have a shallow north facing roof the numbers are surprisingly high
Regards
Bruce

 

[SolarCity]

Does he live in the southern hemisphere?!

If he knows the figures and he wants to go for it, I'd say you'd be mad not to install.

 

[cookiemonster]

Is it something like only 75 days of sunshine a year in uk which leaves 290 days of cloudiness which means that for 290 days a north facing roof is on a par with a south facing roof. Anyway average yield for a 35degree north is about 50-55% of that of south facing roof - doable but a much longer payback time.

 

[MCS Renewables]

I would protect yourself with a statement, signed by the customer and a witness explaining that you are installing on the North at his request even though you have pointed out that this is not the ideal orientation.
No comeback then... ever.

 

[daytona600]

seems mad to me but try thin films best on west/east facing and any inclination flat/vertical good low low/diffuse light
with 97% transformer inverter or dual-axis tracker would add to yield

 

[PVFIT]

I've had a similar quote recently where: front is SE facing at 30 deg (so pretty good) and rear is NW facing at 14 deg. As the NW roof is shallow it does offer better than expected performance (in theory) according to SAP. The customer has asked for near to 4kW, and only has space for 10 x 245Wp panels facing SE, with 6 on back. This is less of a trade off than putting all on back, which apparently every other installer has quoted at the customers request.

As with the other guys feedback, if you put the details in front of the customer (along with disclaimers) then you have done your best to ensure the customer is informed before they proceed. SAP also offers an irradiation figure per sqm for Northerly facing aspects to support your case!

However if they have a perfectly good South facing roof I would not feel comfortable. From a commercial point of view I would always bare in mind that a disclaimer means nothing when the same customer decides after 1-2 years the performance of their system does not match their neighbours, which is South facing at 30 degrees, and then starts to complain about it to their friends, neighbours and on the web.

 

[bobbullen]

Isn't there a rule saying the array should be pointing between E -W or SE - SW? No? What am I thinking of then?

 

[Vassilis]

Hey guys,
I know this will seem a bit weird but i would really appreciate some help. I am a law student in Warwick University and i am working on a case that is all about Solar Panels.
Basically, my imaginary client advised a house owner that if he puts Solar Panels it would save him THOUSANDS OF POUNDS IN ELECTRICITY BILLS. However he then commended that the panels should be put at a side not really obvious for visitors and thats what happened.
Bad thing is that this side happened to be the North facing side of the building so the house owner sued my client.

Now, the way i think about it, if i can prove that the solar panels saved him off at least £2000 not including costs for setting up the panels or repairment costs then my client technically said nothing wrong! So do you think that would be possible?

I cannot give any technical information like the angle of the roof or anything like that. However i really would appreciate some rough estimates.
Thanks in advance

 

[SolarCity]

Did your client give the customer solid figures of estimated generation? He should have and if the figures accurately reflect a north facing install then this shouldn't be a problem. Being an imaginary client makes it hard to really suggest that he has breached MCS rules, but he may well have done.

Whatever happens, it sounds like your imaginary client needs a good shoeing in his imaginary head.

 

[BruceB]

In my opinion if the installer recommended a north facing roof for aesthetic reasons then he has given negligently poor advice unless he made it absolutely clear to the customer what he was sacrificing by putting the panels on that slope.

If he put the panels on the north facing roof at the customers request, then it becomes a little greyer, but I would still expect in the quote documentation the loss from facing north to be made clear.

In my opinion there is more to it than just the quantum of money saved, the customer had a reasonable expectation that the system recommended would maximise the possible contribution from the installation.

Regards
Bruce

 

[jupestar]

I've done one on a north west roof. Got it in writing beforehand that they knew what there were expecting.. Think is was about 679KWh/KWp.

To be fair it was only 6 panels and she was getting 14 on the south east, but ran out of room for more. But i made a point of getting that piece of paper signed.

I've also done it for a felt roof (30 deg pitch), when we had to use slate hooks and screw straight through the felt.

This is what we are going to do.. sign here if you are happy with it.

 

[TedM]

I think it would depend upon what your imaginary client actually said quite specifically.

Did he say "it will save you THOUSANDS OF POUNDS IN ELECTRICITY BILLS" or maybe he said "it will save you THOUSANDS OF POUNDS IN ELECTRICITY BILLS over the next 25 years" or "over the next x years" at least. Did his quote make the time period of the saving clear?

The first could be interpreted as meaning £K's saving per year which is clearly impossible for a normal domestic install irrespective of the orientation of the panels. If over 25 years then there is no real problem as even a N facing setup could achieve that.

It might also need to be pointed out that the saving is net. i.e. the actual bills might not come down by £K's but when the FiTs income is netted off against the bills they would certainly be lower.

 

[Seek-a-Geek]

Hi Guys,

I know this is an old thread so I apologise if adding to it is frowned upon.

We have a client who would like a PV system on a property that is facing approx 10 degrees form north at a pitch of approximately 30 degrees. We have told them that they will not produce much but they would still like to go ahead.

The new assessment says that the system would output 1136 kWh's but I don't think I believe it. Does anyone have any figures for what a north facing system has put out over the course of a year? A colleague seems to think that the inverter wouldn't even fire up let alone produce anything.

Any help would be greatly appreciated.

 

[ktech]

We have installed on a north roof. The client already had 4kw on the back south roof so it was his only option. DNO approved the increase and customer was happy with the figures, from memory was about 50% of the south roof generation.

 

[ktech]

Inverter won't even fire up? That's like saying a west roof won't fire up until after mid day. My 4kw west roof starts at 5am in the morning this time of year, a north roof will also do similar. I would suggest undersizing the inverter is a consideration to maximise the generation.

 

[Seek-a-Geek]

Thanks for the reply ktech.

Please excuse my ignorance on this application. If the system is on a north facing roof at a 30 degree angle will it not be in constant shade from the apex of the roof? Also would it work in winter when then sun is at it's lowest?

 

[BruceB]

If you do the sums for the summer sun you will find that it is about 30 degrees away from the vertical in the Bristol area as an example. So the north facing roof will be in direct sun then. Put some numbers into sunny design and you might be surprised what a north roof will generate. 20 degrees slope will be better than 30 degrees, but even with 30 degrees I suspect you will get between 50% and 60% of south facing annual generation.

 

[Seek-a-Geek]

That's brilliant. I'll knock up the system in Sunny design and see what it comes out with.

Thanks for all your help guys.

 

[BruceB]

Just typed some numbers in myself for 30 degrees slope:
Plymouth c. 61%
Swansea c. 59%
Not recommended, but needs must.

 

[infinity]

I installed 4KW yesterday using solar world and Solaredge, its on a 45 deg pitch and 10 deg off north- north west. Figures still stack up using SAP!

 

[Ian-LS]

I'm not sure how you made a 45 degree north west facing roof figures stack up. I did a site survey a month ago and the customer was on about a north west facing roof with 45 degree tilt and I advised the roof was not suitable. 52-56% of a south facing system 35 degrees and no shading so unless the customers bills are really high then I'm not sure how the figures stack up to be honest.

 

[infinity]

Well they don't have gas for a start.
If you work it out using SAP, the investment is still a lot higher than having it in the bank.
Therefore that makes the figures stack up.

 

[whinmoor]

Well they don't have gas for a start.
If you work it out using SAP, the investment is still a lot higher than having it in the bank.
Therefore that makes the figures stack up.

Makes sense to me. An installation on shallower pitch of 30 degrees facing north should pay for itself within 10 years. If they are heavy consumers of electricity such as off the gas-grid, the annual benefit is considerable and much better value than saving in an ISA at sub 3%.

 

[Worcester]

Remember the 'smaller' the system the more of it's output you will use. Without an immersun type device all domestic South facing 4kWp systems will almost certainly struggle to get up to 40% consumption of generated due to the mismatch of generation / consumption.

 

[infinity]

Exactly, well I have solar edge on the system so I can update with actual figures of how it's performing

 

[darrentowill]

As long as all within MCS then its fine, you can get a good yield from North Facing but no were near as good as South, this is all presented in the MCS with application.
I would be happy to install as give correct advise and information payback etc, if the customer can see the facts and is happy then all is good.