3kw DIY install

[Rossek9]

Ok so I have recieved another quote in for the system.

 

Details below - 

 

12 x 285 Solar World All Black panels

IRFTS Easy Roof in roof system

Generation Meter Landis Gyr single phase

Sofar 3680 Inverter 2 x MPT

 

4mm DC cable x 12m

DC Isolator x1

6mm 3 core 12m

 

This would provide a 3.42kw system via an MCS installer and registered for FIT. The price came back at £3.5k + vat (although I wont be paying the vat due to it being zero rated)

 

 

Edited April 10, 2017 by Rossek9

[PeterW]

@Rossek9 that sounds pretty good to me. 

[Jeremy Harris]

That does indeed sound very good, at that price it's not really worth considering the hassle of a DIY set up, I think, plus you'll get the FIT and export payment, even if it is a lot lower than it used to be. 

 

I'm tempted to have a think about adding a small East - West split system fitted to our garage roof for that sort of price, as it would help to "flatten" our generation curve a bit.  Have to wait until I've finished the other 100 jobs I have to do first, though..............

[Rossek9]

Yeah the installer was also saying that I may be able to get an interest free loan from the Home energy Scotland for £2.5k. This would no doubt help the budget a little but I will need to speak to them first.

 

He is suggesting 8 panels facing south and 4 west, as not all 12 panels with fit on our south facing roof.

 

Anyone know if the  sofar inverter is any good?

[dogman]

if you split the system you will need some sort of optimisation fitted that will bump up the cost.

Also for others info in England (not sure about Scotland) If you have a system that receives FIT you cannot add or extend it and receive any more fit payments

[PeterW]

I "think" he's included 2 optimisers in the price on that quote so is assuming he's going on south and west. 

 

Looking again if he can do it at that price on two elevations then it is very good as it's the edge components on the in roof system that cost the money. 

[dogman]

Just had a look at your inverter and it is a string inverter that should allow you to fit on two different roof orientations

 

[Jeremy Harris]

Some inverters have two MPPT inputs, so could handle a split array OK without the need for optimisers.  Our system is all on a single, un-shaded roof plane, but is still split into two DC strings, each feeding a separate MPPT in the inverter.

Edited April 10, 2017 by JSHarris
Cross posted with dogman, saying much the same

[Rossek9]

37 minutes ago, PeterW said:

I "think" he's included 2 optimisers in the price on that quote so is assuming he's going on south and west. 

 

Looking again if he can do it at that price on two elevations then it is very good as it's the edge components on the in roof system that cost the money. 

 

Yes he is aware that its two elevations prior to him pricing to system.

 

42 minutes ago, dogman said:

if you split the system you will need some sort of optimisation fitted that will bump up the cost.

Also for others info in England (not sure about Scotland) If you have a system that receives FIT you cannot add or extend it and receive any more fit payments

 

I am only getting one shot at this as its an in roof system although I may decide to add some west facing panels to the garage at a later date................although this will be on roof

 

I wonder if I should be going for a bigger system?

Edited April 10, 2017 by Rossek9

[dogman]

At that price i would i have less panels for £1500 more (its a living down south thing)

[Rossek9]

I've spoken again to the installer about the in roof kit and he assures me that if I am installing with slate the roof does not require to be battened at all. Does this sound right?

 

In Scotland it is normal practice to just slate straight onto sarking although I thought that for the in roof kits there needed to be battens and counter battens to allow air flow behind?

 

However I found this via the Easy roof website -

 

 

[Ferdinand]

On 10/04/2017 at 08:53, Rossek9 said:

 

I am only getting one shot at this as its an in roof system although I may decide to add some west facing panels to the garage at a later date................although this will be on roof

 

I wonder if I should be going for a bigger system?

 

That was my logic, and why I went for 9.98 kWp.

 

If you have the extra 5k earning 1% interest in a Bank Account ....

 

Your choice :-) .

 

Ferdinand

 

Edited April 14, 2017 by Ferdinand

[Jeremy Harris]

I looked at this carefully, and there is definitely an advantage in ventilating under the panels.  We have 18mm OSB sarking, counter battens, membrane, then battens, then the GSE in-roof system (near-identical to the Easy Roof system) fitted to the battens.  This arrangement allows a good airflow up under the panels to the ventilated ridge.  Our roof is also "slate":

 

Edited April 14, 2017 by JSHarris

[Rossek9]

6 hours ago, Ferdinand said:

 

That was my logic, and why I went for 9.98 kWp.

 

If you have the extra 5k earning 1% interest in a Bank Account ....

 

Your choice :-) .

 

Ferdinand

 

i had budgeted £5k for our PV install although seeing as the prices of every other part of our build are coming in above expected maybe I should just use the savings to cover other costs...

 

If if only I had this problem with the foundation costs!!

Edited April 14, 2017 by Rossek9

[Rossek9]

4 hours ago, JSHarris said:

I looked at this carefully, and there is definitely an advantage in ventilating under the panels.  We have 18mm OSB sarking, counter battens, membrane, then battens, then the GSE in-roof system (near-identical to the Easy Roof system) fitted to the battens.  This arrangement allows a good airflow up under the panels to the ventilated ridge.  Our roof is also "slate":

 

Is the advantage for performance of the panels or something else?

 

Not having battens and counter battens seems to be bringing the timber frame package down by about £3k.

[Jeremy Harris]

It's mainly panel performance.  The one disadvantage with in-roof PV panels is that they can run a lot hotter than on-roof panels, unless there is really good ventilation behind them to take away the heat.  Panel performance falls off dramatically as they heat up, and even on-roof system performance will dip a fair bit on a hot day, with the panels reaching around 40 to 50 deg C or more.  Getting the best ventilation you can behind the panels reduces the performance penalty from having them mounted in-roof.  When I measured the surface temperature of our panels and compared it with the measured surface temperature of a neighbours on-roof panels I found that our were only about 5 deg or so hotter, which suggests that the ventilation does help.

[Rossek9]

4 hours ago, JSHarris said:

It's mainly panel performance.  The one disadvantage with in-roof PV panels is that they can run a lot hotter than on-roof panels, unless there is really good ventilation behind them to take away the heat.  Panel performance falls off dramatically as they heat up, and even on-roof system performance will dip a fair bit on a hot day, with the panels reaching around 40 to 50 deg C or more.  Getting the best ventilation you can behind the panels reduces the performance penalty from having them mounted in-roof.  When I measured the surface temperature of our panels and compared it with the measured surface temperature of a neighbours on-roof panels I found that our were only about 5 deg or so hotter, which suggests that the ventilation does help.

Yes I did think that this might be the case. I just need to see if spending the extra £3k for battens and counter battens is going to be worthwhile in terms of payback from the panels. 

[Jeremy Harris]

I'm a bit surprised at the £3k for battens and counterbattens.  What sort of area is the roof?

 

The last lot of 50 x 25 roofing battens I bought were about 40p/m +VAT, IIRC. 

[Rossek9]

5 hours ago, JSHarris said:

I'm a bit surprised at the £3k for battens and counterbattens.  What sort of area is the roof?

 

The last lot of 50 x 25 roofing battens I bought were about 40p/m +VAT, IIRC. 

The quote hasn't included tile battens but the price came back as £1700 for supply and install of roof felt and fly batten...........so just a guess at £3k for tile battens as to be honest.