Quote Advice

[DY2 0EH]

Hi folks, hopefully a few of you can assist a solar pv newbie get an appropriate system, well installed at a competitive price.

The house is a 1945 semi, hipped slate roof with the larger side 20 deg SSW orientation. I've recently been attempting to research solar and have got as far as having my first quote from a local installer found from the MCS site.

Quote for a 2kWp PV system £5k
SolarWorld 250W All Black Mono x 8
Enphase M215 Micro Inverter x 8
Onroof mounting system
AC and DC electrical equipment
Ofgem approved generation meter

Estimated output based on SAP calc 1606Kwh/yr
Money earned = (1606x14.38p) + (1606/2 x 4.77p) = £269.25
Money saved = (1606 potentially) x 10p = £160
Total benefit = £429.85

8.5% return on investment


I'm planning on obtaining further quotes but was just after some initial feedback/advice before going any further.

Thanks in advance

 

[TedM]

Presumably 2kWp is the limit set by the hipped roof space. Is there not scope for more panels on the SSE side?

To get the 14.38p rate the system will need to be installed, commissioned and a FIT application in by 31st December. Missing that date will drop the rate to 13.88p.

The £160 'money saved' should be around half that figure.

 

[TJ Anderson]

Hi folks, hopefully a few of you can assist a solar pv newbie get an appropriate system, well installed at a competitive price.

The house is a 1945 semi, hipped slate roof with the larger side 20 deg SSW orientation. I've recently been attempting to research solar and have got as far as having my first quote from a local installer found from the MCS site.

Quote for a 2kWp PV system £5k
SolarWorld 250W All Black Mono x 8
Enphase M215 Micro Inverter x 8
Onroof mounting system
AC and DC electrical equipment
Ofgem approved generation meter

Estimated output based on SAP calc 1606Kwh/yr
Money earned = (1606x14.38p) + (1606/2 x 4.77p) = £269.25
Money saved = (1606 potentially) x 10p = £160
Total benefit = £429.85

8.5% return on investment


I'm planning on obtaining further quotes but was just after some initial feedback/advice before going any further.

Thanks in advance

You can get 4KWp for £5k round here

 

[Leesparkykent]

Yes but slate roofs are a pain in the backside, and depending on how complex the scaffold is.

 

[TJ Anderson]

Yes but slate roofs are a pain in the backside, and depending on how complex the scaffold is.

Yeah that's very true. There is a also the tile drilling & silicone brigade vs the proper slate mounting kit.

 

[DY2 0EH]

Many thanks for the replies, if it helps I've attached a screenshot from google earth along with some dimensions. I've been attempting to do a scale drawing to see how may panels (1675x1001) I could fit on the SSW side and also on the SSE side.

 

[Worcester]

Consider also Sunedison (or LG) panels, same size 285W each. or Benq, different shape however 325W in about the same space...

Bearing in mind the overheads of the installation, on this size in both above options, your RoI will be better than what you've been quoted.

 

[Worcester]

I've just done a layout in PVSol, and if your dimensions are correct, firstly the above panels will all be a better investment and secondly I would insist on a deatiled layout drawing showing edge margins and how they plan to meet the PV Guide and wind loading requirements - to fit 10 panels on that one side of the roof, they MUST have significantly reduced the margins, and maybe even overhanging some parts of the ridges.

Ask to see the wind loading calculations and layout drawings BEFORE you enter into a contract

Recommended margins are a minimum of 400mm (not just ridge and eaves - also the hips )

...
In determining the appropriate pressure coefficient to use in calculations, the location of the PV array on the roof needs to be determined as some, or all, of the array may be in the “Edge Zone” as defined in BS EN 1991-1.
Pressure coefficients for the Edge Zone will be higher than those in the Central Zone of the roof. BRE digest 489 and the other sources listed above include pressure coefficient values for both Edge and Central zones.
...
Unless specifically designed to do so, systems should be kept away from the roof perimeter. For a domestic roof, a suitable minimum clearance zone is around 40-50cm.
The requirement to keep an arrays away from a the edge of a roof is suggested because: wind loads are higher in the edge zones; keeping edge zones clear facilitates better access for maintenance and fire services; taking arrays close to the roof edge may adversely affect rain drainage routes; and when retrofitting systems, there is the potential for damage to ridge, hip, valley or eaves details.
Note – on many roofs a 50cm gap from the edge will still mean that PV modules are fitted in the “Edge Zone” as defined in BS EN 1991-1 where higher pressure coefficients need to be implemented due to the higher imposed wind loads.
...