Huge disparity between Ikea and Energy Trust's solar quotes

blizeH

Hi,

We have a house that annoyingly has an east/west facing roof, but we're still interested in solar panels.

When I get a quote from the Energy Saving Trust they estimate the income to be £268:



However, when I got a quote from Ikea they estimated the total to be a lot higher at £689:



The only thing I can think of is that the first price is just a rough estimate, whereas the second one actually let me trace around my roof to get the exact location and roof size like so:

But either way I'm not sure that would explain the huge difference?



Thanks

Smiley_Dan

This site is independent and the most used amongst solar enthusiasts: http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

You might have more luck in the "green" forum where there's more expertise: http://forums.moneysavingexpert.com/forumdisplay.php?f=100 (including help on how to use the above estimator).

FWIW maybe it's not just about the FiT income? If you have an E/W setup that might get you more useful energy at the start/end of the day which might fit into your lifestyle better.

See also http://www.navitron.org.uk/forum/index.php/topic,23116.0.html

System

There is a lot more to solar PV than just the size of your roof and how many panels can be installed. The site above will give you a lot of information about roof angle, orientation and theoretical output but, beware, that without careful analysis you could well be disappointed. For example, shading from a tree or chimney stack will cause a significant drop in energy across all panels with a potential loss of 20% of the total output pa. For this reason, I have a 2.15KW system: theoretically, my roof would happily taken 4KW plus. I get, on average, about 1850KWHs per year. We are retired household and even when we work hard at it, we find it difficult to use more than 50% of what we produce. Have a look at the YouGen site if you want installer recommendations..

mac2008

The EST has used the lower FiT rate of 6.38p per kWh which is only applicable if you have an EPC rating of less than D. It should be 14.38p which makes the difference lower.

The rest of the difference may be explained by different assumptions about electricity savings and whether inflation is taken into account.

Did the EST ask you about an EPC? If not I would email them that screenshot so they can correct it.


Edit: I've checked the EST calculator and it does ask about your EPC. You must have selected the option for band E or lower.

tunnel

OP, pop over to the green and ethical forums and post your details there. There's many that frequent the forums that will happily advise/help. Don't worry about E/W split either, I've just overseen an installation for my parents on exactly the same scenario.


If you have any shading, don't panic, there's ways and means to minimise the impact of this without the need to downgrade to a smaller system(as has been suggested).


Lastly, I'd take anything that Ikea tell you with a pinch of salt, they really should stick to selling household items.

yangptangkipperbang

blizeH wrote: »

We have a house that annoyingly has an east/west facing roof, but we're still interested in solar panels.

According to the latest "research", solar panels should be facing East/West...........all those panels facing South are facing the wrong way :rotfl::rotfl:

WestonDave

I don't think anyone disputes that south facing is going to be the best for peak generation and the highest daily total - but generating 3.5-4kW off a typical 4kWp system at mid day isn't that much use to most people on a hot summer day when the washing is out on the line, they don't want hot food or drinks and the hot water immersion got topped up sufficiently during the morning generation. Having the flatter spread that comes with the East West combination might mean more used directly in the house and less exported (and with local use you'd get less wasted in line resistance etc). It makes sense that as a nation we need power supplies that cover the whole waking day rather than nothing much from before 8am or after 6pm. I've got a SW/SE split which has done very well.


This is the research http://www.solar.sheffield.ac.uk/panel-data/comparison-of-east-west-arrays/

blizeH

Thank you all so much for the responses guys... seems like I have a lot more research to do then! And yes I did pick band E or lower for the EPC... honestly I wasn't quite sure what it meant so just went with the lowest option

Are there any solar panel companies in particular you would recommend? I went with Ikea because... well, I have no idea why really, but they seem to be the largest/most reputable brand that offer them, and Ikea generally do decent quality at low prices.

Smiley_Dan

There are reviews of companies at the YouGen: http://www.yougen.co.uk/search/

You should get an EPC done. Most modern houses should be at least band D and if not it's not a great deal of work to upgrade... and worth it for many reasons.

If you purchased the house in the last few years there's probably already an EPC for it: https://www.epcregister.com/

blizeH

Thank you very much Dan, I cannot remember exactly what my band was but thinking about it now it was definitely higher than an E... I think it was a C, maybe even a B but I cannot find the RRN to check - I think I have the full details at home though so will take a look over the weekend

That puts the estimate up to £445 at least which seems decent... as a long term investment I'm thinking solar will be awesome, depending no whether or not we actually stay here long enough to get the full rewards I guess (at the moment we have zero interest in moving)

macman

Do you mean that your roof is aligned east-west, rather than faces east-west?
It can't do both, unless you are intending to split the panels over 2 sides of the roof, some facing east and some west.