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Is it worth siting panels on an East facing roof?

Solar Photovoltaic (PV)

Last Post by Carpenterstation 14 hours ago

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Carpenterstation

(@carpenterstation)

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Topic starter 20/03/2025 10:45 am

I am trying to evaluate whether this is viable or not.

our East roof is large 35m2, no windows or dormers and pitched at 35degrees.

we have existing solar so this would just be additional panels connected to current inverter and batteries.

it might be anecdotal - but we seem to get sunnier weather first thing? Clouds coming later on in the day. If this is true then even though we would loose the sun from this face after about 13:00, it might help with early mornings when we tend to use a bit of power

does anyone have any data for an east facing roof that they might be able to share please? Preferably Uk East Midlands for about 12 months. I can then compare this with what we get from the south and see if an investment is viable.

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downfield

(@downfield)

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20/03/2025 11:40 am

Have a look at Solcast or one of many similar apps which will give you forecasts for any location and orientation of panels.

I have 10 panels east and 14 west and got about 7000MWh in total last year. I'm near Hertford.

This post was modified 1 day ago by downfield

Mitsubishi Zubadan 14kW with Mixergy 210l DHW in 220m2 barn property. 24 solar panels = 9kWp with GivEnergy 5.0kW Hybrid inverter and 19kWh GivE batteries. Jaga Strada fan-assisted rads throughout. Landvac vacuum glazing/triple glazed windows.

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Carpenterstation

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Topic starter 20/03/2025 3:33 pm

@downfield 7000MWh? From 24 panels ? Do you mean 7MWh? ( I got 5.8MWh from 29 south facing panels last year)

This post was modified 23 hours ago by Carpenterstation

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downfield

(@downfield)

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20/03/2025 3:35 pm

@carpenterstation oops - yes I do! 7MWh

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Mars

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20/03/2025 11:10 pm

@carpenterstation, adding panels to your east-facing roof could work, but personally, we’d be more inclined to go for west-facing panels instead. In our case, we find that we use more power later in the day, so we’d prioritise west-facing panels to extend generation into the afternoon and evening when demand is typically higher.

That said, if your household tends to use a lot of electricity in the mornings, an east-facing array could still be useful, especially since you’ve already got an inverter and battery in place.

Let us know what you decide… we’d be interested to hear how it plays out.

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Old_Scientist

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21/03/2025 12:02 am

Posted by: @editor

↑

@carpenterstation, adding panels to your east-facing roof could work, but personally, we’d be more inclined to go for west-facing panels instead. In our case, we find that we use more power later in the day, so we’d prioritise west-facing panels to extend generation into the afternoon and evening when demand is typically higher.

That said, if your household tends to use a lot of electricity in the mornings, an east-facing array could still be useful, especially since you’ve already got an inverter and battery in place.

Let us know what you decide… we’d be interested to hear how it plays out.

Interesting. We currently find morning solar is most beneficial for us as we can run the heat pump on solar following an overnight switch off (we often don't get up before 10am). The afternoon is financially less beneficial as we are on Octopus Cosy where the afternoon import rate of 12.86p is cheaper than the solar export rate of 15p so we would happily import in the afternoon.

Hopefully adding a battery to the mix soon, which will totally change the dynamic, and just highlights how these choices are very dependant on personal circumstances and intended use.

@carpenterstation as @downfield suggested, I use PVGIS to model predicted solar generation and have found it to be pretty accurate, certainly sufficiently so to model and compare your proposed solar addition.

This post was modified 14 hours ago by Old_Scientist

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Carpenterstation

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Topic starter 21/03/2025 12:46 am

Yes. Thanks all. I have used the guides and have found that our East is actually 120 degrees (so more ESE than East) and that the solar is only slightly down on south (our “south” is 210 degrees). Our usage suggests early mornings when we prep car for work, tends to be more of a drain than evening- and we don’t really have a West roof.

but it is the clear sun early in the day (rather than later cloudy sun) that I think might be the clincher. Need to check with DNO though as another 5 kw might give them problems. And it is viable with Octopus Cosy while there is still an export market. But if that goes it’s a very different proposition….

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