SolarPV tables / online calculator
Is there some table or an online calculator that I can look up expected solarPV kWh generated by month, for my latitude/longitude & azimuth & tilt? Need the figures by the month. Thanks, Michelle



I'd be interested what others find whilst using that web app, @gary. It's a great resource but it does also highlight how local variations in conditions can affect the theoretical output.
For me, it overestimates by about a quarter which on the face of it is quite a significant margin. However, in practice there are some extras to factor in:
- Shading isn't a big issue but we're not completely immune.
- Although our kWp is calculated on the number and capacity of all the panels, there are four which are not on the main South-facing elevation. This is really important in capturing the early sun and therefore extending the period when we don't have to draw from the battery but it is at the expense of absolute amount of electricity generated.
- Our panels are now four years old so there will be some degradation in their generating capabilities now.
All that is entirely reasonable and if I factor those points in then the web app is doing a pretty reasonable predictive job. However, it's worth remembering these points since if I was making a buying decision based on expecting to generate 6MW/year and ended up getting 4.5-5 then I'd be a bit miffed.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
Posted by: @majordennisbloodnokI'd be interested what others find whilst using that web app, @gary. It's a great resource but it does also highlight how local variations in conditions can affect the theoretical output.
We've only had our solar since last June, but so far for me it's been very accurate and within the published standard deviation each month.
Posted by: @majordennisbloodnokFor me, it overestimates by about a quarter which on the face of it is quite a significant margin. However, in practice there are some extras to factor in:
- Shading isn't a big issue but we're not completely immune.
- Although our kWp is calculated on the number and capacity of all the panels, there are four which are not on the main South-facing elevation. This is really important in capturing the early sun and therefore extending the period when we don't have to draw from the battery but it is at the expense of absolute amount of electricity generated.
- Our panels are now four years old so there will be some degradation in their generating capabilities now.
All that is entirely reasonable and if I factor those points in then the web app is doing a pretty reasonable predictive job. However, it's worth remembering these points since if I was making a buying decision based on expecting to generate 6MW/year and ended up getting 4.5-5 then I'd be a bit miffed.
Yes, I think you'd need to create separate arrays for each roof aspect, and then combine them to get a representative total. Mine is straight forward as it's a single aspect that is unshaded, hence the results seem remarkably accurate.
Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 3.645kWp solar (south facing), Fox ESS inverter.
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.
This guy did a good analysis
https://protonsforbreakfast.wordpress.com/2022/03/16/analysis-16-years-of-solar-pv-data/
in summary go down a bit more at first then steady slighter decline. The “spec” is 20% down in 25 years.
2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with it) open system operating on WC



Posted by: @agentgeorgeyour tag line has a typo
suus should be sumus (always)
Quite right. Amended, and thanks for spotting. Rather proves the point, eh?
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
- 22 Forums
- 2,021 Topics
- 44.1 K Posts
- 54 Online
- 3,193 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
Very much agree. I think OP is over-concerned about th...
By JamesPa , 2 hours ago
-
RE: Performance of Heat Pumps in Mild Weather
'and thus its capacity' assumes that output is a linear...
By JamesPa , 2 hours ago
-
Just an update on the responses received by Smart Heati...
By Eliuccio , 6 hours ago
-
RE: Is your gut better than Math
By SUNandAIR , 7 hours ago
-
@sandman1600 I’ve been following this thread and althou...
By bontwoody , 8 hours ago
-
RE: Would You Find Value in a Premium Installer-Supported Forum?
We are very pleased to announce that Brendon Uys (@heac...
By Mars , 10 hours ago
-
RE: Help me keep the faith with my air source heat pump installation
@adamk Please feel free to post any proposals for com...
By JamesPa , 10 hours ago
-
RE: Ecodan 11.2kw Wireless thermostat drop outs
@skyecraig I've had our FTC7 wireless thermostat lose...
By RobS , 20 hours ago
-
RE: Signenergy AI Mode - How long does it take to learn a usage pattern?
I am definitely interested in this as I am considering ...
By Grantmethestrength , 1 day ago
-
RE: Air source heat pump roll call – what heat pump brand and model do you have?
Hitachi Yutaki SCombi Heat Pump(Indoor Unit ) RWD-3.0RW...
By trebor12345 , 1 day ago
-
RE: Jokes and fun posts about heat pumps and renewables
ми не граємо в карти
By Transparent , 1 day ago
-
RE: Pressure Drop in primary circuit
Nick from Samsung has called me back . He has sa...
By ohdearism , 1 day ago
-
RE: Vaillant water pressure gauge vs Analogue gauge
@adamk not sure I want to mess with the lockshields I a...
By jeegnesh , 1 day ago
-
RE: Hitachi Yutaki SCombi Heat Pump - Thermal Off's
Thanks for your help.
By trebor12345 , 2 days ago
-
RE: Ecodan consuming 100kwh per day in new build!!!
Sorry to hear this is not yet fixed but please do keep ...
By JamesPa , 2 days ago
-
RE: What happens when the outside temperature exceeds the upper WC point?
The focus of this week’s podcast recording is on “Heat ...
By Mars , 3 days ago
-
RE: How many compressor starts per year
@gc61 Less that one start per hour is very good, our pu...
By MikeF , 3 days ago
-
@transparent ,thanks for the reply,I'm just wondering h...
By Browntrout , 3 days ago
-
RE: Opinions please on me putting a 2.5kW roof mounted turbine on my garage - am I mad?
You might want to have a look at some of the posts here...
By IRMartini , 3 days ago
Most Active This Week
# | Name | kWhs |
---|---|---|
1 | JamesPa | 214 |
2 | Mars | 123 |
3 | Toodles | 103 |
4 | AdamK | 98 |
5 | ohdearism | 88 |
6 | trebor12345 | 87 |
7 | Transparent | 77 |
8 | Gary | 76 |
9 | SUNandAIR | 70 |
10 | rhh2348 | 70 |