Estimated production for 6kW panels

[angel99]

Hi,

I am in the process of ordering solar panels and trying to figure out the right size for my needs. I felt 6kW system size would be good based on the usage now and the potential for increase in future. However, looking at the various quotes I have received, the kWh production in a year is the lowest for Tesla at 7700 kwh/year vs 8600 kwh/year for other systems. Is Tesla underestimating its production? Or should I truly be expecting a number around ~7700 kWh for my calculation?

Thanks!

 

[angel99]

Thanks! I tried that, but I couldn't figure how to get the tilt and azimuth degrees for my house. Is there a way for me to figure those out rather accurately? Sorry, if its a naive question, I am new to this world

 

[dareed1]

You can get the azimuth by looking at your house in the satellite view in Google Maps and using a protractor. I checked my roof tilt by going up a ladder and using a clinometer app in my phone.

 

[SaveOurPlanet]

Hi,

I am in the process of ordering solar panels and trying to figure out the right size for my needs. I felt 6kW system size would be good based on the usage now and the potential for increase in future. However, looking at the various quotes I have received, the kWh production in a year is the lowest for Tesla at 7700 kwh/year vs 8600 kwh/year for other systems. Is Tesla underestimating its production? Or should I truly be expecting a number around ~7700 kWh for my calculation?

Thanks!

I would take a simple approach and gather stats on how much energy you use the last 12 months and add 10% to 20% on top of that and tell Tesla that is a system you want. A big question is whether you are 100% electric now or with natural gas for cooking, heating and water. If you are not 100% electric and want to transition some gas use to electric use you need to account for that for your target system. Tesla seems to be very conservative in their estimate because that's what the red line is and they want to make sure they can get that. PVWatts and Google Sunroof will give you a rough estimate but only based on historical data and general assumptions, if you have friends that have access to software like Aurora you will get a lot closer since they use other data including Lidar to model your roof. But getting your baseline need plus the 10-20% extra is what I would do. Do not worry about company A says this and company B says that, whoever can give you what you need and make you feel comfortable regardless of cost is the one you want. Of course, that is just me.

 

[getakey]

you should be able to estimate your roof pitch. Just google roof pitch and compare the common ones to your roof

 

[angel99]

Thanks for the suggestion! Will try that out.