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After a new solar roof is installed, how hard to replace an existing rooftop condenser unit?

So I should have used actual numbers.

1. My house uses approximately 25,000 kWh per year. Over 20 years that’s 500,000 kWh. At LADWP 27 cents, that’s about $125k.

2. My 16.32 / 3 PW system will cost a around $90k over the same 20 years. That’s because it will produce at least 25,000 kWh per year and I get to use all of those kWh. So it’s 27 cents v 19 cents, or an average bill of over $500 vs cost of $300.

3. A solar roof would cost more, but as I said, you get to subtract the cost of the new roof, I stead of just paying for the new roof.

I think other factors even out:

Yes, the system may become less efficient, but power costs could increase by more as a percentage.
The system could also last for more than 20 years, at which point it is however many years of truly free electricity.

So that is with PWs. Without PWs the system cost is about half.

Everyone’s energy costs vary (captain obvious!) but since the cost of the system does not vary, I see no way around doing the calculation for oneself.
Good thing you get to use all of the produced kWh. I don't know about LADWP but for SCE, the buy back rate is very cheap:
So a PV system produces just enough kWh is great because it's low upfront costs.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
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Riverside Co. CA
Good thing you get to use all of the produced kWh. I don't know about LADWP but for SCE, the buy back rate is very cheap:
So a PV system produces just enough kWh is great because it's low upfront costs.

All california buyback rate is that cheap, if you are a net producer for the entire year. They are not incentivizing anyone for trying to become an electric utility and selling power. The goal should be to have a net zero true up at the end of the year and cover 100% of your electrical usage.

In any case, good luck with your decision(s).
 
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