OK rather than clutter up the The &%$#@&&! Thread I figured I would start a new one since this may be a long thread.


Dave,
Taking that apart. We've done heat pumps, which have worked well. Probably was a massive over kill but why use a flyswatter when you have a sledge in hand. ( keep this thought in mind)
It is worthy to note that the solar tax credit is a credit against taxes owed and not a straight refund. If your taxes due don't exceed the amount of the credit you can carry forward to the next year.

We are approaching our limit with respect to being able to make our house more effiecint.
In retrospect, I wish before we did the windows I did a 4 rock wool external insulation and a new external skin.
This is a big house with lots of radiating surfaces areas. They also got cheap and did 4" walls instead of 6", so the R value is lower than it could have been.

As for the general rules of direction yield, shade, etc. I'm an engineer, we don't guess. We model.
https://pvwatts.nrel.gov/ this is a handy little model. You can pull up your house from the satellite shots and frame where the panels will go.
It also accepts the roof slope and true array solar direction.
It will then calculate using historical weather data how much power you can get pre year and per month.

It looks like this


It not perfect but it gives a much better swag at it than back of the envelope chicken scratches.

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This might be a dumb question, but how do you figure out how large of a system to get. Also how about a battery for those hot nights when solar is not producing any energy.

Rod

 

you've got a lot of land there Jerry, perhaps a nice ground based system would be possible on your property , instead of the roof ?

 

not dumb at all. I have data !!! I actually have data down to which circuits are using what.

yes that's kwh
I also know how much roof I have, what I can put there and how much power it can produce.
It turns out my daily demand is for the most part higher than what produce.
at noon I don't use it all up but will later. I then have a choice, sell it back to the grid or charge a battery.
The battery has an upside is it also provides ride-though for power outages.
But batteries ain't cheap. so it becomes a how long do I want to be able to go.


yes and no. I have 3 acres I could clear cut of the trees and put up a crapload of solar.
that just seems to defeat the purpose to a degree.
I do know of a brownfields site I can probably lease rather cheaply and I'm toying with creating an LLC to populate it with panels.

 

we have a heat pump which runs on propane. It is very efficient. We have 32 Tesla solar panels. We love them. They were installed by the previous owner who only lived here for 2 years. So weird that he paid for these and only lived here for 2 years. We love them. 0 electric bills.

 

I wish I could have taken advantage of a previous owner investing all that so I could use it! lol. That up front investment is the big part. Maybe they did not plan on selling and something just happened in life!

 

At least i my area there is a utlity called energysage.
you click in relevant data. they act as middleman and receive teh quotes and present them to you.
When Imentioned that i had recieved 4 quotes my wife was all " Well why didn't you tell me some numebrs then?"
I had to laugh and explain to her, the quotes were all over the place.

This is where being the engineer has come in. There are myriad cobinations of panels, how many, microinverters vs string inverers, batteries and sizes and vendors.
not to mention various quality issues or sizing mismatches.
I've already seen putting high power panels with lower power inverters.
You won't get any more power through the inverter than what it is rated for it doesn't matter how powerful a panel you attach to it.
It also isn't a real good idea to put panels on a 45° slope facing north by northeat. They aren't gonna do doodly squat.

 

Last night I had a solar salesperson come by. She was pleasant and all but it wasn't exactly a peer to peer conversation.
She had to call the mother ship a few times for answers to anything technical.
"oh we have our own proprietary microinverters and panels."
tech guy: " Oh we partnered with Enphase for the inverters and Hanwha for the panels."
Thier model is leasing you te equipment. The lease term is 25 years.
She had a slick little presentation on her tablet. Based on a 6% growth rate on electrical costs we'd save XXXXXX dollars.
It wasn't exactly slieght of hand but lots of assumptions were built into their calculations.
Her pitch was let's get you qualified and signed up tonight. Fat chance! I tend to be spontaneous but I avoid stupid.
Can I see the contract? "No not until you have qualified and it's filled out."
I just traded emails. She won't even send a technical proposal or recap of our discussion with committing to a credit check.
Buh-bye

 

i have a 10.2 system and generate about 1000kwh a month.
i sell power back to the grid, no battery storage. like you mentioned, battery storage is expensive, a propane or natural gas generator is much cheaper and will last way longer in an outage. i was told i'd get less than a day of electricity with 2 power walls as storage so i didn't go that route (which was about 16k IIRC).
my system costed 15k after rebates in 2016 and had a 7 year ROI at that time.
well worth it IMO. Now that i've built a large garage, added ductless splits to my house and an electric car i use a lot more electricity so i'm looking to add a similar system to my garage roof, which is priced at about 17k installed after rebates in 2025, which would be about an 8 year ROI at current electric costs.

 

Interesting, thanks. Does the girl in the photo come with an update? How do you deal with snow since you are in NY? I'm too damn old to have ROI that stretch out that long.