My Math on Solar?

[madhat]

Okay; we had someone come by trying to sell us Solar. First thing is it's a twenty year contract and I don't believe the panels will last that long. I did the math. We use 19,857 Kw a year. The difference in solar and utility is 1 cent. That works out to $198.57 a year in savings if I have an average of net zero for the year. I have to pay a flat Yearly Facilities Charge of $114.00 and a flat Yearly Electric Universal Service Charge of $4.32. That brings my savings down to $80.25. Do you see anything wrong with my reasoning on this point.

Also my Average Daily usage is 54,040 watts, about how many panels would I have to have to just meet my average usage with 4.92 Average Sun Hours per day.

[BNME8EZ]

Lower your expectations.

If you don't look at net zero and think more about less than 50% usage with no buy back from the utility. In other words you use everything you generate. I would think that would eliminate your fees, bonus 1, then cut up front costs, bonus 2, and you lower your utilities, bonus 3.

I am looking at a project that PV will cover my lighting at night and maybe some during the day, and thermal to take care of about 25-33% of my heating with the added benefit of preheating hot water in the summer (it will probably do all the domestic water in the summer). I haven't got all the costs back but looking for a 10 year payback.

[Core_d]

I thought this thread was about a solar calculator..


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[madhat]

They did the Classic, "Bait and Switch" they showed us a more modern Panel, that generated high kilowatts, and was a parallel/series setup. We only wanted the panels on the back and side roofs. When the actual contract was ready for signing, it was for an older Panel, in series, which didn't meet our needs for the kW, even with Street side mounting. This doesn't make any sense, as this is a North exposure. Also they said they would pay and repair any damage to our structure due to roof penetrations leaks, contract said up to 30 days. The penetration could have leaked on day one, and we could have been screwed. So go into this with Eyes wide open and take notes, when the salesman is talking.

[ammoniadog]

Good for you for paying attention and being able to say no to them. That's not always easy to do.

[LoraMoser]

Hey, our family also thinking about solar power source, could you advice me the company who manufacture solid solar panels?

[Ie Energy]

Hey, our family also thinking about solar power source, could you advice me the company who manufacture solid solar panels?

First check out the companies near you. Then check reviews and ask for referrals from old clients. It would also be helpful to you if the company has a reliable support. It would also be a plus if they have a product guarantee of at least 30 years

[VTP99]

So I'll presume you're in the business 🤔

[mostbetin]

You have the right approach to calculations. In the past year, I too have been thinking about installing solar panels. And decided that for me it is not economically feasible.

[BNME8EZ]

I have hot water solar that I need to get finished which involves finishing a building that supports them but I have been running them to heat an uninsulated building. When all done the panels will heat the floor in the house, the building and preheat domestic hot water.

No I do not expect 4 hot water panels to heat all that to wanted temp but the building only needs to be 40° which should be easy once insulated. The floor in the house is supplemental only so every btu I get from the solar is one less that I have to buy. The domestic hot water will be a big one. In the summer all the heat will go to preheating the hot water so my assumption is that I will not have to pay for element use in the summer for hot water. Considering the various uses I will have I don't know how one would ever calculate any savings except by what may be noticeable on the electric bill. In the shoulder seasons I may get enough heat that the heat (geo) won't have to run as there will be enough heat off the warm floors from the solar. The load on the building is 38k @ 70/-2 and house 25k @ 70/-2 won't need much heat when the highs are in the 40's maybe even dropping to upper 30's. We'll see.

[Poodle Head Mikey]

And, unless you install a new metal roof before installing the solar system - you will want to be figuring in the costs of removing the solar system for roof replacement at some point and the costs for re-installing the solar system after the roofers are done.

PHM
------

Okay; we had someone come by trying to sell us Solar. First thing is it's a twenty year contract and I don't believe the panels will last that long. I did the math. We use 19,857 Kw a year. The difference in solar and utility is 1 cent. That works out to $198.57 a year in savings if I have an average of net zero for the year. I have to pay a flat Yearly Facilities Charge of $114.00 and a flat Yearly Electric Universal Service Charge of $4.32. That brings my savings down to $80.25. Do you see anything wrong with my reasoning on this point.

Also my Average Daily usage is 54,040 watts, about how many panels would I have to have to just meet my average usage with 4.92 Average Sun Hours per day.

[causa]

The panels degrade over time. 5 to 8 years max on today's construction. After this, they do not put out the KW as designed. There is a declining slope for this.

Now worming or cracking is also something that can happen, and this makes the panel drop the capacity instantly to the amount of percentage of cells affected.

Snow load renders them no output. Leaf load same reduced output depending on coverage.

Rain, clouds, all reductions of the capacity.

The installation cost is one thing. What about the Maintenace cost?

There is No difference on deterioration on a high output panel versus a low output panel. The angle of the photons is a big factor as well, For output. Having stationary panels versus articulating panels for steady state output is also a factor.

Now, inverter choice. The cheaper inverter option gives the most line noise, that affects the power quality. And affects the sensitive electronics load if you have any.

Battery Backup. will it be included, or will this be eliminated?

So, if you live in an area that has high average of sunny days and you put in articulating panels with a good inverter. Then you might be ok, but you will never pay it out or save enough on your utility bills till 25 to 35 years. only if you get a government grant to help offset the initial cost. But do not think you will feed the grid. this getting a bi-flow meter will be a different story. you will have to prove that the system can produce a minimum amount, and this is all subject to the power company discretion.

So, examine all the Factors before signing on that line and read the fine print. In the contract and the data sheets.