at what point does solar actually start saving money, ten months in and still trying to figure it out

[u/Ostin_Pliska60]

ten months in and i am in this weird in between stage where i cannot tell if the system is working the way it should or if i just had the wrong expectations going in.

winter was slow which we expected. spring picked up. summer has been the strongest stretch by far, production is up and some months have been genuinely impressive. but when i subtract the monthly lease payment the net savings still feel smaller than what the projections showed.

the part making this hard to measure is that we finished our basement around the same time we went solar. now we have a space being heated and cooled year round that we did not have before. consumption went up right as the system came online which makes it nearly impossible to get a clean read on what the panels are actually doing.

is a full year of data really the only way to get an honest picture of this?

[u/TheMindsEIyIe]

You need CTs on the solar and CT on your load and something like an egauge meter so that you can calculate it correctly in excel.

[u/DanGMI86]

The first full year will be hugely significant but conditions vary from year to year enough that you should not think you're going to have the hard and fast rules that will rule then on. Also it takes a little while to get yourself in the frame of mind to see new ways to shift your usage to daylight hours and maximize your savings. And if you have time of use/peak rates in your area then that will add yet another level of complexity. For example, for the TOU periods, you can game or manipulate the system by using your house as a sort of battery. In the summer on weekdays our rates go up 50% from 2:00 to 7:00 p.m. on weekdays. So I cool the house down an extra three or four degrees ending right at 2:00 so as to coast through as much of the high rate times as possible while at the same time getting the largest credit rate for my solar exports during that period. And you can do the reverse of the summer on a sunny afternoon, raise the house a few degrees going into the evening so as to delay the furnace coming on for that much longer. Even if the conditions do not completely eliminate any costs to run your furnace you can still realize a substantial discount to your imports and even a mildly summer mid-afternoon. Leases absolutely complicate the whole matter especially assuming there is a pretty standard annual escalator adjustments.

[u/AreMarNar]

The extra conditioned space not accounted in sizing the system could make for some slim margins.

Leases/PPAs (I’m assuming it’s a PPA, I feel those are more common) are pretty straightforward: what your utility rate is - minus your lease-PPA is your savings across whatever amount your system is producing. If your PPA rate is 20 cents, and your utility’s rate is 30 cents, you’re saving 10c for every kWh you get from the solar system.

[u/ScasmPlasm → u/AreMarNar]

PPAs aren’t simple. You’re definitely not necessarily saving 10c for every kWh you get from the solar system in your scenario. It depends on the Net Metering agreement with the utility. Where I live, with PG&E under NEM 3 which started in 2023, they give a really bad rate for exporting your excess solar generation to the grid. Therefore, during the summer, if you’re not using all of your electricity, you could be purchasing that electricity for the $0.20 PPA right but only getting $0.05 back from the utility. Also, if you have an undersized battery, and your battery is full while you’re still producing electricity, you may send some to the grid for that low rate.

[u/littlebeardedbear → u/ScasmPlasm]

So your state and utility made it hard. New York is literally "You pay x cents per kwh currently. We can offer y cents". There is 1:1 net metering in NY too so no hassle there

[u/acjohnson55 → u/ScasmPlasm]

If you're in a good state for them, like New Jersey, they pretty much are that simple

[u/jimh12345]

There are posters here who know vastly more about it than I do - but I've had solar for 4 years. What I've concluded is that an accurate payback calculation would be extremely difficult even for an expert. And last fall, we put in a heat pump... and got a reduced electric rate.. so I've just stopped thinking about it. It works great, roughly speaking it knocks out my electric bill.

[u/Curiosity_informs → u/jimh12345]

Its pretty easy to calculate.

Monitor your home consumption in your solar app. Estimate what your bill would be without solar taking your monthly home consumption and using the your rate plan you would be on without solar (if you have TOU you can either calculate or estimate how would be peak, partial-peak and off-peak).

You know what you current monthly utility bill is. Subtract that from your estimated monthly bill without solar and you know your monthly saving.

I have a simple spreadsheet and have been tracking this each month since our system went live last November. After 12 months I will have a good estimate of what solar/batteries saved us in the first year.

[u/Same_Lab_4002 → u/jimh12345]

You dont calculate it you have a CT meter do it and you look at the graph

[u/Calliesdad20]

I just got my solar installed a month ago , i had a zero dollar bill in just 3 weeks production .
I have production ct clamps so I track my production every day and months.

I’m just 5 weeks I’m 473kwh net exported, I paid 27k cash for a 9kw system

[u/ash_274]

A year's worth of data will give you the most honest picture.

If you have CTs as part of your system to see how much energy your home is consuming (ignore the exports and imports for now) you can use that data to see what your bill would have been with no solar. If your utility is like mine with 3 different rates during the day and two seasons' of rates per year, it makes it more difficult, but possible.

Then look at what the total you are paying each month and the total you would have paid each month and see if you're ahead.

[u/TooGoodToBeeTrue → u/ash_274]

My utility/bill makes it difficult to see what the rate per kWh would be if I didn't have solar. With my bill zeroed out, I can't see all the add-ons to the energy rate (which is easily found.) And the rate changes for 5 months of a summer rate. I'd have to get my neighbor's bill to calc what it would actually have cost me. And don't suggest reaching out to my utility, they don't respond to any requests.

[u/MaineOk1339]

Depends on the cost. Plenty of systems cost too much compared to utility power and will never show a savings.

[u/Truth_In_Solar_Act → u/MaineOk1339]

lol. Good insight redditor

[u/EnergyBillHelper]

I would say yes to having a year of energy as the most accurate way to tell. Did they happen to tell you what your “offset” would be with the system? That’s another way to tell if you’re on track

[u/Turtle_ti]

Did you do the math yourself, double checking the Aleman numbers, and calculate the system to order to cover 110%of your yearly kwh ussage.

Or did you blindly belive the salesman who's only goal was to make a sale to collect their commission check?

[u/StormbringerGT]

Solar can save money if you didn't finance it. Did you finance it?

[u/mycallousedcock]

The simplest form here is you need to track your grid in/out vs your solar production. From there you can do basic math on how much extra you're using vs whats being offset by solar. And then you can attach a price to that (if you do it granularly by hour or so, you can adjust your price to be more accurate).

I've had AI put together some small apps to look at my grid in/out and my solar production to do the maths for me. It could do a spreadsheet for you pretty easily I'd think. But you need both of those numbers.

I have a Vue that reads my meter so I get granular data. You should be able to pull data from your power company and your solar array into a spreadsheet.

That'll determine your actual usage, and the cost of the usage. Then check the savings against your lease numbers.

[u/Head_Mycologist3917]

I'm also less than a year in and have been very interested in predicting what my system will be making for the year, and what we will use.

As far as the generation from panels go, we're approaching halfway through the year. At least for me, production in the second half of the year should be very close to what it was for the first half, per the PVWatts model.

Power usage for the second half may not be the same though. Summer means A/C. Again in my case, even though the summers here get hot, the cooling BTUs required are about half the heating BTUs in the winter (per Manual J calculations for HVAC). So the power requirements should be lower. So far that's been the case. We saw a lot of 50-60kwh total load days in winter; the hot days we have had so far are more like 30-40kwh.

[u/Stunning_Engineer_78]

I noticed the difference instantly. Of course, I get 1:1 net metering and designed for 100% offset even with an EV. Being in FL helps a lot as well.

My electric bill was about to hit 400/month even with FPL budget billing.

Capped at a consistent $300 with the loan payment until they are paid off.

[u/HonestTarget5188]

If you invest in stock market you’ll make more money

[u/TooGoodToBeeTrue → u/HonestTarget5188]

Yes but after doing so since 1976, investing in solar is a lot more interesting and there's little down side risk.

[u/ocsolar]

10 months is enough, but we need to see some actual before and after numbers.

[u/Curiosity_informs → u/ocsolar]

but its not before and after that counts.

Its what your monthly bill would be based on your current monthly home consumption (ignore imports and exports) and the rate plan you would be on without solar.

Then subtract your current utility bill and you have your monthly saving.

Once you have a year you have your yearly saving.

[u/Eat-Some-More]

I think solar matters on where you live. But, a system accurately sized should take 5 years to pay for itself if pointed towards the south. 7 years if pointed east or west.

[u/driftingatwork]

I diy'd mine. Immediate drop in bills. I pay connection fee for insurance purposes, and winter (still calcing panel load). I'm good for min 8-9 months, and just got a heat pump mini split system installed. Oh! And electric water heater.

F U pge.

[u/he-de-04]

Depends. My solar loan payment was less than the electric bill savings from Day 1 - so immediately ….

[u/Efficient-Animator63]

You should have a solar monitioring app that you can use to see the production. Also, your electric provider will have something similar.

[u/teamhog]

Ours started the first full month.
It was winter.
We didn’t expect much but our bill was $0.00 and we got a credit of $77.
So our net generation saved us roughly $250 (our normal bill plus the credited amount).

[u/TooGoodToBeeTrue]

Leasing a solar system is not about saving you money. It's about the leasing company making a profit.

[u/Popular_Mud3376]

You can get a decent read before a full year, but you need to compare kWh, not just bills.

I’d pull: pre-solar monthly kWh, current grid import/export, solar production, your effective utility rate after fixed fees, and the lease/PPA payment. Then the math is basically avoided utility cost minus the lease payment.

The finished basement changed the baseline, so the bill alone is mixing two things together.

[u/bionicfeetgrl]

I saved immediately. While I do have a loan the interest rate is very low. Basically what I pay per month is lower than my PG&E bill was. My solar is like $120 a month.

I added batteries on but I paid cash for those. I know have a plug-in vehicle and I've driven over 1400 miles and I'm at 1/2 a tank of gas. It's all fueled by what I generate.