Compare sales estimate of savings to after-install real life savings?

[Calsun]

The state of California has online calculators for the output and payback period for systems based on the individual components that are used. If I provide a helpful link I will be banned from this forum so you need to search for yourself.

The monopoly utility companies in my state have increased their rates by 50% over the past 5 years and changed their time of use charges as well. My payback period was based on current rates at the time but I knew that rates would jump.

A lot depends on your usage and which tiers you fall in with your provider. I wanted to stay in the bottom tier where the rate is half that of the next tier and solar was a way to insure this happened.

What I had not counted on was having to pay for a new inverter when my Sunpower inverter failed under warranty. Sunpower is currently estimating new inventory until late February at the earliest so my system will be have been down for at least 6 months, best case. My choice is to install micro inverters or buy a second hand inverter and have it installed for $2,000 with no warranty or wait until March of 2023 to get the system back online.

[Will792]

What I had not counted on was having to pay for a new inverter when my Sunpower inverter failed under warranty. Sunpower is currently estimating new inventory until late February at the earliest so my system will be have been down for at least 6 months, best case. My choice is to install micro inverters or buy a second hand inverter and have it installed for $2,000 with no warranty or wait until March of 2023 to get the system back online.

I thought that Sunpower used Enphase microinverters with customized firmware. These should be less than $100 on eBay and loss of one should not significantly affect total power production. One of my IQ7s failed at one point and I was debating if I should bother to replace it under warranty. Eventually did call Enphase and received replacement in ~2 weeks.

[nomadh]

I had a few vendors try to estimate but it was worthless. At the time I had 2 near 20 yrold boys that may or may not move out. A nice that may not be here a fathering law on hospice that sometimes needed breathing concentrator (check the power on those babies) and other random hangers on.
in the end I guessed at 5 kw. It was a decent guess in the end all I really missed on is my wife's ability to waste power and her dumb chickens.

[MattSl]

I might be in a bit of a unique situation here also. My power company is also my water and sewer provider, so they all show on a single bill. My system produces more than I need, which my utility uses to cover all the electric bill (and minimum meter fee), then it starts chipping into my water and sewer bill. Which, I'd prefer in contrast to them sending me a check at the end of the year, along with a 1099 that I'd have to pay further taxes on.
I use a considerable amount of electricity, even though my rates (with feed rate + fuel charge + taxes) average around 20c per kwh. My average usage is around 1600kwh per month, which spikes quite a bit in the summer months to around 2200. My system is 20.4kw with 4 PW+, averages generation of about 2200kwh per month.
My utility only pays back on fuel charge, which averages between 6-8c per kwh, but I didn't include those numbers into my ROI.
1600 * 20c = $320 per month. My solar panels only (not including the PW+s) after incentives and rebates were ~$28,000. Using the minimum monthly electric bill savings of $320/month, that's approximately a 7 year 4 month ROI from my installer's calculations.

However, I'm 5 bills in (system installed late Aug 2022, and got my 2 way meter on Jan 27th), I've calculated that I've saved $2,070 in just the winter months so far, averaging about $414 per month. A lot of that was a big spike in fuel charges, rates increased up to 31c for a few months. If this calculation continues, I'm looking at a 5 year 6 month ROI. My Jan/Feb bill just came in, and the excess NEM reduced my water bill. I'm keeping track in detailed spreadsheets, and Home Assistant data mining, and so far it looks a lot better than what was estimated. I'm a data geek, so it's fun for me .

I didn't include the batteries in my ROI, as they are for peace of mind. My initial ROI including the batteries was a tad over 12 years, which is right about the time they would need replacing, or at least past when their warranty expires. If the $414 keeps up, I'll reach ROI at 10 years 2 months.

Considering that my utility's rates continue increasing like they have been (>15% over 2 years), I'll most likely see continued reduction of ROI.

[Calsun]

I thought that Sunpower used Enphase microinverters with customized firmware. These should be less than $100 on eBay and loss of one should not significantly affect total power production. One of my IQ7s failed at one point and I was debating if I should bother to replace it under warranty. Eventually did call Enphase and received replacement in ~2 weeks.

I said nothing about enphase microinverters. The SunPower INVERTER was made by Sunny Boy and rebranded. A new Solis inverter ost me $1400 plus another $700 for the electrician to remove the old inverter and wire in the new one. So $2100 is significant to me. Of equal concern is having paid for a warranty when I installed the system I expect it to be honored by SunPower but that is not the case. Honesty and integrity have gone out of fashion in this country.

I knew that my monopoly energy provider PG&E depended heavily on hydroelectric power and that that power source would be greatly reduced with the effects of global warming. Add in the subsidies for their nuclear power plant and rates are increasing greatly and will continue to do so with the PUC operating as a captive agency. PG&E rates have increased by 57% since I installed the solar system which is far more than SCE at 15% over the same period.

[MattSl]

Calsun, I can definitely see the frustration in a vendor not honoring their warranty. I'm keeping my fingers crossed that my vendor is a) still around in the event I need a warranty claim, b) honors it if I do. Especially in today's manufacturing process, where every part is CAD stressed to survive warranty period only. Here's hoping to my unit being built on a Tuesday, Wednesday or Thursday. Nobody wants a unit built on a Monday or Friday.

Everyone talks about 'sustainability', but yet 9 out of 10 people replace major items before they need it. We seem to be really good at sustaining marketing execs, sales people and manufacturers.

[SunEagle]

Calsun, I can definitely see the frustration in a vendor not honoring their warranty. I'm keeping my fingers crossed that my vendor is a) still around in the event I need a warranty claim, b) honors it if I do. Especially in today's manufacturing process, where every part is CAD stressed to survive warranty period only. Here's hoping to my unit being built on a Tuesday, Wednesday or Thursday. Nobody wants a unit built on a Monday or Friday.

Everyone talks about 'sustainability', but yet 9 out of 10 people replace major items before they need it. We seem to be really good at sustaining marketing execs, sales people and manufacturers.

While I agree people seem to replace items before they fail are jumping the gun I have to think of those that wait until it leaks to replace a water heater tank. Seems ass backward to me.

[MattSl]

Ok, I think a water heater that is about to leak would fall into the category of 'Needs Replacing' I'm talking about - for instance - changing out a perfectly working fridge because it is a certain color, and wanting a new fridge because it is the newest fancy color.

[SunEagle]

Ok, I think a water heater that is about to leak would fall into the category of 'Needs Replacing' I'm talking about - for instance - changing out a perfectly working fridge because it is a certain color, and wanting a new fridge because it is the newest fancy color.

Yeah that doesn't make sense to me either. I feel as long as something is functioning why change it.

[Calsun]

Most of the water heater failures are the result of people not bothering or realizing that the anode needs to be replaced at intervals. The anodes are cheap at around $30 for the part. When ultra low NOx water heaters were introduced the rate of failures increased dramatically. What fails is the electronic board that controls the NOx emissions and when it fails it is never covered by the warranty and even if it fails within the first few months the homeowner pays the cost for a plumber to pull the failed tank and replace it outright.

With electronics when one has more complexity there are more parts or firmware that can fail. What I like about the Solis inverters is that they can use an external Wifi or firmware adapter that is separate from the inverter internals so the homeowner can update firmware or monitor via the internet or a home computer or a smartphone. Solis does the design and build in house so one does not have to negotiate past the installer and the distributor or re-branding company for support. Their field sales engineers are stupid (at least the two I encountered), but their in-house tech support people are terrific.

[MattSl]

Fair point. I set a 3 year reminder in Google calendar to remind me to check/replace the anode in my hot water heater. I was doing 4 years, but got this on my first change-out on a new one.


sshot-25.png

Great point on your Solis inverter, glad to hear it is modular and easy to service.