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1
FortWayneHatesRealtors
2022 Mar 27, 7:23pm
don’t have them. but friend installed panels, we did work together wasn’t bad at all, saved a lot of money. just paid 500 for design. because of very low cost of self install with friends help he is saving money according to him after 4 years.
he isn’t disconnected, no battery, just panels pushing to grid. some cheap chinese panels.
hope this helps.
he isn’t disconnected, no battery, just panels pushing to grid. some cheap chinese panels.
hope this helps.
2
HeadSet
2022 Mar 27, 7:39pm
HeadSet
2022 Mar 27, 7:39pm
Eman says
ROI works if your capital remains intact. That is, if you put that $17.4k in the bank and got $230/mo, that would be 15% ROI. In the case of solar panels, that $17.4k is a sunk cost and you must include a payback period to calculate a return. You are 6 years before you make a dime, and that is if the solar panels wipe out your entire electric bill for that time.
Cost is $17.4K after tax incentives. It would cover my monthly electricity bill of $230/mo on average. Add in a powerwall will increase the cost by $8k. Without the powerwall, it’s about 15% ROI. What am I missing?
ROI works if your capital remains intact. That is, if you put that $17.4k in the bank and got $230/mo, that would be 15% ROI. In the case of solar panels, that $17.4k is a sunk cost and you must include a payback period to calculate a return. You are 6 years before you make a dime, and that is if the solar panels wipe out your entire electric bill for that time.
3
Hircus
2022 Mar 27, 8:09pm
Hircus
2022 Mar 27, 8:09pm
How did you calculate it?
I think the right way to model a decision like this is to make sure you account for cost of capital, and the calculations should use compound interest math, including expectations of future electric prices. I usually code my own calculators (which I wont share, as it would disclose my identity), but here's a calc that's on the web and can be shoehorned into working decently for this type of solar calculation.
solar cost = 24K + tax - 6600k rebate = about $19k capital outlay
monthly savings is usually your current bill minus about $10 minimum fee = $220
The idea is to model 2 scenarios:
#1 no solar, no $19k solar capital outlay, you will still pay $220 electric bill every month (w/ a 3% / yr bill increase), but you buy 19k of stocks or some other investment that will grant 7% CAGR (or whatever rate you feel is realistic).
#2 you buy solar instead of stocks, no more electric bill.
1 https://financialmentor.com/calculator/compound-interest-calculator?principal=100000&annualInterest=7&compoundingInterval=360&growType=2&yearsToGrow=20&additionFrequency=30&additionalAmount=-220&increaseContributionsBy=3&annualInflationRate=0&compute=1&source=patrick.net
2 https://financialmentor.com/calculator/compound-interest-calculator?principal=81000&annualInterest=7&compoundingInterval=360&growType=2&yearsToGrow=20&additionFrequency=30&additionalAmount=0&increaseContributionsBy=3&annualInflationRate=0&compute=1&source=patrick.net
The trick is to enter a sufficiently large starting account balance number to avoid going negative during the sim due to 20yrs of monthly electric bills. It doesnt matter what number you choose is, as long as you use the same figure for both calculations minus the 19k in #2. I used 100k and 81k. The reason the number doesnt matter is because we compare the ending figures to arrive at our desired final figure, which tells you how much better scenario 1 was vs 2.
I used 20 years since that's a typical solar system lifespan. I also set inflation to 0% because we account for inflation via the "Increase yearly contributions by" field, and assume the 7% CAGR for stocks is already inflation adjusted. So using the "average annual inflation rate" field would double adjust.
in 20 yrs, scenario #1 leaves you with $245,609 and #2 leaves you with $313,444
313,444 - 245,609 = $67,835
So in this case, scenario 2 was better by 67k, meaning solar offered gains above and beyond stocks by a good margin. It worked out to about 13% CAGR. Of course everyone needs to enter their own variables though.
Breakeven, where solar overtook stocks, occurred at about yr 9.
I think the right way to model a decision like this is to make sure you account for cost of capital, and the calculations should use compound interest math, including expectations of future electric prices. I usually code my own calculators (which I wont share, as it would disclose my identity), but here's a calc that's on the web and can be shoehorned into working decently for this type of solar calculation.
solar cost = 24K + tax - 6600k rebate = about $19k capital outlay
monthly savings is usually your current bill minus about $10 minimum fee = $220
The idea is to model 2 scenarios:
#1 no solar, no $19k solar capital outlay, you will still pay $220 electric bill every month (w/ a 3% / yr bill increase), but you buy 19k of stocks or some other investment that will grant 7% CAGR (or whatever rate you feel is realistic).
#2 you buy solar instead of stocks, no more electric bill.
1 https://financialmentor.com/calculator/compound-interest-calculator?principal=100000&annualInterest=7&compoundingInterval=360&growType=2&yearsToGrow=20&additionFrequency=30&additionalAmount=-220&increaseContributionsBy=3&annualInflationRate=0&compute=1&source=patrick.net
2 https://financialmentor.com/calculator/compound-interest-calculator?principal=81000&annualInterest=7&compoundingInterval=360&growType=2&yearsToGrow=20&additionFrequency=30&additionalAmount=0&increaseContributionsBy=3&annualInflationRate=0&compute=1&source=patrick.net
The trick is to enter a sufficiently large starting account balance number to avoid going negative during the sim due to 20yrs of monthly electric bills. It doesnt matter what number you choose is, as long as you use the same figure for both calculations minus the 19k in #2. I used 100k and 81k. The reason the number doesnt matter is because we compare the ending figures to arrive at our desired final figure, which tells you how much better scenario 1 was vs 2.
I used 20 years since that's a typical solar system lifespan. I also set inflation to 0% because we account for inflation via the "Increase yearly contributions by" field, and assume the 7% CAGR for stocks is already inflation adjusted. So using the "average annual inflation rate" field would double adjust.
in 20 yrs, scenario #1 leaves you with $245,609 and #2 leaves you with $313,444
313,444 - 245,609 = $67,835
So in this case, scenario 2 was better by 67k, meaning solar offered gains above and beyond stocks by a good margin. It worked out to about 13% CAGR. Of course everyone needs to enter their own variables though.
Breakeven, where solar overtook stocks, occurred at about yr 9.
4
Hircus
2022 Mar 27, 8:22pm
Hircus
2022 Mar 27, 8:22pm
btw, https://projectsolar.io/?source=patrick.net has really good prices, both for a self install kit and full service install. Not sure of quality, but parts wise they use black mono panels and enphase micro inverters, which is considered good stuff generally. I plan to use them for a small system maybe this year.
5
Eman
2022 Mar 27, 8:41pm
Eman
2022 Mar 27, 8:41pm
Hircus says
Thanks for sharing Hirus. You’re getting too fancy with the calculations, but I get the point. You’re likely an engineer with the way you analyze things. 9 years to break even is good enough. About 11% ROI.
btw, https://projectsolar.io/?source=patrick.net has really good prices, both for a self install kit and full service install. Not sure of quality, but parts wise they use black mono panels and enphase micro inverters, which is considered good stuff generally. I plan to use them for a small system maybe this year.
Thanks for sharing Hirus. You’re getting too fancy with the calculations, but I get the point. You’re likely an engineer with the way you analyze things. 9 years to break even is good enough. About 11% ROI.
6
WookieMan
2022 Mar 28, 5:54am
WookieMan
2022 Mar 28, 5:54am
Solar panels are ugly on a home. I am going to research it more when we go to build, but likely won't pull the trigger due to hail storms here. It would be built into the final home loan, so it would be the best time to do it, but my insurance rates go up because of the panels. Or I risk not insuring them. If I insure then I still have a minor monthly cost. But this is the forever home, so it might be worth it. We'll see.
If the build happens I'll probably start a thread for it and talk about all sorts of shit. Solar, pool, low voltage wiring for speakers and whole home shit, etc. I've been involved in a lot of builds, but this one is my baby and I'm not going to fuck around. No expense spared and I want to plan for future stuff. Gas lines, electric, internet and speaker cable run everywhere inside and out. Natural gas backup. Radiant heat in garage so I don't have a noisy heater and driveway so I don't have to shovel during winter. Hard wired cameras. Might do sprinkler system with a connection I have (inside) and also outside. My dog will likely pass soon, but still may put in an electric fence for a dog while excavating for the foundation. Lots to think of.
If the build happens I'll probably start a thread for it and talk about all sorts of shit. Solar, pool, low voltage wiring for speakers and whole home shit, etc. I've been involved in a lot of builds, but this one is my baby and I'm not going to fuck around. No expense spared and I want to plan for future stuff. Gas lines, electric, internet and speaker cable run everywhere inside and out. Natural gas backup. Radiant heat in garage so I don't have a noisy heater and driveway so I don't have to shovel during winter. Hard wired cameras. Might do sprinkler system with a connection I have (inside) and also outside. My dog will likely pass soon, but still may put in an electric fence for a dog while excavating for the foundation. Lots to think of.
7
zzyzzx
2022 Mar 28, 6:07am
zzyzzx
2022 Mar 28, 6:07am
I've been using a small solar panel to maintain a questionable vehicle battery for several years now. This vehicle is rarely used and parked outdoors. Solar panel wasn't even installed until the battery was already almost bad.
8
WillyWanker
2022 Mar 28, 6:35am
WillyWanker
2022 Mar 28, 6:35am
I wanted to have solar panels installed in my last home in Las Vegas. The house was about 6000 square feet and being in Vegas I figured it would be ideal to have solar. Well, the house was too big for the special discounts that they offer so I would have had to spend way too much money up front to get eventual savings down the line and then, if I kept the house, the panels would have to be replaced, so I said, eff it and just made sure the house was as insulated as possible and we did triple glazing in all the windows and doors. Because I had the place done with 8 zones for the air and heating, it wasn't too bad to air condition in the summer. It was much cheaper than my house in Palm Springs which was a bit smaller. Putting in lots of different A/C zones allowed me to close off parts of the house when not in use (guest suites) and just cool the places I use most often. I have friends who installed solar in Vegas and who love the fact that their energy bills are super low.
9
WookieMan
2022 Mar 28, 7:10am
WookieMan
2022 Mar 28, 7:10am
WillyWanker says
This. Optimization of what you plan to use and when you plan to use it. And the ability to control the use.
You can get huge savings from basic things like zones, insulation, blinds, lights, motion sensors, toilets, shower heads, etc. that are relatively cheap when compared to the costs of a solar setup. Regardless of solar covering all your costs, you still pay taxes and fees for it being connected to your house to the utility. At least here in IL. Insure the panels.
I don't know, I don't think it's worth the effort. At least here in IL for sure. Too cloudy. Also, saving $50-100/mo is not really worth it for solar. We make over $100/hr anyway, so it kind of feels like coupon clipping to me. Though I'd consider it on a build.
It was much cheaper than my house in Palm Springs which was a bit smaller. Putting in lots of different A/C zones allowed me to close off parts of the house when not in use (guest suites) and just cool the places I use most often.
This. Optimization of what you plan to use and when you plan to use it. And the ability to control the use.
You can get huge savings from basic things like zones, insulation, blinds, lights, motion sensors, toilets, shower heads, etc. that are relatively cheap when compared to the costs of a solar setup. Regardless of solar covering all your costs, you still pay taxes and fees for it being connected to your house to the utility. At least here in IL. Insure the panels.
I don't know, I don't think it's worth the effort. At least here in IL for sure. Too cloudy. Also, saving $50-100/mo is not really worth it for solar. We make over $100/hr anyway, so it kind of feels like coupon clipping to me. Though I'd consider it on a build.
10
EBGuy
2022 Mar 28, 1:37pm
Eman says
Looks like PG&E just upped summer rates to $.49/kwHr for above baseline usage during peak hours (4-9pm) summer months. Yikes. For the amount you use, it be insane not to get solar...
. It would cover my monthly electricity bill of $230/mo on average.
Looks like PG&E just upped summer rates to $.49/kwHr for above baseline usage during peak hours (4-9pm) summer months. Yikes. For the amount you use, it be insane not to get solar...
11
SunnyvaleCA
2022 Mar 28, 2:02pm
EBGuy says
I believe that here in California there are many more considerations about how the prices work. Someone I know even splurged the extra $8k(?) for battery, and not for backup. Something about how payments work is that you can get a hefty price charge from PG&E because of time-of-use metering. You can have enough solar panels to completely cover all your electrical use and then still wind up with a fairly hefty electrical bill at the end of the year.
Looks like PG&E just upped summer rates to $.49/kwHr for above baseline usage during peak hours (4-9pm) summer months. Yikes. For the amount you use, it be insane not to get solar...
I believe that here in California there are many more considerations about how the prices work. Someone I know even splurged the extra $8k(?) for battery, and not for backup. Something about how payments work is that you can get a hefty price charge from PG&E because of time-of-use metering. You can have enough solar panels to completely cover all your electrical use and then still wind up with a fairly hefty electrical bill at the end of the year.
12
Eric_Holder
2022 Mar 28, 2:11pm
Eric_Holder
2022 Mar 28, 2:11pm
What happens if the roof under the panels needs repair? Who is responsible for removing/re-installing them? Will removal of the panels by someone other than the original installer void the warranty? What happens if the original installer is already out of business by then?
13
Eman
2022 Mar 28, 2:12pm
Eman
2022 Mar 28, 2:12pm
SunnyvaleCA says
Yeah, it’s one of those things we don’t know until we try it. 😂
Yeah, $8k is for each powerwall after the incentive. Otherwise, it’s $11k a piece.
I believe that here in California there are many more considerations about how the prices work. Someone I know even splurged the extra $8k(?) for battery, and not for backup. Something about how payments work is that you can get a hefty price charge from PG&E because of time-of-use metering. You can have enough solar panels to completely cover all your electrical use and then still wind up with a fairly hefty electrical bill at the end of the year.
Yeah, it’s one of those things we don’t know until we try it. 😂
Yeah, $8k is for each powerwall after the incentive. Otherwise, it’s $11k a piece.
14
Eman
2022 Mar 28, 2:16pm
Eman
2022 Mar 28, 2:16pm
EBGuy says
I’m a YOLO guy. I blast the A/C when it’s hot and crank up the heater when it’s cold. I don’t care if it’s peak or off-peak. At the end of the day, spend an extra $100-$200/month to be comfortable is a small price to pay.
The reason I looked into solar b/c my biz partner wanted to install solar panels for a couple of our apartment buildings. A few years ago, my friend told me to install solar, but I ignored him. Back then, each powerwall was $6.5k a piece. Talk about inflation.
For the amount you use, it be insane not to get solar...
I’m a YOLO guy. I blast the A/C when it’s hot and crank up the heater when it’s cold. I don’t care if it’s peak or off-peak. At the end of the day, spend an extra $100-$200/month to be comfortable is a small price to pay.
The reason I looked into solar b/c my biz partner wanted to install solar panels for a couple of our apartment buildings. A few years ago, my friend told me to install solar, but I ignored him. Back then, each powerwall was $6.5k a piece. Talk about inflation.
15
SunnyvaleCA
2022 Mar 28, 2:19pm
Eman says
Do these powerwalls act as a UPS for the entire house? So far this year my computer has gone down twice — both times thanks to PG&E.
Yeah, $8k is for each powerwall after the incentive. Otherwise, it’s $11k a piece.
Do these powerwalls act as a UPS for the entire house? So far this year my computer has gone down twice — both times thanks to PG&E.
16
Eman
2022 Mar 28, 2:28pm
Eman
2022 Mar 28, 2:28pm
SunnyvaleCA says
According to Tesla website, the powerwall should be able to provide about 2 days worth of electricity for the entire house when the power is out.
Do these powerwalls act as a UPS for the entire house? So far this year my computer has gone down twice — both times thanks to PG&E.
According to Tesla website, the powerwall should be able to provide about 2 days worth of electricity for the entire house when the power is out.
17
RWSGFY
2022 Mar 28, 2:33pm
RWSGFY
2022 Mar 28, 2:33pm
Eman says
Really? With AC and pool
pump and such? Color me skeptical.
SunnyvaleCA saysDo these powerwalls act as a UPS for the entire house? So far this year my computer has gone down twice — both times thanks to PG&E.
According to Tesla website, the powerwall should be able to provide about 2 days worth of electricity for the entire house when the power is out.
Really? With AC and pool
pump and such? Color me skeptical.
18
Eman
2022 Mar 28, 3:08pm
Eman
2022 Mar 28, 3:08pm
RWSGFY says
It’s based on an average $230/month usage. If you average $460 for that month, don’t be surprise it only lasts for a day.
Really? With AC and pool
pump and such? Color me skeptical.
It’s based on an average $230/month usage. If you average $460 for that month, don’t be surprise it only lasts for a day.
19
EBGuy
2022 Mar 28, 3:28pm
PowerWall+:
Energy Capacity
13.5 kWh
Backup Power
9.6kW / 7kW continuous*
22kW / 10kW peak*
*Full sun / no sun
You're definitely going to want to shed some load if you're at the higher end of the usage range.
For comparison:
The first generation Nissan Leaf came with a 24 kWh battery which allowed it a maximum range of 84 miles. The 2016 model bumped up battery capacity to 30 kWh and range was increased to 107 miles.
Energy Capacity
13.5 kWh
Backup Power
9.6kW / 7kW continuous*
22kW / 10kW peak*
*Full sun / no sun
You're definitely going to want to shed some load if you're at the higher end of the usage range.
For comparison:
The first generation Nissan Leaf came with a 24 kWh battery which allowed it a maximum range of 84 miles. The 2016 model bumped up battery capacity to 30 kWh and range was increased to 107 miles.
20
mostly reader
2022 Jul 23, 10:01pm
Eman says
I've started on that journey by trying to decide between Tesla roof and just panels. It's a hard choice because my roof is in not new but in a good shape. My understanding is that when panels and roof lifecycles are out of sync, there's extra headache involved - you can't replace the roof without taking down the panels and then reinstalling them. On the other hand, Tesla roof is significantly more, and I'd be giving away the unused portion of the lifespan of the roof that I have today. Not sure how to go about it.
Who here installed solar panels on their home? How has it been working out for you?
I've started on that journey by trying to decide between Tesla roof and just panels. It's a hard choice because my roof is in not new but in a good shape. My understanding is that when panels and roof lifecycles are out of sync, there's extra headache involved - you can't replace the roof without taking down the panels and then reinstalling them. On the other hand, Tesla roof is significantly more, and I'd be giving away the unused portion of the lifespan of the roof that I have today. Not sure how to go about it.
21
FortWayneHatesRealtors
2022 Jul 24, 8:56am
mostly reader says
best advice i can give you.
never combine tech.
keep em separate. your panels break, you still got a roof.
Eman says
Who here installed solar panels on their home? How has it been working out for you?
I've started on that journey by trying to decide between Tesla roof and just panels. It's a hard choice because my roof is in not new but in a good shape. My understanding is that when panels and roof lifecycles are out of sync, there's extra headache involved - you can't replace the roof without taking down the panels and then reinstalling them. On the other hand, Tesla roof is significantly more, and I'd be giving away the unused portion of the lifespan of the roof that I have today. Not sure how to go about it.
best advice i can give you.
never combine tech.
keep em separate. your panels break, you still got a roof.
22
clambo
2022 Jul 24, 10:13am
I'm going to put some panels on a little place in Baja California Sur Mexico.
It's sunny all the time there.
I'm going to get a mini split air conditioner which can run on solar (AC/DC).
We'll see how it goes.
It's sunny all the time there.
I'm going to get a mini split air conditioner which can run on solar (AC/DC).
We'll see how it goes.
Comments 1 - 23 of 247 Next » Last » Search these comments
I did the math of Tesla solar panels. Cost is $17.4K after tax incentives. It would cover my monthly electricity bill of $230/mo on average. Add in a powerwall will increase the cost by $8k. Without the powerwall, it’s about 15% ROI. What am I missing?