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Imagine instead of paint if we could come up with some sort of material that generates electricity. P.S. - If you look into the white paint thing more carefull

Imagine instead of paint if we could come up with some sort of material that generates electricity. P.S. - If you look into the white paint thing more carefully you'll be rather disappointed.

highwaylights 4y ago
Wouldn't a reflective coating work better? Given it's a once off cost it seems like this should be doable.
- thombat 4y ago
  Neighbors and pilots may complain
  - highwaylights 4y ago
    I dislike people and planes are noisy. I take your point, I’m doing it anyway.
throwaway3334 4y ago
Actually, I was looking into installing solar, to offset $400/month of air-conditioning costs, during the summer. I could have had around 1.5kW of solar. But the cost of this is north of $25k, plus all the hassle to get the permits, plus all the extra complexity. While the cost of painting the roof is $100 + work. And now it is very rare that I have to run the AC.
- sxates 4y ago
  Do you mean 15kw? 1.5 is only like 4 panels, it wouldn’t make $400 per month and wouldn’t cost anywhere near $25k.
  - throwaway3334 4y ago
    I was looking at installing a very small solar array, just to offset the AC costs. The quote for the solar kit that could produce ~1.5kW (2170W Solar Kit: 7xURE NSP 310W - Mono 60 Cell - All Black Panels + 7xEnphase IQ7 60-Cell Microinverters w/QCables + 1x Enphase IQ Combiner 3 + Wireless Monitoring) was $6.5k. But, I was also considering having a 10kW battery to store that energy and to have a backup power, like Tesla Powerwall - $10k. And then there was work to install, permits, my time. Overall my estimate was, realistically it'd be ~$25k. Maybe I was wrong. On my house I have two sections of roof that are flat/horizontal. Roof is pretty thin there and although there is insulation, on hot days ceiling was getting worm in the 2 rooms under these sections. I also was hoping that an extra layer of solar would insulate my roof a bit more. So I wouldn't have to run AC that much. So the hope was to stop wasting annoying $400 on AC in the hottest months. But the cost of installing solar felt prohibitive. So I've made a quick calculation and spent $100 on the reflective roof paint instead...
    - recuter 4y ago
      Sounds wrong, check this out: https://www.youtube.com/watch?v=QWJpafOHoD0 https://www.youtube.com/watch?v=QWJpafOHoD0 5kWh battery thing for $1,500: https://signaturesolar.com/eg4-lifepower4-lithium-battery-48v-100ah https://signaturesolar.com/eg4-lifepower4-lithium-battery-48... Growatt 3kW Stackable Off-Grid Inverter for $700: https://signaturesolar.com/growatt-48v-3kw-150vdc-stackable-off-grid-inverter https://signaturesolar.com/growatt-48v-3kw-150vdc-stackable-... Solar panels are $2-$3 per watt depending where you live. 4x300watt panels is just the ticket, depending where you are and whether you can get a 30% tax credit that's about $2000. Whole thing all together would be about $5000. It would generate about $1 of electricity a day. Would eventually pay for itself over its lifetime if you don't mind faffing about with it to get started. > On my house I have two sections of roof that are flat/horizontal. Roof is pretty thin there and although there is insulation, on hot days ceiling was getting worm in the 2 rooms under these sections. I also was hoping that an extra layer of solar would insulate my roof a bit more. It will be slightly cooler underneath it.
      - ComputerGuru 4y ago
        That’s insanely cost prohibitive, tbh. No wonder more people aren’t jumping at the opportunity. You would need 14 years just to pay back the cost of installation, and that’s assuming zero maintenance simultaneous with magically sustained like-new performance. After those 14 years, you “make” an annual non-compounded 7% ROI (again in 2022 dollars). Spending some of that money on insulation and sticking the rest in a savings account somewhere is a much wiser bet.
- 10u152 4y ago
  1.5 kW of solar for $25k ? Somethings way off, closer to $1 per watt.
  - wlll 4y ago
    This is more reasonable. I have 2x400W solar panels sitting in my kitchen right now (they’re going on a boat) that cost me £215 each.
- beAbU 4y ago
  I think your math is off my an order of magnitude somewhere. Your $25k can buy a 40Kw kit according to this¹ South African retailer (excl installation, but my point still stands. Also, don't unferestimate painting a roof. I recently had my ~400m^2 roof painted, and the final bill was 50k ZAR (~3k USD), and this is in a country with dirt cheap manual labour costs. It's a very labour intensive operation if done properly. 1 - https://www.sustainable.co.za/collections/grid-tied-solar-power-kits?sort_by=price-descending https://www.sustainable.co.za/collections/grid-tied-solar-po...
  - wffurr 4y ago
    Installation is most of the cost. So "excl installation" isn't a useful number.
mumblemumble 4y ago
I have photovoltaics on my roof. I won't be doing it again. I'm almost certain that putting the money that they cost into making my home more efficient in the first place, by doing things like sealing leaks, upgrading the insulation, and, yes, making the roof a lighter color, would have reduced our energy consumption by more than the amount that the PVs are generating. The PVs absorb a lot of thermal energy, too, more than the shingles themselves do. So they make the roof hot. You can actually feel the difference inside the house - the rooms that are underneath the solar panels get warmer in the summer than the ones that aren't. So some amount of that electricity we're generating would seem to just be undoing the effects of the PVs on the house's thermal situation. There's still a net benefit, but probably because we're people who are inclined to accept that summer is hot in the first place. Trying to keep those rooms at or below 80F/26C might be an expensive endeavor. Also, I've discovered that one does not simply have a roof leak fixed when there are solar panels on the roof, because they are in the way. So maintenance has been rather more expensive than I expected. In general, I'm sanguine about solar as a renewable option. I'm just increasingly inclined to believe it's better implemented as an industrial technology, and that homeowners probably have better options for greening their houses.
- grog454 4y ago
  > The PVs absorb a lot of thermal energy, too, more than the shingles themselves do. I've found this to be interesting going back as far as middle school, where we're taught renewable energy sources like solar panels can help reduce global warming by replacing greenhouse gas emitting alternatives. Yet fundamentally, they are designed to turn the only external source of energy our planet receives (sun light) into heat and other forms of energy that will eventually become heat rather than reflecting it back out into space (albeit through the atmosphere). Seems so backwards to me.
  - XorNot 4y ago
    What do you think normally happens to the 1000w per square meter which the sun radiates?
    - 4y ago

Imagine instead of paint if we could come up with some sort of material that generates electricity. P.S. - If you look into the white paint thing more carefully you'll be rather disappointed.

highwaylights 4y ago

Wouldn't a reflective coating work better? Given it's a once off cost it seems like this should be doable.

thombat 4y ago
Neighbors and pilots may complain
- highwaylights 4y ago
  I dislike people and planes are noisy. I take your point, I’m doing it anyway.

throwaway3334 4y ago

Actually, I was looking into installing solar, to offset $400/month of air-conditioning costs, during the summer. I could have had around 1.5kW of solar. But the cost of this is north of $25k, plus all the hassle to get the permits, plus all the extra complexity. While the cost of painting the roof is $100 + work. And now it is very rare that I have to run the AC.

sxates 4y ago
Do you mean 15kw? 1.5 is only like 4 panels, it wouldn’t make $400 per month and wouldn’t cost anywhere near $25k.
- throwaway3334 4y ago
  I was looking at installing a very small solar array, just to offset the AC costs. The quote for the solar kit that could produce ~1.5kW (2170W Solar Kit: 7xURE NSP 310W - Mono 60 Cell - All Black Panels + 7xEnphase IQ7 60-Cell Microinverters w/QCables + 1x Enphase IQ Combiner 3 + Wireless Monitoring) was $6.5k. But, I was also considering having a 10kW battery to store that energy and to have a backup power, like Tesla Powerwall - $10k. And then there was work to install, permits, my time. Overall my estimate was, realistically it'd be ~$25k. Maybe I was wrong. On my house I have two sections of roof that are flat/horizontal. Roof is pretty thin there and although there is insulation, on hot days ceiling was getting worm in the 2 rooms under these sections. I also was hoping that an extra layer of solar would insulate my roof a bit more. So I wouldn't have to run AC that much. So the hope was to stop wasting annoying $400 on AC in the hottest months. But the cost of installing solar felt prohibitive. So I've made a quick calculation and spent $100 on the reflective roof paint instead...
  - recuter 4y ago
    Sounds wrong, check this out: https://www.youtube.com/watch?v=QWJpafOHoD0 https://www.youtube.com/watch?v=QWJpafOHoD0 5kWh battery thing for $1,500: https://signaturesolar.com/eg4-lifepower4-lithium-battery-48v-100ah https://signaturesolar.com/eg4-lifepower4-lithium-battery-48... Growatt 3kW Stackable Off-Grid Inverter for $700: https://signaturesolar.com/growatt-48v-3kw-150vdc-stackable-off-grid-inverter https://signaturesolar.com/growatt-48v-3kw-150vdc-stackable-... Solar panels are $2-$3 per watt depending where you live. 4x300watt panels is just the ticket, depending where you are and whether you can get a 30% tax credit that's about $2000. Whole thing all together would be about $5000. It would generate about $1 of electricity a day. Would eventually pay for itself over its lifetime if you don't mind faffing about with it to get started. > On my house I have two sections of roof that are flat/horizontal. Roof is pretty thin there and although there is insulation, on hot days ceiling was getting worm in the 2 rooms under these sections. I also was hoping that an extra layer of solar would insulate my roof a bit more. It will be slightly cooler underneath it.
    - ComputerGuru 4y ago
      That’s insanely cost prohibitive, tbh. No wonder more people aren’t jumping at the opportunity. You would need 14 years just to pay back the cost of installation, and that’s assuming zero maintenance simultaneous with magically sustained like-new performance. After those 14 years, you “make” an annual non-compounded 7% ROI (again in 2022 dollars). Spending some of that money on insulation and sticking the rest in a savings account somewhere is a much wiser bet.
10u152 4y ago
1.5 kW of solar for $25k ? Somethings way off, closer to $1 per watt.
- wlll 4y ago
  This is more reasonable. I have 2x400W solar panels sitting in my kitchen right now (they’re going on a boat) that cost me £215 each.
beAbU 4y ago
I think your math is off my an order of magnitude somewhere. Your $25k can buy a 40Kw kit according to this¹ South African retailer (excl installation, but my point still stands. Also, don't unferestimate painting a roof. I recently had my ~400m^2 roof painted, and the final bill was 50k ZAR (~3k USD), and this is in a country with dirt cheap manual labour costs. It's a very labour intensive operation if done properly. 1 - https://www.sustainable.co.za/collections/grid-tied-solar-power-kits?sort_by=price-descending https://www.sustainable.co.za/collections/grid-tied-solar-po...
- wffurr 4y ago
  Installation is most of the cost. So "excl installation" isn't a useful number.

mumblemumble 4y ago

I have photovoltaics on my roof. I won't be doing it again. I'm almost certain that putting the money that they cost into making my home more efficient in the first place, by doing things like sealing leaks, upgrading the insulation, and, yes, making the roof a lighter color, would have reduced our energy consumption by more than the amount that the PVs are generating. The PVs absorb a lot of thermal energy, too, more than the shingles themselves do. So they make the roof hot. You can actually feel the difference inside the house - the rooms that are underneath the solar panels get warmer in the summer than the ones that aren't. So some amount of that electricity we're generating would seem to just be undoing the effects of the PVs on the house's thermal situation. There's still a net benefit, but probably because we're people who are inclined to accept that summer is hot in the first place. Trying to keep those rooms at or below 80F/26C might be an expensive endeavor. Also, I've discovered that one does not simply have a roof leak fixed when there are solar panels on the roof, because they are in the way. So maintenance has been rather more expensive than I expected. In general, I'm sanguine about solar as a renewable option. I'm just increasingly inclined to believe it's better implemented as an industrial technology, and that homeowners probably have better options for greening their houses.

grog454 4y ago
> The PVs absorb a lot of thermal energy, too, more than the shingles themselves do. I've found this to be interesting going back as far as middle school, where we're taught renewable energy sources like solar panels can help reduce global warming by replacing greenhouse gas emitting alternatives. Yet fundamentally, they are designed to turn the only external source of energy our planet receives (sun light) into heat and other forms of energy that will eventually become heat rather than reflecting it back out into space (albeit through the atmosphere). Seems so backwards to me.
- XorNot 4y ago
  What do you think normally happens to the 1000w per square meter which the sun radiates?
  - 4y ago