[HN Gopher] Water Cooled Rooftop Solar Panels
___________________________________________________________________
Water Cooled Rooftop Solar Panels
Author : gardenfelder
Score : 65 points
Date : 2023-08-10 18:05 UTC (4 hours ago)
(HTM) web link (evergreenoffgrid.com)
(TXT) w3m dump (evergreenoffgrid.com)
| KaiserPro wrote:
| When I had my panels installed, I had the option to "embed" them,
| rather than have them mounted over the top of the roof tiles.
|
| I chose over the top for three reasons:
|
| 1) ease of replacement, panel dimensions change, so getting a new
| panel the right size in the future could be hard.
|
| 2) faff. Getting the roofer to talk to the solar people and agree
| on dimensions would have been expensive and time consuming.
| Assuming that they would actually agree to do it.
|
| 3) Thermal bridge. Because there is an airgap between the panels
| and the roof, I get a radiative barrier between my roof and the
| sun.
|
| combined electric and thermal panels seem like a grand idea, and
| perhaps I might get some in the future (not inside 10 years
| though) But, having them as your roof tiles I'm less keen on. It
| makes the MPPT less efficient and there are more connectors.
|
| for over roof type panels though, I think they are a slam dunk.
| hathawsh wrote:
| Nice idea. I have questions:
|
| - Are the pipes and liquid heavy enough to increase strain on the
| roof and panel mounting hardware?
|
| - How does this solution deal with the risk that the pipes might
| freeze, expand, and burst?
|
| - Would it make sense to run an antifreeze and water mix, similar
| to cars, to prevent freezing?
| Freestyler_3 wrote:
| Yes its heavier. They would have to keep the water moving or
| for heavy winters have it drained. Also possible to have a
| liquid in there with much lower freezing point like you said.
|
| The problem I think is that when the panels need cooling the
| most the system to disperse the heat to would need to be huge,
| because you just have a large surface heating up water fast and
| you don't want the house floor to heat up and your water tank
| for showering is already at max temp. Also gotta be careful not
| to evaporate the pool.
| cogman10 wrote:
| Winterizing the lines, leaks, and the added weight are the
| downsides to this. If you are in a climate where you don't need
| to winterize, you are probably in a climate where you can get
| away with a heat pump on your water heater/pool/AC. In fact, they
| make AC adapters that dump excess heat into the pool.
|
| I really want this to work, but heatpumps just make a lot more
| sense with a lot less cost.
| btbuildem wrote:
| From what I've seen, solar preheaters in the northern climes
| tend to use antifreeze instead of water, and have an exchanger
| in the loop. This way they can withstand below-freezing temps
| overnight, and be functional in the sunshine of the day. The
| additional benefit here being that you potable water isn't
| travelling through materials that are potentially degrading in
| the sun.
| f-securus wrote:
| I think you would only do it for the hot water input which
| isn't potable after it runs through a traditional hot water
| heater?
| DrNosferatu wrote:
| Price per KWh?
| gardenfelder wrote:
| >Some combinations were just meant to be. Peanut butter and
| jelly, ice cream and spoons, solar panels and canals, and solar
| photovoltaic (PV) thermal integrated roofing. Who'da thunk.
| pstuart wrote:
| Not clear on how that works with the plumbing re: tiles, but
| this idea has long intrigued me (I figured just using standard
| panels with a thermal block on the back.
|
| I hope this is successful, we need all the options we can get
| for energy independence.
| happytiger wrote:
| There was a manufacturer doing this a few years back when we did
| solar on our house and I looked deeply into this problem.
|
| The issue they had was that they had two manufacturers with
| different guarantees -- one for the water and one for the panels.
| Love the idea -- works like a charm (I got my hands on their unit
| and tested it out -- glorious), but when you're deploying capital
| to prepuchase an offset to alternative expenses it needs the
| warranty or it's foolish to do the deal.
|
| Now there is another manufacturer (dualsun.com) claiming they own
| the global patents to the idea (don't know how, they weren't the
| first to commercialize it).
|
| The issue is definitely the incompatibility of materials. The
| engineering required to make a plastic water system last 25-30
| years is so much more expensive than what it takes to make a pv
| unit last that long, so it gets expensive.
|
| Further, the warranty is dependent on the small volume
| manufacturer still being in business in 20 years to have any
| warranty claim at all, and with the turnover in solar a lot of
| homeowners aren't willing to take that chance.
|
| So you get a double edged disincentive. It's expensive to buy,
| and the warranty uncertainty is high. It's all the classic
| problems of something that needs a mass market success to get to
| scale, but needs that scale to deliver mass market success.
|
| If someone could bond the warranty support or similar solution,
| it could take off.
|
| I wanted to use it to heat a hot tub or a pool and that had added
| complexity as the chlorine degraded the system and it wasn't
| advised. Another twist. :)
|
| Hopefully advances in materials and manufacturing will make it
| viable because it's a GREAT idea and it WORKS! It definitely kept
| the panels cooler and it definitely heated water well.
|
| Edit:
|
| For those interested this is the product I know of... no
| affiliation with them though.
|
| https://dualsun.com/en/products/dualsun-spring
| ortusdux wrote:
| Tech Ingredients on Youtube did an interesting video about
| actively air-cooling panels. In the video he uses 3 watts of fans
| to cool a 100 watt panel, which increases its output by 6 watts.
| The gains are modest (~5%), but his argument is that the lower
| operating temp will increase the longevity of the panels, which
| should make the ROI positive. I'm sure the designers of the
| panels could engineer more efficient solutions.
|
| It did get me wondering about the importance of the roof
| underneath the panels. Most people install black panels over top
| black asphalt shingles for aesthetic reasons, but I wonder if
| some other variation would increase efficiency and/or longevity.
|
| https://www.youtube.com/watch?v=Mt9qLRN7JvA
| dymk wrote:
| Still not worth it aside from the "neat" factor. 3 watts net
| increase won't pay for the cost of the fan over the lifetime of
| the panel, and a moving part like a fan won't make it to 25
| years (5 years if it's lucky).
| byyll wrote:
| Many people run Noctua fans for more than 10 years.
| PaulKeeble wrote:
| 25 years in all weather, not even a Noctua fan is making it
| that long. Its not the cost of the panels that is the issue
| its getting them on the roof, repairing them is enormously
| expensive as they have no gaps between them and buying
| replacements a decade later is almost impossible as people
| are finding out. Longevity to maximise returns is a
| necessity with an investment that takes 7 years to break
| even.
| JamesSwift wrote:
| Exposed to the elements on a roof?
| dymk wrote:
| Sure, in a PC case. Not outside exposed to the elements.
| Freestyler_3 wrote:
| White background with double sided panels.
| pengaru wrote:
| You could configure the installation to create a natural
| convection current of air traveling between the panels and the
| roof deck, so no power wasted at all on the "fan".
|
| Then you could take it a step further by running some "earth
| tubes" up to the low/entry point of this cooling channel, so
| the incoming air for the convection current is cooler.
|
| All passive.
| PaulKeeble wrote:
| This is why the panels are raised off he roof with racking.
| Its allows the air to flow underneath them to cool them. The
| issue with heating is you have a mostly black object getting
| ~1400Watts/m^2 and just 20% of it is turned into electricity
| and the rest is heating the panel. Its a lot of heat.
| friend_and_foe wrote:
| This is similar to my plan. I plan to cool and warm my house
| using an earth tube or two, which leaves electricity required
| for very modest use, lighting, charging phones and what not
| and a refrigerator. Combined with a white or silver metal
| roof and a good gap between the solar panels to allow wind to
| flow through in leu of an attic should do me just fine, and
| on top of that the inside air will always be fresh from
| outside. The energy saving will be tremendous, and digging a
| trench for the earth tubes will actually cost less than
| installing a central air conditioning unit. Additionally you
| don't really need insulation, since fresh temperate air is
| always cycling in and is available pretty much endlessly, the
| limiting factor on efficiency is air flow, not insulation.
| Also, no condensation in the walls; they'll always be above
| the dew point in the summer, and in the winter the air will
| be well below 100% relative humidity since the ambient air is
| being warmed, not cooled, and so the walls will never be
| below the outside ambient temperature in the winter.
|
| The only downsides I can see are that I can't set the
| temperature, it would be whatever it is in the ground, which
| at the right depth should be around 73F year round, and 100%
| relative humidity in the summer. That and that the house must
| be designed for maximum air flow but I don't really see that
| as a downside, people have designed houses this way forever
| until the advent of air conditioning, and to be honest I'm
| not a fan of a house design that doesn't take air flow into
| consideration.
| pengaru wrote:
| I don't think earth tubes are ideal for such direct
| plumbing into living spaces.
|
| My understanding is that they tend to develop mold and
| _stagnant_ moisture will pool in the underground portion.
| Imagine a hot and humid day, the humid air will condense on
| the cool walls while passing through the underground
| section of the tube. Do you really want _that_ to be your
| fresh air duct?
|
| But it seems like a useful mechanism for delivering ground-
| coupled outdoor air to an outdoor application, which could
| be a heat exchanger participating in regulating indoor
| temperatures.
| friend_and_foe wrote:
| Yes, my design right now includes a HEPA filter on the
| _intake_ , preventing spores from ever even getting in
| the tube, a slight grade downwards towards the intake and
| a water catchment system at the end with a float tank
| activated pump to pump the water out periodically.
| Scoundreller wrote:
| Looks like you beat me to it by a minute, but worth pointing
| out those numbers were at around 60w of output.
|
| The difference probably increases at full output.
| derriz wrote:
| Putting solar panels on roofs doesn't make a lot of sense to me.
| Per kWh, rooftop domestic PV costs can be unto 10 times more
| expensive on a levelized cost basis
| (https://www.lazard.com/media/2ozoovyg/lazards-lcoeplus-april...)
| compared to a ground based utility/grid scale installation.
|
| In fact, adding any complexity to a solar panels hardly makes any
| sense any more because of the incredible fall in panel prices (by
| 90% in about 12 years).
|
| This price fall has made a lot of solar ideas defunct. For
| example, when panel prices were much higher, solar plants often
| had mechanical systems to orient panels to track the sun - but
| now nobody bothers - it's cheaper and simpler to just install an
| extra 10 or 20% more panels and have a no-moving-parts/low
| maintenance system.
|
| Same with this idea - the extra complexity and maintenance cost
| of adding active cooling to a panel to increase efficiency by 10%
| - I cannot see the economics stack up.
|
| For the same reason, the enthusiasm for the idea of installing
| solar plants in north africa and exporting power over
| interconnectors to Europe is gone. It's cheaper to install twice
| as many panels in a field in cloudy northern Europe (where
| capacity factors are half of what they would be in the Sahara)
| than deal with the costs and complexity of underwater
| interconnectors and transmission system upgrades.
| 1-more wrote:
| > Putting solar panels on roofs doesn't make a lot of sense to
| me. Per kWh, rooftop domestic PV costs can be u[p]to 10 times
| more expensive on a levelized cost basis
|
| Yeah an idea I've had kicking around for a bit: if my roof is a
| good place for solar, it should make some kind of sense to
| lease it out to someone else who owns the panels and their
| output. I've never heard of anyone making that arrangement.
| There are people near me who own property with no water rights
| who are able to lease that land out to solar utilities.
|
| I'm not against solar and I do think that we need to have every
| available square inch of the world making energy if we're to
| survive the next century. I'm just saying that the current
| incentives kind of don't support it.
| jl6 wrote:
| > For the same reason, the enthusiasm for the idea of
| installing solar plants in north africa and exporting power
| over interconnectors to Europe is gone.
|
| Are you quite sure, when you factor in the cost and
| availability of land?
| derriz wrote:
| Yes - all the serious proposals are dead (the xlinks guy is a
| grifter) because underwater HDVC costs have risen while panel
| prices are a tenth of what they were.
|
| Not only the finances, but (as I described in another
| comment), the security aspects of depending on fixed
| infrastructure in unaligned and relatively politically
| unstable countries are very unpalatable. Such infrastructure
| is incredibly vulnerable and difficult to protect.
| PaulKeeble wrote:
| They are doing this in the UK, a high voltage DC line is being
| connected to Northern Africa where power where about 2.5-5GW of
| power will be produced. Its very viable economically but I also
| think we have more than enough roof space for solar panels and
| surround sea for offshore wind to meet our power needs for the
| foreseeable future.
|
| Even if a commercial installation is half the price per KWh the
| economics still work out personally. The reason is a
| combination of taxes, profits and substantial business
| overheads that make personal Solar substantially cheaper than
| the current grid power which is all tied to gas prices. I am
| about on average 9p a KWh over the life of a Solar system which
| I can export for 15p currently and buying from the grid is 45p
| through the day. Its a substantial saving yet wholesale prices
| are hovering on average around the same 9p. The overheads of
| the grid and businesses are most of the cost and substantial.
| derriz wrote:
| You're talking about Xlinks? They are nowhere near doing it.
| They have been talking about it since 2018 and trying to get
| investors to give them money but despite favourable press and
| interest from politicians, a heavyweight board, nobody who
| has looked at their business plan has stepped up to the plate
| to back the project. Desertec is the other one which has
| raised nothing despite touting a similar idea since 2008.
|
| Xlinks is going nowhere - in fact the founder, Simon Morrish,
| seems to be mostly spending his time on other projects these
| days.
|
| Even their website claimed last year that the PS16B project
| could be profitable if a CFD at PS48/MWh (CDF is a type of
| contract electricity suppliers bid for in UK auctions to win
| 15 year contracts to supply electricity). Unfortunately local
| solar pv, on-shore and off-shore wind auction prices in the
| last auction round were all lower than this.
|
| Regarding local subsidies and supports for rooftop solar, of-
| course it can make sense for an individual. My point is that
| on aggregate, it does not make sense - if the government is
| going to spend $X to encourage the production of solar PV,
| then supporting rooftop solar provides a poor return on the
| subsidy. And the difference is more than half the price -
| typically the multiple is 3 or 4 times cheaper.
| AlanSE wrote:
| > For the same reason, the enthusiasm for the idea of
| installing solar plants in north africa and exporting power
| over interconnectors to Europe is gone. It's cheaper to install
| twice as many panels in a field in cloudy northern Europe
| (where capacity factors are half of what they would be in the
| Sahara) than deal with the costs and complexity of underwater
| interconnectors and transmission system upgrades.
|
| I don't know about that, because long-range transmission
| significantly reduces the intermittency, even for the same
| longitude. It's not just about smoothing out the curve of solar
| production, demand patterns (due to weather, industry,
| behavior) will also have variations from place-to-place and
| these allow opportunities for power export.
|
| Some places will have more dispatchable and expensive power
| plants than others, which also creates an export opportunity so
| that power is exported so that one country can burn less fuel.
| However, I admit this argument is slightly undercut by the
| question "can't we just build solar panels in the country with
| dispatchable dirty power?" True, but there's also a connection
| to wind power which is super local and random.
| derriz wrote:
| In general, yes, more interconnection and better transmission
| can only be good.
|
| But in the specific example I gave, the finances just don't
| work. Underwater HDVC is just too expensive and panels are
| too cheap - even with the value of the uncorrelated
| intermittency.
|
| And even if the numbers could be made work financially, I
| can't see European countries lining up to become dependent on
| fixed infrastructure in politically unaligned and/or unstable
| countries like Algeria or Libya - especially given recent
| experience with Russia. Securitywise, Nord Stream has shown
| that underwater infrastructure is vulnerable to attack and
| difficult to protect/guard.
| hedora wrote:
| A few years ago, solar panels dropped a lot more than 10% in
| efficiency when they got hot. I can see investing in water
| cooling them back then, but suspect that technology trends have
| already made this product obsolete.
|
| If they really can cool the panels at a price + reliability +
| installation complexity comparable to conventional panels, it
| might be worth it.
|
| However, our heat pump water heater is under 10% of our
| electricity bill, so if it's cheaper to just add 10% more
| panels + batteries, then this product seems like a non-starter
| to me. I guess it's possible this would make sense for heating
| swimming pools (they create an extremely large reservoir for
| the waste heat during the summer).
| BHSPitMonkey wrote:
| For some homeowners looking at a residential installation, the
| added independence itself is a feature (as is the autonomy to
| be able to slightly accelerate the world's shift to renewables
| -- the average person does not get to participate in deciding
| when and where to build a grid-scale solar installation).
|
| Of course, reducing a home's energy consumption would be even
| more preferable than just offsetting it with localized
| generation - but reality is complicated.
| toast0 wrote:
| I think the autonomy is the big thing. Redundancy is nice,
| but many or possibly most residential rooftop solar installs
| are grid tie only; adding the ability to power locally when
| the grid is down adds signifigant expense.
|
| Tarriffs are a thing to. It's common for rooftop generation
| to offset grid usage, but if you used your construction
| budget to buy into a larger project, you would likely not be
| able to offset usage, you'd more likely earn wholesale rates
| on generation at the facility and pay retail rates on usage
| at home. Probably you get more generation capacity, and maybe
| that works enough, but probably not. There's also a lack of
| these projects to buy into.
| PaulKeeble wrote:
| The primary reason why most panels don't do this is longevity. A
| panel is designed to be put onto the roof and stay there for 25
| years, it is entirely solid state and its weather hardened to
| survive hail, wind and lots of sunshine. The moment you introduce
| water to just the panel you make the panel more efficient but you
| also drastically increase its failure rate, water corrodes and
| over 25 years its much more likely to cause a failure. On top of
| that the pump is a moving part and its going to require
| replacements over the lifetime of the panel.
|
| In many countries around the world Solar heaters for water are
| quite common. Using tubes to heat water you can get near 99%
| efficient capture of the suns energy to heat which compares very
| favourably to the 20% of a solar panel to electricity. But their
| rated lifetime is quite a bit shorter and their pay off period
| looks quite different as a result.
|
| So while there are benefits to combining them it increases the
| cost considerably and decreases the longevity and it just doesn't
| make much economic sense most of the time. Besides on a hot sunny
| day your panels are going to do great anyway, its clouds that
| really reduce the collection.
|
| As an example my system will give me 34KWh on a cool 100% sunny
| day but on a hot day its more like 31KWh. But on a cloudy rainy
| day it can get down to 7KWh. The heat isn't as big as an issue as
| its made out to be.
| hef19898 wrote:
| As long as the utilits scale projects in the UAE don't use
| active cooling or systems tracking the sun, I don't see a
| reason why I would do it.
| tjoff wrote:
| I feel the failure mode should be pretty good though, degrade
| to a normal solar setup - probably with less airflow and higher
| temps but not worse than that.
|
| Heat degrades panel longevity too so I'd actually assume a
| water-cooled system to outlive a normal one, in the long run I
| would be surprised if it wouldn't end up being cheaper.
|
| I do agree with the simplicity of a solid state setup though.
| Whether it makes sense probably depends on where you live.
| Thinking about it, temporarily running "warm" water might help
| with keeping snow away, though I am aware that many setups
| won't generate much in the winter anyway.
| bluGill wrote:
| Longevity doesn't really matter as most roofs are only good
| for 25-30 years. As such you are removing the panels anyway
| to repair the roof, there is not much additional cost to just
| replace them. Odds are newer solar technology will exist by
| then and so you will want to upgrade.
| londons_explore wrote:
| My tile roof is 120 years old, on a house that is 220 years
| old.
|
| Yo my knowledge it has had basically no maintenance in that
| time.
| MichaelZuo wrote:
| As long as it's properly designed, built, and assembled,
| keyword properly, then a 25 year service life is absolutely
| achievable for the median customer even with an integrated
| water cooling system.
| dymk wrote:
| Well that sounds like you'd have a higher failure rate in the
| margins then, because current solar panels can practically be
| thrown on the roof with nails and they'll work for 25 years.
|
| There's value in simplicity, and something that's going to be
| ignored on a roof for multiple decades needs to have an idiot
| proof installation process.
| MichaelZuo wrote:
| I imagine many customers will opt for simplicity, some will
| opt to pay more for properly built installations with
| integrated cooling and enjoy the advertised benefits, and
| some will opt for cut-rate installations that will
| prematurely fail, thinking they got a deal.
|
| That seems to be the general pattern whenever a new, non-
| trivial, innovation is introduced.
| dymk wrote:
| People will pay for the system with the best ROI, which
| is a simple system with simple installation and simple
| failure modes.
| bluGill wrote:
| If this is really a win (see other posts - I question
| that), then solar panels can be made with integrated
| pipes for the cooling, and pumps that will last. We can
| even make a wire/water pipe all in one unit so you just
| have one connector to install. The pump likewise can be
| combined with other parts you have to have. All of this
| will reduce costs for this.
|
| Again, I question if the ROI can be good enough to be
| worth it, but if it really is a win there are lots of
| options to reduce costs.
| [deleted]
| Scoundreller wrote:
| this fellow added fan cooling to his panels. An immediate net
| benefit on output (5.5w increased output for 3w of fan) at 60w of
| output.
|
| Then there's the longevity improvements.
|
| Really starts around 15 minutes but a good video overall.
|
| https://youtu.be/Mt9qLRN7JvA
| friend_and_foe wrote:
| That guy got me on the solar water heater bandwagon. I plan to
| build one out quite similar to his, using a thermosiphon rather
| than active pumping. The downside to this is that the tank must
| be above the panel, which means it will cast a shadow on the
| panel at some point during the day, and also added structural
| complexity to keep a heavy water tank on a roof, but proper
| placement of the tank will ensure that the shadow gets cast in
| the summer when heat isn't as much of a hot commodity.
| pfdietz wrote:
| I wonder if there would be a good return for a selective surface
| on top of PV. Make it reflective for near IR below the bandgap of
| the PV cells, but transparent for light of shorter wavelengths
| and opaque in the far IR for high emissivity for radiative
| cooling.
| jrmg wrote:
| Before PV became efficient and cheap enough, it was not uncommon
| to see 'solar panels' on roofs in California that actually
| contained water pipes rather than silicon. Water circulated
| through them and was used either as regular hot water for the
| house, or in a 'heated' pool.
| nonfamous wrote:
| My Dad did something like this for our pool in Australia in the
| '80s. He ran a bunch of black PVC pipe in a zigzag pattern on
| the garage roof and ran water through it from the pool filter.
| It was pretty effective at heating the pool!
| capitainenemo wrote:
| We have the same, and it works great. Was (relatively) cheap,
| durable, and also helps a lot to keep the upper level of the
| house cool.
| dymk wrote:
| Those were likely evacuated tube solar collector systems. They
| can boil water in direct sunlight when there's snow on the
| ground.
| Scoundreller wrote:
| While it's a lot less energy efficient, once saw a video of
| someone that replaced one of his tank-based residential water
| heater elements with a combo 240v/24v element and attached a
| panel to the 24v element with a temperature-driven cutoff
| relay. Set the tank to 50C or whatever and the element to a
| higher point to dump extra heat when possible without getting
| too hot.
|
| A very cost efficient approach that probably gets you some
| double digit reduction without a lot of risky plumbing or
| freezing issues.
| philjohn wrote:
| You see them far more than Solar PV in Denmark as well, because
| IIRC you get taxed per kWh consumed, no matter where it's
| generated, so it's more economical to use the roof space for
| domestic hot water instead.
| Scoundreller wrote:
| I wonder how many semi/complete guerilla setups there are.
| jacknews wrote:
| The output of your own panels that you use yourself is taxed
| per kWh? That's insane. And unenforceable, surely?
| Freestyler_3 wrote:
| Australia has had houses with tubes on the roof to heat the
| pool for a long time already.
| friend_and_foe wrote:
| I don't see the benefit here. In the summer you want a cool
| pool, and in the winter you need that heat to hit your house
| to reduce heating costs. Unless you live somewhere so warm in
| the winter that you still have to cool your house, in which
| case a pool would be pretty temperate and need no heating. If
| you've lived in a house like this, what's the energy benefit?
| bluGill wrote:
| In most cases the average temperature is a bit lower than
| what your comfortable swimming temperature is. Sure it gets
| hotter than that some days, but pools are very slow to heat
| up/cool down and so they generally track the average
| temperature not the peak temperature. (you are probably
| swimming when it is peak temperature, and not at night when
| it is colder outside)
| friend_and_foe wrote:
| Yeah I suppose. I enjoy the unpreditctability outside,
| it's a bit of a philosophical point for me I guess, I
| don't want the whole world finely tuned to keep me in my
| comfort zone. A nice cool dip, even a little
| uncomfortably cool, is exilirating to me.
| jeffbee wrote:
| You still see new buildings in California with rooftop solar
| water heaters. I can't make it pencil out but builders seem to
| disagree. Here's one I happen to know of which is especially
| baffling because they have no rooftop PV despite an
| overabundance of space.
|
| https://www.google.com/maps/@37.8027685,-122.2898842,118a,35...
| Scoundreller wrote:
| Maybe a LEED credit (scam) thing?
| bombcar wrote:
| Part of it is licensing/permits/requirements - you can often
| add rooftop solar water with no additional permits or a minor
| one, whereas solar PV is an electrical permit at minimum, and
| likely plans and licensed electricians, too.
| hedora wrote:
| This is doubly true in California, where adding PV means
| dealing with PG&E. Also, if you're grandfathered in on a
| NEM 2 electricity bill rate, then they apparently penalize
| you for upgrading your installation (by forcing you onto
| NEM 3).
| Guvante wrote:
| The ROI on a solar water heater is terrible. Cost us $10k
| before rebates (half that with) and saved us less than $50 a
| month in electricity.
|
| If I stuck around for a decade it might have paid off but given
| a family member's unit didn't last that long (the part that
| held water went bad and a replacement was $4k, not exactly
| economical on a 4 year old system)
|
| Ended up it was a pop up company designed to appropriate the
| green money by "improving your A/C efficiency" which of course
| probably only lasted a year or two given it was just blasting
| foam into the vents...
| smolder wrote:
| There are a lot of grifters out there wasting peoples money
| spent with good intentions, which is really frustrating.
| Sometimes it's not even a grift, just incompetence will lead
| to poor ROI, because contractors lack the skills to be
| efficient or do quality work.
|
| I'm somewhat convinced I'm going to have to become a home
| builder myself to end up with something that's long-lasting,
| comfortable, healthy, and energy efficient, all without being
| robbed blind.
| friend_and_foe wrote:
| It's really starting to get that way isn't it? You
| basically have to build your own house to get something
| that isn't made of paper.
| [deleted]
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