# Going solar!



## jetsam (Jun 8, 2019)

It's finally time for a new roof, so I'm going solar this year.  I am tickled to see the advances in PV tech since last time I looked at it (microinverters/power optimizers, 20%+ efficiencies).

I am getting in just in time to get 1:1 net metering, so no batteries for me. I have a generator for outages. I like the idea of onsite storage, but I don't like the idea of replacing batteries regularly.

I am getting an oversized system with a view towards adding a split system, electric DHW, and hopefully electric vehicles at some point.

The whole thing is adding up quickly ($13k roof, $23k for a 20 panel PV system, plus the house needs a new main lug and 200A service entry upgrade...).

It'a still looking like a good deal after the tax credits right now. ROI at my old rate of power usage is about 8 years, and I plan to about double my usage (I currently heat with 100% wood and don't use AC, oil hot water heater), so you could argue that it's significantly lower.

Anyone have any gotchas, tips, or things to consider before jumping in?


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## EatenByLimestone (Jun 8, 2019)

I'll be watching.   A new roof will be going on my house this year too.  I'm interested in solar, but I'm not sure I'm ready to jump on that yet.

I want to systematically tear out old insulation and closed cell foam my upstairs though.   I really don't expect that to pay back in any reasonable time, but make the house much more comfortable.


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## begreen (Jun 9, 2019)

Get the basics figured out first, like solar exposure and roof capacity. Is there a substantial portion of the roof sloping to the south? Will the roof support the weight?


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## peakbagger (Jun 9, 2019)

Keep good records on the things like service entrance upgrades as they are covered by the 30% fed rebate.

How is your shading and does your states electric code require Rapid Shutdown Devices (RSD) on the array?.The 2014 NEC requires that the array output has to drop below a low voltage sertpoint (Ithink 80 volts DC?) within so many seconds after a loss of grid power of when manually initiated. The 2019 is similar but requires it at the panel level.  String Inverters can comply with the 2014 adding a remote shutdown relay in the local combiner box near the array. The relay is controlled remotely by low voltage signal run in a separate conduit. If you have shading issues, microinverters or panel optimizers meet the standards but add cost and complexity compared to a central string inverters for 2014 installations but for 2019 there is no option for conventional panels for just a string inverter, you either need a panel mounted optimizer or microinverter. Either option puts electronics on the back of each panel, its just the level of complexity. Microinverters (or so called AC modules) do not require a central inverter and are easier to configure since shading is less of an  issue making them a favorite of some installers but the material cost is higher. The reliability of microinverters has been rocky, there have been multiple premature failures of multiple brands, the claim is that each generation is getting more reliable but they are in tough location for electronics. Optimizers also are panel level and deal with shading but the electronics are far less complex at the panels. They have not been 100% perfect on reliability but seem far better than microinverters. The trade off is you need one or more central string inverters located in hopefully in more optimum location.

Pole mounts and ground mounts do not require RSD which offsets some of the extra cost for the mounts. The panel efficiency is slightly higher with a pole or ground mount as they run cooler which potentially extends component and panel life. I think a lot more folks are more comfortable doing a ground or pole mount compared to roof mount. I did both types by myself and came to the conclusion that each had its challenges but a factor for those who do not like working on roof.

Factor in snow on the arrays, the snow does not magically disappear and contrary to the salesmens claims may not be gone the next day. If the snow does not stick its going to slide and anything below it will need to be protected. Frequently decks and porches are in the slide zone. You can get clips installed similar to those used on metal roofs but then your panels hold snow longer. Landscaping also can get wrecked. 

Run metal conduit through the interior of the house and have it terminated with a roof box that is installed when you have the roof done. Running conduit outside the house is a compromise and many installers cut corners. Keep it out of sight and avoid the hassle.

Make sure there is a quality Surge Protection Device (SPD)between the main panel and the PV system.Nothing protects from a direct strike but the PV system is far more likely to be an entrance from a secondary surge. They work both ways, surges from the utility do happen on occasion. I had an inverter smoked by a utility surge several years ago. I also believe in a SPD on the roof at the junction box to keep surges from getting in the house. Note that there are cheap surge suppressors that may keep your house from burning down but will not protect the electronics.

Consider buying some spare panels. Panel models change every 2 or 3 years and no one stocks old panels. Even if you have a great warranty and the company is still in business its unlikely they will have an exact spare. The installer buys them in bulk so a spare should not be expensive. Panels usually die quickly if defective so the spare is for physical damage like a golf ball, rock or a critter gnawing at the leads. Make sure you have good spot to store them.

Unless you are a "tech geek" and atypical, the panels will rapidly become an appliance like a refrigerator or a washing machine. There are all sorts of very profitable options that the installer will gladly sell you. The reality is if configured correctly a typical person is not gong to look at all the bells and whistles after the first year. Odds are the cost of the options will exceed the electric output. I look at my 3 inverters when I walk by from about 5 feet away,one has no display except for a flashing LED and the other two have wattage readings. When I get my monthly power bill I note the credit and that is it for care and feeding of my panels. Summer rainstorms in my area wash them off. I do change panel angles on my wall mount and my pole mount quarterly but its quick and if I dont get around to it I do not stress over it.

Factor in SRECs, some states have very profitable SREC programs and some installers keep the SREC revenue to themselves by hiding a clause in the contract assigning the SRECs to them. They just register the system in their firms name and the owner is none the wiser as the reporting goes through the same web ap that the owner uses to monitor the system. The web reporting is handy as its PITA for me to read my production meter every month and report it but the trade off is a lot of folks have issues with communications and usually the installer has to be the one that fixes them as it may require special software.The software gets upgraded on occasion ever years after the installation and on occasion the patch knocks the software out and the installer will need to reset it (usually at a call in fee). My theory is KISS (keep it simple stupid)

Array bonding and grounding is a "black art" and even electricians and engineers seem to disagree on the proper approach.I have #4 cables running direct outside the house that terminate at the main house ground. My pole mounts ground goes to a local ground rod that ties into my main ground via a #4 run in the conduit trench to the main house ground. All the SPDs also tie into the main ground grid outside the house.


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## begreen (Jun 9, 2019)

Great advice as usual pb.


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## jetsam (Jun 10, 2019)

Yeah, I'm going to sit down and pick through his reply in detail after work. Multiple things to research in there!  I definitely hadn't thought about surge protection or spare panels.


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## georgepds (Jun 12, 2019)

Re" 20%+ efficiencies"

Remember the limit on most residential systems is 20% of the busbar amperage on the main panel. My understanding is most residential 100 amp services have 200 amp bus bars... so that's 40 amps, 

Might limit how many of those efficient panels you can put up


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## georgepds (Jun 12, 2019)

Re microinverter reliability... some anecdotal experience

I've 18 enphase M215s for ~7 years, no problems yet
I've another 10 enphase S280s for~ 3 years, no problems with those either


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## Where2 (Jun 18, 2019)

georgepds said:


> Re microinverter reliability... some anecdotal experience
> 
> I've 18 enphase M215s for ~7 years, no problems yet
> I've another 10 enphase S280s for~ 3 years, no problems with those either


Of my present 20 "operational" microinverters, I've lost one M215 in ~5.75 years, and they sent me an M250 as a replacement. (I have 41 more M215 units, they're just not installed yet...)

As for PV prices, a week or two ago I got an email with panels + M215 microinverters for $0.44/W. My last freight shipping was ~$500 for a pallet of panels moved 3,000 miles...


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## maple1 (Jun 25, 2019)

jetsam said:


> The whole thing is adding up quickly ($13k roof, $23k for a 20 panel PV system, plus the house needs a new main lug and 200A service entry upgrade...).



How many watts is that? Guessing maybe around 6000? Which would be pushing $4/watt - and sounds a bit pricey? I might be off base a bit.

This is still in the back of my head, and I should really stop in to see the (new) local solar guys and ask some questions.

One main thing I really have reservations about is the snow aspect. If panels went on the roof, there is no way I would be cleaning them off (two stories). And not sure I would want them dumping snow where it would be heading. And not sure we have the yard space/location for ground mount - and really not sure I could sell my other half on that kind of setup. There is a new incentive program here, put in place the past winter. But they only have a limited pot and not sure how much uptake they've gotten - I really need to poo or get off the pot.


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## georgepds (Jun 27, 2019)

Re snow

I never clean my panels of snow, and it snows a lot on the ocean in NE MA

Generally the snow sticks a day or two, with it sticking to the panel bottom at the end. I think that's because the panel is exposed to cold air underneath. I never have the snow fall off in a big lump. I think it mostly blows away as a powder, melting is another possibility.


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## peakbagger (Jun 27, 2019)

Mine usually slides off in sheets from the second story. It would damage people and landscaping.


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## georgepds (Jun 27, 2019)

Hmm, I wonder what accounts for the difference, maybe roof pitch

Mine is 5/13


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## Rob711 (Jul 9, 2019)

Im strongly looking into solar as well. Had a guy come out from a company that 4 co workers used.  He called about hr before he was to arrive to say he’s on way but we have a few strikes. 45 degree pitch, east west roof and  shading from neighbors trees. 
  We’ve extensively remodeled this house, and only have been in it since mid June so it’s hard to get a accurate usage as far as kWh. 
  The salesman calculated using 12000 kWh a year. Said that’s average for family of 5. Central air, electric dryer. After rebates it would be close to 30k which I’d have to finance at this point. 15 yr loan. 267 a month for 18 months. Then 222 for the remainder. Last bill was 175 but we weren’t living in the house at least half that billing cycle. I’d be good even if it was a bill swap. I’m told this would cover all our electricity. 
  Jetsam I believe we pay same rates. I’ll be curious how it goes.


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## jetsam (Jul 9, 2019)

I wound up going for a 7kw grid-tied system. I started out wanting a battery bank, but then I found out that the local power company offers 1:1 generation credits- so from a money point of view, they are a 100% efficient battery that never needs replacing.

I am looking at paying $3.06/w installed, with the 21% LG 360w panels and the newest enphase IQ 7+ microinverters.

The system is going to end up costing about $12k after tax credits.

The whole project (which includes a new roof, 200A service entry/meter pan, and a main panel upgrade) is about $40k up front, since labor for everything is through the roof around here. The solar is actually less than the infrastructure (though it was time for a roof anyway, which is why we are doing the solar now.)

I told my wife that I could get Chuck In A Truck to do the roof for half the price of her Angie's List guys, and she wasn't having any.... 

After that I think I'll put in a split system- and have AC in the summer, and be a "supplemental heat" wood burner in the winter! (We heat with 100% wood wood now, but why split all that wood to save on free solar power?)

Not sure if I'll light one fire in the fall and just burn 24/7 but on low, or light bigger fires as needed.  Guess we'll see!

I would say that greatly reduced wood consumption will be nice, but I will miss poking at the fire. Right now I get to play with it 3x a day in the cold parts of the winter... after solar, it'll be on low burns and 24 hour loads.... if I even burn 24/7.... horrors!


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## maple1 (Jul 9, 2019)

Rob711 said:


> Im strongly looking into solar as well. Had a guy come out from a company that 4 co workers used.  He called about hr before he was to arrive to say he’s on way but we have a few strikes. 45 degree pitch, east west roof and  shading from neighbors trees.
> We’ve extensively remodeled this house, and only have been in it since mid June so it’s hard to get a accurate usage as far as kWh.
> The salesman calculated using 12000 kWh a year. Said that’s average for family of 5. Central air, electric dryer. After rebates it would be close to 30k which I’d have to finance at this point. 15 yr loan. 267 a month for 18 months. Then 222 for the remainder. Last bill was 175 but we weren’t living in the house at least half that billing cycle. I’d be good even if it was a bill swap. I’m told this would cover all our electricity.
> Jetsam I believe we pay same rates. I’ll be curious how it goes.



What is the system size? Sounds pricey for an after incentive number?


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## Rob711 (Jul 9, 2019)

42 lg panels. About 15kw system but will produce 12 due to roof and shade. Salesman said the grade systems. I’m a D!


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## Rob711 (Jul 9, 2019)




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## Rob711 (Jul 9, 2019)

I think I can get a separate bill from contractor for the cost of roof and 200 amp upgrade that was done. So if I understand I could get 30% of that back at tax time. What’s a roof and panel upgrade go for??


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## jetsam (Jul 10, 2019)

Rob711 said:


> I think I can get a separate bill from contractor for the cost of roof and 200 amp upgrade that was done. So if I understand I could get 30% of that back at tax time. What’s a roof and panel upgrade go for??



How are you getting a tax break on your roof and service entry?

Roofing is really, really variable. Shingles are around a hundred bucks a square and the price difference between cheap ones and good ones isn't much at all.  Almost all of your price is labor.


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## peakbagger (Jul 10, 2019)

Taking the tax break on the roof and service upgrade is one of these talk to your tax accountant issues. That said some folks like to roll the dice and push it and hope they don't get audited. One of the reported tricks of the trade by the leasing firms is they push the outer limit on the front end cost by adding in a lot of overhead on their installs to boost the rebate. The reality is the company really only cares about the next quarter so if the write offs get disqualified three or four years down the road they will worry about it when it happens.

That said, if the service panel needs to be upgraded due to the 20% rule or not enough space for a dual pole breaker many folks do write off the service upgrade even if they are getting additional benefits like the panel was ancient or undersized for other reasons. Of course one can argue that in that situation a line side tap may be the more economical option.

The roof replacement IMHO is another story. Sure folks claim to write off the entire roof and deal with totally unrelated repairs but they also can under report their income and a whole host of other illegal or questionable acts. If the solar panels cover all the exposures of the roof (highly unlikely) then IMO charge the entire cost of the roof. On the other hand, if the panels are on the south exposure (which is far more typical) then IMO either do just half the roof or write off half the charge. Sure some may argue that they need to do the whole roof because the color will not match and some may be comfortable sitting across the table from an IRS auditor trying to sell it.


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## jetsam (Dec 13, 2019)

They put the panels on the roof today. System was making 150 watts when we first turned it on. Looks like it'll be possibly even less all day tomorrow, but the panels will get a good rinse anyway.    

I got 20 of the new LG 370s with enphase inverters.  If the sun ever comes out, it'll be good for my electric bill!

Next project is to swap out the oil fired DHW for an electric heater! Should break even on the equipment there, as I'll have a $1500 oil fired one in good condition to sell.


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## Rob711 (Dec 14, 2019)

Nice! Almost a month ago I got 42 of the same panels, should cover 102% of my electric, of course oct nov dec are bad producing months. Now volcanoes are erupting so expect dusty hazy skies. My neighbor bought a new snow blower so at least we won’t get any substantial snow this yr


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## peakbagger (Dec 14, 2019)

Great, you even got the system in before the deadline for the 30% fed rebate. Have fun learning the characteristics of the system. It definitely puts most folks more in tune with the local weather conditions affecting the sun.


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## jetsam (Dec 14, 2019)

peakbagger said:


> Great, you even got the system in before the deadline for the 30% fed rebate. Have fun learning the characteristics of the system. It definitely puts most folks more in tune with the local weather conditions affecting the sun.



The blue line is cloud cover for today!  

Making ~800w at the moment.


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## SpaceBus (Dec 14, 2019)

jetsam said:


> The blue line is cloud cover for today!
> 
> Making ~800w at the moment.
> 
> View attachment 253484


Wow, that's amazing. I'm hoping to have a solar system with storage operational in the next ten years. That's really great to see even 800w with such cloudy conditions. We have been working hard to reduce our usage to the point that we could go through winter with just solar.


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## Brian26 (Dec 15, 2019)

The GOES 16 satellites provides real time visual cloud data here. 









						COD NEXLAB: Satellite and Radar
					

Check out COD Meteorology's Satellite and Radar Data




					weather.cod.edu


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## begreen (Dec 15, 2019)

SpaceBus said:


> Wow, that's amazing. I'm hoping to have a solar system with storage operational in the next ten years. That's really great to see even 800w with such cloudy conditions. We have been working hard to reduce our usage to the point that we could go through winter with just solar.


We're hitting 1kW today with clouds or about a fifth of system capacity, but it is frequently dropping to 200W as clouds scud by.


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## SpaceBus (Dec 15, 2019)

begreen said:


> We're hitting 1kW today with clouds or about a fifth of system capacity, but it is frequently dropping to 200W as clouds scud by.


What kind of daily usage are you seeing, if you don't mind me asking? Right now we are around 11.5 KWhr/day average. I'd really like to get down to less than 9 KWhr/day


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## begreen (Dec 15, 2019)

About 24kWh/day at this time of year. My wife is baking stuff for Christmas, heat pump comes on some times, winter lighting, electric HW and clothes dryer bring it up a lot and we charge the car too. Summer drops down to about 15kWh/day including car charging.


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## Rob711 (Dec 15, 2019)

I love data! MY natural gas hot water heater is over 10 years old so I feel it should be replaced soonish. I’m not sure I wanna commit to electric on this yet. I briefly looked into on demand electric water heaters, wow those need some serious juice!


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## SpaceBus (Dec 15, 2019)

begreen said:


> About 24kWh/day at this time of year. My wife is baking stuff for Christmas, heat pump comes on some times, winter lighting, electric HW and clothes dryer bring it up a lot and we charge the car too. Summer drops down to about 15kWh/day including car charging.


Thanks for the data points. This makes me confident we could live with solar for the majority of the time.


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## semipro (Dec 15, 2019)

Rob711 said:


> View attachment 253572
> 
> 
> 
> ...


You should consider a heat pump water heater.  They're more efficient that a resistance unit and they pull way less peak power - nice when you're on backup power whether solar, wind, or generator.


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## SpaceBus (Dec 15, 2019)

semipro said:


> You should consider a heat pump water heater.  They're more efficient that a resistance unit and they pull way less peak power - nice when you're on backup power whether solar, wind, or generator.


I'm using an on demand electric water heater and it uses far less electricity than my old resistance unit. Sure, it takes two dual pole 40 amp breakers, but there only two adults and I have a 40 gallon tank heated by a coil in my cookstove doing the heavy lifting. Usually input sensor on the water heater never reads lower than 75 df and I have the output set at 130df. So far with the change over I'm using less than half of the power I was using previous. 

My situation is far less than usual, but in the right situation electric on demand water heater heaters can be really great.


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## Where2 (Dec 19, 2019)

SpaceBus said:


> Usually input sensor on the water heater never reads lower than 75 df and I have the output set at 130df. So far with the change over I'm using less than half of the power I was using previous. My situation is far less than usual, but in the right situation electric on demand water heater heaters can be really great.


What temp does your water come out of the ground at SpaceBus? In South FL, mine comes out of the city water pipes at around 75°F. When I have washed my car at our farm in Maine, I managed to fog up the inside of the car windows on a summer day with that unheated north Maine ground water coming straight off my well pump in the basement.   Seems to me, my well water was somewhere between 47° and 52° in September.

My PV Watts calculations put the 4.6kW array I intend to install in Maine at ~5MWh/yr. That's ~685Wh per PV panel per day.
At our house in FL, my actual average is ~790Wh per PV panel per day. Our daily home consumption is basically double what we produce with PV when averaged across a year.


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## sloeffle (Dec 19, 2019)

My HPHW water heater costs me between $5 - $7 a month to run. The HPHW I just installed will be even cheaper since it has a UEF of 3.45. I'm sorry but there is no way an on demand electric unit can make hot water that cheap. I doubt your can even make it that cheap with natural gas.

Simple electrical match ( V over I,R):

80 amps x 240 volts =19,200 watts

19,200 / 1000 watts ( 1kwh ) = 19.2kW

19.2kW * .14 cents ( my cost 1kWh of electric ) = $2.688 per hour to run

At $7 a month I'm using around 50kWh of electric all month to make my hot water.


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## SpaceBus (Dec 19, 2019)

Where2 said:


> What temp does your water come out of the ground at SpaceBus? In South FL, mine comes out of the city water pipes at around 75°F. When I have washed my car at our farm in Maine, I managed to fog up the inside of the car windows on a summer day with that unheated north Maine ground water coming straight off my well pump in the basement.   Seems to me, my well water was somewhere between 47° and 52° in September.
> 
> My PV Watts calculations put the 4.6kW array I intend to install in Maine at ~5MWh/yr. That's ~685Wh per PV panel per day.
> At our house in FL, my actual average is ~790Wh per PV panel per day. Our daily home consumption is basically double what we produce with PV when averaged across a year.


Wow, those are great numbers! 

The well water is possibly even less than 42df. It's the coldest well water I've ever had, and my grandmother had a mountain spring fed well. On a day I'm using the cooker to heat and/or cook the water is more like 120df+ on the output. We do tend to use a lot more hot water now that it's almost free. My wife likes to take a lot of baths due to some pain from medical problems. I think in the future I will put an r7.5 wrap on my range boiler for a while. After we remodel the bathroom I plan to put a loop or two in the water coil in my stove to accommodate another 40 gal range boiler so we can get a 60" bathtub.


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## Brian26 (Dec 19, 2019)

sloeffle said:


> My HPHW water heater costs me between $5 - $7 a month to run. The HPHW I just installed will be even cheaper since it has a UEF of 3.45. I'm sorry but there is no way an on demand electric unit can make hot water that cheap. I doubt your can even make it that cheap with natural gas.
> 
> Simple electrical match ( V over I,R):
> 
> ...



I agree. I monitored my geospring and for just the wife and I it only used like a kwh or two a day. It was like $10-15 a month with CT's really high electric rates.  Just to be connected to gas here the service charge is double that. 

I also read those on demand units are horrible for the grid as well. They can put a serious strain on the equipment with that many amps surging  when it comes on.


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## SpaceBus (Dec 19, 2019)

sloeffle said:


> My HPHW water heater costs me between $5 - $7 a month to run. The HPHW I just installed will be even cheaper since it has a UEF of 3.45. I'm sorry but there is no way an on demand electric unit can make hot water that cheap. I doubt your can even make it that cheap with natural gas.
> 
> Simple electrical match ( V over I,R):
> 
> ...






Brian26 said:


> I agree. I monitored my geospring and for just the wife and I it only used like a kwh or two a day. It was like $10-15 a month with CT's really high electric rates.  Just to be connected to gas here the service charge is double that.
> 
> I also read those on demand units are horrible for the grid as well. They can put a serious strain on the equipment with that many amps surging  when it comes on.




That depends on the unit and the water temp. My unit can only pull 80 amps max which is an oven and washer running together. Since my ecosmart unit can modulate and detect input and output Temps it uses very little. I think last month we used 390 kwhr and it is on track to be 300 or less next month.

Here is what the power company told me I used. This involved dumping a few hundred gallons outside while getting my house plumbed. Certainly my experience is a typical since my input Temps are usually over 100df, if not much higher. If my wife doesn't spend 4 hrs in the tub the range boiler stays hotter of course. She won't be in the tub for at least four weeks, if not longer so I will really be able to compare.


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## SpaceBus (Dec 19, 2019)

This is a day with only a face wash and washing dishes. We were out all day and the range boiler was at 75df.


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## lml999 (Dec 26, 2019)

We had 37 SunPower panels installed 3 years ago, currently generating about 140% of our annual needs. Haven't paid a dime to the electric company in 3 years. 

Silly squirrel tried to take up residence under the panels last summer...we chased him away with repeated dousings with a garden house. He's back, so we're having "critter" guards installed in January. Not a big deal, costs about $1K, will protect the wiring against hungry rodents. He didn't cause any damage last year, but I'm not willing to chance it. Good friend did have substantial damage from rodents chewing his wiring...

I'm ASSuming that the $1K is eligible for a 2020 fed tax credit as its part of the cost of my solar panel installation. I don't see anything in the tax instructions about expenses being limited to a one time event....


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## jetsam (Dec 27, 2019)

So far the system has been generating about half of what we use- but that's with December weather.  I had been hoping to switch to mostly-electric heat, but I'm putting that off to next year when I have the summer's solar credits built up.

It's making 177w right now with full cloud cover. The best panel is making 10w right now, and the worst one is making 7w (that's a 1-minute average).


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## Brian26 (Dec 27, 2019)

jetsam said:


> So far the system has been generating about half of what we use- but that's with December weather.  I had been hoping to switch to mostly-electric heat, but I'm putting that off to next year when I have the summer's solar credits built up.
> 
> It's making 177w right now with full cloud cover. The best panel is making 10w right now, and the worst one is making 7w (that's a 1-minute average).



I assume by electric heat you mean heat pumps. Electric resistance heat is not very efficient compared to heat pumps. They can produce 4 times the heat of electric resistance heat for the same energy consumption.

I have 2 12k hyper heats and solar and its the best combination. Practically free heat and I am not burning any fossil fuels. Here was a random day where my panels were powering my whole house, mini splits and sending power back to the grid.



An Air Source Heat Pump (ASHP) will typically produce around 4kW thermal energy for every 1kW of electrical energy consumed, giving an effective “efficiency” of 400%. It is thermodynamically impossible to have an efficiency of more than 100%, as this implies that more energy is being produced than is being put in.  For this reason the performance is expressed as a Coefficient of Performance (COP) rather than an efficiency. The above example would be expressed as having a COP of 4.  The reason that it appears that more energy is being produced than is consumed, is because the only “valuable” energy input is electricity used to drive the compressor and circulating pumps.  The remainder of the energy simply transferred from a heat source that would otherwise not be used (such as the ambient air, ground or a river) so is not considered as an energy input.


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## jetsam (Dec 27, 2019)

Brian26 said:


> I assume by electric heat you mean heat pumps. Electric resistance heat is not very efficient compared to heat pumps. They can produce 4 times the heat of electric resistance heat for the same energy consumption.
> 
> I have 2 12k hyper heats and solar and its the best combination. Practically free heat and I am not burning any fossil fuels. Here was a random day where my panels were powering my whole house, mini splits and sending power back to the grid.
> View attachment 254231
> ...



Resistive right now.  Heat pump minisplits are the next thing on the menu.  I think I have the wife sold on LG because of that stupid picture frame head they offer.  But whatever gets it the green light, I guess!


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## peakbagger (Dec 27, 2019)

I caution that the COP of 4 is decidedly optimisitic depending on outdoor air temp. COP of air source minisplits drops as well as heat output drops with the outdoor air temp.  I find the intersection of an increase in building heat load and decreased minisplit COP and output is around 20 to 30 F for my house. Many early adopters of cold climate mini splits  I know also have this general range. The options are install extra units or have backup heat sources that are temperature independent.  

Note the ASHRAE ratings really are not a good fit for colder climates. Its worth taking a look at this link from NEEP which has more realistic ratings for cold climate units, scroll down a bit and read the background section.  




__





						ccASHP Specification & Product List | Northeast Energy Efficiency Partnerships
					

Click here to access




					neep.org
				



Here is link to a Mitsubishi unit grabbed somewhat at random. https://neep-ashp-prod.herokuapp.com/#!/product/28983 Note the COP at 17 F and 5 F plus notice the derate in heat output. COP is still 2 which is better than 1.0 for electric heat but the required air flow leads to drafts which for most people means they need to run a higher space temperature setting.  I keep a cool house normally but I do have electric fan forced space heater in my bathroom for use when I take a shower. I heat up that small space with a COP of 1 versus heating up the entire house to higher temp with COP of 2. 

Practically I also know of a dealer that sells and services rebuilt Monitor kerosene space heaters and they are  getting a lot of business and new installs in coastal Maine in homes that thought air source minisplits were all they needed.  Its nice fit except using the monitor during cold spells and then letting the air source units take over. The problem is that kerosene is expensive and in some areas hard to get. The heaters also are banned in some states as they were lumped in with older style Kerosun unvented heaters (Monitiors are thru wall vented very similar to pellet stoves. The market for these units was dead for years but they noticed a major uptick of late.


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## Brian26 (Dec 27, 2019)

peakbagger said:


> I caution that the COP of 4 is decidedly optimisitic depending on outdoor air temp. COP of air source minisplits drops as well as heat output drops with the outdoor air temp.  I find the intersection of an increase in building heat load and decreased minisplit COP and output is around 20 to 30 F for my house. Many early adopters of cold climate mini splits  I know also have this general range. The options are install extra units or have backup heat sources that are temperature independent.
> 
> Note the ASHRAE ratings really are not a good fit for colder climates. Its worth taking a look at this link from NEEP which has more realistic ratings for cold climate units, scroll down a bit and read the background section.
> 
> ...



The technology is advancing rapidly using vapor injection compressors. My Gree is AHRI rated at a COP of 4.47. I believe that is a seasonal rating as most mini splits arent running in subzero weather all winter.

My Gree can put out almost its full rated output at -22 as well.


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## lml999 (Dec 27, 2019)

begreen said:


> Get the basics figured out first, like solar exposure and roof capacity. Is there a substantial portion of the roof sloping to the south? Will the roof support the weight?



Not sure why the weight question comes up so often.

The 'average" panel weighs about 40 lbs. My 37 panels weigh about 1500 lbs, roughly equivalent to one inch of snow covering a 40'x30' roof.

And panels tend to shed snow more quickly than roof shingles, so solar installations potentially will reduce the amount of weight carried by the roof in a snow storm...


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## jetsam (Dec 27, 2019)

lml999 said:


> Not sure why the weight question comes up so often.



I pulled a light fixture so we could get an inspection camera into the attic space for the engineering crew when they were inspecting for my install.  I asked what they were looking for aside from beam spacing, and the guy said "We're looking for 2x4s. I hate it when we find 2x4s." 

In a related story, I once told a guy he couldn't use 3/8" sheathing for decking on a roof, and he said, "We stand on the beams, and it'll last long enough for the check to clear."

So from the outside, ya really never know if a roof can even hold up the weight of a roof, let alone any additional stuff like panels and snow!


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## peakbagger (Dec 27, 2019)

I looked up that GREE unit on the NEEP site using the AHRI number listed on the catalog cut





						ASHP
					






					neep-ashp-prod.herokuapp.com
				




Note the COP down in the colder temps, quite a difference between 4.47 and 1.85.  I don't dispute that an air source minisplit COP is great for milder winter temps and its a fine supplemental heat source. I also note that if I plot the temps verses COP the trend line looks to hit 1 long before its gets to -21 F.  Granted there are only three data points but the trend looks like a baseboard heater for heating up a spot location beats heating the entire space with a minisplit somewhere around 0 F.

The NEEP Semninar goes into why the ASHRAE values were not useful for units in colder climates.

Standard heating practice is to size the heating appliance for the design cold temp steady state outdoor air conditions. Using that basis there is the option to install multiple minisplits to deal with winter design temps but unless the far lower COP is factored in the homeowner who uses a seasonal COP is going to be quite cold on that cold day as they will be short 60% of the expected heating load, thus the recomendation that in cold climates the minisplit should be regarded as supplemental versus a primary heat source.


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## Brian26 (Dec 31, 2019)

peakbagger said:


> I looked up that GREE unit on the NEEP site using the AHRI number listed on the catalog cut
> 
> 
> 
> ...



The OP is on Long Island. His 99 percent design temp is 17 degrees which means 99 percent of the year his temperature is above that. 1 percent of a average year he is below 17. At his 17 degree 99 design temp it still has a cop of  3. I bet OP would easily average a COP near 3.5-4.

I am on the CT shoreline and rarely ever see subzero cold but I have a wood insert and 80k btu oil furnace if I need it for those rare polar vortexes. My 2 mini splits have been heating my entire house so far this winter.

I lived in VT for many years and its a completely different world up there temp wise.

I believe you are in New Hampshire where the 99 design temps are single and subzero. If I lived there I would only run my min splits in shoulder season. Down here they are amazingly efficient most of the winter.

I attached the 99 percent design temps for NY and New Hampshire.


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## begreen (Dec 31, 2019)

Catching up on this Brian. Sounds like you liked the one you installed last Jan. so much that you added a second? Are you heating all of your house now or just area heating? How many sq ft.?

Our design temp is probably even higher. What source is this info from?


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## lml999 (Jan 23, 2020)

jetsam said:


> They put the panels on the roof today. System was making 150 watts when we first turned it on. Looks like it'll be possibly even less all day tomorrow, but the panels will get a good rinse anyway.



Welcome to solar!

Just for fun, check your system output on a _night_ with a full moon and clear sky.


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## begreen (Jan 28, 2020)

Battery backup systems discussion moved to it's own thread here:





						Home battery backup systems
					

Moderator moved from Going Solar! thread to new thread for discussion  :ZZZ  Total novice here, but I have a few questions. My water heater is rated at 18kw max and I'm trying to see if it were even possible to run it off of a battery bank. Does this means I should get at least an 18kw inverter...




					www.hearth.com


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## jetsam (Jan 28, 2020)

This thread had just moved into stage three (moderate derailment) and was about to get to the best part.   Now we have to start all over...


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## begreen (Jan 28, 2020)

jetsam said:


> This thread had just moved into stage three (moderate derailment) and was about to get to the best part.   Now we have to start all over...


Nah, it left the train and went on its own track concerning storage, not generation. You declared in the first posting - no batteries for me. They are separate projects and technologies, each deserving room for development and discussion.


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## jetsam (Feb 7, 2020)

ricardos said:


> Very interesting article.



That IS an interesting article.  It reads like one of those script-generated pages they use to park domains and drive google searches to empty pages at the same time.

The weird part is that it oddly toes the line between looking like it's generated by a script and looking like it's written by someone who has English as a second language- but even an English learner wouldn't write stuff like "Circular solar panels round solar panels are unquestionably the best approach to save on electricity price".  You can google that idea in any language and see that it's nonsensical.

So I am going to say that maybe this whole site is AI-generated and lightly edited by a person? Some of the photo choices aren't ones that I think an AI would make (for example the round solar panel photo is all right angles, but it IS a round array made up of rectangular panels, though I doubt an AI image sorter could work that out).


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## Piney (Feb 8, 2020)

I just want to see more updates on OP's power production. 
This ongrid solar thing interests me academically. 
I'll never see the grid in my lifetime but I still like to hear about what people get up to...,


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## Woodsplitter67 (Feb 12, 2020)

I went solar in September of 18.  it was a great investment.  havent paid an electric bill.. im still on a credit. i will use it up this month, but next month ill be at the breakeven point where ill generate as much as i use..


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## black smoke signals (Feb 14, 2020)

Local installer did my solar enlighten panels (March 2019) produced 7.4 Mega watts total 8 months I didn’t oversize my solar panels because of net metering and service fees which are starting to rise. Like most have said they don’t have a electric bill but you need to figure all of your costs (property tax -insurance service fees)this unit saves me 1000 buck a year. Energy companies here don’t like net metering they want to charge us for sending my solar electric that I produce back to the grid at a reduced fee for using there power lines then they resell it to neighboring homes at increased rate . This isn’t fair what the energy companies are doing to offset there loss when coal sales in Wyoming dropped


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## ABMax24 (Feb 14, 2020)

black smoke signals said:


> Energy companies here don’t like net metering they want to charge us for sending my solar electric that I produce back to the grid at a reduced fee for using there power lines then they resell it to neighboring homes at increased rate . This isn’t fair what the energy companies are doing to offset there loss when coal sales in Wyoming dropped



In reality I think its the feasible option right now. On my electric bill I pay an energy charge, transmission charge and distribution charge when I buy electricity from the grid. When I sell it back to the grid I get only the energy charge back. As much as I wish I got more this system makes sense. Since my solar power is intermittent the power company needs to have the infrastructure in the neighborhood from the power plant anyway. To me it seems fair that the end user of the energy should pay for this infrastructure cost. So it doesn't make sense to charge my neighbor these transmission and distribution fees just to give them back to me, if everyone had solar panels there would be little money left for the power company to build and maintain the system.

The fact is net metering is a subsidy that the public is forced to pay for the benefit of the solar generator. Many jurisdictions are doing away with it because it isn't an economically viable system when a large number of solar generators come online.

Imagine you owned a gas station and the government passed a law saying that anyone could show up to your station with fuel and you had to buy it from them at full retail price. They could show up any-day of the week, even when you didn't need more fuel and offload. How would you pay for your station maintenance and employees never mind take a profit if you bought and sold at the same price. This is what net metering does to power companies.


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## Woodsplitter67 (Feb 15, 2020)

black smoke signals said:


> Local installer did my solar enlighten panels (March 2019) produced 7.4 Mega watts total 8 months I didn’t oversize my solar panels because of net metering and service fees which are starting to rise. Like most have said they don’t have a electric bill but you need to figure all of your costs (property tax -insurance service fees)this unit saves me 1000 buck a year. Energy companies here don’t like net metering they want to charge us for sending my solar electric that I produce back to the grid at a reduced fee for using there power lines then they resell it to neighboring homes at increased rate . This isn’t fair what the energy companies are doing to offset there loss when coal sales in Wyoming dropped



i disagree with you a bit. the utility companies need to keep up the cost of the infrastructure that is associated with your home and the area you live in. you really think its fair to use there line's and stuff when you dump your extra power into the grid and not expect to recive a fee for your use. I get charged extra fees and im not really excited about it, but i understand. I dont like it at all but i look at what i generated,   what i have saved,and for the 10 bucks a month  im still way ahead and not stressing over it


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## Piney (Feb 15, 2020)

It seems fair for utilities to buy power at wholesale and sell it at retail. I get government regulation forcing this much upon them but not mandating the prices.
But what keeps me up at night is wondering if some fool politician will interfere in the battery market or ban wood heat or propane.
My family would be in trouble then.
We like flooded batteries. Our current golf cart bank of 8 pieces is 9 years old and replacement is coming in a couple years. I'll be pretty bent if they can't be purchased at that time due to some misguided edict from on high.


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## CaptSpiff (Feb 15, 2020)

black smoke signals said:


> .... Energy companies here don’t like net metering they want to charge us for sending my solar electric that I produce back to the grid at a reduced fee for using there power lines then they resell it to neighboring homes at increased rate . This isn’t fair what the energy companies are doing to offset there loss when coal sales in Wyoming dropped



Net metering was legislated in order to promote distributed energy resources (ie solar production) behind the meter. When the Govt no longer deems that desirable, it'll be adjusted. That is happening here in NYS.

Our local Electric Utilities no longer own the Generating Plants. They were "forced" to sell them off over 20 years ago, and now buy the electricity form a "market" run by the NY ISO. My Utility calculates the avg cost for buying power and passes that on to me as a bill line item. It is about 10 cents per kwh. The lines and transformers and cost to keep it all running is charged as a separate line item on my bill. This cost is directly regulated, and is about 9 cents per kwh. The third line item on my bill is various Taxes, which are about 2 cents per kwh. So my total retail rate is about 21 cents per kwh.

When a solar producer makes extra power he sells it into the grid for retail rates, then buys it back after dark for that same retail rate, so his transaction is net zero. But two questions come up:
1. Why is the Utility paying (crediting) the producer at retail power prices when they could easily buy the power at lower wholesale market prices?
2. What about the taxes lost during the re-purchase portion of the transaction?

Don't worry, the Govt makes the Utility whole on any effect to their bottom line, and those tax losses appear to have been made up by (you guessed it) an additional tax line on the bill.

I like solar and I desperately want it on my roof (not a good candidate I'm told). But net metering is on life support and will likely pass on when all the home meters are changed to smart meters and we begin being charged on "time of use" basis.


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## Where2 (Feb 16, 2020)

CaptSpiff said:


> I like solar and I desperately want it on my roof (not a good candidate I'm told). But net metering is on life support and will likely pass on when all the home meters are changed to smart meters and we begin being charged on "time of use" basis.



Don't bet on TOU rates being hinged on smart meters: My utility rolled out smart meters ~10 years ago (my PV array went on the roof back in 2013, I got a different brand of smart meter as a result). We have yet to get TOU rates, and I don't hear much clamoring for TOU rates (especially from businesses). My utility (a subsidiary of Nextera Energy) is rolling out their own PV farms as fast as they can install them... (500+ acres at a time) Their shareholders seem to like the low maintenance, low carbon footprint, high profit margin that PV provides.


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