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Debate switching to solar power

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Cadillac

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I’ve been toying around the idea of going solar power for acouple years now and would love to hear from someone that already has or has good informed knowledge of the process.
I average between 400-500 kWh per month in a 1700sq ft ranch house. To my eye my roof should have adequate room for panels mostly full sun all day. My one concern would be I wouldn’t want to put panels on street side so they wouldn’t be seen from street. Wondering what surface area to power needed is to see how much roof I would need?
Are their better systems out there and ones to stay away from ?
Long term I plan on staying here for maybe 10yrs. Need to move for better schooling choices once boy is of age. Main reason for wanting to do this is to not be reliant on the power company paying all the fees and bla bla bla. My normal consumption is cheaper than the delivery rates then add all the taxes and fees for programs it’s just ridiculous. I want them to start paying me:p I would also think it would help a lot with resale of the house which I have completely renovated to make very efficient consisting of insulation, windows all appliances, tankless water heater and 96% furnace,LED’s everywhere.
I’d really like to learn as much as possible about going solar so if you have any knowledge of it please inform me and thanks for reading let me have it.
 

newbydave

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I’ve been toying around the idea of going solar power for acouple years now and would love to hear from someone that already has or has good informed knowledge of the process.
I average between 400-500 kWh per month in a 1700sq ft ranch house. To my eye my roof should have adequate room for panels mostly full sun all day. My one concern would be I wouldn’t want to put panels on street side so they wouldn’t be seen from street. Wondering what surface area to power needed is to see how much roof I would need?
Are their better systems out there and ones to stay away from ?
Long term I plan on staying here for maybe 10yrs. Need to move for better schooling choices once boy is of age. Main reason for wanting to do this is to not be reliant on the power company paying all the fees and bla bla bla. My normal consumption is cheaper than the delivery rates then add all the taxes and fees for programs it’s just ridiculous. I want them to start paying me:p I would also think it would help a lot with resale of the house which I have completely renovated to make very efficient consisting of insulation, windows all appliances, tankless water heater and 96% furnace,LED’s everywhere.
I’d really like to learn as much as possible about going solar so if you have any knowledge of it please inform me and thanks for reading let me have it.
One site is Simply Solar. "simplysolar@yahoo groups.com". They are a group of solar enthusiasts that have a wealth of information. Join the group and ask questions.
 

markba633csi

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Are you going to stay on grid or are you thinking of going totally off grid? I believe the on-grid option is cheaper, the off- grid system requires a sizeable investment in batteries+ charge controllers and inverters plus more pv panels
Mark
ps my brother in Phoenix is contemplating an off grid system- the irony is that even though he's got plenty of sun the high outdoor temperatures require lots of air conditioning which eats up a lot of the system capacity
 

mattthemuppet2

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for that amount of usage you're not going to break even before you move unless your state has a generous feed in tariff. I've looked into it some and it just doesn't make sense for us financially, even in Central Texas with a large south facing roof. I've also heard conflicting stories from realtors and buyers, so I wouldn't bank on it increasing the resale value. It might even make it harder to sell.

If you don't mind the high pressure sales tactics, get 2 or 3 installers out for quotes. They'll know how much you'll need, how much you can fit and what the various federal and state programs are. Don't forget that those programs can (and will) be withdrawn at some point, so base your calculations on the most pessimistic forecast you can. A friend back in south eastern WA (lots of sun in the summer) spent alot of money on an install only for the state government to reduce the feed in tariff a couple of years later, increasing the break even point from 7 years to something like 15. Still worth it for them, but less so than they thought.
 

savarin

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I've had solar water heating and power on my roof for around 20 years now.
I jumped in a bit too quick just before they dropped the price of panels so only managed a 1.75KW system.
My feed in tariff was 44c/KW, if I want to increase the size of my system I loose the 44c down to 7c (or around there)
If I had the spare cash I would load the roof with as much as it could bear and go off grid because prices are escalating here and the new panels are more efficient and produce more power per panel that mine.
Be aware they do not produce as much as they are advertised to do and what the sellers say they will.
I get rebates on every bill but not as much as when we were both working and every drop went back to the grid.
Most of my power is used during the day now.
 

kb58

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This is an enormous topic. I really recommend some serious research before jumping in, because there are many dimensions to this. I highly recommend https://www.solarpaneltalk.com/forum because they're both end users and some are engineers who've shined light on what's really going on behind the sales pitches.
 

Aaron_W

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I was involved in a project to convert the off grid (LPG generator) fire station I worked at to solar. A few years out of date since that project started 5 years ago and only went into service last fall, a year after I retired.

What I found out during that process.

Panels are cheap, and getting cheaper, some are less than $1 / watt. Installation is now a more significant cost than the actual panels.

Batteries and inverter are not cheap, so full off grid costs a lot more than a grid tie in system that sells the power back to the power company and deducts the power sold from your bill.

Grid tie in agreements vary by location, some power companies basically just roll your meter back, so if you use 3000 watts, and your panels produce 1000 watts, you only pay for 2000 watts. Some areas sell the power to the power company, at a set rate which is deducted from you bill. If you are selling power, some areas may tax the power you generate. It is important to know how your area handles this, the roll back method seems to be the better deal, and just easier to deal with.

Avoiding shadows on the panels is more important than, the actual quality of the sunlight. Panels work on a differential method, sunlight on one side, shade on the other (bottom side). A tree branch casting a shadow over a relatively small area of a panel has far more of a negative effect, than a cloudy day with evenly distributed sunlight.

Dirty panels are less efficient, so you need to clean them periodically.

As panels age they lose effectiveness, so if you go off grid you need to start with more power than you need to compensate for the loss of power as they age. Life expectancy of a solar panel is 10-20 years depending on quality.

On the plus side, if you go with a grid tie in system, you can start small, say 1000 watts which is probably around 4x8 feet give or take based on panel quality, sun light quality / length of exposure and the installation type (fixed or sun tracking). Since it doesn't have to power the whole house you can start small and see if it justifies expanding. I've thought about putting 1000-2000w of panels on my house with the idea it would offset the AC bills during the summer.
 

RJSakowski

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Our neighbor has a solar array which ties into the grid and I believe that she has achieved payback already after around ten years. Wisconsin has a mandate that power companies must generate a certain percentage of their power from renewable resources so the the power company pays her more per kwh than they charge. Also there were significant incentives for installation which reduced the capital outlay. She happens to live on a hilltop and has an array which tracks the sun so overall efficiency is around double that of a fixed array.

I have looked at going solar but decided that, due to my location, I would not achieve payback in my lifetime (I'm 74). Sun rises about an hour after actual sunrise and sets behind the trees to the west around 5PM.

Since that determination, capital costs have decreased and solar panels have become more efficient. One thought that I had was to use passive reflective panels to increase the solar flux, thereby reducing the number of panels required.

One consideration in determining the size of the system is the amount of cloud cover. There is a very big difference between Illinois and the desert southwest. Madison, Wisconsin has around 55% sunny or partially sunny days. December has less than four hours/day of sunlight while July has over ten.
 

Boswell

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A little over a year ago I installed a grid tied system. Max output is just under 15kW/H. We contracted the entire installation and we sized it to provide 80-85% of our usage. The undersizing was intentional because our Electric provider will only pay us about 1/2 as much as they charge so we wanted to minimize the times that we produce more than we use in a given month. Every electrical provider and state have different rules and rates so you need to do your research. Where I live we have what is known as Net Metering. This means that we reconcile the Over/Under only at the end of each month. So we overproduce during the day and of course do not produce at all at night. At just over 14 months, we have produced 83.8% of all of our electrical needs via solar. 3 months we had less than $20 bills and 1 month they paid me but the remaining months we still had a bill although much much smaller than before. The installation and panels (we used SunPower). You need to do some financial calculation to know when your break even point will be but expect 10+ years. Our panels are guaranteed for 25 years and I expect they will last longer than that. The calculation can be a bit involved. All Solar panels degrade a certain % each year so you will need to take that into account. Also if you have to borrow money to purchase the panels, then the cost of the loan needs to be calculated in. Also in the US there is a substantial Federal Income Tax Credit. I think it was 30% of the cost of the panels and installation for the 2018 tax year. I believe it is scheduled to reduce this year but not sure. states and local governments and electric provides sometimes offer rebates that stack. Also remember that even if you don't live in the house for 10 + years, you can add to the asking price when you sell. Who wouldn't want to buy a house with next to no electric bill.

Anyway, tons of stuff to look into. And all the above does not take into account the value to our planet by using the sun instead of coal or gas.
 

davidcarmichael

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I’ve been toying around the idea of going solar power for acouple years now and would love to hear from someone that already has or has good informed knowledge of the process.
I average between 400-500 kWh per month in a 1700sq ft ranch house. To my eye my roof should have adequate room for panels mostly full sun all day. My one concern would be I wouldn’t want to put panels on street side so they wouldn’t be seen from street. Wondering what surface area to power needed is to see how much roof I would need?
Are their better systems out there and ones to stay away from ?
Long term I plan on staying here for maybe 10yrs. Need to move for better schooling choices once boy is of age. Main reason for wanting to do this is to not be reliant on the power company paying all the fees and bla bla bla. My normal consumption is cheaper than the delivery rates then add all the taxes and fees for programs it’s just ridiculous. I want them to start paying me:p I would also think it would help a lot with resale of the house which I have completely renovated to make very efficient consisting of insulation, windows all appliances, tankless water heater and 96% furnace,LED’s everywhere.
I’d really like to learn as much as possible about going solar so if you have any knowledge of it please inform me and thanks for reading let me have it.
The things you need to consider (assuming you are going to be grid tied) are:
1) Cost of electricity. It varies greatly and if too cheap it will take a long time to break even.
2) Net metering. If your utility company pays you 1 KWh for each KWh you supply to them then you are OK. If they are cheapskates and pay you a lower rate then once again it takes longer to recoup your costs.
3) Roof direction. Conventional wisdom is that south facing is best, but depending upon your situation regarding sun-hours, shade, and your tariff then SouthWest or even West may be better.
4) Roof area. You need enough to make the installation overheads worthwhile.
5) Roof slope.
6) Temperature. It isn't just the amount of sun that matters it is also how hot it gets. The hotter it is the less efficient the panels are.

There are many other things but a good contractor will spell out all of your choices, like what kind of inverter or inverters you should have, panel size, quantity, etc.

I contacted 5 companies that were highly rated and told them all that I was going to pay cash. Four gave me sensible quotes, one gave me an excellent quote and another matched it and offered to pay my electricity bills until the install was done - and they did.

It was the best investment I ever made, much better than any 401K or stock investment. It dropped my annual bill from $3600 to $600. It was fully paid off in five years, two years ago. Remember the 30% federal tax credit drops at the end of this year. My Electricity Company even paid us some cash for doing it.

Good luck.
 

mickri

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When I was living on my sailboat I went solar to keep my batteries charged instead of running the diesel engine on the boat. This was a total off the grid situation. My experience may not be a good comparison to a house. I was in Mexico most of the time and then in San Diego. I did not find that slight shading like the shade from the back stay going across a panel made much if any difference in the amount of power that the panels generated. The biggest problem for an off the grid set up is battery storage. You can never have too much battery storage. The batteries require constant maintenance. Primarily keeping the terminals clean with good connections and keeping the batteries topped off with distilled water. The old standard lead acid batteries are the best bang for the buck.

To get a good estimate on power usage you need to keep track of how much power you use on a daily basis. This is important in determining the size of the battery bank. Then you need to estimate how many days in a row that you won't have sunshine. Multiply the number of days times your daily power usage. Multiply this by 4. Why do you need 4 times your estimated power need. The batteries in an off the grid system will never be at full charge. 80% charge is typically. You also never want to drain your batteries below 50%. Doing so will damage the batteries. A battery bank will not except a charging rate of more than around 25% of the size of the battery bank in amps. Even this will be hard to achieve. For example I had 400 amp hours of battery capacity on my sailboat. I never achieved a charging rate of more than 25 amps per hour and that was with my diesel engine using a 105 amp alternator. The solar panels never produced more than around 15 amps per hour going into the batteries. No matter how may amps you system may be capable of producing the charge controllers will not allow more than the battery bank can accept to be transmitted to the batteries.

This is just the start of what is involved with living with an off the grid system. You will have to change your life style if you go off the grid.

Based upon my experience I would never have an off the grid system in a home. A grid tied system with at most a generator backup IMHO is the way to go.

If at all possible I would not mount the solar panels on the roof. The supports for the panels require lots of holes through the roof. Everyone a potential leak point. Also if your roof and the solar panels are not in sync life span wise, you will have to remove and reinstall the panels to replace the roof. Another cost to factor into the calculations.

I was a real estate appraiser for most of my working career. Although it has been many years since I did that, I was never able to actually measure an increase in value from solar panels. I still follow value trends watching sales in my area and still can't attach a value to solar panels on a home. I think the reason for this is the life span of solar panels. The closer you get to the end of the life span solar panels may even turn into a negative due to the cost to remove and replace the panels.

As has been mentioned above what your utility company is mandated by law in your area to compensate for the power you generate will have have a big impact on the cost effectiveness of a solar system. California requires the utility to give you dollar for dollar credit up to the amount of electricity that you use and pay you at a reduced rate for any excess that you pass onto the grid. Not many states are this pro solar.
 

mattthemuppet2

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based on your location your monthly bill should be around $80/mth or about $1000/yr. A fairly standard 5kW install (9-10,000kWh per year depending on location etc) seems to be coming in around $3/W give or take after rebates and incentives, which comes to $15,000. If that takes your bill down to zero per month, you'll take around 15 years to make your money back. Payback time shortens with higher electricity costs, higher feed-in tariffs or better net metering rules, more generous Federal (ha!) or state subsidies and rebates and so on.

Our use is similar, from $60 to 150/mth depending on time of year, and our neighbours are always moaning about how miserly our city power company is - net-metering with $0.016/kWh paid for the excess - that it didn't make financial sense. I'd rather spend some of that money on more attic insulation and a more efficient AC, then invest the rest.
 

MikeInOr

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Every time I try to pencil out a solar electric installation I can never make the economics work. Solar electric installs seem to be more about making a statement than actually saving money or even saving electricity.

A few years ago I inherited a bit of money and looked into a solar electric system. I live in the high desert region of Central Oregon which should be one of the better return on investment areas for solar electric. The pay back time was going to be longer than 10 years... on paper. I am confident my actual milage would vary from the paper esitmate... and NOT in my favor. It just didn't make sense.

Instead I added a centrally located (great room - kitchen, dinning room and living room) high efficiency (Highest efficiency Fuji) mini split AC / heat pump system. Not having natural gas all my heating is electric. The mini-split lowered my electric bill about 20% for summer and winter. I was all excited to get the government and electric company kick back until I found that a mini split is only eligible if I had the system installed by a "qualified contractor". Well the "qualified contractors" best price was $9k to install their 18seer 12000 btu mini split. For get that! Instead I purchased the 26 seer 12000 btu Fuji mini split and installed it my self for just under $2000. I didn't get the tax credits but I still came out way ahead. And quite frankly the two different HVAC guys I talked to didn't impress my at all... i.e. the thought of them butchering my house kept me awake at night. If you are in the mini-split AC buisness should you know atleast as much about mini-splits as your customers?

I absolutely LOVE the mini-split. We are much more comfortable while saving real money and electric power. My central AC hasn't been on since we installed it. My next project will be to install a 3 head mini-split in our 3 bedrooms.

If I ever do install a solar system: 1) I will install it myself. 2) It will almost definitely be a solar hot water system as it will be by far the best bang for buck with the quickest pay back considering I do not have natural gas service.
 
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davidcarmichael

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Net metering is not always dollar for dollar especially if you have a TOU (Time-Of-Use) tariff. It may depend on when you generate the power.
If you have an old roof then often the installer will suggest you replace the roof at the same time. Solar systems generally come with a 25-year warranty and I assume most roofs should last that long.
If you examine your last 5 years of bills and the total is low then the chance that you will benefit from solar is also much lower. However you should never make the mistake of trying to generate all of your usage from solar panels. That is just a waste, especially if you have a tiered electricity tariff where the first few hundred KWh are priced at a low level. You want just enough solar generation to stay in the bottom tier all of the time except for short periods when the weather is very hot and you use a lot of A/C. There definitely is a sweet spot and a good installer will help you find it.
It had not occurred to me that you might not have gas for water and home heating. That does change some of the calculations as using solar power for water heating is a pretty poor choice.
 

kb58

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On the site I recommended above, some of them are electrical engineers who've installed their own systems. They did a TON of monitoring and computations, finding that solar is a real mixed bag as far is being a net positive. There's cost of the equipment, installation cost (if not done yourself), daily exposure, equipment reliability, degradation over time, electrical pricing tiers, time of use (TOU) policies, etc.

Their strong advice is a bit surprising: consider simply using less power instead of installing solar. This is extremely telling, having people who "been there done that" came to the conclusion it may not be worthwhile.
 
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mickri

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I think that a solar hot water system makes a lot of sense. Especially if the solar panel is lower than the water heater by about 2 feet. As water heats in the panel it will naturally rise up the pipe and into the tank while at the same time sucking cold water from the bottom of the tank. You actually have to be careful because the water will get really hot. So hot that you can get scalded by the water. I used solar to heat water on my sailboat and I had to keep the tank under shade cloth that filtered out most of the sun.

You have to be really careful if you enter into a TOU contract with your utility company. I have read about people having higher electric bills after installing solar with a TOU contract.
 

BGHansen

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My in-laws put in a 7.5Kw roof top system a year ago. Cost was just over $40K on a 5.99% note (they didn't read the fine print and were surprised by the interest rate). They live in Southern Michigan and without the AC on had a $26 bill last month. But the payment on the loan is something like $220 a month so really haven't seen a benefit yet. They're both about 80 and might not hit the cross-over point during their lifetimes.

Biggest problem is Michigan is about as cloudy as Seattle, so like real estate, think location, location, location. He commented on July 4 that he probably wouldn't do it again. But that's based on our climate. You might get a little more sun in Chicago so it'll pay off.

Bruce
 

Larry42

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Solar hot water makes a lot of sense. I've traveled a lot and there are large areas of the world that have simple hot water systems, often jury rigged. They require no electrical and very little maintenance. In my climate they would be more complicated due to our low temperatures that get to -20F. As for electric solar, I ran the #s before we bought our house, 19 years ago. A total looser, but things have improved. I live in tornado alley with lots of high winds and hail. Our house is on its 3rd new roof, (4 if your count the first one) several new windows and new siding due to hail. I'd like to know how the solar panels fare with those conditions. How do insurance companies view solar panels? Lots to consider!
 

kb58

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Oh, and another thing to consider. There are two types of DC-AC converters. One system uses a large single unit, typically near the power meter on the side of the house. The other type uses "micro converters", where one is attached to each panel. The latter type can cause a lot of radio interference, so if you're out in the country such that you count on through-the-air TV, radio, or ham radio, the former may be your only choice.
 

davidcarmichael

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I think that a solar hot water system makes a lot of sense. Especially if the solar panel is lower than the water heater by about 2 feet. As water heats in the panel it will naturally rise up the pipe and into the tank while at the same time sucking cold water from the bottom of the tank. You actually have to be careful because the water will get really hot. So hot that you can get scalded by the water. I used solar to heat water on my sailboat and I had to keep the tank under shade cloth that filtered out most of the sun.

You have to be really careful if you enter into a TOU contract with your utility company. I have read about people having higher electric bills after installing solar with a TOU contract.
Solar water heating for your home is a non-starter if you have a gas supply and as long as gas is ridiculously cheap. The repayment period would probably be longer than you will live.

We only moved to a TOU electricity contract after we bought a Tesla. TOU makes A LOT of sense when you have an electric car. However pretty much every utility in every state is going to go there eventually whether you like it or not.

So far, thanks to our solar panels we are running 100% off-peak which has reduced our overall electricity per-KWh cost by more than 22%. This is because all of the daytime off-peak is handled by solar, some of the nighttime off-peak is reduced by daytime solar over-production, and all of the (manually limited) on-peak time is covered too. In fact this month we have negative numbers of KWh used on-peak. To give you an example we are likely to buy 550 KWh this month at the off-peak rate (it is hot and we do use A/C) and our solar system is producing a total of about 500+ KWh this month, so our final bill is more than halved.

I agree wholeheartedly with all suggestions about saving energy, within reason. As with all engineering problems there is a sweet spot that you have to find and many building codes expressly prevent you from modifying existing homes to improve efficiency. And don't get me started on home owners associations.
 

kb58

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Yet another variable. Some power suppliers credit you for the power you make for the same amount that they charge everyone else. This is unsustainable as a business model (who's paying to maintain the grid)? For this reason, more and more (and likely, eventually all) suppliers will switch to giving you a very small fractional credit for the power you make, so give up any delusions of making big bucks selling power back to the grid. The point is, sizing the system to make the most economic sense isn't trivial, and usually ends up being smaller than what people want - which of course installers are all to happy to screw you over on.

One more thing is that you'll likely find is that your utility's pricing tier structure over a 24-hr period is will be nearly impossible to determine. Next to national secrets, power company's charges are a very frustrating and opaque thing, which is very likely on purpose.
 

davidcarmichael

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Yet another variable. Some power suppliers credit you for the power you make for the same amount that they charge everyone else. This is unsustainable as a business model (who's paying to maintain the grid)? For this reason, more and more (and likely, eventually all) suppliers will switch to giving you a very small fractional credit for the power you make, so give up any delusions of making big bucks selling power back to the grid. The point is, sizing the system to make the most economic sense isn't trivial, and usually ends up being smaller than what people want - which of course installers are all to happy to screw you over on.

One more thing is that you'll likely find is that your utility's pricing tier structure over a 24-hr period is will be nearly impossible to determine. Next to national secrets, power company's charges are a very frustrating and opaque thing, which is very likely on purpose.
Actually they are moving to a basic monthly charge to pay for the grid in this area and leaving the net metering alone.
I think this is a better idea as everyone needs the grid whether they use a little or a lot of power. Might be tough on low income folks but I think they have price breaks in some cases.
 

Janderso

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Are you going to stay on grid or are you thinking of going totally off grid? I believe the on-grid option is cheaper, the off- grid system requires a sizeable investment in batteries+ charge controllers and inverters plus more pv panels
Mark
ps my brother in Phoenix is contemplating an off grid system- the irony is that even though he's got plenty of sun the high outdoor temperatures require lots of air conditioning which eats up a lot of the system capacity
Boy, you would want a home that is built with the best high tech insulation known to man.
I didn't know, going off grid, was an option.
 

mickri

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Back in the 80's there was a lot of hype about solar home heating with more options being floated than you could throw a stick at. I was doing RE appraisals at the time and looked into becoming an expert in the valuation of solar homes. Everybody was waiting for a study that was being done by a university in New Mexico. The study included a typical for the time building with typical insulation. Next was a very well built, well insulated building. Then there were well built, well insulated buildings each with a different type of solar heating. The end result was that 90% of the energy saving came from the well built, well insulated building and none of the different solar heating options added more than 10% energy savings.

Well built well insulated buildings are very tight. They don't breath and trap moisture inside the home. They have to have positive ventilation built into the home. This was unknown to me and when I remodeled my house at the time I did not provide ventilation for the home to breath. My super insulated tight home literally rained inside the house. I had to punch holes in the roof for vents and create small gaps at the top of the cathedral ceilings to create airflow. It was a mess. Live and learn as the saying goes.
 

davidcarmichael

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Boy, you would want a home that is built with the best high tech insulation known to man.
I didn't know, going off grid, was an option.
It's not really an option unless you have no option.

The cost of batteries to store all of the solar, wind and maybe water energy you collect, so you can have electric power 24x7 is prohibitive and the control systems very complex. Added to this the fact that all (non-exotic) batteries have a limited lifetime, plus all of the insulation you would need, and you are talking about a lot of cash. Storing solar heat is less of a problem but even that requires a huge amount of well insulated storage.
 

davidcarmichael

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Back in the 80's there was a lot of hype about solar home heating with more options being floated than you could throw a stick at. I was doing RE appraisals at the time and looked into becoming an expert in the valuation of solar homes. Everybody was waiting for a study that was being done by a university in New Mexico. The study included a typical for the time building with typical insulation. Next was a very well built, well insulated building. Then there were well built, well insulated buildings each with a different type of solar heating. The end result was that 90% of the energy saving came from the well built, well insulated building and none of the different solar heating options added more than 10% energy savings.

Well built well insulated buildings are very tight. They don't breath and trap moisture inside the home. They have to have positive ventilation built into the home. This was unknown to me and when I remodeled my house at the time I did not provide ventilation for the home to breath. My super insulated tight home literally rained inside the house. I had to punch holes in the roof for vents and create small gaps at the top of the cathedral ceilings to create airflow. It was a mess. Live and learn as the saying goes.
Have a look at this guy. He says all homes in the south are built wrong and backs it up with sound reasoning.

 

mikey

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My home is 3,000 SF. All walls are insulated, as is the attic. I have a new Architect 80 roof with ridege vents, 2 large solar fans and have 4 Mitsubishi split system air conditioners, two of which run most of the day.

I had a solar water heater installed. This is an electric 80 gal heater that is powered during the day by 4 solar panels and off the house supply at night.

I have 29 Panasonic 330 HIT panels to supply the house, along with 2 Tesla Powerwalls. On sunny days, which is most days in Hawaii, my home is almost 100% supplied with this system. My home was 99% powered by this system in June and July.

My previous electric bill was over $300/month. It is now less than $27.00/month and $25 of that is the mandatory charge to stay hooked up to the grid so actual cost for grid supply now averages less than $2.00 per month. My system has been in place for about a year now and I like it. I also got a 30% Federal and State rebate so the cost was not too bad. I would say that whether or not a PV system is worth the cost depends on a large number of variables but for me, it was a good investment.
 

markba633csi

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I have told my brother to take the number of panels he's been planning on using and double or even quadruple it- not sure if he believes me yet
but I keep trying
 

Boswell

Hobby Machinist since 2010
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When we built our home we built it with 12" think walls. Just build two standard 2x4 walls spaced 3.5" apart and then filled it all with fiberglass batt insulation. No east or west facing windows and large overhangs on the south side. I/R barriers on the East and West facing walls along with the roof. I agree with others that Insulation is the most cost effective way to save energy cost. different climates require different techniques though.
 

Aaron_W

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On the site I recommended above, some of them are electrical engineers who've installed their own systems. They did a TON of monitoring and computations, finding that solar is a real mixed bag as far is being a net positive. There's cost of the equipment, installation cost (if not done yourself), daily exposure, equipment reliability, degradation over time, electrical pricing tiers, time of use (TOU) policies, etc.

Their strong advice is a bit surprising: consider simply using less power instead of installing solar. This is extremely telling, having people who "been there done that" came to the conclusion it may not be worthwhile.
During the evaluation for switching from generator to solar at the station I worked at, one of the things that was done, was having an electrical engineer evaluate the current lighting, appliances, HVAC etc. More efficient appliances means less power required. The cost of new appliances in some cases can be more than offset by the savings from reducing the amount of power generation required.

In that particular case, since the station was already on a generator, efficiency was pretty high, but one area we hadn't expected to change was due to the batteries. Our estimates for the solar field was based on the size of the current generator. The generator was oversized to handle the starting load of the HVAC. They were able to significantly downsize the solar field from our estimate, because the battery system was able to absorb the brief power spike caused when the HVAC started.
 
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