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Question DetailsAsked on 4/4/2018

Solar panels. If only enough space to install panels to reduce pwr bill 49%. Still a good idea?

Thinking about installing solar panels to be green and reduce power bill. Due to our location, configuration of our house and size of useable roof space it appears we can only install 16 panels. The estimated kwH production from these 16 panels is 4800 annually. Our averaged/estimated annual kwH useage is 9737. So our "savings" would appear to be about 49%. With that information is it really cost effective to go with the proposed solar plan?

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You need to go through an economic analysis - and probably the most critical questions in the analysis is how long you are pretty sure to live in the house, both to be around to recoup the savings (if any) and also because solar powered homes are generally harder to sell (most people do not want the hassle or potential cost liability if a leased or company-owned system.

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BTW - you talk about available roof space - if legalin your area and you don't mind the appearance and would not be subject to kid's balls or such, there is a growing trend to putting some on the walls also - usually on south side and maybe the east or west side with the longest sunlight period, depending on local trees, neighbor's houses, mountains, etc. ........ Also, if some of this power would be sold back to the utility, the rate it is sold back at makes a tremendous difference - and if a high rate (like near the retail rate) you also have the added risk of running into the situation nevadsa is into - of initially passing laws pricing sold-back power at retail rartes, but the utilities then (properly) arguing the rates shoulde be much less to compensate for the hassles of dealing with small site generated power, the demand/production cycle mismatch during the day, and their need to maintain backup generating systems and the transmissionand distribution system - which can cut the reimbvursement rate by as much as 50-75%. Indeed, in a few areas mid-day and/or summer solar generated power is worthless to some utilities as they have an excess baseload capacity at that time. So you may have a significant $ risk in assuming future power repurchase rates will be high, or in assuming that your house-consumed power will be competing against higher public utility rates if you assume that.
........ Basically, assuming you would be "saving" (nd that assumes your house would use all the generated power, which is not a good assumption if the house is vacant in the daytime and does not have a large (expensive) battery storage unit, use your own power rates but assuming about the average of $0.16/KWHr power charges, you are talking maybe $770 in annual power savings. ........ And remember a salesman is likely to have given you best-case power estimates, and without a daily use and seasonal cycle analysis (how much power would be generated versus how much demand your house has at that time of day and season) unless your utility will buy it back (and remember to factor that metering system into installed cost) at all hours, you may find some of the power will go to waste unless you have storage capacity installed (at significant added cost) to store it for when it is needed. Also, a comparison of your exact location solar radiation versus the "book value" for your local can sometimes show a significant decrease in available power, based on roof slope, house orientation, neighboring trees or houses or such, mountain ranges partly blocking the theoretical sunlight for your area, local fog and cloud and smog and ice/snow conditions, etc. It is not uncommon for these factors to cut 25% off the theoretical power generation, and in some areas can be far more dramatic than that. ........ So, find an amortization calculator at a financial site or one smarter calculator - to find the present worth of a series of payments - plug in $770 (or your final estimate of savings from above factors) as the annual payment or income, a reasonable value of money as the interest rate (say around 5% historically, or more like 8-10% if your money is invested in the stock market, or the interest rate you would be paying on the system if using borrowed money), then play with the number of years as a variable and see what the present worth of that time series of payments is. If it is less than the up-front total cost of the system, not worth it. At more than the number of years where it is about equal to the installed cost it becomes economic. ........ Of course, one of the tough parts is figuring the life of the panels (many are failing at a few years despite claims they will last for 20-40), and annual maintenance cost - both due to any damage, plus the need to wash them at least yearly and sometimes every month or two in dirty air conditions. The annual maintenance estimate has to be deducted from that $770 inferred savings (or whatever your number comes out to at your KWHr power rate). ........ Another important consideration - are they even legal in your area, and how long will it be before your roof needs replacement. The cost of removing panels to reroof can be substantial. ........ Then - if you are talking a lease or power generation agreement with a company which installs them and you basically "sell" the power back to them, there are a lot of uncertainties about whether those conditions will last for many years, and be sure to read the fine print - many or maybe most of those agreements have enough weasel words to ride a pink elephant through, do not guarantee anything other than that if it is abandoned or you decide to remove it you pay the full cost, and commonly hold you liable for the system costs in that event EVEN if another subsequent house buyer "assumes" the contract. Before getting into one of those type contracts have an attorney go through it for loopholes - they are many and sometimes fatal. Read the articles on the FTC.gov website about solar panel contracts and sales scams. ........ There is also the issue of power stability and battery/regulating system cost, life and maintenance - generally unless going with a really high-end and sophisticated (hence pricey) system, the power regulation and cycle matching and such is not perfect, so you can get flickering lights, damsge to electronic devices, etc. And of course, if in lightning or high wind country, the risk of wind or lightning damage has to be factored in - especially as many homeowner insurance policies require a separate policy or pricey rider to insure them. ........ Generally speaking, while it is technically possilbe to come out ahead, for an individual home it is actually pretty rare unless in an extremely high-cost power area, or if the solar system is competing against say ann on-site diesel generator. And bear in the mind, especially if insurance does not cover it,, that one good wind storm or tornado/hurricane tearing it off the roof (likely damaging the roof in the process) or having falling tree debris/branches or ice or hail seriously damage it is a distinct risk over a long enough life to pay it off. My recommendation is always, except for very remote sites, not to take the leap at the current cost and state of the art. ........ One last consideration - how much competent local maintenance support there is for solar systems in your area - because you don't want to just call a handyman or local household electrician to do troubleshooting or repairs. So in major city areas on the west coast and a few midwest/rocky mountain areas you might have local support available from multiple vendors in the future - not so much in most and many suburban rural areas. ........ Here are several links to similar questions with answers FYI - some with a bit more details on the financial decision issue. ........ http://answers.angieslist.com/What-re... ........ http://answers.angieslist.com/Is-wise... ........ http://answers.angieslist.com/i-live-...

Answered 7 months ago by LCD

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OK - the Angies List computer is taking paragraph breaks and double-spacing out again - I have put in this

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dot dot dot marking where each paragraph break belongs, sorry it is not more readable but beyond my control.

Answered 7 months ago by LCD




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