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Thinking of going with this solar installer/proposal. Please comment/critique/discuss

Discussion in 'Energy, Environment, and Policy' started by Al Sherman, Mar 18, 2014.

  1. Al Sherman

    Al Sherman It's about THIS car.

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    We're thinking of going with these guys (Icon Solar, Cincinnati) for our solar. Please comment, critique, and discuss. Any and all inputs welcome. I don't want to screw this up! :smile:
     

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  2. VolkerP

    VolkerP EU Model S P-37

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    I studied the cash flow. break even in 12 years? that's a looong time. Put all the assumptions in question and figure out if it is best case, worst case, or fair case calculation.
    Does the plan include all-hazard insurance? or inverter repairs?

    On your setup: Sure go as big as your roof allows. I wonder what your electric consumption is, since a 20kW system can offset just 52% of your bill?!? Might look into energy saving investments there, they might provide even better ROI.

    I can't advise on using micro inverters. Last time there was controversial discussion of benefits vs. hassle to repair in this thread:
    Solar energy questions and answers - Page 5

    Latest installation I get to know in detail used "power otimizers" which convert DC/DC in every module to optimize its output. DC then goes to a central inverter.
    power optimizer as well as micro inverters are good for irregular roof shapes, or trees that can cast a shadow during some season. Can you describe your roof setup?
     
  3. Al Sherman

    Al Sherman It's about THIS car.

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    Thank you. Yes, I've read the thread about the enphase inverters. Definitely an issue if the company isn't around to honor the 25 year warranty. What about the Suniva Optimus Series panels?

    I guess the biggest assumption is the 5% increase in electricity cost. I think national average is 4.75%? Our has gone up 83% on 10 years.

    Our roof is large but somewhat irregular. We have some shade issues but not that bad. The proposal includes some panels that are not exactly South facing. The estimator says that his computer algorithm compensated for those there are some trees that we'll have to have trimmed initially and periodically.

    I'll read the actual warranties more specifically. What I have now says the inverters are "25 year limited warranty." The panels are "10 year warranty on workmanship and materials." AND "25 year linear performance warranty delivering 80% power at STC."
     
  4. Al Sherman

    Al Sherman It's about THIS car.

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    #4 Al Sherman, Mar 18, 2014
    Last edited: Mar 18, 2014
    As far as usage goes, ours is unfortunately very high. It's a large house with two Geothermal heat pumps. They're due to be replaced so I may go with dual fuel to use LP backup instead of the AUX electric heat which is VERY expensive. Our average monthly usage is about 3900 kWh. I know it's a lot and we're working on it but right now it's accurate.
     
  5. You probably meant to write 39000 kWh?
     
  6. Al Sherman

    Al Sherman It's about THIS car.

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    Sorry. Actually I meant to write "Monthly." Editing now.
     
  7. GlennAlanBerry

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    Wow. 3900kWh per month is extremely high for electrical usage. Anything you can do to reduce that electrical load (such as adding insulation, improving the air sealing of your house, etc.) would make a big difference in the size and cost of the PV system you need to cover your needs. Insulation and air sealing are not that sexy, but they usually have the best ROI.

    You might want to consider getting an energy audit, where they do a blower door test and use a FLIR camera to spot problems with leakage and heat loss. Most utility companies offer subsidized energy audits.

    Don't get me wrong, I love PV electric ( I currently have a small 3.15 kW system), but for most American houses, spending a few thousand dollars on insulation should be the first priority that would save a lot of money over the long term. Getting new Energy Star appliances is usually the next step.
     
  8. Owner

    Owner Active Member

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    I agree with Volker.. So to get a 100% offset you would needs a 40kW system!!!

    I have 100% offset with a 3.8kW system. So you are using 10X the electricity of my house? I can't say my home is small by any stretch of the imagination.

    Don't know much about Geothermal heat pumps. Tell us more about how much electricity these are pulling.

     
  9. dhrivnak

    dhrivnak Active Member

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    I just put in a system in NE Tennessee and my costs and expected output are in line with yours. Microinverters are very nice if you have some shading issues. I do not have a shade problem so I went with SunnyBoy SMA that allows for some power if the grid is down.

    I too would get an energy audit. You should never see resistance heat with geothermal. Even my air unit did not go to resistance heat when we were below 10F. Cutting usage is likely easier than a larger solar.

    PS my pay pack is 18 years as we have low power costs. But for us the environmental impacts are a big plus.
     
  10. TexasEV

    TexasEV Active Member

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    I agree completely. Your first, second, and third steps should be to improve your home's energy efficiency before even considering solar. That's where you'll get the biggest return on your investment. To put 3900 kWh/month into perspective, we have a 3000 sq. ft. house in Texas and our monthly average is only 1/3 that, and houses in Texas use a LOT of air conditioning.

    The solar company is showing hypothetical cost savings using an assumption of 5% annual increase in electricity cost to give you a average cost of over 20 cents per kWh over 25 years, when your current cost is only 11 cents. This savings is hypothetical in the future, but your expense is real and now. Most of the purported savings come in the years 20-25 when small changes in the projected rate of increase compounded over that many years turns into big numbers. Try putting 4% per year into the spreadsheet and you'll see a dramatic difference in the out years. It's like trying to project the federal budget 10 years from now, but worse. You can get any answer you want depending on the growth assumption you put it.

    Today is the first day of operation of our 7.5kW system which is sized to supply about 75% of our electricity use. Our payback is projected to be 7 years with conservative accounting (we have a significant local rebate you don't have). I wouldn't have done it with 12 year payback.
     
  11. Owner

    Owner Active Member

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    Your numbers seem more inline with mine. I have A/C but most years I only need to turn it on say 2 days for a couple of hours.:biggrin:

     
  12. TexasEV

    TexasEV Active Member

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    This is probably obvious, but I should have added that your payback will take even longer than 12 years if the increase in electricity cost is less than 5% per year over that time.
     
  13. Al Sherman

    Al Sherman It's about THIS car.

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    Yes. Our electric rates have increased 83% in the last 10 years.

    As far as our usage; no doubt it is high. Even for a very large house. I really believe it's the Geothermal Heat Pumps. They're 17 years old and due to be replaced. I've had the system "checked" by more than one contractor. They say that they're working correctly. I'm not so sure. We can't compare before and after since we installed them when we put the huge addition onto our cabin. The aux heat (emergency) runs a lot in the Winter. A lot of the research I've read indicates that the aux heat should almost never run. I would like to replace the system but want to find a contractor that understands (believes?) this and sizes and installs the system correctly.
     
  14. TexasEV

    TexasEV Active Member

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    As the investment disclaimers say, past performance does not predict future results
     
  15. Al Sherman

    Al Sherman It's about THIS car.

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    No doubt. However, it's never gone down for us. My understanding is the national average annual increase is 4.75%.
     
  16. TexasEV

    TexasEV Active Member

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    I know nothing about geothermal heat pumps, but if you only look at that you're missing half of the equation. Your energy use depends both on production and loss whether it's heat as you have or air conditioning which is the major cost in Texas. You really should look at heat loss with an energy audit-- insulation, windows, doors, air ducts, etc. Money spent reducing heat or cold loss almost always gives bigger results than changing how the heat or cold is produced.
     
  17. Zaxxon

    Zaxxon Member

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    Same thoughts here. If you have an attic and you don't use it for storage, that can be one of the most tantalizing low-hanging fruits out there. We had insulation blown into our attic a few years back, and the difference that single change made to our heat/ac usage was quite large. It wasn't a very significant cost, either--and was partially tax-deductible to boot.
     
  18. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    #18 ItsNotAboutTheMoney, Mar 19, 2014
    Last edited: Mar 19, 2014
    Well, the question on the heat pump is when the electricity use went up significantly. A heat pump has a maximum output and if that's your central heating system it needs to match up to the demands of the total space heated or else it would have to provide supplementary heating. Or there could be other issues like a broken thermostat or a loss of insulation increasing demand.

    I've recently been energy-audited. The big ticket item is our earth basement. The attic needs insulating and sealing and then our walls. We'll actually do attic+some 2nd floor walls because we're renovating a couple of bedrooms anyway. Oh and we currently heat with oil and I want to switch to NG this year. Then maybe in a year or two I might get an air-source heat pump for the sitting room/kitchen area (which would also act as AC for the month my wife would like it in summer).

    (On solar, we have most of our poor insolation in winter and summer and my roof is kind of E-W or ENE-WSW so it'll be several years at least before there's a chance of it being really economical.)
     
  19. miimura

    miimura Active Member

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    I would probably not have done solar if my electric price was flat (non-tiered) and below $0.15/kWh. In CA you can't get away from both tiered pricing and time-of-use, so solar makes a lot of sense and has a short pay-back. I would do the energy audit as suggested and possibly install an energy monitoring system with separate sensors for each significant load. With those you can figure out how to reduce your usage with targeted efficiency improvements and IMHO that would be a better use of money.
     
  20. Al Sherman

    Al Sherman It's about THIS car.

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    #20 Al Sherman, Mar 20, 2014
    Last edited: Mar 20, 2014
    Energy Audit scheduled.

    In the meantime: What do folks know/think of the Suniva panels?

    Is 3600/kW before the tax credit, out the door reasonable?
     

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