interested in solar

I am just getting interested in solar energy, I would welcome any info. I am looking at what are some dependable companies that could install a system, I have heard a 4 KW system would fit my needs.

I have a 2100 sq ft home in Phoenix Az with a 20K gallon swimming pool

What would be a price range that I could expect?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: interested in solar

    Without knowing anything about your installation (and the fact that I have zero connections with the solar industry other than posting here as a hobby), roughly $8 per watt installed or $32,000 for a Grid Tied system (should include everything, even permits).

    Power wise, there is a nice calculator here. Pick the city closes to you (and matching in weather), take the defaults, unless your installation differs (panels don't face south, roof pitch different than your latitude, etc.). For your 4kW (worth of panels) GT System:
    Month
    Solar Radiation (kWh/m2/day)
    AC Energy (kWh)
    Energy Value ($) (based on $0.085 per kWhr)
    1 5.09 451 $38.34
    2 6.05 486 $41.31
    3 6.61 566 $48.11
    4 7.54 613 $52.11
    5 7.54 619 $52.62
    6 7.28 559 $47.52
    7 7.14 569 $48.37
    8 7.17 576 $48.96
    9 7.15 557 $47.34
    10 6.75 565 $48.02
    11 5.59 469 $39.87
    12 4.88 438 $37.23
    ============================
    Year 6.57 6468kWhr/yr $549.78

    If my price guess is anywhere close, your cost, assuming a 20 year life (panels should last longer, inverter probably less and would need replacement during this time--you can adjust the formula to your guesses):

    $32,000 / (6,468kWhr per year * 20 year) = $0.247 per kWhr.

    You might find some rebates available for your location on this site and there is the federal tax credit.

    Right now, it appears that the price of the solar panels (close to 1/2 of the total system cost) may come down this year ($1 a watt or so????)--don't know about other costs (labor and such)--Price of electronics are probably going up or, at best, staying roughly flat.

    In general--your first task should probably conservation... Insulation, double pane windows, more insulation in attic, solar heater for pool, two speed pool pump, new high efficiency heat pump--possibly used to heat pool (if needed) to improve A/C efficiency, etc.

    Almost always, any money spent towards conservation will pay off quicker than building a larger solar PV array.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: interested in solar

    windsun or some others could correct me on this as things change, but the last range i have heard is that it can be about $6 to $10 per watt installed. now i'm not sure how you determined what you would need or who did it for you and how, but i'd be a bit skeptical yet that that is what you'll need. maybe you could tell us how you came to that conclusion? i do have to ask if this is to be grid-tie or off grid? i also should mention the sponsor of this forum has installed systems too. northern arizona wind & sun. before you jump into it you should be somewhat more knowledgeable about it all by reading up on this stuff be it here, other forums, and home power magazine. while you learn of solar you can learn of conservation too as it is easier to conserve a watt of power than produce it and far cheaper too. this is a big step to do and many that did not learn prior left themselves open for a system that did not meet their expectations or they got ripped off. i'm not calling you dumb or naive, but this is better for you to do just in case too as there might be something you didn't think or know of and of course you will benefit from other's and their experience/knowledge. this is much bigger of an investment, than say a car, and you need to know what to do and how, just like the car.
  • System2
    System2 Posts: 6,290 admin
    Re: interested in solar
    niel wrote: »
    windsun or some others could correct me on this as things change, but the last range i have heard is that it can be about $6 to $10 per watt installed. now i'm not sure how you determined what you would need or who did it for you and how, but i'd be a bit skeptical yet that that is what you'll need. maybe you could tell us how you came to that conclusion? i do have to ask if this is to be grid-tie or off grid? i also should mention the sponsor of this forum has installed systems too. northern arizona wind & sun. before you jump into it you should be somewhat more knowledgeable about it all by reading up on this stuff be it here, other forums, and home power magazine. while you learn of solar you can learn of conservation too as it is easier to conserve a watt of power than produce it and far cheaper too. this is a big step to do and many that did not learn prior left themselves open for a system that did not meet their expectations or they got ripped off. i'm not calling you dumb or naive, but this is better for you to do just in case too as there might be something you didn't think or know of and of course you will benefit from other's and their experience/knowledge. this is much bigger of an investment, than say a car, and you need to know what to do and how, just like the car.



    First I would like to thank BB you were helpful, the link you had posted about the location had a 4KW system for my area and I had previously heard the $35k-$40k figure. So far the only knowledge I have is a few newspaper articales and thats why I titled the post "interested in solar", I am here to start getting info. I am looking at a grid tie in system. Here in Arizona they say you about 60% of your energy needs is with cooling during the summer
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: interested in solar

    In my area (near SF California), we can do fine without A/C (maybe a few warm weeks)--So, I cannot give you any "A/C" advise from personal experience.

    In the end, work on conservation first.

    For my own home, that is what we did... Our home is 60 years old, had no insulation, leaky single pane windows, and a old clunker of a heating system (not even sure it worked--it was 1/2 submerged in water from poor drainage).

    Decided to do a fairly major remodel before we moved in our home a few years ago (before I joined this board)--and really aimed at a true energy efficient remodel 1/2 way through the project. If I was paying attention, I would have done more...

    But at this time, the things I would do (add hot water pipe insulation, adding more insulation in a couple rooms, possibly adding a heat recovery unit--my wife really hates stale air--a higher efficiency central heat unit, better sealing of forced air ducting, etc.). Now, the cost to rip into the home to do that work is just not worth it right now for the few extra dollars saved in power costs.

    Am I happy with my Solar GT system--yes--it is nice. And for us, generates more power than we use.

    But the system only really makes sense when you have net metering--basically, the power company runs the normal once a month bill. For us, if we generate more power than we use, the utility "pays us" the retail power rate--and puts it in the "bank". If we use more power than we generate (winter for us), the utility takes money from the "bank". We only owe the minimum monthly billing charge (~$5.50 per month). At the end of one year, if the "bank" balance is negative, we pay it. If the bank balance is "positive", we lose it and the balance is set back to zero.

    Not a bad deal for the consumer--not great for the utility (selling and buying power at retail). Over the next couple years, I would guess that we are going to lose this plan and go with "real time power pricing"--how that will affect us--I have no idea. It certainly will be more complex and filled with unknowns (probably will still be nice to have our solar to buffer against "price shock"). But this is California--one of the crazy states.

    For you, check your electric bill and learn how to read your utility meters... With a stop watch, you can time how fast the disk spins and figure out how much power your A/C takes--and try other experiments like turning the A/C off one day (when you are on a trip) and see how much it saves...

    Also, reducing power use in the home will help save lots of A/C costs too... An old fridge, big entertainment system left on when nobody is around, 100 watt lights in ceiling cans, etc. all add heat to the house which has to be taken out by the A/C.

    For smaller items, the Kill-A-Watt meter is great way to measure individual appliance power usage over a few days or a month.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: interested in solar

    BB

    I have a brand new home with new appliances, during the winter time our power bill is just under $100 but in the summer it will be between $300-$350 a month with the AC set at 80 degs and the ceiling fans running, about 8 months ago I changed out all out light bulbs with CFLs.

    How big of a system do you have? (KWs)
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: interested in solar

    Mine is 3.5 kW of panels--3.0 kW rated for California Rebates (after the deratings of panels and inverter efficiency). 1 year average of ~400 kWhrs per month of generated power. I have a Time Of Use plan, so during the summer I "buy" power at $0.09 per kWhr and sell it back around $0.27 per kWhr==1 year net metering, sell back at "retail" rates).

    My home, we run around 200-250 kWhrs per month (and I have gotten down to 170 or so a few times--before we got a freezer).

    Solar Guppy is a poster here, who lives in Florida. He usually recommends huge amounts of attic insulation to cut A/C use.

    Checking the ratings of your A/C system to see if a new--high efficiency--unit would be worth the $$$$ (might be able to get rebates from your utility).

    Our electric bill, even before solar, was never more than $20-$40 per month, and our gas bill around $20-$60 per month (summer/winter). We have added skylights for natural lighting and ventilation, and such... But have worked fairly hard to keep our power usage down (not too many electronic toys, smaller TV, fridge, freezer, etc.).

    One thing for us, that was a pleasant surprise was adding solar panels to our roof--really cooled our attic down in the summer.

    It is really hard to compare our home to yours... The climate is so different and the power costs are different too.

    For $350, you might purchase close to 4,000 kWhrs per month (or a bit less)...

    In California, with our tiered pricing, $350 might buy around 1,200 kWhrs per month... (we are paying "marginal costs" around $0.45 to $0.59 per kWhr at those usage levels--depending on power plan time of year, and time of day).

    So, extreme conservation measures and solar PV GT can make real economic sense here. But, those utility bills and taxes (plus other government "programs") are driving business out of the state (now 9% unemployment and a net outflow of people).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: interested in solar
    I am looking at what are some dependable companies that could install a system,
    You might want to start with Northern Arizona Wind & Sun, this forum's sponsor. They have offices in Flagstaff and Phoenix.

    See this link for more info: http://store.solar-electric.com/capr.html

    HTH,
    Jim / crewzer
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: interested in solar

    from a payback prospective, better appliances are a more cost effective way to go.

    If I were in AZ, the first thing I would do is make sure the insulation in at a minimum R40 in the attic. Next, I would either look into replacing the AC unit with an Ultra efficiency unit SEER17 or higher or install a Geo Thermal heat pump. A heat pump can have SEER into the 20+ range, and could cut or electric usage by half or more. Cost wise it is about 8 to10K and in KWh basis would out-perform the PV system 3 to 1, that being the Geo-Thermal would reduce 3x the amount of electric the PV system could generate in your climate

    Just because its all new, builders are all cheap and put in the lowest grade equipment the local code will allow, same for insulation. The builders build for profit and are not the ones stuck paying the utilities bills every month
  • System2
    System2 Posts: 6,290 admin
    Re: interested in solar
    from a payback prospective, better appliances are a more cost effective way to go.

    If I were in AZ, the first thing I would do is make sure the insulation in at a minimum R40 in the attic. Next, I would either look into replacing the AC unit with an Ultra efficiency unit SEER17 or higher or install a Geo Thermal heat pump. A heat pump can have SEER into the 20+ range, and could cut or electric usage by half or more. Cost wise it is about 8 to10K and in KWh basis would out-perform the PV system 3 to 1, that being the Geo-Thermal would reduce 3x the amount of electric the PV system could generate in your climate

    Just because its all new, builders are all cheap and put in the lowest grade equipment the local code will allow, same for insulation. The builders build for profit and are not the ones stuck paying the utilities bills every month

    I know the insulation in my attic is R30 and my AC unit is a SEER 12, thanks for the info it has been helpful
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: interested in solar

    Azjc,

    As has been said so many times here and elsewhere, your best RE $ is conservation first, followed by more conservation, followed by a little more conservation,,, and then solar hot water, (Domestic and pool) solar space heat, (which isn't much of a problem in AZ) and then,, and only then PV Solar.

    The old rule of thumb is that for every dollar spent on conservation saves ten in PV costs.

    For example adding insulation in the ceiling from R-30 to R-50 or even R-60 comes a a very low cost (comparatively) and will reduce AC costs considerably. Adding awnings, or plantings to shade the house in the summer sun is way cheaper than using AC for the same result. As Solar Guppy has suggested on other threads, retro-fitting you AC to use the waste heat to heat the pool and/or the hot water has the double benefit of reducing you hot water/pool cost, as well as reducing you AC cost.

    I would find a good LOCAL energy consultant who can give you specific ideas to your situation.

    Good luck, and welcome to the club,

    Tony
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: interested in solar

    Both are code minimum for your area.

    Going to R40 will reduce the AC load @ 20% ... its cheap as well. Here in Florida, to go R30 to R40 is about 500 bucks for a 2500ft home

    SEER 12 is below our minimum, which here in Florida is 13 SEER. I just installed a new 15 SEER, ( old unit was a 10 SEER ) had the insulation increased to R40 and on the heat pump went down from a 4 ton to a 3 ton ( more insulation means less load means use a smaller unit for better efficiency )

    The AC watts for the Heat pump, measure has been reduced 45%. Last two days we had night time temperatures in the upper 20's, system had no problem keeping the house at 74 deg.

    Cost was about 4K as I did the heat Pump work myself, quoted cost, it would have been another 3K for a dealer to do the work. The savings in kWh is in the 400 -600 KWh/ month range. PV to make that much energy would been about a 4KWh system .. figure 30k+ vs the 7K to have what I did by a dealer.

    These are rough numbers but highlight well that everyone should start first by insulation, better doors, windows and appliances. Its MUCH lower cost to not require the additional energy than have your own solar power plant to feed poorly insulated structure and low efficiency appliances

    By the end of the year, GE is coming out with heat-pump hot water heaters, will cut in half the hot water electric usage for 400.00 more tank cost.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: interested in solar

    don't just address the attic insulation as the walls and even crawl spaces need addressed as well for much heat passes through those areas too, be it unwanted heat gain or unwanted heat loss. i understand that the attic has the worst case conditions and is the easiest to address, but going high insulation values in the attic are wasted if the r values elsewhere are too small.
  • System2
    System2 Posts: 6,290 admin
    Re: interested in solar
    Both are code minimum for your area.

    Going to R40 will reduce the AC load @ 20% ... its cheap as well. Here in Florida, to go R30 to R40 is about 500 bucks for a 2500ft home

    SEER 12 is below our minimum, which here in Florida is 13 SEER. I just installed a new 15 SEER, ( old unit was a 10 SEER ) had the insulation increased to R40 and on the heat pump went down from a 4 ton to a 3 ton ( more insulation means less load means use a smaller unit for better efficiency )

    The AC watts for the Heat pump, measure has been reduced 45%. Last two days we had night time temperatures in the upper 20's, system had no problem keeping the house at 74 deg.

    Cost was about 4K as I did the heat Pump work myself, quoted cost, it would have been another 3K for a dealer to do the work. The savings in kWh is in the 400 -600 KWh/ month range. PV to make that much energy would been about a 4KWh system .. figure 30k+ vs the 7K to have what I did by a dealer.

    These are rough numbers but highlight well that everyone should start first by insulation, better doors, windows and appliances. Its MUCH lower cost to not require the additional energy than have your own solar power plant to feed poorly insulated structure and low efficiency appliances

    By the end of the year, GE is coming out with heat-pump hot water heaters, will cut in half the hot water electric usage for 400.00 more tank cost.

    when you go from R30 to R40 do they remove the existing insulation or would they add to the existing
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: interested in solar

    Added insulation is just blown in over the existing insulation ... a whole house takes less than 1 hour if you hire out for the work ( which I recommend )

    Here in my home town, the cost of just the insulation at a home depot or Lowes cost more than the installed price from an insulation company

    In climate like AZ or FL, the Sun Angle being so high most of the year, most of the heat gain is from the attic.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: interested in solar

    sg,
    heat gain is not just dependant upon where the sun hits a home for the air itself is going to pass that heat into the home via convection and sometimes conduction from other materials such as the earth, bricks, or concrete. even if going only by the misnomer of only solar gains being detrimental to home heat gain in southerly areas, one must keep in mind that the sun does hit the walls seeing as it rises in the east and sets in the west. this is only at its worst at solar noon on the summer solstice and thereby possibly miss hitting the south facing wall. the east and west walls will get a great deal of direct solar radiation in the morning and evening even if smaller than what hits the roof. a wall or ceiling both will pass heat based on the r factors and makes no differentiation as to its source, the sun or ambient air temp. i stand by what i said that going with high r factors in the roof will be negated some when the heat can access from other places without getting insulated.
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: interested in solar

    I agree Neil all places that attribute to heat gain ( cooling season ) need to be addressed.

    Southern Construction differs greatly from the North. One area that effect the OP and me is that AC load is our greatest electric load and they build houses that put all the duct work and a lot of the time the air handler in the super heated air of the attic.

    When one goes R40 or more, the duct work can get buried into the insulation, which is a huge improvement as most ductwork is R5. For the investment and effort, getting the attic addressed is number one on a long list of improvements, but for band for buck, nothing beats get R40+ and the duck worked covered for our climates for energy savings

    On my Air Handler i just put in, I wrapped the unit in 1.5" of ridged insulation, going from about a R5 to R20 ... also the send and returns, my unit hangs in the Garage which can get quite warn in the Summer. ( The strapping is used as I have the Front panel removable for service )
    AH.JPG 58.1K
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: interested in solar

    Heat loss (or heat gain depending on which direction you are looking at it!) is a matter of the Delta T between the conditioned space and the unconditioned space. In warm climates the DT in the attic might be say 80F (70 in the building 150f in the attic) by contrast, the crawl might have a DT of say 20f (70f in 90f under the house). So it is obvious that spending extra money in the attic is way more efficient than spending it in the crawl,, same with non sun facing walls in warm climates.

    In cold climates, the DT is much more constant. The DT of the attic might be say 70f. (70 in the house, 0f in the attic) The walls and crawls might have a DT of about the same. The attic MIGHT be a bit warmer than the surrounding air, but if it is properly vented it isn't going to be much. The crawl might be a bit warmer due to the earth temp depending on where you are and how it is vented as well.

    SG's point about insulating ductwork to some significant R-value is important in ANY climate. The idea of throwing away heat (or cold) out of the ducts is crazy!

    Tony
  • Ecnerwal
    Ecnerwal Solar Expert Posts: 101 ✭✭
    Re: interested in solar

    Of course, some attic venting might also be a good idea, even without ice dams to convince you it's a good idea (which is the method that Murphy and Mother Nature use to convince skeptics up North/Nawth).

    Put in a functional cupola (among the best) ridge vents (a poor second or third) and gable end vents (if you even have gable ends). Make sure there is plenty of intake venting down at the eaves so the air can flow. If your attic is 150F, it needs help...
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: interested in solar

    If memory serves, the UBC requires venting at the ratio of 1/150, with half as intake vents and 1/2 as high exhaust vents. I think that attic temps ~ 150f are not only quite possible, but in fact quite common. A wind activated turbine vent works pretty well, but induces noise in the house.

    One of the curious things with venting is different conditions require different venting strategies. I once read the following excerpt. " If you look in your attic in the winter and see frost on the roof sheathing and you have no venting,,, add some. If on the other hand you look up and see frost on the sheathing and you have vents,,, close them!"

    It is not an exact science. The object of most venting is to remove moisture that has condensed from the conditioned space. At added benefit in northern climes is preventing ice dams, in warmer climes to reduce building envelope heat gain from the roof.

    If I lived in a Ac climate, I would insulate the hell out of my ceiling, preserving vent space over the insulation, cut in tons of high vents and as many intake low vents as I could.

    Icarus
  • System2
    System2 Posts: 6,290 admin
    Re: interested in solar

    when its at least 115 degs in phoenix for about 30 days a year its has to be at least 150 degs in the attic...at least its a dry heat.....:grr
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: interested in solar

    As I understand, adding venting to your roof in a hot climate will also help reduce the temperature of the roofing materials... If you have composite (or wood) shingle (or synthetic/plastic tiles)--you should also have a longer life.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: interested in solar

    well i never said that the roof isn't primary or that it shouldn't have more insulation. ductwork in an attic without a doubt should be heavily insulated. i only said the roof isn't the only part of a home that needs it or the extra effort on the roof will get negated somewhat and sg agreed so there's no problem. if one gets r40 on the roof, then there's nothing wrong with r20 or r30 for the walls, or whatever you can get for them as it isn't always as easily done as the roof area is, but no insulation in the wall is unacceptable.
    i also agree the ventilation to be good to do as bad ventilation can also negate some of the insulating in some types of insulation. it may also thwart mold and mildew from forming.
    edit to add: i've seen my own attic here in pittsburgh at 125 degrees on 80+ degrees f days and we don't usually see temps in the 90s and rarely the 100s.
  • System2
    System2 Posts: 6,290 admin
    Re: interested in solar

    I have concrete "S" tiles, here in Az that is the latest ...concrete tiles are supposed to be gauranteed for 50 yrs
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: interested in solar

    Tile roof s are largely unaffected by heat and have a almost unlimited life span,,, but the downside is that they have tons of thermal mass that holds heat over night, adding to the AC loading.

    Tony
  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    Re: interested in solar

    I considered tile but decided on an achitectural fitted standing seam steel (comes in a couple of gauges) metal roof, ridge vents, synthetic underlayment over ply framed with R40 throughout.

    Baked enamel light color enabling a high degree of refelectivity in the hot Arizona sun.

    Turned out quite a bit more expensive than tile but its insulation value was very good, less structural weight than concrete tile and warranty was years longer.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers