Planning a new home & solar - Need Help

Hello all, thank you for reading.

I am in need of valuable knowledge :D. This is the first forum that I could find about solar. I live just west of St. Louis, Missouri. My family and I are planning on building a new home on the ground that we currently live on. And I would like to incorporate a new solar array on to the new place. I am a commercial/industrial electrician. So I have knowledge of how the workings are, just not the best/newest products.

This home will be an on the grid system, and hopefully back feed the grid during the day. I am going to install a 240v - 400 amp service on the home for plenty of space and supply (and maybe a future work shop in the back yard :D). But my demand that I am figuring would be more like a 200 amp service. There will be a geo-thermal system in the hvac to facilitate the furnace/ac due to the miserable humid/hot summers and the windy cold winters. This will be an all electric home roughly 2200-2400 sq ft ranch.

? With this info, roughly what size solar array would be required. And what else would be required. (inverter....) I was not planning on installing a battery back up, but it could be a future possibility.

? With having 1.5 of 3 acres available for home/yard, would the array be best on the roof or hang vertically on the poles of the back deck? Both would face same direction and both would have the same sun. The house would be on a hill facing E-NE

? What brands are currently the better/best for the buck and for what parts?

Any help would be great

Thank You :D



  • BB.BB. Super Moderators, Administrators Posts: 29,699 admin
    Re: Planning a new home & solar - Need Help

    Welcome Doug,

    First three recommendations are conserve, conserve, and conserve.

    Solar power is not cheap--so anything you don't need to power, means your solar installation can be just that little bit cheaper--and you avoided paying that 1 extra kWhour every month, for the next 30 years.

    Check out Home Power Magazine for ideas on conservation and home design.

    Next, once you have figured out your monthly (and seasonal loads), you need to check with your utility company to see what kinds of power plans they have...

    Some don't allow grid tie connections at all. Some just pay you the wholesale rate for electricity (typically, around 1/4 the retail rate)... Others will have 1 month or 1 year net metering plans--basically, add all of your usage together, and all of your generation. At the end of the period (1 month or 1 year), you pay what you owe (if negative balance) or, if positive balance on the bill, the power company "eats" your "profit" (you buy/sell power at retail).

    The 1 year net metering is probably the best residential plan out there.

    Also, there are flat rate and time of use plans. Depending on your power consumption pattern--Time Of Use may help you (for me, I sell power in the afternoons at $0.30 per kWhr, and buy back power off-peak at $0.09 per kWhr).

    Once you have the approximate monthly power requirements--then you can size the array with this online Solar Power Calculator (use the defaults for a start). There is also a PDF version of the data so you can see how your sun varies over the seasons and the years.

    Next, you can see what rebates/tax credits there are for your location.

    Next, what vendors are good? Check out NAWS' store (our host, "WindSun"). They do a pretty good job of only selling some of the better vendors out there, and will remove those (from their website) those vendors that fail to perform. There are also FAQ's and other links for useful information.

    Cost wise, your choices for solar power--
    • 0. Conservation. Insulation, Windows, EnergyStar appliances, more insulation, site-ing of home & window/overhangs, etc.
    • 1. Solar Hot Water--typically the best $$$/watt (although, plumbing issues; leaks, seals, pumps, controllers, etc. make the maintenance an issue.
    • 2. Solar PV Grid Tied... Simple grid tied can get close to the cost of utility power (especially after rebates). Little maintenance required.
    • 3. Solar PV Grid Tied with backup batteries... Can increase the cost of power by 2-4+ times because of cost of batteries, charge controllers, battery replacement, backup generator (if wanted), etc.
    • 4. Solar Off-Grid... Somewhat more expensive than #3--because you cannot backup 1 month or 1 year of power (through grid tie and net metering).
    • 99. Wind Turbine.... Possibly good for stormy weather and very windy locations.
    Just to give you an idea of costs... (retail pricing including installation and permits, really wild guesses)...
    1. Solar Hot Water for 9 months of the year--$5-$10,000 for four people
    2. Grid Tied Solar... ~$0.15-$0.35 per kWhr
    3. Grid Tied Solar + backup batteries ~$0.50-$1.00 per kWhr
    4. Off Grid Solar ~ $1.00+ per kWhr
    5. Wind Turbine ~Priceless (OK, joke--maintenance issues and poor performance plague large numbers of small installations).
    Conservation--That is so location and owner specific.

    Off grid users, probably aim at less than ~100 kWhrs per month.

    In moderate climate, (my home south of San Francisco)--for electricity I use ~200-250kWhrs per month and a 3kW rated (3.5kW worth of grid tied panels, for ~$28,000 list price, before 1/3 rebates) generates way more power than I am currently using.

    For people with extreme temperatures--1,000-2,500 kWhrs per month during heating/cooling seasons is not out of the ordinary... Cutting those numbers, before thinking about solar, is important (solar PV installations are expensive).



    Add, solar panels, especially solar PV electric panels, need absolutely clear access to the sun from ~9am to 3pm... Any shading will reduce output... And for solar electric, a power line running across the panels, or a single panel shaded by a vent stack or building facade can easily cut output of an entire array by 50%.

    Watch for potential issues... That cute little tree on the property line will grow up. That neighbor with the 1 story home, will eventually have 6 kids and add a couple stories, etc.

    Of course, lots of this stuff is rule of thumb type information. Local conditions can impact design... For example, hot afternoons with clouds--facing the array more towards the South East may increase your output. Early morning fog, then a westerly array may be better.

    There is no "right or wrong"--just things, if not done correctly, will cause you to lose output... A lost 1kWhr per day x 365 days x 25 years all adds up.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,466 ✭✭✭✭✭
    Re: Planning a new home & solar - Need Help

    > This is the first forum that I could find about solar

    I think you found the best.

    > (for me, I sell power in the afternoons at $0.30 per kWhr, and
    > buy back power off-peak at $0.09 per kWhr.0
    Gotta watch those hours for TOU plans, if the "high" rate extends till 9pm, Your solar generation from 11AM - 5pm, may get eaten away from 5-9 when you are home, busy, and not producing power, I don't know how BB gets it to work.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

  • BB.BB. Super Moderators, Administrators Posts: 29,699 admin
    Re: Planning a new home & solar - Need Help

    Mine works (for me) because I am grandfathered under the old E7 plan--which has one peak period from noon to 6pm, Monday thru Friday.

    The new plan, E6, has a very complex TOU schedule:
    TIME PERIODS: Times of the year and times of the day are defined as follows:

    Summer (service from May 1 through October 31):

    Peak: 1:00 p.m. to 7:00 p.m. Monday through Friday
    Partial-Peak: 10:00 a.m. to 1:00 p.m.
    AND 7:00 p.m. to 9:00 p.m. Monday through Friday
    Plus 5:00 p.m. to 8:00 p.m. Saturday and Sunday

    Off-Peak: All other times including Holidays.

    Winter (service from November 1 through April 30):
    Partial-Peak: 5:00 p.m. to 8:00 p.m. Monday through Friday
    Off-Peak: All other times including Holidays.

    Holidays: “Holidays” for the purposes of this rate schedule are New Year’s Day, President’s Day, Memorial Day, Independence Day, Labor Day, Veterans Day, Thanksgiving Day, and Christmas Day. The dates will be those on which the holidays are legally observed.

    DAYLIGHT SAVING TIME ADJUSTMENT: The time periods shown above will begin and end one hour later for the period between the second Sunday in March and the first Sunday in April, and for the period between the last Sunday in October and the first Sunday in November.
    And, if I had a choice between flat rate and E6--I probably would choose the flat rate because the E6 TOU runs into when we cook dinner and is just plain too complex to explain to the family and have them "follow" the rules.

    I probably would do better on E6 vs E1 flat rate--but I don't want the exposure to what happens if I mess up.

    The rules between E1, E6, E7, E8 have constantly been changing... Originally, I had a choice, then new users had to pick E6, then back to a choice among all, for new users--for a bit of time. Then back to a choice between E1 and E6. Just a huge mess.

    But, I see the utility's side too...E6 does a better job of mapping utility costs against when peak usage really happens... During some parts of the year, a second peak daily usage occurs around 8pm. E7 is much more favorable towards the customer with solar power.

    But, that will probably all change in the next couple of years. They are starting to install "smart meters" (remote read) that can support any rate plan (with one meter), but also a "real-time pricing plan".

    And, as I understand, as a grid tied solar generator, I will be required to convert to the new plan... Where times and price change every 24 hours, with 24 hour notice (I think).

    This is going to be a nightmare... I have no idea how this is going to work. The exposure to "making a mistake" and turning on the wrong appliance at the wrong time will quickly add up... For example the current summer rates (E6 as an example) range between $0.09 to $0.58 per kWhr. For those people with large electric loads (all electric homes, A/C, etc.) may be in for real shocks when this plan rolls out.

    The new real-time billing rate may be optional for non-RE equipped homes--but will most likely be required for Grid Tied RE homes (or, we may have to pay reservation charges, which are their own can of worms that may end up punishing GT RE homes with larger arrays--not sure about that yet).

    I have no idea how anyone will be able to calculate a rate of return for a solar GT installation when this happens.

    It will be a "brave new world" for Californians coming in the next few years.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Planning a new home & solar - Need Help

    I greatly appreciate all of the info and will be reading all night. Thank you very much... I first noticed that Sharp has a whole package (OnEnergy). Would I be better off to go strictly with them or are there better packages offered, or should I stay away from the packages?

    Once again, Thank you very much
  • BB.BB. Super Moderators, Administrators Posts: 29,699 admin
    Re: Planning a new home & solar - Need Help

    In the end, get the parts list of major components (inverter, solar panels, rails) and understand what the warranties are and and special issues (tile roofs, running of conduit, etc.).

    A poster here has his own forum (solar guppy's forum) and has some great sections on Solar Panels and other components discussing reliability and other issues. SG designs GT Inverters and other devices--so he has lots of direct experience to talk about various issues around solar RE products.

    If the components are good quality, the companies backing them will be around for warranty service (not sure anyone can guarantee that anymore) and there is nothing proprietary (solar panels that use special plug+rails so 10 years later repair/upgrades are a hassle; odd-ball inverter connections or voltage requirements, etc.)--then local installer price and reference checks are probably the most important.

    For the run-of-the-mill Grid Tie install, there is not two much that makes it important to match a package of components together (pretty much any good quality panel will work with any good quality GT Inverter which will work with any standard breaker panel).

    If you will be into computer monitoring--there is quite a bit of variability between vendors in the available monitoring connections, software available, and costs to monitor.

    If you are looking for a Hybrid System (GT and Off-Grid capable), I would first suggest looking at Xantrex and Outback and stay within the mfgr's family. I would avoid mixing components between vendors. Having a common communications bus (between inverter, solar charger, AC charger, autostart for generator, etc. and the ability to point at one vendor and say "I don't care which component is acting up--fix it" is sometimes very handy.

    If you are looking at GT Inverters, any of the vendors listed here is a good place to start (Enphase is brand new--interesting concept, but probably not cost effective for larger systems).

    Lastly, you mentioned that you are thinking about migrating from GT to GT with battery backup... In general, it is very difficuilt to "grow" and "morph" RE systems in size and function.

    A change from GT to GT+Battery would include the need to rewire the array from ~200-600 VDC to ~65-140 VDC. You would need to replace the GT inverter with a Hybrid GT/Off-Grid Inverter (plus rewire your AC to include a transfer switch for your protected loads), add Solar Charge Controller(s), and install a battery bank.

    About the onlything saved are the panels themselves (although, the rewiring may mean that you need a couple extra, or drop a couple to match the string voltages/currents with the change from High Voltage GT Inverter to medium voltage MPPT solar charge controllers).

    My recommendation is that you don't plan on morphing your system--but plan for exactly what you want/can afford. You may be able to oversize the Inverter and add panels later (watch the series/parallel connections as you add panels)--but that is your choice.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Planning a new home & solar - Need Help

    I've been looking on my local utility's website (Ameren UE) and I dearly hope that they have updated their rates, from this documents posting.

    These rates are terrible.

    $ 0.0347 (10a-10p Summer)
    $ 0.0195 (10a-10p Winter)

    I hope that I am just reading this wrong!!!
  • BB.BB. Super Moderators, Administrators Posts: 29,699 admin
    Re: Planning a new home & solar - Need Help


    There is a section about one meter Net Metering that is much newer than the rest of the document.

    There also is an older section which talks about charging and paying for power (two meters, one read forwards, the other backwards).

    The newer section is about a net meter which runs forwards/backwards and they just read the net value once per month.

    That second one is what you want. I could not find anything about how the net reading is managed if you generate more than you use...

    For me (Kalifornia), we get paid "retail" for our excess power generated, and it goes into the "bank". After 1 year, the amount detected from the bank (winter) and the amount added to the bank gives either a net consumed bill (I pay). Or a net generated bill (balance is lost).

    At worst, you have a 1 month net metering state... if you use more than you generate--normal bill. If you generate more than you use (over the one month), you only pay the minimum connection charge (around $7-$8 per month).

    If you get a generation credit--it may be at the "commercial" rate (yep, really low) or at the retail rate (like done in my state)... But your power rates are really low anyway ($0.06-$0.08 per kWhr).

    So, your low utility payments for generated power makes sense (they only pay you for the cost of power--the utility still makes their margin on charging you for the cost to distribute the power).

    In any case, your cost of power is CHEAP... My cost of power $0.09-$0.37 per kWhr off-peak. $0.30 to $0.58 per kWhr peak...

    Which would you rather have? Solar and $0.58 per kWhr, or no solar and $0.06 per kWhr?

    As long as your rates remain low (for how long????), GT solar is not going to save you any money unless you have really good rebates (like 80%+ rebates).

    With 33% rebates for my GT system, it still generate power around ~$0.15 to $0.17 per kWhr. Not even quite breaking even for me.

    Where I saved money was in conservation (insulation, windows, appliances, CFL's, training kids).

    For you, if saving money is important--Looking at solar hot water (and possibly solar thermal heating) may have a better return for you.

    Since you are building a new home--looking at design/build issues up front--will help you way more than designing a "standard" home and bolting on GT solar after the fact.

    Also, have you looked at a energy recovery system (for home ventilation)? If not, this may be a big help for you too.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Planning a new home & solar - Need Help

    check out

    Looks like your state just passed the final net metering regulations, I did a quick read and one thing thing that stuck out was
    Customer net excess generation (NEG) during a given month is credited to the customer's next bill at a rate at least equivalent the utility's avoided-cost rate. Any NEG remaining at the end of a 12-month period is granted to the utility with no compensation for the customer.

    So in your state the utility provides retail net metering BUT if you generate an excess, that is only credited at the wholesale for carry forward.

    Spring/Fall this can happen when the loads are at there seasonal lowest with a moderate sized GT system, payback calculations depend on these KW's for the Summer/Winter high demands can typically used these banked KW's, but in your state, you get what would appear to be 1/2 to 1/4 the value
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