Thinking of switching your home to solar? With energy costs on the rise, more homeowners are investing in renewable energy sources. Here are some helpful tips to get you started! Today, many residential and commercial building owners are finding that installing solar water heating and photovoltaic systems really pays off.  Completely installed residential 2 kW(peak) systems with inverters and interconnections for net metering now are quoted from 9.5 down to 7.5 $/W(peak)[1], and for larger commercial systems down to 6.5 $/kW. Even if a 2-kW(peak) solar PV system costs $15,000 and produces only the equivalent of 3 full sun hours each day, the system will pay for itself in 10 to 18 years, at zero cost of capital. If you can get 4 full sun hours/day, the payback time reduces to 7.5 to 13.5 years, depending on whether or not you take advantage of the tax credits (State 35% and Federal 30%). respectively. If you have to borrow money at 4% to pay for the solar PV, the above payback period of 7.5 years stretches to 9.1 years.      

In case you wondered about which forms to use for claiming rebates and tax credits for your home renewable energy investments, state tax technical support at 808-587-1577 is very helpful. I found out that individuals can
use the 2009 form N-334 (to be available in Jan. 2010) to claim both renewable energy tax credits (35% but capped at $5000) or, for folks w/o Hawaii state tax liabilities refunds of 70% of that credit or 24.5% (0.35 x 0.70 = 24.5%), as attachment to the regular tax return form N-11. Downloading of the forms is easy from the alphabetical list of forms at (click here), but e-filing the HI state return with above forms may take some searching; www.1040.com by Drake Software is among the few that offers such service.

What should a homeowner embarking on installing a PV system look for? Here is a short list:

1. Total installed cost of system, after taxes, monitor (see #10 below) and fees for engineering drawing (latter ~$ 200; I did my own, and it was a fun thing to do). Total cost should be under 7.0 $/W in 2010 for the total system, or under $14,000 for a 2-kW system, before rebates or tax credits.
2. Check that the salesman/marketer/consultant payment is included in the above
3. Because the 35% State tax credit for a system may be over the limit of $5000 in Hawaii, consider installing in at lest 2 steps
4. Roof space: Do you have enough S-facing roof space for 12 SolarWorld 175 W panels or 9 of their 220 W panels (they are larger)
5. Individual microinverters (recommended because 1) then the 1st and 2nd set of PV panels are considered to be “systems” qualifying for the State Tax Credit; 2) Lower cost according to the data I have and 3) shading or failure of one panel does not pull down all the panels in series in one branch of the system, feeding one big inverter. If you also need to put panels on E or W-facing roofs I just learned that E-facing is better (assuming no shading), because the atmospheric haze generally increases in the afternoon. Another way to add “roof space” is to add trellises around the house
6. Consider positioning the PV on parts of the house that need more cooling, because the PVs will keep the roof underneath shaded and cool.
7. Consider the merits of adding a bit more PV for hot water, rather that messing up your plumbing system with solar water heaters – if your hot water needs are small
8. Ask if the contractor will provide State and Fed Tax Credit forms
9. Ask that the PV disconnect switch is of the easier-to-operate “Lever” type rather than the “Plug-in” type
10. Check that the contract includes the ~$200-300 monitor and display (Enphase or equivalent on-line data acquisition and monitoring; after the first 6 months of free monitoring service, Enphase charges $2/year per PV/inverter module)
11. Consider the desirability of being able to add-on and install battery back-up in the future, to charge your PHEV. Enphase micro-inverters are designed to switch off as soon as the grid voltage goes down. Therefore, a switch "box" is needed to 1) Interrupt the grid connection when the grid goes down, 2) Con-tinue to generate a 120 VAC signal for the micro-inverters with power from the batteries, and 3) Switch off all home-generated power only when the battery charge level reaches the low limit as indicated by its low voltage. Such "boxes" may be available from Xantrex or SunnyBoy
12. Insure you have the following papers ready to be submitted by contractor to your electric company ASAP after completion of installation: 1) County Inspector ( called by contractor) approval, 2) Signed engineering drawing by PE and 3) NEM agreement. (Hawaii's HELCO does not recognize your generated kWh until they approve the installation, after receiving the above papers. They also may exchange the meter, supposedly with one that is more accurate, but is digital, w/o the rotating disk, which was nice because you could tell at one glance whether the PV system was making the meter go backwards)