Doing the leg work for a big project

Right now the Federal government has a 30% tax rebate on many different alternative energy sources and other rebates on energy saving items. http://www.energy.gov/taxbreaks.htm

In my state South Carolina there is also a 30% tax rebate for solar systems installed by dec. 31 2009 and the 25% till 2016 I believe.
http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=SC08F&state=SC&CurrentPageID=1&RE=1&EE=1

There is also the PACE program in my state. http://www.palmettocleanenergy.org/ The thing there is if I install a solar system that generates power back into the grid they will pay me on top of what the power company will pay me with net metering. That depends on how much money they raise etc. You have to put in an app and you may not get in that program.

Right now I'm waiting for an estimate for a geo thermal heat pump. Here my problem. I checked out running my house completely on solar and we are talking around $62,000 to do it which with the tax rebates is about $23,000 actual cost to me except I'm limited to $3,500 a year rebate from SC but it will be rolled over for up to 10 years. Big up front costs which there are loan programs through the solar dealers etc. In my case a simple pay back would be this, my power bill is about 2800 a year and the solar system would be 23,000 so about a 8 year pay back. Assume electric rates going up and a low interest rate and it's very much doable if I come up with that size loan.

Next problem is I would have to fill my roof with PV panel plus somewhere else I would need some. Not so good looking and HOA may have a problem with that. I also live in a hurricane zone and I have no idea how insurance would work out on those. Just seems like too big of an investment with a long pay back period with the possibility of high winds doing damage to all the panels. Not liking that. Other problem is production of all the solar parts has been ramping up and costs dropping so would I be better off waiting a year or two? Got a few serious question marks with an all solar system.

Next up geothermal heat pump which in my area we almost all use heat pumps for AC and Heating. All electric houses BTW. The thing there is you have a few different options and in my case an open loop system would be the best option. Simple plumbing, one hole drilled with a pump and another hole drilled to put the water back to where it came from. That's really the expensive part. After talking to a driller I would need two 250ft wells more or less at $10 a foot. $5,000 for the wells alone. There are closed looped system and pond systems but I don't want to go into all that. The upside is your heating and cooling are most of your electric bill. In my case the water would be about 65 degrees F year round so it gets rid of spikes in my electric bill during the summer and winter. You can also run a irrigation system off the hole you already drilled with the same pump. In my area that is big because water costs a family of 4 about $80 a month and my irrigation system will use another $100 a month if I run it 3 days a week. End result bonus savings for me. Another thing you can do is hook a desuperheater to the geo unit which gives you hot water anytime the AC is running, simply dumps the heat into your water heater. That is even used during the winter to heat water since the water coming out of the ground is relatively warm. Another bonus is you can use the geo as a pool heater. I don't have a pool but maybe down the road I may have one.

End result is the geothermal heat pump may very well lower my costs and power usage enough that I can cut the amount of solar in half. Best guess is saving about $1,000 a year on heating cooling and another $400 on hot water. I haven't got back the exact costs yet on geo so we will see.

What I'm trying to do is figure out the best bang for the buck to supply as much power as I need for the lowest costs. Jury is out and the pay back time is up in the air, once you get out to 8 or so years I'm worried that it might not work out, if things start breaking it just won't pay for it's self. We will see where the Geo thermal goes.

The item that will pay for it's self fast in SC is solar water heating. Simple long lived system. Talking 20-30 years without touching it.

Solar water heating for a family of 4 with 80 gallon water heater.
$6800 cost installed
30% SC tax rebate
30% fed rebate
2720 cost
Should save $60 a month on water heating which is $720 a year
3.8 years pay off at $60 a month saved.
After that 25% tax free return on your money, 720/2720=26%
The higher rates go the fast the return and the higher the return.