Cost

The prices varies depending on your electricity needs, climate in your area, incentives of your state and some other factors.

If you want to see an example of such a calculation, lots of information on rebates, incentives and tax credits categorized by states than check http://www.solarpowerrocks.com . You can find there the actual calculations of costs after rebates and tax credits plus how much you save per year, so you can derive the return on investment.

As a general rule of thumb, return on investment for residential solar power system is between 3-8 years.

I know my parents wanted to go solar, but the really good and conclusive solutions are very expensive, and you might not actually see a return opf the investment in your life time. I thing the government should encourage people to use solar energy by various incentives. Otherwise I can't see normal people going for this in mass.

a system with power output of 2-4 KW will cost around 13000-26000 Euros, You can calculate your ROI from here and see how many years will it take.

The solar panels come with a long manufacturers warranty (up to 20-25 years).  

You can get an estimate from one vender (not promoted by respondee) at:   http://www.sunefx.net/Evaluation.htm

My general experience indicates that a typical residential system designed to be off grid through net metering will cost between $12 and $15 thousand dollars and can pay back in as few as 5 years depending on the local utility rates, net metering availability and rates, and actual cost of the system and how frugal the users are.  Self-adhering PV panel materials are available for a litte as $4/sf and apply to cleaned metal roofing or can be purchased already applied to the roofing. Installation varies too much to commment on or try to give an estimate for. Do your research. Work with someone with at least 5 years full time experience in design and installation of system...yes...they have been around that long....more like 30-40 years. 

larry the architect/LEEDap in Texas

I checked out solar panels at a local home show.  I can't remember the name of the two companies I talked to, but the average price was around 20,000 dollars.  The payment on that would be more than my power bill is now for the next 15 years.  Sorry, I can't afford to go green.

Depends....are you talking about lighting, heating, heating water, or generating electricity. And then all that depends on what you spend, how you spend, and how much you make yourself. Do you have more specific questions? Please feel free to write: Woodclaver@aol.com

It truly does depend on where you live and I have lived in six different places in the past two years. I have finally settled outside of Houston, Texas. My average utility bill is probably in the range of $250 per month. The bulk of that is for the fuel not the usage. Usage is low per killowatt here, but surprisingly the fuel (which is almost local) is 50% more than the usage cost. I have been looking into solar power and find that it you can do it yourself. It may take longer than to have it installed, but you CAN do it. In which case the cost would be minimal and only for materials on which the prices vary. So it would be worth shopping for the materials and getting the best prices. But my guestimate is that it would be cost one third of what it would cost to get it done professionally, if you do it yourself. I am a 54 year old single Mom and have had to learn to do everything myself. It is not just to avoid the high cost of everything, but because I like to work. If I can do it anyone can..... And I know that I can..... A little at a time....

A photovoltaic system will cost between US $8,000 and $10,000 for a 1kW system. (or $8 - $10 /Watt)