Yes, at this point I see a max. 4-5 year ROI at today's energy costs so it may very well be less than that as energy costs continue to rise. When my funds allow it I will most certainly add more collectors and storage as soon as I can and this even before adding more voltaic. As you know in this snow belt area of WNY we require some home heating for 9 months of the year with at least 6 months of that being full time.
I've done my home work and yes solar is boring compared to wind but with costs at around $1.00 per watt, 10-25 year warrantees, very little maintenance, no expensive towers, noise, shadowing and fewer permit issues and neighbor conflicts for me it's now a no-brainer. Wind is still fun but for my location comparing manufactured wind and solar systems of the same capacity who offer warrantees, small wind loses the ROI to solar by at least 3 to 1 (not including a tower) Site dependent yes and your numbers for your site will vary.
I am as excited about solar now as I ever was for wind, it just plain works and with less to think about. For those not familiar with the evacuated tube thermal system just google it. Ambient temperature really doesn't matter much to it's efficiency, it really is an amazing system. Dave B.
www.dcbenergy.com