Off Grid Home Forums Technical Discussion Passive Solar or Active Solar better for your home? Re: Passive Solar or Active Solar better for your home?


Our roof is at a 45* angle to south and has limited room. Our calculations showed that we needed 11 75 watt panels in a seasonally adjustable fixed mounting, or 8 panels with a full tracking array. We did not have the room to mount the panels on the roof, so went with the 40% more efficient full tracking array.

So, initially it cost an extra 2,500 to mount, over the cost of seasonally adjustable fixed mounts. The 3 less panels saved 1,200, for a net extra cost of 1,300 for a 100Ah/day @ 24VDC system. Our minimum winter sun was affected by a mountain on one side and trees on the other.

Bringing in grid power would have cost 5,000 and our monthly bill would have been 100, so our 9,300 self installed full tracking system paid for itself in 43 months (9,300-5,000=4,300/100=43mos.) It must be noted that, installed by someone else, it would have been 17,100 (on bid), so then would have taken 121 months to pay for itself.