Yes, as Ben said, the panels will be for heating DHW and will assist in space heating through the use of hydronic radiant floors. As my chart shows, they'll provide quite a bit of heat (20%+ of my gas usage) even in in the worst of winter. My house is not all that efficient either (yet). Rough estimates show it saving me just under $400 a year.
The setup will be kept as simple as possible. It will be a drain back system to a ~400 gallon tank in my basement so no antifreeze. The DHW and space heating loops will need to go through their own heat exchangers inside the tank to pull the heat out.
Since my last post with that chart, I've tweaked it a bit to calculate things with the collectors at a specific tilt and also tweaked the collector efficiency per month. So, it should be a bit more accurate now.
