The furnace just has a single speed fan, and from what I can tell so far I'll need all the air flow I can get with the low temp water.
Here are a few pictures of some insulating I did yesterday. I’m using 1” thick EPDM closed cell foam made by Areoflex (
http://www.aeroflexusa.net/products/aerocel_sspt/). It’s a bit pricey here at ~$3 a foot, but I’ve got a significant amount amount piping outdoors. It is also UV resistant and theoretically does not require any additional covering.
For the ‘trench’ to the house I’m using 2” rigid XPS board. I had to make a compromise/sacrifice here since it’s a drainback system the trench becomes a protrusion closer to the panels. I’m relying on the rigid box to help maintain a gradual slope back to the basement. I plan to do some grading to cover it, but the pipe and insulation is definitely not below the frost line. Time will tell whether this was a mistake.