![\"IMG_20131002_154552\"](\"http:\/\/jcremin.com\/house\/wp-content\/uploads\/2013\/10\/IMG_20131002_154552.jpg\")
<\/a><\/p>\nNext on the list was to dig trenches for the hot water lines from our outdoor wood boiler, which will heat the house, the garage, and our hot tub.\u00a0 All of the lines run from the boiler to the house, and from there, they branch out to the other locations.\u00a0 I was very unhappy with the performance of the insulation on the old lines that ran from the boiler to the garage, so I decided to start over and design my own system to keep the pipes from wasting heat by dumping it into the ground all year long.<\/p>\n
The problem with the old lines is that they were only wrapped in a very thin foil\/foam material, which only provided one wrap between the two pipes and 3 wraps between the pipes and the corrugated tube they came inside of.\u00a0 While I can’t find any data on what the insulation values of the foil wrap really are, my guess is that it is roughly R1 per wrap, giving R1 between the two pipes and R3 between the pipes and the ground.\u00a0 It didn’t make any sense to build a very well insulated house, and then dump our heat into the ground before it even got to the house.\u00a0 The foam box I designed provides 2 inches of XPS foam between the two pipes and 6 inches of XPS foam between the pipes and the ground.\u00a0 XPS insulation has an R-value of R5 per inch, meaning that the new lines will have R10 between the two pipes and R30 between the pipes and the ground.\u00a0 Talk about a huge improvement (10 times the insulation value).<\/p>\n
Here’s a picture to better explain the difference between the old insulated lines I bought a few years ago, and the way the new ones will be insulated (click on image for a larger version):<\/p>\n
The first step was to dig the trench that the new boiler lines would go into.\u00a0 The old lines were only about 2 feet below the ground, and in the spring or fall, you could see exactly where they were because the snow would melt off of the ground in a 5 foot wide path.\u00a0 Since the frost reaches a depth of around 4 feet, I wanted to make sure to get the new lines as deep as possible so the insulation could do its job even better.\u00a0 We used a small backhoe to dig down 4 to 5 feet, and then finished cleaning up the bottom of the trench by hand.<\/p>\n The next step was to build the box.\u00a0 Here’s the box about 50% built.\u00a0 The part we are working on has the first 3 layers of 2″ foam, plus the 1″ pieces of foam to hold the pipes in place.\u00a0 In the background, you can see we have one more layer of 2″ foam added.\u00a0 The finished product gets two more layers of 2″ foam.<\/p>\n Here’s the completed product getting ready to be moved into the trench.<\/p>\n Here’s one more picture of the end of the foam box so you can see how the pipes come out of it:<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n