Greetings, I’ve moved over 50 times across seven countries and never owned a home! I’ve designed golf courses, scheduled and managed their construction, and maintained the turfgrass afterwards, but home construction and management are in another realm. Bouncing across the net in research for radiant floor heat and geothermal heat pumps led me to your chat forum, which reads as a reliable place for practical answers, and I need all the help I can get. I own a piece of central Minnesota—out in the sticks! The buildable area is on a peninsula 21 feet above the high-water line of a bog to the west with lakes beside it, and a small swamp behind it. It’s over 200’ long x 100’ deep. There’s a set-back from the high-water mark, which puts my 46’x 26’ home behind center; about forty feet from the slope to the swamp. The soil is clay and frost penetrates to 5’, and I wonder about that penetration and the proximity of the slopes to my slab. The home will be stud wall construction on a monolithic pour, packed with insulation, and radiant heat in the ~750 sq ft residence, and in the ~450 sq ft garage, too, maybe. I’ll trench the interior perimeter for a gravel drain before the base sand goes down for polystyrene and concrete, and after construction, I’ll trench for a drain around the entire perimeter of the home; all for water removal and alleviate clay and frost expansion/contraction. Some things I’m wondering are: Would a geothermal heat pump be practical in a home of 750 sq ft? (I’ll rent a backhoe/loader for excavation to level the site and dig/fill for the septic tank. The south lawn is over 3,000 sq ft, so it would be convenient to trench and bury tubing at the same time.) Somebody has to design this geo / radiant system? And hook it up? A plumber? How much space would this combination system take up in a mechanical room? I’m considering a mini split for transition times, spring and fall, and perhaps omit the radiant in the garage and rely on a mini split for it. (It’s not necessary for constant heat in the garage.) I’m having second thoughts about propane for a primary energy, and going with electricity! (and a generator for back up) Also, I’m inclined to include an Energy Recover Ventilator for my little tin cabin. As small at the place is, I tend to think this set up lends heavy to the green side of the energy equation at a modest expense. But I want to know for sure, and how it all works together. Thanks for reading & any words of wisdom, direction, or moral support are appreciated! Track

Sounds like a very cool project. Can you drop a couple loops for geothermal into the bog? That usually is the cheap easy efficient way to do Geo.

Also, I have done radiant in a garage and wouldn't do it again. Working in a garage is usually not a planned event and slabs can take 8 hours to heat up and you usually don't want to constantly heat a garage. I am currently doing the mini split thing in my garage.

Good Luck.

The bog is off limits. My garage work is limited, and I, too, think the mini split is the way to go. Thanks for the comments.

I wouldn’t bother with geo (more properly called ground source heat pump). Geo can get pretty pricy and the complexity can often be problematic. You can get nearly the same efficiency with a mini split (air source heat pump). For the size of the building you are considering, mini splits would likely be a great solution. If you really want a heated floor, just realize that it won’t feel warm in an energy efficient home. However, it can keep the slab from feeling cold, so maybe some combination of mini splits and heated floor might be your best solution. There’s lot of stuff about heated floors and other things on our website that you might find useful for your project.

After more though about what I didn't understand, the geo doesn't sound logical, or practical, with in-floor heat. In a closed loop floor heat, once the fluid is warmed/hot, it's not going to drop below 55 degrees (the geo temp.) I'll look into your web site. Thanks.