i literally just completed my 60x100 shop with a 30x30 office space connected on the side. 6900 sq ft total. two zones one for office and one for shop.
I did my homework on this talking to many engineers, hvac technicians , and parties that have had it for many years. ill say one thing stay away from tankless water heaters...
You need to keep in mind the effiecency, capacity, flow rate, tubing spacing and size of tubing. Boiler LP or NG is the best way to go, and make sure they are modulating. That is a huge advantage 80% of the new boilers out there are but when looking at menards ones some were not. Capacity, and temp pull plays a big part in sizing your boiler along with what your trying to achieve temp wise and maintain.
Most large companies have programs that will run a pull test for what your trying to achieve, and usually is a free service and also will design the tubing layout.
Just my experience and system, this saved me about 4K. I laid all the tubing myself, following a designed plan. I used foil backed insulation underneath with it rapping up the bam board on the side to not allow heat escape and soak to the outside. Insulation is key obviously, creatherm boards are very nice and allow you snap in the tubing rather than tying it to a wire mesh grid, but its rather expensive anywhere from 1.25-2.00 dollar a sq ft.
I opted for manifolds that could control flow to each loop, REHAU is a good one, each run will need to stay within range of equi-distance, but is hard to achieve sometimes. This way longer and shorter runs you can achieve the proper flow rates to achieve proper efficiency to each loop. I have two 9 circuit manifolds in the shop and a 3 circuit manifold in the office space.
I hired in a company to complete the boiler hookup, pressure test, manifolds, gas lines etc.
Went with 5/8" tubing on 12" centers, connected to a 155,000 btu Wells Mclain boiler, max draw at 0* was 114,000 btu but with nights reaching less than 0* sometimes in ohio, the assurance was worth it having the extra capacity. Between Wells Mclain and Traingle tube are your two top and most popular boilers i found.
I have a lot of the paper work i would be happy to share on the load pull calculations and all that, along with the over all cost. I have $9500 in the boiler, installation, pumps, copper lines, gas lines etc... $3500 in tubing, $2600 in insulation and $900 in the wire mesh to tie the tubing too. I think a complete job with them doing it all was roughly 20-21k. so i saved a lot by doing some installation myself.
I hope my experience helps, its def worth the money for sure i feel, but after talking to enough people the boiler is the heart of the operation. Really spend the time in research and money there is what i found. A lot of guys in my local area have done it twice and switched to a boiler.
I can post pics if that may help also..
Thanks
-Clinton
