Advice on boiler/tankless/hot water heater for radiant garage and workshop

Ned

I've spent many hours lurking here, trying to get an idea of the best way to heat the detached garage and woodshop I'm just finishing building. I'm at the end of my budget, and trying to figure out the best way to heat this.



Some particulars:

24x26 foot garage

Radiant tubing in slab and in dormered workshop above

Located in Maine, so it gets cold

Bathroom with only a sink and toilet, but may make this an apartment down the road

R30 walls (2 inches closed cell foam, r11 batts, inch of foam on outside)

Approx R45 roof (4 inches closed cell foam, r19 batts)

R 19 batts between floors



My plumber would like me to go with an Axia because he is familiar with them, but they are 3k and 86% efficient, if I remember correctly. I have looked at the Takagi, which looks good, but about the same cost. Same with the Triangle Tube. I've also looked at the Eternal which looks good, and the Navien, which seems to have been questionable on some of the forums.



I don't really need hot water in the bathroom. Would be nice, but right now I don't need it. I am interested in keeping my monthly costs down as LP is about $3.50 a gallon here right now. So here's my real question:



Why not find a decent LP hot water heater for under 1k to do this? Am I going to pay a lot more in monthly costs? I'm only going to keep it around 40-50 degrees most of the time, and I don't mind waiting for the workshop to heat up (I may have a woodstove as well).



Any thoughts or suggestions would be appreciated. Looking to keep my initial costs down, but not at the risk of high heating bills. I would also prefer to vent through pvc, if possible.



Thanks in advance,



Ned

NRT_Rob

the triangle tube

would be much more efficient.



Tank heater would be about 70%-75% efficient for heating. about 20% different than, say, a solo 60 Triangle tube boiler.



Your total heat load is probably fairly low, so payback won't be 1 or 2 years for sure, but a real load calc would be needed to answer the usage question.



do not use on demands for heating.

Ned

Thoughts on brand?

Thanks, Rob. Hate to start a Ford/Chevy flame war, but any opinions on which of the units I listed?



Thanks.

NRT_Rob

hardly ford vs chevy

nearly all the units you mention are on demands. don't use them. For nearly any situation they would be a good choice for, you should use a much cheaper tank water heater. None of them are equivalent to a similarly priced boiler.



the triangle tube and axia are boilers, of those two, I don't think anyone could argue that the axia is a better choice, though installer familiarity does count for something. that said there are plenty of people around here in maine that should know the TT unit by now.

kcopp

another option...

Emabassy Onex.... It comes in a combi version and a heat only option... a bit of a break on the price. neat unit.

kpc

BobbyG

Ned

Hey Ned.  What do you do for a living?  I might need some advice sometime.....

Ned

Thanks for the advice

Hey Bobby,

I own a small advertising/marketing company. You can check out some of our work at www.harbourlight.com . What kind of help are you looking for? I have a lot of clients in the contracting/plumbing/electrical realm.

kcopp

gee...

you are right in my back yard... I'm in Dover.

Ned

small world

Wow, that's crazy. Small world. Granite Group is my supply house.  Do you know Atlantic Plumbing and Heating/Jay Mard? Very good friend of mine.

kcopp

I also do...

a lot of bussines w/ TGG... hence the reason I mentioned the Onex. I have about 6 in service... sleeker that the TT solo and exelleance. concentric venting. On effect it is a 93% afue Axia. If you want I can show you one that is working.

I am not famiiar w/ your friend... kpc