Any radiant heat experts here?

[stuckincincy]

I'm finally building a new house with the garage space I want. I'd like to install radiant heat flooring, I don't spend every night and weekend in the garage and when I am out there in the winter I think I'll try to keep the temp around 65*+/- a few degrees. I'll have about 2000 square feet of garage and about 1000 feet of walkout storage/work area underneath about half of the garage that will be heated also. I've talked to a couple of sales people that say I need 3000 feet of tube based on 12" spacing, and I've talked to a coworker that is partners in a construction company who says I can use 18" spacing which would mean around 2000 feet of tubing.

So do I trust the sales people or my coworker who does the occasional install? (which is usually under wood floors.)

Any input is appreciated.

Thanks

 

[melloelky]

i don't know anything about that but if it was an automotive situation who would you listen to= someone that makes their sole living off this craft or someone that screws around with the subject?

 

[stuckincincy]

The salespeople I've been able to talk to are basically just parts guys that sell for all kinds of plumbing supplies, not installers or designers. Talking with them I feel like when I go to the auto parts store for something like a T-stat and they say "You need this temp and you'll also need hoses, clamps, a drain pan, etc and don't forget the 50/50 mix anti-freeze." The installers I've called are happy to quote installing a full system, but don't want to help a DIY'er doing it in stages as my budget allows.

 

[pontiacgp]

Why not do you own research instead of trying to rely on others who may sound credible but are giving you the incorrect information, As for the spacing you don't mention what tube diameter they were talking about but the tube diameter has a direct effect on the spacing

 

[Streetbu]

There is a pipe layout designer specifically for this and it will tell you exactly what you need. I'll see if I can find it....

Edit: here's the first one I found

https://www.warmlyyours.com/en-US/tools/online-design-tool

 

[O. D. Showtime]

One thing to consider is the tubing, in most cases, is the cheapest component in the system, once the concrete is poured there's no going back. Generally 1/2" diameter pipe @12" on center spacing is used for below grade basements or slab on grade residential garages. Normally a heat loss calculation is done on the structure which will determine the amount of BTU/HR and/or BTU/SQFT that is required to heat said structure at a given temperature setting. The heat loss calculation will also provide required flow rates and head loss for the radiant panel. Another big consideration is the use of insulation below the slab, and although not completely necessary does limit the downward loss keeping the heat where you want it. Under slab insulation is a must with a high water table area. Of course you'll have to also consider the heat source along with pumps/valves, manifolds etc and controls. Although not terribly hard, it can be involved and you can certainly end up with a poor performing non efficient system if not given enough thought.

 

[stuckincincy]

The more research I do the more confused I get. I've watched dozens of online videos and read several articles, some conflict each other and some bring up good points others omit.

I'm planning to use 1/2' PEX-AL-PEX with 1-1/2" to 2" of under slab insulation. From what I've read, tubing size has more to do with the loop lengths and bend radius than actual heat transfer. I did find an online program from UPONOR to plan the tube layout.

 

[Streetbu]

Use a MINIMUM of 2" of xps foam both under AND around the edges of the slab. 1/2" pex-al-pex is fine with 12" centers, make sure the runs are no longer than 200' each. Too much loss and the boiler won't be able to keep up. When we did my buddies shop we didn't have a layout guide, just kind of eye balled it. We also made sure to leave large squares, about 3', where the lift posts were going to be going to absolutely ensure we didn't hit a heat pipe when installing them.... We zip tied the pex to wire mesh and made a couple of hooks to pull it up into the concrete. Now they have those nice little plastic stands for it to sit on.

 

[64nailhead]

Use a MINIMUM of 2" of xps foam both under AND around the edges of the slab. 1/2" pex-al-pex is fine with 12" centers, make sure the runs are no longer than 200' each. Too much loss and the boiler won't be able to keep up. When we did my buddies shop we didn't have a layout guide, just kind of eye balled it. We also made sure to leave large squares, about 3', where the lift posts were going to be going to absolutely ensure we didn't hit a heat pipe when installing them.... We zip tied the pex to wire mesh and made a couple of hooks to pull it up into the concrete. Now they have those nice little plastic stands for it to sit on.

What he^^^said. And it's hot.

 

[TURNA]

The Levitt houses where built after WWII as affordable homes for returning vets, all had radiant heat.

None of them have worked in over 60 years.

If it breaks do you really want to have 2 bills??

1. fix the heat

2. fix the floor