shop heating question

[Byron Chastain]

I just finished building a 30x60 10' high pole barn/ shop. I had it insulated with that white/ foil insulation.

My question, I want to heat the shop but wondering the best way.

I am going to pour a 5 inch concrete floor next week and was thinking of putting the pex in the floor and running an outside wood furnace to heat the floor. The cost of pex about 400.00 and then the cost of the furnace 3500.00

Or do i put in the inside furnace like the larger Fire Chief type for about 1/3 of the cost?

I am leaning toward the outside furnace so i can run a line to the house for heating my hot water heater and a coil in the furnace.

Opinions very welcomed!!!

Thanks

[Dale Benham]

I've just finished a 30' X 24' shop with 10' ceilings and have radiant heat in the 4" concrete slab (5/8" PEX tubing from Radiantec) - I plan to post some photos soon. The slab has 2" of foam under it. I'm using a 50 gallon high efficiency gas water heater that I put in a 4' X 4' closet, sealed off from the shop area with a door to the outside. Although it has not been that cold yet this fall, but it is a wonderful system with thermostat controlled heat that surrounds me with warmth as I work. This is a great way to go for heating. The folks at Radiantec could answer lots of your questions (they are a DYI company - I have no affiliation with them, just good service from them).

[Logan William]

At the very least put down 1-2" of foam board underneath, and I would say put the PEX in as well. This way you have some insulation from the soil temp and the slab won't get as cold, plus when you decide to heat the slab you're ready. The 400 bucks in PEX and the labor to lay it is minimal IMO to the benefit you'll get out of it down the road.

[Dave Beauchesne]

Byron:

Radiant in floor is the way to go - radiant tube gas is another option; a 50 foot tube would work very well as well.

The radiant tube heater should run around 2k if you have lpg or nat. gas available.

If you don't do the wood boiler now, by all means spend the $$ and install the PEX when the slab is done. Also, the foam under the concrete is crucial.

Good luck - - -

Dave Beauchesne

[Dale Benham]

Byron,
I've been thinking about your post concerning pouring concrete over PEX to use later. I think it is a good idea, but you may need to also purchase a manifold and connect all of the lines in the floor (I have three circuits in my 720 sq ft of floor) to the manifold. My manifold was placed on top of the foam and concreted poured around it (it is containined in a plywood box allowing the PEX to remain at the concrete level). This will also allow you to pressurize the PEX with air (30psi or so) during the concrete pour (which is recommended to keep the PEX from collapsing and also allows you to check for leaks before you pour). I'm no expert (just have one experience with radiant heat) but I would encourage you to talk to your supplier for PEX and the other equipment needed (manifold, expansion tank, pump, etc.) before you pour. Hopefully this makes sense....I just wouldn't want you to lay down PEX and then be stuck with other problems later.
-Dale

[Dave Beauchesne]

Byron,
I've been thinking about your post concerning pouring concrete over PEX to use later. I think it is a good idea, but you may need to also purchase a manifold and connect all of the lines in the floor (I have three circuits in my 720 sq ft of floor) to the manifold. My manifold was placed on top of the foam and concreted poured around it (it is containined in a plywood box allowing the PEX to remain at the concrete level). This will also allow you to pressurize the PEX with air (30psi or so) during the concrete pour (which is recommended to keep the PEX from collapsing and also allows you to check for leaks before you pour). I'm no expert (just have one experience with radiant heat) but I would encourage you to talk to your supplier for PEX and the other equipment needed (manifold, expansion tank, pump, etc.) before you pour. Hopefully this makes sense....I just wouldn't want you to lay down PEX and then be stuck with other problems later.
-Dale

Dale:

I am a HVAC guy who has worked on several radiant floor systems, but by no means an true expert.
Anything I have worked on has the manifolds above the slab - not having joints in the slab is the general practice. I have seen several places that PEX has been installed for future considerations - the loops are marked, plugged and come up in a common area. If I were in the enviable position of pouring a slab for a new shop and could not afford a full radiant in floor system, I would be sure there was PEX in the slab.

Dave B

[Gary Curtis]

If you really wanted to save money, consider this: ace hardware sells $140 electric heaters running on 220. I have one to heat a 25x27 foot shop -- all new construction. Considering that each unit puts out about 14,000 btu, my shop warms up in minutes with only one. Near the Calif/Oregon border with winters that get down to the teens at night.

My home in Southern California has hydronic heating in the walls (it's an older home). Radiant heating is wonderful. Some people I know with the floor tubing complain about 'hot foot syndrome'. Ask a fireman who's got floor heating at his station. But hydronic is economical to run. And I would follow Dale's suggestion about an electric water heater for heat input. Boilers are expensive.

Gary Curtis

[Byron Chastain]

Well thanks for all the input! I think I'm gonna put the Pex in the slab for use down the road! Thinking that's the smart thing to do! I was gonna put the ends above the floor so I can get to the manifold on etc etc. I bought the Pex and planning on laying it myself. 2000' six zones with each run one foot apart.

Talked to a guy who installs the wood furnaces and he said they instal 1/2 " Pex and said you really don't need to place the tubes under pressure. Wasn't to sure about that one!

[Randy Henry]

Byron,
I just went through the same decisions you are going through, and did alot of research and talked to several friends that have the outdoor wood furnaces that have the water/fluid that gets heated and sent in to the radiant floor heating. They all said they would probably not do it again, as if they leave their house for a couple of days, they have to drain the tank over the firebox, or they fear it will freeze and crack the tank. One has had to repair cracks in his holding tank,...

With it being my shop, I am not in there every day, and I do not want to have to drain/fill the tank based if I am not in the shop for more than 2-3 days (I'm talking if its below 15 deg.). I ended up getting a Bryan outdoor forced air furnace. Its basically an outdoor wood furnace that blows hot air into the shop, and it has an air return for circulation. It keeps the open flame and mess out of the shop. If I put 3-4 logs on, it will keep my shop warm all day long. I got lucky and got mine off of Craig's list very reasonable. Here is the link to their website:
http://www.rik-mar.com/Products/Product-Line.html

[Byron Chastain]

Thanks, I also was concerned about leaving for a couple of days in the winter and coming home to a frozen tank! I kinda liked the idea of the Bryan Furnace. I found the same thing about craigslist.

[Scott T Smith]

Bryan, I did pex in my shop, here is what I learned.

Where you stub out of the slab, be sure to put it in some type of tubing or insulator. This helps protect it in a critical location. I used radiused PVC conduit elbows on mine, and have also seen HVAC foam insulation used.

Also, cold enters the slab from the outside (or underneath). Consider insulation on the outside of the slab. Also, decrease the spacing in-between your tubing on the outskirts of the slab (such as 9" spacing on the outer two rows) will help to mitigate the effect of the cold migrating in.

Finally, many installations have a tendency to have a "hot spot" near where the tubing stubs up out of the slab, due to the fact that the spacing between the tubes becomes compressed where they all come together. It's a good idea to put some insulation (such as the foam insulation that goes around freon lines on HVAC systems) around some of the pex tubes so that you maintain consistent heat in this area.

The folks at Radiantec are great to work with, and really know their stuff. Pricy, but good.

[Greg Roberts]

At the very least put down 1-2" of foam board underneath, and I would say put the PEX in as well. This way you have some insulation from the soil temp and the slab won't get as cold, plus when you decide to heat the slab you're ready. The 400 bucks in PEX and the labor to lay it is minimal IMO to the benefit you'll get out of it down the road.

+1

Go for 2" foam under the whole slab.

Greg

[Greg Roberts]

If your electricity rates are reasonable, an electric water heater will heat the shop through the radiant tubing very easily. Here in Maine our electricity rates are too high to make this viable.

It's a very easy system design to integrate the water heater to the floor.

+1 on whoever mentioned insulating the edge of the slab as well as underneath. The greatest difference in temperature between the slab and outside is at the edges of the slab. You don't get a second chance to insulate properly under a concrete slab.

Greg

[Chris Friesen]

My question, I want to heat the shop but wondering the best way.

Do you plan on keeping the shop at a constant warm temperature, or leave it cold most of the time and warm it up when you're in it?

An in-floor system is great for keeping constant temperature, and feels really nice on the feet. However, if you're going to leave it cold most of the time, an in-floor system will take much longer to come up to temperature.

Either way you should insulate the slab and put a vapour retarder under it.

[Jim Finn]

[QUOTE an in-floor system will take much longer to come up to temperature.QUOTE]
...........................This its the reason , as a former HVAC contractor, I would not advise in floor heating, of any type. It can take hours to efficently heat the slab enough to warm the room. Forced air or electric heater (like mine) are amost instant heat sources.

[Byron Chastain]

I guess my main idea is to keep it warm all winter long. Then to run a line into the house for the furnace/ water heater.

I can see all sides of the argument and im still not sure the way i am going to go. I have to talked to a lot of people and it seems they are about 50-50 on the outside wood furnace. Most seem to get tired of going out twice a day and stoking the fire. However, they like the constant warmth from the floor.

I know others who hated it so much they got rid of them and went gas, electric, wood stove, forced air, or nothing.

I just dont know....

[Ken Fitzgerald]

Byron,

What are you going to do if you go away for a few days in the winter?

I had some friends who bought a home here in Idaho. Gorgeous home except the only heat was wood. Somebody had to stay home in the winter to feed the stove to prevent water lines from freezing. I was surprised that a bank would even loan them the money on the house.

I am not trying to talk you out of it but rather raise a question.

[Byron Chastain]

I know.... I keep thinking about that and I just dont know! I brought that up to one vendor. His reply was to run a 50-50 anti-freeze in it.... Ummmm 75-100 gallons worth???? Im not thinking so! lol

I keep going back to the Bryan forced air type. But then the thought of starting the fire and getting the building warm before i go out and work on something. That seems to be a pain also! Plus a cold floor! :)

So i guess what its gonna boil down to is picking between the two evils!

[Ken Fitzgerald]

Sadly sometimes we have to make some tough decisions.

When I built my shop, the LOML gave me a very tight budget but....she could have retired and she is still working 5 years later to pay for it. She retires 1/1/2011. I wanted radiant floor heating so badly but.....the cost of running water to the shop would have put me over budget big time and.... I checked into do it without water in the shop. To meet code the heater would have had to have some special designed safety circuitry...again busted the budget.

So I built the shop.

2 years later the LOML for Christmas gave me a Lennox overhead 75,000 btu natural gas furnace. It works well. When I have a project going I set the thermostat for 65ºF. When I don't have a project going I set the thermostat for 58ºF. If I am getting ready to finish a project 2-3 days before I run the temperature up to 70º.

The shop is well insulated and really isn't expensive to heat.

[Jim Finn]

[QUOTE=Byron Chastain;1571630] Plus a cold floor! QUOTE]


Cold floor is fixed by a raised wooden floor.

[Tom Cornish]

I have a separated combustion gas heater in my shop. 2-stage 100,000BTU that heats about 650 sq ft of shop and 1000 sq ft of garage. It's north of 80% efficient.

I debated the whole radiant floor heating route. The thing that pushed me over the edge to just skip it was the need (for me at least) to have instant heat, which would mean raidant plus some kind of forced air heat.

Radiant would keep the area at some marginal temp (about 50 degrees), but if I wanted to go out and work for an hour or so I would either have to pre-plan to crank the heat up early, or be stuck with 50 degrees.

With the forced-air heater I can leave the shop a little cooler, and if I want to crank the heat up a bit, it only takes about 5 minutes to warm things 10 degrees.

[Byron Chastain]

I gave my shop specs, 30x60x10 insulated walls and a 5" concrete floor, to the guy designing my system. He said with the layout he gave me I should be able to maintain 69 inside with an outside temp of 0. He said to use a gas hot water heater (I can't find the specs on it) with 1/2" Pex 6-7 zones each tube spaced 1' apart.

I don't know if that's right or wrong. I know he makes a living designing radiant heat systems.

I was just worried about the cost of running the hot water heater. I would have to use an electric water heater. I don't want the hassle of placing a prop tank etc etc.

I guess im just wanting my cake.......

Ken I hear ya about the budget thing. I won't be able to afford the furnace until next year! (maybe!)

[Bud Millis]

Radiant floor heating is awesome. No need to worry about dust/heater problems. It warms everything up in the room. My next shop will have this.

[Byron Chastain]

Well I think I'm going to go with radiant heat. Now I need to decide if I want to do the outside wood furnace/boiler or an electric hot water heater! Any words of wisdom?

[Jason Pinsonneault]

why not put the wood stove system in or perhaps a corn furnace which will run in the same manner and if the proper hopper is installed can reliably run for itself for a few days without any attention or needing to be refilled, that way you can go away for a few days no problem, or you cousd stick with the wood furnace and find an inexpensive hot water heater to plumb into the system as well that could be shut off and only turned on when you plan on being away for a while, one thing ive heard of lots of people doing is running a complete second set of pex lines in the floor while you already there installing that way if the first one ever gets a hole in it somehow you have a backup, especially if you ever decide to drill a hole in your cement to install something such as a hoist or even a secondary wall. the extra pex line makes for cheap insurnace if you ever have a problem with the first one because then youll have to find a whole new heating method

[Ken Fitzgerald]

Byron,

If you live in a town...check with the building code office as to what they will or won't accept with regards to radiant floor heat.

If you don't live in a town, talk carefully with some of the radiant heat experts and land on the conservative side of the design from a safety standpoint.

Our local building code required a constant water source piped into the building or a special safety circuit on the water heater to prevent it from continuing to run should the system develop a leak and run the water heater dry.

Keep in mind, that if in the design you shortcut any safety aspects, should something bad happen, your insurance company could justifiably leave you hanging out to dry.

This is the route I wanted to take but didn't want to spend the extra bucks to plumb water into the shop. It was as costly or more when I got quotes from several local HVAC/plumbing contractors to install a system with the safety circuits involved. I finally gave up in disgust over the hassles.

[Byron Chastain]

Well I'm kinda lucky. I have a friend that's a plumber and one that's a manager at a plumbing supply company(Discount!!) We have already plumbed for a bathroom, washer, and going to run a water line from the house to the shop.

It's just a matter of more time than money right now. So I'm gonna get the floor in with my Pex and stub it all off until next summer after the old tax check comes in.

I thought about the water heater as a back up if I leave in the winter. Talked to my buddy and he said we can do that.

Gee this seems to be going from a simple system to major undertaking! I guess it will be worth it when it's all done and I have my man cave all done!

Thanks for all the input guys!

[Chuck Gallup]

Thanks for all the input guys!
I pumped concrete for many many lucky fellows building a shop.
About 8 years worth. As I live in a relatively small community, I see my customers all the time. It is only natural to ask about the "Shop".

Where we live it gets cold. Real cold.

The guys that put in pex get all gushy when asked about their shop.
"Oh ..... its so nice!"

With those who have worked in their new shop through a winter...I get the shake of the head...."Yeah, I wish I woulda put in in-floor heating"
They scratch and say...hindsight is 20/20.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In floor heating makes sense if your area gets cold.
20ºf is not cold.
Where I live, wrenches burned my hands in the summer and freeze to my hands in winter.
But I only worked in a rented shop for short periods. When it is cold...few heating systems work. I once spilled a bucket of hot water over a -20ºƒ floor and watched it freeze. The ice patch remained til spring.
A cold slab simply sucks the life out fella. Unless your life is on fire, you will find more ways to stay out of the shop.

Now, I'm building "My" shop. I want to be itching to get to the shop every morning even when it is 20 below!
But....I'll be making my living from the work within the shop.
Big difference.

Cold weather and my inability to get my drawings into permitting shut us down. We saw temps down to -12ºƒ.
So here my Pex sits.
http://i76.photobucket.com/albums/j18/Navigator7/IMG_0404.jpg
And my footings will probably fill up when it melts:
http://i76.photobucket.com/albums/j18/Navigator7/IMG_0405.jpg

;-)

[Byron Chastain]

BUUUUUUUURRR!!! We only get to the single digits or below for maybe a week or two in the winter. But the summer is hot and humid!