Heating a woodshop

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Forum topic by IHRedRules posted 07-15-2015 01:27 AM 2329 views 1 time favorited 20 replies Add to Favorites Watch
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113 posts in 1471 days

07-15-2015 01:27 AM

Fellow LumberJocks, I will be building a new 30’x32’x10’ wood shop this fall. I want to heat it (I live in central Michigan so winters are somewhat long and cold), so that I can have a place to work in the winter. I am looking for any and all opinions on how you would heat the shop. I am leaning towards radiant floor heat, since it should be quieter, reduce dust, and hopefully be one less source of a spark if I decide to spray finishes in the shop. Regardless of which type I go, how many BTU’s would I need to keep my shop comfortably warm?

20 replies so far

View WoodNSawdust's profile


1417 posts in 1171 days

#1 posted 07-15-2015 01:48 AM

I have been working on upgrading the heat & cooling in my shop. My HVAC guy said 1 ton of cooling for every 400 square feet. The Internet says 1 ton = 12000 BTU.

For my shop we are going with a Mitsubishi MZ-GE24NA 24,000 BTU ductless system. According to the customer service people it will work (heating) down to 5 degrees.

One advantage of a ducted system would be to also use it as an ambient air filter. Place air return inlets over places that generate a lot of dust and the heated / cooled air vent to cause a circular air flow throughout your shop. If I had the room in the shop to run ducts I would use this method.

-- "I love it when a plan comes together" John "Hannibal" Smith

View Woodmaster1's profile


956 posts in 2582 days

#2 posted 07-15-2015 02:07 AM

I have a 50,000 BTU Big Maxx gas heater. My garage is 30×33 with 6” walls insulated with R19 and ceiling is R30. I live I northern Indiana so our winters are the same. I did not get the insulation done in the ceiling but my gas bill on budget just went up $10.00 more a month. I kept the garage at 60degrees when not in the garage and 70 when working. I will gladly pay $10.00 extra a month for the comfort in the winter.

View distrbd's profile


2252 posts in 2441 days

#3 posted 07-15-2015 02:16 AM

Take a look at Schwank heating system, the HVAC contractor that installed our furnace highly recommended that brand for my detached shop, I am still using propane for now, but sooner or later I’ll have to call him to have him install the Compact tube heater that he had in mind .

-- Ken from Ontario, Canada

View bigblockyeti's profile


5112 posts in 1715 days

#4 posted 07-15-2015 02:52 AM

My shop is just over 400sqft with 9’ ceilings and I have a Dayton heater hanging from the ceiling running on natural gas. It’s 40K btu and heats the shop quite well, so well in fact I leave the thermostat set at 50 and when I venture out, it can run the temperature up to 75 in less than 20 minutes even when the outside temperature is in the single digits. The big advantages to this type of setup is they’re cheap and so is the installation. The negatives are many: They’re inefficient, they’re a combustion hazard, they stir up the air, they’re noisy. They have many of the problems you stated you’re trying specifically to stay away from, but it was installed when I bought the house and knowing I won’t be here forever has me really not wanting to change anything. Given the opportunity to build a new shop (along with a new house) on a decent piece of land I think I would be leaning toward radiant tube heating with a boiler or hot water system. This would be best if the temperature is to stay at a constant vs. going up and down all the time as they’re slow build or loose heat.

View Andre's profile


1827 posts in 1801 days

#5 posted 07-15-2015 03:13 AM

Your shop is 9600 cu/ft, my shop is 5760 cu/ft, I use a electric boiler with in floor radiant heat. Insulated my heat sink with 2” styrofoam.
Compare the cost of gas over Electricity (electric heat is 100% efficient).
I live in north central Alberta and I dose get real cold here – 30 F.
Draw back to in floor heat concrete floor and no air circulation, if i was to do it again I would go with 1 zone floor heat and 1 zone wall mount radiant heater.
That being said I have a 25000 btu Infrared tube heater in my garage which is great, cheap to run heats up a hell of a lot quicker, but chimney, open flame and noise!

-- Lifting one end of the plank.

View Fred Hargis's profile

Fred Hargis

4981 posts in 2488 days

#6 posted 07-15-2015 11:18 AM

The only downside to radiant floor heat (IMHO) is the reported slow response time. In the 2 detached shops I’ve had, I went with forced air furnaces, and while they also have their downsides they do heat the place up quickly. Don’t get me wrong, I would love floor heat but I think if I had it I would just keep the shop heated to working temp all the time. Forced air gives you a breeze that can be a problem blowing dust around, especially when trying to do finishing. But you don’t have to worry about flames/sparks if you get a direct vent furnace (outside air for combustion). My first one had a wall furnace (45,000 BTU…24×28x10 with R13 walls and R 19 ceiling), the current one has a ceiling hung unit (45,000 BTW, 24×32x8, R40 ceiling, R18 walls). Sizing yours will depend on the insulation, but my guess is your looking closer to 75K BTU’s. If your curious, I live in NW OHio, and last year burned 145 gallons of LP heating this shop, but that’s only to 50º when I’m not in there, and 65º when I am. Since I’m retired, I’m in there most days.

-- Our village hasn't lost it's idiot, he was elected to congress.

View RogerM's profile


792 posts in 2394 days

#7 posted 07-15-2015 01:46 PM

My shop is 28 ft by 50 feet and I heat it with a wood stove with a heat pump for backup. I have really enjoyed this arrangement.

-- Roger M, Aiken, SC

View Richard H's profile

Richard H

489 posts in 1675 days

#8 posted 07-15-2015 02:02 PM

My understanding is radiant heat is very efficient as long as you want the temperature to remain the same. If you turn it down when not in the shop it’s going to take a long time and use a lot of energy to recover. The more mass of concrete you have the longer it will take to recover. It works best for space that you want conditioned 24X7 to near the same temp. It’s up to you if the cost to maintain the temperature all the time is going to be cheaper than the cost to warm the space back up when needed if you should set it lower or not and will likely depend on how often you are out there.

I like the idea of a radiant primary system to keep the shop a base temperature in the 60’s than a small secondary air handler system like a split system for quick recovery and what little AC you would need up there but that’s me and I am by no means a HVAC specialist.

View runswithscissors's profile


2750 posts in 2020 days

#9 posted 07-16-2015 12:16 AM

For me, this is the wrong season to be thinking about this question.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View pmayer's profile


1028 posts in 3060 days

#10 posted 07-16-2015 12:25 AM

I went with in-floor radiant and absolutely love it. Super comfortable all the time. I have the therm set for 60 and just leave it there all the time. I have a long sleeve shirt on when I start working and within an hour I’m down to a t-shirt. I installed it myself which was not hard, and it brought the cost down a lot (roughly half).

-- PaulMayer,

View JollyGreen67's profile


1669 posts in 2757 days

#11 posted 07-16-2015 01:43 AM

Mini-split with heat pump – only way to go.

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected !

View canadianchips's profile


2600 posts in 2992 days

#12 posted 07-16-2015 12:34 PM

In floor radiant heat IS the way to go. I lived in Northern Alberta, winter temp can hit -35. I set my heat temp at 70 degrees and left it there. I had 3 zones in a 1000 sq. ft. building. My walls were R20, ceiling R40.
My cost avg. $64 per month (including monthly delivery fee)
I would not consider any other heat method in wood shop. I did not have to worry about sparks.
Even if you plan on hooking up floor heat later, spend the few dollars it takes and PUT THE pipe in floor now.
“just my thoughts”

-- "My mission in life - make everyone smile !"

View them700project's profile


115 posts in 1013 days

#13 posted 08-12-2015 07:49 PM

Radiant all the way. There is no better form of heat. It is also more effiicient.

View them700project's profile


115 posts in 1013 days

#14 posted 08-12-2015 07:54 PM

Another key factor for radiant is it uses 110 degree water to heat the same space 160+ degrees water would be needed for baseboard and radiators. So less energy and longer boiler life. A small boiler sized for this radiant loop and a thru the wall ac unit is the way to go.

View JeffP's profile


573 posts in 1386 days

#15 posted 08-12-2015 11:15 PM

For up there, radiant floor heat is probably best.

To me the biggest down-side is that there isn’t a practical way to use it for cooling in the summer.

For that reason, I think the two-zone idea, and using radiant to keep a minimum temp all winter and a heat-pump based forced air system for comfort in winter and summer.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

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