# Shop heat decision



## Reddinr (Jan 16, 2018)

I'm thinking of upgrading my shop heat.  Shop is 24x36x9 Ft.  6" insulation on walls, 6" in ceilings.  I have two large propane vented blower type heaters mounted near the ceiling.  They are really loud and the shop is unevenly heated and they suck up the propane.  I'm thinking of changing that out.  I would like to stick with propane.  Being quiet and reliable is a priority.  What are people's thoughts on these options:  Hot water/steam radiant heat or a small forced-air furnace.  I do woodworking and metal working.  I would need to keep dusting the radiators if I had radiators I guess.  I wouldn't mind keeping the shop at about 50F through the winter and 65F when I'm working.  Outside winter temps. are usually in the 30's-50's but it very occasionally dip to 10-20F.


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## whitmore (Jan 16, 2018)

Reddinr said:


> I'm thinking of upgrading my shop heat.  Shop is 24x36x9 Ft.  6" insulation on walls, 6" in ceilings.  I have two large propane vented blower type heaters mounted near the ceiling.  They are really loud and the shop is unevenly heated ...  Outside winter temps. are usually in the 30's-50's but it very occasionally dip to 10-20F.



Forced air will work best if you want your woodwork precise, because there's frequently a rough-cut phase,
stacking to 'relax' the wood, and final dimensioning afterward.  The stacks will equilibrate best if
there's forced air, or at least a whole-room fan (ceiling fan in center  might be enough).   Downside: there's
a sawdust/airfilter ongoing maintenance issue.

As you probably know, a heat pump (which both heats in winter and cools/dehumidifies in summer)
can be effective in your mild climate.   Turning it off during the coldest week of the year would make
the shop uncomfortable 2% of the time, but save big on the electric bill.

Radiator heat can work, but if you move things around the shop (most folk do) the usual baseboard emitters
are problematic.   Tubes embedded in a concrete slab floor, on the other hand... are impossible to
do as an upgrade.

As a cheapskate, I'd look into ceiling fans to even out the heating that's there already.


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## RJSakowski (Jan 16, 2018)

I would opt for the forced air furnace.  Hot water/steam would be slow to heat up a cold shop.  Overhead propane fired radiant heating can be effective at keeping you warm and has a fairly quick response but if your intent is to stabilize your machines.  it won't help much there.


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## MikeInOr (Jan 16, 2018)

I have a mini-split heatpump that does a really nice job.  Much more efficient that a straight electric heater in my neck of the woods and much less hassle than propane.  I installed it myself.

When I was growing up my father put an old natural gas forced air furnace in the corner of the garage... without any ducting.  It did a nice job.  Make sure you put some kind of dust collection on the intake to filter the shop air and keep the innards relatively clean and efficient.


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## Reddinr (Jan 16, 2018)

Thanks for the comments.  Very helpful.  You guys from my neck of the woods understand the "moisture" issues I'm sure.  I'm hoping that keeping is reasonably warm will help with that too.  I'll need to check out the $$$ for heat pump install and operation vs. propane.  I think our electric rate is somewhere in the $0.11/KWHr. around here.  Propane varies in price quite a bit.


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## tjb (Jan 16, 2018)

I converted a dirt-floor pole barn into a nice shop.  It is 24 x 48 with an L wing added on to it that is 16 x 20.  I know I'm from the South, but we get some reasonably cold weather down here as well.  (Tonight, we're headed for about 23 with a high tomorrow of 32.)  The building has metal siding with a shingle roof, the entire front side (48') has four garage doors on it, there is no insulation on the inside, and the ceilings are exposed all the way to the gables.  I had a natural gas forced air heat system installed by a qualified HVAC guy.  He installed vents in all the critical work stations, and it works great.  I turn the system off at night and only use it as necessary.  On the absolute coldest days, it can stay pretty 'cool', but I've never had to stop working because it was just too unbearably cold - and it's never necessary to wear a jacket while working.  Usually, I'll need to manually turn off the heat while I'm still working because it gets too warm.  In the farthest corner of the shop I had a vent fan wall unit installed to keep the air moving.  (AC would be nice down here, but not very efficient in my type of building.)  The real trick to making the system viable is that the heat exchanger is in the 'attic', that is, up in the gable.  It takes up no floor space, and it has a filter element that is easily accessible.  If your shop is like most, you'll need to keep an eye on that pretty regularly.  Obviously, the system is not as optimal as a home unit with proper insulation/sheet rock/etc., but it's really nice for a shop.  You need to be comfortable, but when you're working, it takes far less heat than when you're resting.  I tried the space heater approach with very poor results (you're not always going to be that close to the centralized heat source).  Bottom line:  I've been very pleased with this setup.  I live in a farming community, so I have several friends who, like me, have converted barns into shops.  NONE has a shop as uniformly comfortable in cold weather as mine.  If you can get a forced air system installed without using up floor space, give it some serious consideration.  A good - and honest - HVAC guy can help you decide it it's right for your application.

Regards,
Terry


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## Hukshawn (Jan 16, 2018)

If the option is there, boiler fired (can be a tankless hot water unit or a tank) radiant heat piped through the floor. 
That’s the most efficient heat there is. Keeps a constant temperature for the cheapest price. I used to work for an hvac guy and we installed lots of these in garages, driveways, and shop spaces as well as homes. Can’t beat it. 

Or, it would be forced air for me. 
I have a hotdog unit heater in my garage and I had set up a blower on the other side oft he garage to move the cold air pockets once the unit had shut off. But found in order to get consistent heat, it would have to be running constantly. Annoying. 

Find a used furnace if possible and some duct work. Run a plenum up to the ceiling then a trunk across the ceiling in a corner with vents every few feet to blow the heat across the shop. You could build a small shack around the furnace equipped with air filters to keep the dust out and cut down on noise. Sounds like a fun project.


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## jcp (Jan 16, 2018)

I have a 30 x 40 metal shop with batt insulation. When I decided to heat it I found a gymnasium heater from a school remodel job. It's natural gas fired and while I can certainly tell when I've been using it by the gas bill, it's tolerable. As far as making the shop comfortable, it's great. Got an extended range thermostat so I can set it at 40 to keep the bathroom from freezing.


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## Glenn Brooks (Jan 17, 2018)

Shop heat? What is shop heat? 

Seriously, one answer could  be to install some kind of ceiling fan or desk top box fan to keep air circulating during the winter. Then you might even lower your temp settings when you are not in the building, as the air circulation will keep condensation from forming. 

I don’t have any heat at all and have several,periods throughout the winter where condensation becomes horrendous - water literally weeps off my machine tools and runs down on the floor.  Last time this happened was December. I  plugged in a cheapo 18” box fan from Costco slowing cold air in the direction of my mill and lathes.  next morning the machines were dry as a bone.  Simply amazing.

Only thing I don’t about is cost to run a fan, versus an efficient natural gas or propane heater.

Glenn


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## Cadillac STS (Jan 17, 2018)

Don't forget the simple things.  Like wearing a few thin layers of clothing if it is cold.  Or a light jacket to throw on while out there.  

Ceiling fan is helpful to circulate the air and get even heat.

One trick is to install a furnace with a thermostat, the older kind round with the mercury switch.  The thermostat is supposed to be mounted level for accurate degree readings but you can mount it with a tilt that allows you to set the heat at 45 degrees or so while you are not there so it keeps some heat and won't allow freezing.

Search Craigslist or Canadian version for furnaces.  Frequently used ones are there and they are there because employees of a furnace place are selling things pulled out and refurbed from a new install.  Some employee (Or owner) working on the side for himself.  So you have access to the lower cost equipment and more important maybe an expert in HVAC to help out for free...


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## bluechips (Jan 17, 2018)

My experiences with radiant in the floor are all positive.  Building is 28' x 40' with 10' ceilings with one bay being a high bay.  6" walls, trusses with 6" foam in ceiling.  2-10' insulated garage doors.  No windows !   I use a oil fired 30 gal. HW heater, 1100 ft. pex tubing on about 6" centers and 12" or 18" from edge of reinforced slab.  Slab is insulated on bottom and sides with 2" owens-corning foam.   I use about 175 gallons fuel a yr. to heat and keep at 50 degrees during a cold upstate NY winter.


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## ThunderDog (Jan 17, 2018)

MikeInOr said:


> I have a mini-split heatpump that does a really nice job.  Much more efficient that a straight electric heater in my neck of the woods and much less hassle than propane.  I installed it myself.
> 
> When I was growing up my father put an old natural gas forced air furnace in the corner of the garage... without any ducting.  It did a nice job.  Make sure you put some kind of dust collection on the intake to filter the shop air and keep the innards relatively clean and efficient.



I too installed my own mini-split.  Takes up very little space on my garage wall and it's great for the summer, too.


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## Reddinr (Jan 17, 2018)

Do the mini-splits allow for air ducting or are they just a single radiator/fan unit on the wall?  Cooling would be a nice bonus since the sun actually does come out sometimes here.


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## Bob Korves (Jan 17, 2018)

Reddinr said:


> Do the mini-splits allow for air ducting or are they just a single radiator/fan unit on the wall?  Cooling would be a nice bonus since the sun actually does come out sometimes here.


A mini split works just like a typical heat pump/air conditioner.  It is just a lot smaller.  The indoor unit mounts on the inside of any wall, and the outdoor unit is like a miniature heat pump or A/C unit.  They are quick and easy to install.  The hoses are pre-charged, so all you need to do is run the hoses through the wall, mount the outdoor unit on concrete or similar, hang the indoor unit on the wall, and run wiring to both.  It is as quiet as the central heat in a house, perhaps more so.  A lot of people put streamers on the outlet so they can tell if it is running.  They may not be the best choice is a really cold climate, because they are taking the heat out of the air, and that air is COLD, so it is less efficient and has less output under those conditions.  In more moderate climates, they are almost always a winner.  They are hugely more efficient than resistance heat and window air conditioners.  HUGELY.  They are also a lot less expensive than you think.  Advice:  look very closely at the efficiency numbers and quality ratings before buying, and look for ones with really high ratings.  The cost of power quickly overtakes a few dollars saved on the initial purchase and installation.  My other advice is to insulate and stop air infiltration really well before adding any heat or cooling to a shop.  Otherwise you are just throwing money away heating and cooling the outdoors.
https://www.energystar.gov/products/heating_cooling/ductless_heating_cooling


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## Cheeseking (Jan 17, 2018)

Electric heat is 100% energy efficient. Assuming you meant cost effective which it is not. Clean, convenient, and expensive on day 2 

Kinda like Inkjet printers!!
Lol


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## Bob Korves (Jan 17, 2018)

Cheeseking said:


> Electric heat is 100% energy efficient. Assuming you meant cost effective which it is not. Clean, convenient, and expensive on day 2
> 
> Kinda like Inkjet printers!!
> Lol
> View attachment 254774


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## Bob Korves (Jan 17, 2018)

Heat pumps and air conditioners are MORE than 100 percent efficient under typical conditions.  That is possible because they are not creating the heat, they are only moving it from one place to another.  A decent mini split will be about 400 percent efficient while heating at 35F outdoor temperature.  It gets worse as it gets colder.  Same thing happens with cooling, in reverse.


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## gi_984 (Jan 17, 2018)

Went from bare walls, zero insulation, and wearing heavy winter coat/boots to this:

http://www.reznorhvac.com/en/na/products/udas

Rated for commercial and residential use.  So the insurance company has zero issues with it.  Also got the recommended fresh air intake/vent.  Separate combustion chamber so you aren't burning the dust and crud in the shop air.  So better air quality.  Got the 45K BTU size.

Fiberglass insulation in the walls (R-13), Insulated garage doors & entrance door, Drywall interior walls & ceiling,blown in fiberglass in ceiling (R-60).  Thermostat set at 40.  During the cold months it only runs when the temps stay below freezing.  Easily holds it at 40.  When I want to work in the shop area just turn it up to 68.  Takes about half an hour to bring to temp.  Very little increase in the gas bill.  Was expensive but worth it.  Only regret not doing it before moving in.


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## Reddinr (Jan 17, 2018)

gi_984, How big and high is your shop area?  That unit is similar to the one I have now but am thinking of trading in for something less noisy.  The fan in mine is very loud.


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## Reddinr (Jan 17, 2018)

I did a little more research and found a surplus high-efficiency propane furnace/air-handler locally.  I think I will go with the propane / forced air route.  It seems to make sense for my situation.  I found a bunch of resources for HVAC sizing, laying out ductwork and air-handler sizing.  A little complicated but interesting!  If nothing else, a challange!  These all appear to me to be open-source documents and tools.

BTU Calculator:  http://www.calculator.net/btu-calcu...=50&temperatureunit=f&calctype=heat&x=76&y=24

ACCA Manual D is apparently the bible for HVAC mechanicals.

ACCA Manual D Spreadsheet:  https://www.acca.org/viewdocument/acca-speed-sheet-for-manual-d

ACCA Manual D (Newer draft on ACCA Website):  https://www.acca.org/HigherLogic/Sy...tFileKey=7fc1b1b0-d18d-8eb1-7949-3fa6ed32d50f

ACCA Manual D Video:


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## MikeInOr (Jan 18, 2018)

The Fuji mini-split I installed has a console like interior unit that mounts high on the wall.  There are several other options for the interior unit: Floor mount, Mount in the ceiling between joists, mount in the ceiling/attic and use short runs of conventional AC or flexible AC duct.  The interior console units are most common but with a little looking around you will find there are a lot of options.  The Fuji I installed is one of the highest efficiency rated units and I REALLY like it!   Dead silent!


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## MonkMan (Jan 18, 2018)

I have a Mitsubishi Electric Split-System Heat Pump in my 26' x 40' x 11' shop building. Works well for A/C, struggles a bit when it gets below 20 degrees outside.


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## frugalguido (Jan 18, 2018)

gi_984 said:


> Went from bare walls, zero insulation, and wearing heavy winter coat/boots to this:
> 
> http://www.reznorhvac.com/en/na/products/udas
> 
> ...



In my old shop I finally got this same unit, best desision I ever made! Went from the open flame propane infrared heat to the reznor separate combustion chamber (no open flame in the area your heating) What hasn't been mentioned is when you have a open flame you are creating moisture. Moisture and machine tools are a bad idea. Fighting rust on Tools/ metal/ machines, etc. went away after getting the Reznor.


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## gi_984 (Jan 18, 2018)

"gi_984, How big and high is your shop area?"
Approximately 38 feet by 28 feet, 9 foot 8 inch tall ceilings.  The 45K BTU works fine for this space.  The biggest heat loss is around the garage doors (even with insulation and weatherstripping).  My heater runs off natural gas.


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## amuller (Jan 20, 2018)

You need to do a heat loss calculation as suggested.   In my small shop (about 18 x 20) I use a sidewall venting condensing gas furnace gotten off craigslist for $50.  Easy to install and very "efficient."  The only real issue is that it has to be drained in freezing weather.  With a good inlet air filter it can serve double duty as a room air cleaner for woodworking.   Some of these are "multipoise," meaning you can hang them up horizontally if you have the headroom.

In some places, if the alternative is propane, a heat pump might be a good alternative.  Prices vary a lot from place to place.

Radiant floor heating gives good comfort but is slow-responding, so is good for continuous heating but not so much for I-turn-it-on-when-I'm-working.

Just my thoughts.  Not a HVAC designer.


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