My Shop Heating Dilema

[Kevin Post]

There have been a number of threads lately dealing with shop heating issues. I have a home which is currently under construction with an 24x44 attached, 4-car garage with 10 foot ceilings. Half of it will be my shop. It will be well insulated.

Here's my dilema. I had planned to install in-floor heat in the garage until I got the bid. I have since decided not to do it for a couple of reasons:

1) Cost... The house will be heated with forced air and the basement floor and portions of the first floor will be "warmed" with hydronic heat. That could be done using a beefier water heater for the house that would have a transfer plate to draw off heat for the hydronic system. The additional load on the system to add the garage would require significant upgrades (including a boiler) that added $10 - $15K to the cost of my HVAC system. I'm planning to check with another HVAC contractorto get another opinion/design but I can't afford that much $$$.

2) I am not planning to keep the garage/shop heated continuously due to the utility costs associated. Heating with a hydronic system, I'm told, would take quite a long time to get the area from cold winter temps to a comfortable working temp. I want to turn on the heat and have it warm up quickly.

Instead, I am considering a forced-air unit heater (like a Hot-Dawg) or an infrared heater. Either would be operated by natural gas. In addition, I want to install a wood stove to provide supplemental heat and save fuel costs and as a way to dispose of scraps and mistakes.

I have read other threads which contained comments cautioning people on using infrared heaters because they become uncomfortable to work around. (Like working under a broiler...) I can confirm this to a degree because the hockey rink has one of these and when I sit under it for too long my forehead gets 'sun-burned'. The advantage, however, is they heat the objects in the room (cast iron and concrete) which will radiate the heat into the room. In my mind, this offers some of the advantages of an in-slab hydronic system. I still plan to install insulation under the concrete. A disadvantage of forced air systems is they blow dust around.

In my last place, I had a 15KW electric, forced-air furnace hanging from the ceiling. It was a salvage item... It heated the space well. I had installed filters on it so it doubled as an air-cleaner. I wonder if I could buy a small, cheap furnace and use it as an air-cleaner as I had before. I could maybe install an AC coil in it to cool the place during the summer too. Could I use the same compressor that operates the house AC or would I need a separate unit?

Any thoughts or suggestions? Please consider where I live in Wisconsin when offering advice. Winter temps here are generally close to zero and frequently stay below zero for extended periods during January and February. In other parts of the country (possibly where you live) winter temps may be more mild. This translates into lower BTU loads on the system and lower costs for both the system as well as the energy to operate it.

-Kevin

[Bob Noles]

Kevin,

Not much help for the main system, but just a tip to consider.

If your washer and dryer are in that space, you may want to consider not ducting the dryer to the outside, but leave it blow into the garage instead. You can put a filter of some kind over the vent to keep the lint and dust down and let the warm air supplement the heat system to warm the space up faster. Just plan your woodworking schedule around the wife's laundry schedule and you have it made.

Best of luck on whatever you go with. I know it is a tough choice with energy costs these days.

[Scott Loven]

I live about 80 miles SW of you in Decorah, IA and am also dealing with the same issues. I saw an add in the paper for a used LP furnace for sale for $75 I was thinking of checking out. My concerns are with trying to keep the heat from escaping through the garage door.
Scott

[Al Willits]

IMHO FWIW

Infra reds may heat the shop and not the air, but they need a lot of head space or they'll become uncomfortable quickly, also they don't do well with a lot of chemicals, think open flame/same as, and vapors, do a bit of painting and you'll see, stink big time.
Probably not all that good for ya either?

If I had a dedicated shop, I'd run a regular furn and supply combustion air from outside, (also keep ya alive if your wood stove outdrafts your furnace) I'd also filter the room air before it got to the furnace, not hard to do, a couple of 16x20x1" plain filters in a rack and it would do wonders on keeping the furnace clean.
Also with a furnace running an AC unit would be possible.

Second choice would be a hot dog style unit heater, and maybe a ceiling fan or two to help keep the air from stratifying.

Keeping it simple would be a key factor in my opinion.

Al... just a thought.

[Kyle Kraft]

Kevin,

Not much help for the main system, but just a tip to consider.

If your washer and dryer are in that space, you may want to consider not ducting the dryer to the outside, but leave it blow into the garage instead. You can put a filter of some kind over the vent to keep the lint and dust down and let the warm air supplement the heat system to warm the space up faster. Just plan your woodworking schedule around the wife's laundry schedule and you have it made.

Best of luck on whatever you go with. I know it is a tough choice with energy costs these days.

I would approach this scenario with caution, as the purpose of a clothes dryer is to remove water from fabric and put it somewhere else. If you pump high humidity air into a garage full of ice cold cast iron machinery, you will have the rustiest tables in Wisconsin.

The same thing happens in the spring when you get a 60 degree rainy day in February and open the garage door. AMHIKT

[Kyle Kraft]

Radiant tube heaters can be used in "hazardous" environments safely, but you must provide outside combustion air hooked directly to the intake of the burner.

Did this at the last employer, where we had trichloroethylene vapors present in some areas of the plant. The old unit heater's heat exchangers were rotting in about 2 seasons.

[Ron Blaise]

a wood stove to heat during the times you would need it. You probably generate wood scrap anyway so it might be worth considering.

[Kevin Post]

The garage door thing was something I discussed at length with the HVAC guy and the garage door guy. I'm installing insulated steel doors. They were numerous models from which to choose. Each model had an option of enhanced insulation with better R-value for an additional cost of about $500 per door.

The guy selling the doors is a friend of mind. He recommended not wasting the additional $$$ on the improved insulation. He said they measure the R-value in the center of the door panel where the door is solid. The better R-value offers little benefit because garage doors are so leaky between the panels and around their perimeter.

The HVAC guy also said that he wouldn't bother spending more on the extra R-value insulation for the garage doors. The most important place to add extra insulation is in the attic because the heat rises and escapes through the roof more than through the walls.

The message I got from both was to definitely buy insulated garage doors but don't spend the extra money they charge for better insulation.

-Kevin

[Kevin Post]

If you pump high humidity air into a garage full of ice cold cast iron machinery, you will have the rustiest tables in Wisconsin.

Yeah, I was thinking the same thing. Too much moisture... The lint would become a problem too. Even with a filter, some is bound to get through and cleaning the filter would become a chore. Plus, the shop would smell like a laund-r-mat...

One thing I may consider is routing the dryer duct through the garage but vent it to the outside. The laundry room is adjacent to the garage. It would radiate a litle heat into the garage. The problem is this would happen in the summer too. I wouldn't want that extra heat during the summer.

[Al Willits]

You'll get the vapors burning on the outside of the tube, may be ok for haz duty, but you'll still get the smell, good for you or not, I don't know.

Al

[Brad Townsend]

What I see as part of your problem is that you are going to be heating half of your total garage space for no good purpose (unless you want to keep your cars toasty warm). Also, you will be fighting with debris, moisture, road salt and who knows what else in your work area.

Is it possible to stud in a wall down the center of the garage, giving you two bays to work in, isolated from the other two with vehicles? It would be half as much to heat and you wouldn't be losing all your heat everytime someone has to take the car out.

I heat an area 20x30 with a small 5000w electric in northern Illinois. Like you intend, I only run it when I'm working there and in spite of high electric rates, it really doesn't cost all that much.

[Frank Hagan]

Kevin,

Not much help for the main system, but just a tip to consider.

If your washer and dryer are in that space, you may want to consider not ducting the dryer to the outside, but leave it blow into the garage instead. You can put a filter of some kind over the vent to keep the lint and dust down and let the warm air supplement the heat system to warm the space up faster. Just plan your woodworking schedule around the wife's laundry schedule and you have it made.

Best of luck on whatever you go with. I know it is a tough choice with energy costs these days.

I would not do this in a heavily insulated space due to the amount of carbon monoxide you are introducing. At least with a gas dryer, that is. The secondary concern would be the water vapor, but that might not be a problem in cold areas where the relative humidity drops so low during winter.

[Kevin Post]

What I see as part of your problem is that you are going to be heating half of your total garage space for no good purpose.
...
Is it possible to stud in a wall down the center of the garage, giving you two bays to work in, isolated from the other two with vehicles?

Good point, Brad!

I do plan to install a wall down the center. This will protect the cars from dust, etc. from the shop. It will keep SWMBO from discarding things in the shop. And conserve heat in the shop when someone opens the garage door.

However, I had planned on heating the two halves separately (two zones) when hydronic was being considered. I want to have heat available in the portion with the vehicles so I can work on them during the winter. Granted, I could use an alternate method of heat for the side with the vehicles.

Also, since I will not have a dedicated finishing room, I plan to use the garage half as a finishing room when I have a large project or a bunch of cabinets to finish.

Either way, I will only heat each space when necessary.

[Brad Townsend]

Good point, Brad!

I do plan to install a wall down the center. This will protect the cars from dust, etc. from the shop. It will keep SWMBO from discarding things in the shop. And conserve heat in the shop when someone opens the garage door.

However, I had planned on heating the two halves separately (two zones) when hydronic was being considered. I want to have heat available in the portion with the vehicles so I can work on them during the winter. Granted, I could use an alternate method of heat for the side with the vehicles.

Also, since I will not have a dedicated finishing room, I plan to use the garage half as a finishing room when I have a large project or a bunch of cabinets to finish.

Either way, I will only heat each space when necessary.

Another advantage to the "two room" configuration is that perhaps you can squeeze out a few square feet in the auto side for your dust collector and air compressor. More room and less noise on the woodworking side.

[John Bush]

Hi Kevin,
I think you can get an appropriate hydronic system done for $2K --maybe $3K. I heat my 1600sq ft shop with an 80 gal natural gas hot water tank and minimal other mechanical stuff. You could add a dedicated tank inexpensively, if needed, and create zones for both sides of the garage. I keep my shop at ~ 55 deg during the week and crank it up as needed for weekends, etc. It does take a little time to get up to temp, but usually it's not a problem. Once the slab mass heats up the tank doesn't fire up often, so it seems efficient. If you planned on keeping the heat off until you needed it and wanted a rapid rise to comfort temp, hydronic wouldn't be the best choice. I used 2" dense cell foam sheets to insulate below the slab, so that is an extra expense you may not have considered for hydronic as well. I recommend that you bury the hose when the slab is poured even if you don't plan on using it right away, as you may want to use it in the future. If you can get a better price on the system I'd recommend just going for it, you will be happy that you did. Good luck, JCB.