in the process of updating my shop with some wiring, insulation, etc. I have a GFA unit I am going to install. The shop is like 24x24 with 10' ceiling. Do I need to run ducts or can I just blow the heat right out of the furnace? How high off the floor does it need to sit to be safe? Anything else I need to know to heat the shop?? thanks-
I have mine mounted between the rollup doors and about eight feet off the floor facing in with no ductwork. it works fine for what it is but if I were to redo it I would run ducting all around the perimeter it would be good to have heat in the corners instead of one big blast in the middle.
The unit has to be elevated up off the ground so that any fumes that might collect will not ignite. I forget what the standard is but I thought it was around 14 inches.
I don't know what a GFA furnce even is, but I will say what I did when putting a furnace in the garage. I put it in the attic!!! (I followed the manufactures installation istructions as far as the general installation went). The MAIN reason to do it this way because there is NO OPEN FLAME in the area of the garage where the cars are. Some guys swear by their Radiants and various other units as well (and I am sure they have a LOT of redeeming points) but for me there's no comparison to the extra level of security. One winter I hurt my back and wasn't in the garage for a month - sure woulda sucked if a car started to leak gas or something and an OPEN FLAME from the furnace lit the sucker up!!!!!! BOOM!!!! Normally I am in the garage daily and I realize that alot of people use this to convince themselves that THAT is good enough - and maybe it is - how lucky do you feel?????? Just some food for thought.
Dan, Randy has his furnace set up like you are thinking. It works well in the same size garage. He lights the pilot when he needs the heat.
I assume GFA stands for Gas Forced Air as in stand alone central heating mine uses what seems to be a huge amount of fuel, but will take the 2000 foot plus shop from cold to hot in no time at all. the only issue I've had with it was when I did some heavy bondo sanding with the doors closed and heat on, the plastic dust on the hot heat exchanger must have produce some toxic fumes, 'cause even with a good quality mask on it kicked my ass bad, I was sick for a couple days. live and learn, learn to live..
I am thinking of putting the furnace in the corner and running one duct down the center of the ceiling with vents opening down, the furnace will be up off the ground to hopefully avoid lighting any fumes...is there some "math" to determine how many and where the vents should go?? On another note, I am thinking dedicated circuit for: -mig -arc -aircompressor -furnace -lights and garage door opener (int. & ext. on same) - a/c -outlets does this sound legit?? thanks-
yeah, but have a couple circuits for outlets maybe? and enough 240v outlets that you can buy some more equipment later and have a place to plug it in
It's best to point the ducts toward the doors. I know, it makes no sense, but it's all about recovery. The air blasting out, keeps the cold from rushing in. You do intend to vent the exhaust from the burner, right? You could get by with a "Y" shaped splitter, and blow it right from the furnace. 24 x 24 isn't that big. I wouldn't spend the time and money on complete ductwork. Joe knows cold.... JOE
it will be vented, the more I think about it, I think I'll go simple to begin with and then I can add ducts and vents later it I think I need them
Dan, O.K. I design the installation of this stuff for a living; so lets make sure you do yours safely. Per the International Mechanical Code, 2003 Ed. (IMC) 1. Install the furnace so the ignition source, (pilot light, ignitor, etc.) is at least 18 inchs above the floor. Follow the manufacturer's written instructions. This will keep you safe and within the warranty. If you do this any ignitable vapors (think spilled gas, etc.) will be below the ignition source. 2. Use ducts to distribute the air to the opposite side of the garage from the furnace. This way you will get circulation of the air. The furnace fan will draw suction from the area of the furnace and the air will flow from the discharge of the ducts back to the area of the fan. Don't use all flexible duct. Its expensive and the fan will have a hard time pushing the warm air through the duct. 3. Vent the furnace exhaust outside!!! Make sure you don't get any recirculation from the exhaust discharge back into the garage. There are rules in the IMC about this. 4. Make sure you have grille openings in the outside wall for combustion air. This is air that is needed by the furnace to burn the fuel. It is separate from the forced air used to distribute the heat. You will need 2 openings one near the floor and one near the ceiling. Each one with 1 square inch per 1,000 btu of furnace capacity. 5. Install a CO monitor in the garage. Carbon monoxide is a silent killer and you won't realize it until you are almost dead. You'll also have a treamendous headache. CO monitors are cheap insurance so get one along with a smoke detector. Remember you are installing an ignition source into your garage, so any flammable vapors in enough concentration can and will ignite. Garages are considered "hazardous" occupancies and so building inspectors are extra tough on these areas. You should be able to go to your public library and get a copy of the International Mechanical Code. It will be in the reference section. PM me if you have any other questions.
VERY good info! that is what I was looking for, I am take awhile to digest this and come up with some more questions but I will definately email you for some more help, thanks!
uh huh... nordern fellers tend to know when its time for headin in the house. LOL i bought a small ceiling heater for my garage this year and need to stuff it up in the rafters to keep my fat ass warm this winter... NEVER again will i loose 5 months to the cold. my thoughts are: keep the thermostate on the oposite side if the room from the furnace, out of the direction of the forced air. let the cold air come to the thermostat... small helper fans can work WONDERS for keeping "dead air" spots from staying dead. a lot easier than adding ducts IMHO
Thermostat should be on an interior wall if you have one. If mounting it on an outside wall make a bracket to allow a small air space between the thermostat and the wall. Even if you have insulation in the walls this still makes a big difference. I have a big "Resnor" heater in my shop, hangs from the ceiling. My brother-in-law(HVAC contractor) mounted the thermostat on a wall underneath the heater. The idea being that the heat blows out and away, circulates back around. If the thermostat is where the heat blows on it, it will cycle constantly and you'll freeze your ass.
that was another thought, but i wondered about radiant heat from the unit itself. Reznor makes some good stuff for sure. i really like how the new ones can be damn near flush mounted to the ceiling. . . i always think what a waste of space above em
okay, heres the next question... gonna do some painting after sheetrocking, the garage is actually 24x28, I have 4 4' flourescent fixtures (with 2 bulbs each)...what paint do I want to use to reflect as much light as possible? I assume white...do I want flat, semi-gloss, gloss etc.?? I am imagining the shop divided up into 4 12x14 sections, with a light fixture centered in each 12x14 area, would that be a good idea i.e. the best distribution of the light?? thanks-
you want at least a satin gloss so you can wipe dirt off the walls....full gloss would probably look funky. I have semi-gloss or satin, in my garages. That sounds a bit skimpy for lighting, I have about that many 8' fixtures in that much area in the shop. And it's still not light enough.
i gotta agree with Squirrel here and say first a good semi gloss especialy for the walls,,, altho if its that slippery maybe the dust wont stick? lol second! YEA BUDDY you need more than that for light unless you are going to have a couple of them silly lookin worksite flood lights sittin around your garage like i have now... they ARE handy for working inside a closed car or under one, but they are a PITA big time and i plan to hang more lights from the rafters before winter. even if you double the four 4' fixtures you have now, it wont be enough. my garage is 3 stalls wide by 1 1/2 deep... not sure about the dimensions but anyhow,,., i plan to have 10 yes TEN 8' two bulb fixtures in there with three or four of the four footers i now have hangin above the center of each stall i drew up a fast and dirty diagram to help explain my layout idea... from working with wood for years and trying to spray a decent finish over a pourous surface like wood, you learn fast that light is your best friend and you really CANNOT have too much if its directed right...
Those flourescent lights won't work for shit when it's cold, so have some regular incandescent lights, either, on a different circuit, or wired into that one. I put regular double wall outlets on my ceiling, in one plug, I have my 4' flourescents plugged in, and in the other, I took some $2 extension cords, cut off the female end, wired on double sockets for two 100w bulbs, and made drop lights. It puts the light right over your head... and works great for changing them, as I have a 16' ceiling. You can, always, swing them out of the way if you need to. JOE
FiddyFour has the right idea. More fixtures, placed correctly. If you put your fixture in the center of the work bay, then the car makes a big shadow on the floor. If you place them on the sides, you get fewer shadows. On fixture length, pick ONE length, either 4' or 8'. You'll have to keep less spare light tubes. The eight footers are nice, but a bitch to store and not get broken. I have all four footers. The fixtures may be less $$$ in 4' lengths. Figure out your light layout and then figure the cost of using 4' fixtures and with 8' fixtures. You might be surprised at the cost difference. Include the cost of the light tubes in the cost as well. 8' tubes aren't cheap. You can butt the ends of the 4' fixtures together or even remove the end plates and wire them together. Don't forget a light over the work bench. I have a shelf above the pegboard behind the work bench. I attached a single tube surface mount light to the bottom of the shelf and have a well lit work bench. Oh yeah, don't put the ceiling lights where they'll be covered by the garage door when you open the door. You'll get a hugh shadow.
I'll be using 4' fixtures as I am salvaging them from inside the house, I may be able to get 8 of them though...just cant afford to replace the flour. with regular fixtures in the house right now. When pumbing the gas into the garage do I need to put a "drop" into the pipe, look you do when hanging a heater from the rafters?? I am thinking I might raise the unit high enough off the floor that I can run the duct on top of the rafters and drop the vents down through the ceiling, that way I dont have a duct running down the middle of the ceiling, should be easier to sheetrock that way?? Anyone want to draw up a plan for me showing where the ducts/vents GFA should be placed? The shop is 24 wide by 28 deep, 10' ceilings. 16' door on north wall, walkthrough door in sw corner and the gas is on the SE exterior of the shop, not run into the interior yet. Thanks for all the help so far!
I agree with Joe about the flourescents not working for shit when it's COLD ---UNLESS you get the newer style with the ELECTRONIC balasts - they work GREAT even in the cold. One other thing I'd reccomend for wiring a shop - keep the lights and wall circuits on separate breakers - this way a blown fuse/breaker won't leave you in the DARK. Matter of fact if I were starting over I would put HALF the ceiling lights on one leg and the rest on the other - aside from balancing the load (big deal I know) you could also use them in BUDGET mode - only using half under normal conditions and use the rest in HIGH VISIBILITY situations like painting/bodywork. Other things you might consider: Keep outlets above 48" high - this way a sheet of plywood or steel laying against the wall won't obstruct your power. Definitely add your 220v drops NOW - better yet add some 3 phase ones in there too---- oops maybe I am getting severe overkill. Aparently my furnace in the attic isn't all that well received, but I'd suggest you consider it - no open flame - no lost floor space - you can even get a ceiling mounted air filter housing so you don't even need to go into the attic for routine maintence. One by product of burning fuel is WATER - in the form of humidity - separating your furnace's combustion area from your work area can eliminate this as a problem. I know guys who use infra red heaters to heat their garage and some of them HAVE to use a dehumidifier to keep the moisture under control. Everything is a Pro or Con - you just need to weigh them for your application/needs. For instance those 90% (High Efficiency) also refrred to as Condensing Units - MUST have a DRAIN nearby to deal with the water that they create. Compare this to the less efficient 80% unit which are liess efficient but require no additional drain. Some funraces have a freaking MPU on them - forget that - I want to fix mine myself!!!! There are a TON of differences between a 90% unit and an 80% unit - for me - KEEP those 90% jobs - I heard of TONS of trouble with them.
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