Heater for a poorly insulated garage

[yooper]

yooper i already know that i am an idiot, so you really do not have to respond to this post.



ok i am not familiar with the Gas or propane infrared heaters, but on an electrical one they have a tube, kind of like a fluorescent light, inside that tube there is a resistor, what ever else is present in that tube, i have no idea, but when that tube heats up it does heat the air, and if the heater is pointed at say a tool box it will heat it, but the air is heated to, so what makes this different than say a base board electric heater?

The temperature of the heating element makes the difference. The hotter something is the higher frequency of radiation it will put out. If you care to learn about it, look up something called black body radiation, it is the spectrum of radiation put out by an object based on its temperature. If you don't know what the electromagnetic radiation spectrum is then you will need to look that up first.

IR heaters have elements with a temperature around 1000-2000°C and they put out most of their energy as radiation with a wavelength of somewhere between 750nm and 1mm. If they were even hotter they would put out visible light, like an incandescent light bulb. In fact when you see a heating element glowing then it is putting out some energy at visible wavelengths by definition.

Simpler heaters like a baseboard electric heater or a hot water radiator aren't nearly as hot so their output spectrum is weak and of longer wavelength and they end up losing a lot of heat to convection just by the air moving past them.

Also it's nothing like a fluorescent light, but I won't address that.

 

[yooper]

Industrial shops use IR heaters indeed for that reason, they heat the floors and other objects and use them as heat sinks, so when you have a big blast of cold air from opening a garage door or similar you don't lose as much energy.

Wayne the people that sold you your heaters are not necessarily experts, they are heater salesmen. I'm afraid I can't address why yours are not performing as advertised as I am also not a heater expert, just trained in physics.

You may be losing heat by conduction through your walls or more likely your floor. Concrete slabs conduct a lot of heat into the ground if you don't insulate under them.

You also may get some benefit from a slow ceiling fan, pointed up. It will break the stratification of air and push some of that hot air back down. Usually it's worth the cost of running the fan in saved heating cost.

Yes a wood stove is a black body radiator, but isn't as hot as your IR heaters.

 

[crushers]

Definition of temperature:
The tendency of a substance or an object to transfer heat to its surroundings.

did not know that there was a difference.

my system puts out 1200F at the heating end of the tube, 20ft later the temp is 600F and the exhaust is 120F.
so, if what you say is true, and i have no reason to doubt it, it is just the first few ft that is actually infrared and the rest is just a normal radiating heater. correct?

 

[yooper]

Definition of temperature:
The tendency of a substance or an object to transfer heat to its surroundings.

did not know that there was a difference.

my system puts out 1200F at the heating end of the tube, 20ft later the temp is 600F and the exhaust is 120F.
so, if what you say is true, and i have no reason to doubt it, it is just the first few ft that is actually infrared and the rest is just a normal radiating heater. correct?

To some extent, but there is no cutoff, it's a continuum, the whole tube is putting out some IR, but the hot end is doing a way better job of putting out useful IR than the cooler end.

The whole thing does lose some heat to convection as well of course. If it's poorly designed then maybe a lot.

 

[crushers]

when i moved in the walls were not insulated.
the ceiling was very well insulated as well as reflective foil was installed over that.
the floor was disgusting.

i changed out the windows to insullated one
the walls were spray foamed to 3" thick
the floor was dug up, 6 mil poly laid down, 3" foam over that, 4" of 3400 l/sq inch concrete over that.
it is VERY well done with excellent insulation.

yes, they were salesmen, i also talked to the maker of the system since they said on their front page of their website "Satisfaction guaranteed". after chatting for an hour with him i finally said "i am not satisfied" and his response was "did it fire up? then you are satisfied". that is when i started looking closer at the system, had the firebox sent out for testing, checked for the twisted liner, i have done everything possible to make this thing more fuel efficient. the shop is 20 X 30 with a 8.5 ceiling heated with 40,000 BTU heater. it is going through, on average, 10L per day of propane. i was told $30-$45 a month to heat it. it is $300 to $330 per month. you can see why i do not recommend these POS to anyone.

i have to say, thanks for not talking down to me over this.

cheers

 

[yooper]

Yeah that's a lot of propane and it does sound like you did a good job insulating.

Sounds like the manufacturer is an asshat and might be putting out a crappy heater.

 

[crushers]

2 weeks ago i installed a small 4500w 220V heater. it comes on every 20 min for 5 min. it can't keep up if there is a bigger heat loss (big door open). i have the infrared set just below the electric. if there is a big loss then it can reheat the room much quicker but the electric seems to do the job just fine.

it will be interesting to see how much electricity is being used. i can't see it being $300/month.

in Calgary, i had the same size shop, poorly insulated windows and doors, no insulation under the cement, the water heater, dryer, barbecue and house being heated with Natural Gas. even on the COLDEST days my heating bill never went over $300 for everything. this is just ... stupid.

that being said, this unit went up forsale last week and i will try something different ... maybe even go back to forced air furnace.

 

[crushers]

funny, these guys said the same thing ... run a fan.

but that disputes the whole idea of a infrared heater ... at least in my books it does.

 

[nomembername]

when i moved in the walls were not insulated.
the ceiling was very well insulated as well as reflective foil was installed over that.
the floor was disgusting.

i changed out the windows to insullated one
the walls were spray foamed to 3" thick
the floor was dug up, 6 mil poly laid down, 3" foam over that, 4" of 3400 l/sq inch concrete over that.
it is VERY well done with excellent insulation.

yes, they were salesmen, i also talked to the maker of the system since they said on their front page of their website "Satisfaction guaranteed". after chatting for an hour with him i finally said "i am not satisfied" and his response was "did it fire up? then you are satisfied". that is when i started looking closer at the system, had the firebox sent out for testing, checked for the twisted liner, i have done everything possible to make this thing more fuel efficient. the shop is 20 X 30 with a 8.5 ceiling heated with 40,000 BTU heater. it is going through, on average, 10L per day of propane. i was told $30-$45 a month to heat it. it is $300 to $330 per month. you can see why i do not recommend these POS to anyone.

i have to say, thanks for not talking down to me over this.

cheers

2 weeks ago i installed a small 4500w 220V heater. it comes on every 20 min for 5 min. it can't keep up if there is a bigger heat loss (big door open). i have the infrared set just below the electric. if there is a big loss then it can reheat the room much quicker but the electric seems to do the job just fine.

it will be interesting to see how much electricity is being used. i can't see it being $300/month.

in Calgary, i had the same size shop, poorly insulated windows and doors, no insulation under the cement, the water heater, dryer, barbecue and house being heated with Natural Gas. even on the COLDEST days my heating bill never went over $300 for everything. this is just ... stupid.

that being said, this unit went up forsale last week and i will try something different ... maybe even go back to forced air furnace.

Raymond Wolfinger aside, the plural of anecdote is not necessarily data.

funny, these guys said the same thing ... run a fan.

but that disputes the whole idea of a infrared heater ... at least in my books it does.

it doesn't, because you can use convection and radiation in conjunction to have a more effective (if not always more efficient) heating system.

It sounds like they sold you a larger heating unit than you actually need, to be honest. It may also be a poor design or a poor installation. As a result, you are using more fuel than necessary to underperform.

When we rebuilt my firehouse, we spent a significant amount on heat and light engineers to spec out what we needed then we went to the companies that manufactured the products. We ended up with 5 IR propane fired units. To heat 4 truck bays with 16' ceilings, 50' deep and 22' wide each, we are spending about $600/mo on propane - and that's with the doors going up and down a few times a day. The heat is set to 62 (thermostats are mounted to the back wall, concrete block below grade), but the air temperature is seldom over 55 yet the trucks will sit there at around 66-70 degrees.

The danger in under-spec heating with these units is they will run constantly and create hot spots but never enough convection to warm the air by the thermostat... Going the other way, over-spec, the heater will never run long enough to fully heat the tube before it warms the room contents sufficiently to heat soak them... or sometimes the thermostat will be placed too close to the output of the heater and the housing itself will warm up sooner than the room, and conversely cool down quicker as it transfers its heat to the cooler things around it (exterior wall, for example).

Each of these design and installation issues will cause gross inefficiencies, which it seems you re experiencing.

The IR heating systems are also best used in large spaces with high ceilings and large static masses. This allows both conduction and convection to take place without added blower fans or spot heat sources.

You asked about why the ceiling is hotter... you have two things going for you there: convection and proximity. The closer something is to a radiant source, the more radiation it will be able to absorb (with exceptions, such as the sun and the earth in winter... the winter hemisphere is technically closer, but tilted away so the radiation penetrates the atmosphere at a lower angle, spreading the energy across a wider surface area). The ceiling is closer, so a smaller surface area is receiving the same amount of radiation as the larger surface area. Hit your thumb with a hammer at 50 lbs of force... now use 50lbs of force to hit a nail into your thumb. The radiant thermal energy source, being closer to the ceiling, will heat the small area above it to a higher temperature because it's the same energy as is reaching everything below, but concentrated. Then, there is the saying that "hot air rises" or "heat rises" - once the objects in the shop are warmed to a point that they create minor convective currents they are also helping to send warm air up there, compounding the heat discrepancy.

Running a ceiling fan to send that convection current in the direction you want it will help significantly, but it's only masking the symptoms of a poor design and or incorrect system and or poor installation.

Edit - i just read the ceiling is 8.5' high? The typical IR heating system is a poor choice for a low ceiling like that. Not saying you made a poor choice, but that the salespeople seem to have sold you a false bill of goods and should have been honest enough to tell you their system is better suited to a higher (warehouse-type height) ceiling.

 

[crushers]

thanks nomembername,
i will be in contact with a couple reputable companies to see what will be the best heating for my shop. in reality, it should be very cheap to heat this place and keep it at a comfortable 61C.

cheers and peace.

<apology for the original post, frustration of the facts vs misinformation received from the local companies has given me a short fuse>

 

[yooper]

thanks nomembername,
i will be in contact with a couple reputable companies to see what will be the best heating for my shop. in reality, it should be very cheap to heat this place and keep it at a comfortable 61C.

cheers and peace.

<apology for the original post, frustration of the facts vs misinformation received from the local companies has given me a short fuse>

Oh, the other thing I keep forgetting. No way in hell are you keeping your shop at 61° C or is the ceiling at 85° C, and if you really are then that explains your fuel usage.

Those are 141° and 185° F!

 

[crushers]

ummm, correct F is what i meant

duh.

 

[Madogeoff]

Helpful dialogue, all of it . My shop is 21x21 feet with about a 12 foot ceiling,(2x12) earth and plank floors, no heat. This year I will finish insulating and organizing space. Most certainly I will build a masonry chimney, and install one of my wood heaters. One has a built in fan, catalytic burner, another has an oil drip arrangement. Still, the off hours of work will require some kind of "base" non wood heating system to keep things from freezing, and readily up heated by wood when I work in there. There is no gas where I live in the country, and my experiences with propane leave me wondering if more heat exits the exterior vent! Electricity is too expensive, and I am wondering whether I just should put in a used oil heater and burn Alberta Crude and be done with it. I have a construction background and really think that insulation is expensive, but necessary. I suppose I will lay SM Blue down before I pour concrete, but am still considering hot water in floor heating. Still, nothing like firing up a good wood heater to get you down to you t-shirts. But wood is also expensive and labor intensive. Having your own woodlot would help.

 

[crushers]

if it was my Mad and i was doing it again, i would make sure i at least installed the piping for the infloor heating. with all the rage being GeoTherm you can get 1 or 2 year old oil furnaces and tanks dirt cheap come summer. using oil i heat the house for under $300 during the coldest months in Ontario. not cheap but cheaper than gas. from Feb to end of Nov it cost me $600 for the house and then $300 for Dec, Jan.

i love wood fires, i love the heat, the aroma, the stoking the fire, the cutting the wood, everything BUT getting up at 3AM to stick another block in the fire.

going from scratch like you are, definately do your research and ask a LOT of questions, don't beleive the hype that some salesman spew forth.

 

[Madogeoff]

Putting the hosing for the in floor heat as a contingency plan is a great idea. I have been around the installation of these often on worksites and even helped install one once. Same plumber could supply me with hose and a manifold, and drop by to inspect it for me. A warm floor is a good backup heat, even though it would be electric water heat. One tip for any one considering keeping a shop at low heat is to avoid drywall which will develop mould at cool damp temperatures from slush and damp vehicles. With wood or similar interior, wood and or oil work heat...it could be a comfortable cruisen shop!

Your comment of getting up in the wee hours of the morning to stoke up the fire brought back a lot of bad memories. Did that for years in an old cold farmhouse. I burned over 10 punky bush cord, (yes, 40 face cords) to keep my family warm one year. Decades later, things are far more comfortable !...Thanks for the ideas

 

[Toyo FJ40]

If your laying radiant tubing make sure you put insulation down first. There is a huge heat loss through the slab and it will be much cheaper to heat. I put 2" foam insulation under a 6" slab for the radiant in my shop. The only down side is if you want to bolt something down to the floor you have to allow for it when you lay out the tubing. If you use it as back up heat you should use glycol to protect the loop from freezing. Water and mold resistant drywall is a good point, I did the first 4' of my walls in green board and used concrete siding trim for floor trim so I can wash down my floor without worrying about getting my walls wet.

 

[Toyo FJ40]

Back to the original post I've installed several Modine Hot Dawg garage heaters and they work great. It's a direct vent propane heater that can be bolter directly to the ceiling and vented out the side wall. Runs on a wall thermostat. They have a model that uses outside combustion air also.

Modine Hot Dawg

 

[Madogeoff]

Hey Spook,

'been given your situation more thought... 'steadin hijacking your thread..hummm and it occurred to me that since you got the heat sources basically covered...and so it is really a containment and expense problem.

Since insulation costs are ruled out, I think your best option is to address the two major heat loss factors. Warm air rising and drafts. I suggest that you acquire a roll or lengths of plastic vapor barrier. Cover the ceiling and down the walls a few feet, (all the way to the floor if you can afford it) Not much use having the heat up in the rafters. Be sure to use light batten strips and small nails or very long staples for the ceiling. You wouldn't want the plastic to fall down on your heat source! This will keep the heat in your shop while you work, but will dissipate rapidly afterwards. Even insulation without a vapor barrier will lose heat fast.

Next, you can lessen the worst drafts around the garage door etc. but not too much as you need some ventilation for your heat sources.

My final suggestion is to dress for outdoors, cap that bald head. ( those special operations black wool caps from Calvary One arn't warm enough ) wear gloves with the fingers cut off ( do those operations separately) and cosy up to the heat source when too cold, drink bad hot hard cider and whatever, and return happily to your task that you are indoors.

Hope that is constructive, cheers

 

[se2000]

I do not get, I rent so it is a waste to insulate. Well if you are moving in a few months, it would be true, but how long are you going to be there? and how much do you want to use the garage?
You can take insulation with you.

First thing is to seal air drafts. once that is done, decide what works for you. Maybe some 2" rigid high density foam boards will work. You could lightly tack them up, tape all seams and be able to remove in minutes. Could even make a cover for the garage door if you have a side entrance. Then it would take little to heat the space.

Any heater will be an ongoing expense, insulation is a one time expense, and it only take 6th grade math to figure out which pays off the best.
I'm betting the foam total cost is less than a sizable heater just to buy.

 

[Spook50]

Heh, just came across this thread again after moving into the new house.

Now I've got a nicely insulated shop, but no heat source!

No worries though. Sometime during the summer I'm going to get my hands on a used pellet stove and install it so I'm ready for next winter. I own this bitch now, so I can do what I want