Hello Everyone,
I am new to the forum and am looking forward to participating in it. I have been a general contractor/finish carpenter/cabinetmaker for about thirty years and am still very appreciative by how much one can learn from other tradesmen.
I am drawing up plans for an 844 square foot detached garage/workshop behind my house. As much as I would like to use a hydronic system to heat it that is too expensive for my budget. I would appreciate any suggestions from any of you who have come up with good, economical solutions to heat a shop. I cannot use a wood burning stove as they are no longer allowed in our area.
I live in Northern California and do have natural gas available. The structure will be fully insulated.
Thank you,
Jim
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Replies
Hi Jim Welcome to the forum,
As of now I'm using a gas type hanging space heater to heat my garage workshop, it's around 33k BTU for 720 sq feet. It's a low profile type (12" high) with a 3" forced vent. The only thing I don't like about is it blows the dust around little, otherwise it's automatic and I leave it on all winter, Indiana you know. In the next shop I'm looking in to an air handler with filters with heat and air, the hot water system in the floor though does sound like a good idea.
Paul
Hi, Jim. Have you considered the units that are used in Motels? You would have both heat and AC in one unit. A shop your size may require 2 units, but I've heard they're about $2,000 each. At one time I had considered a mobile home furnace, too.
Hi Larry, I was confused by the name Jim in the post, my name is Paul, are you looking for Jim?
Paul
Larry, Now that you bring it up I realised I was confused by the name Paul. But I was not confused by the name Jim. Are you looking for Fred?
Tom
Edited 9/4/2002 3:11:30 PM ET by IronDog
Hey Tom, isn't Fred is looking for you.
Paul
Hi Paul,
I saw Fred the other day at Elmer's corner store. He says Hi.
He was going fishing with Vern.
Hasta la vista! ;-)
Tom
Tom,
I'm glad you guys hooked up (really laughing here).
Have a good one, Paul
Larry,
I have installed a few of those electric units that have heat and AC in residential remodels that I have done. I had not considered using them for the shop as they strike me as being fairly expensive to operate. We have only installed them in rooms that would be used only occasionally or where there was really no other alternative.
Air conditioning might be nice sometimes, though our weather is pretty moderate here in the San Francisco Bay area, so I guess that probably won't happen.
Thanks,
Jim
I
Sorry Jim, but I have no alternative solution for you. I put hot water radient heat in my cast slab and have no regrets. Sure it cost a bundle, but my feet are warm, the dog loves it, spilled and tracked in water dries quickly, there are no cold spots, the shop is warm again minutes after closing the overhead door for loading, no heat registers to clean or keep clear, etc.........the list goes on and I've already forgotten the money it took to buy the system.
Do it, your bones will love you.
Jeff,
I know that it has to be the best way to go. I was given a rough quote of $10,000-$13,000 to put the system in. Seesm like an awful lot. I may get a couple more quotes and give it some more thought.
Thanks,
Jim
Jim,
What are the problems associated with a wood-burning stove? I'm just curious.
Lenny,
Around here we are no longer allowed to build wood burning fireplaces in new homes or additions due to the pollution they cause. I am not sure about the newer more pollution free wood stoves, so I will check on that.
Jim
Jim:
I too live in No. Calif. Most communities will allow the new wood/pellet stoves. Tub Makers in Berkeley can give you more info. Sorry, I don't have their number, but they are listed.
Also, take a look at infra red heaters. I am about to install one or two in my shop. I am tired of numb fingers and being able to see my breath. You can get either natural gas or electric. I am going electric to make install easier, maintenance easier, and I will eventually hook up to photovoltaic cells (bye-bye PG&E!)
Michael
Jim, a couple of thoughts here. First of all, if the more advanced woodburners are within code and you start seriously considering one, I'd recommend the pellet stoves. I have a woodburning stove, which I'm ever-so-thankful for, but if I could afford it I'd definitely go for the pellet stove. It "feeds itself" so you don't need to take time out to stoke it!
Methods of heating differ in the amount of moisture they put into, or take out of, the ambient air. Something to take into consideration when storing wood. Since I'm in the Great (Damp) Northwest, the woodstove is the method of choice because it serves as an inexpensive dehumidifier while it's heating. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
$10-13K for in-floor heat sounds like a very high quote to me. You ought to get that refined and shop it around. Look for a contractor who will let you install the flexible tubing in the slab-- it's a no-brainer but takes a fair amount of time. For that matter, if you don't need a plumbing contractor, the entire installation is not beyond the capability of a competent homeowner DIYer. Check it out for sure before you reject it.
Thank you to everyone. What a great forum. You have given me much to consider.
All the best,
Jim
Jim,
I would look into a gas fired Modine heater..possibly used. You would not need very much heat given No. CA. It's hard to do a heat takeoff form 3000 miles away but i wuld assume 10-15, thousand BTU's would do it. I just got finished putting a filter from the big box stores behind my blower which will trap the dust ...made the box form scraps. Good luck with whatever you deicde
I agree with Jim ( about # 12 in responce to your # 5). The quote IS high especially when the cost of material is about 2 grand. I am in the process of building a seperate (from the house) shop. Definitely want hydronic heating. Easy for you to do it yourself. Plenty of info on the web with instructions. I live in Western North Carolina so I believe our climate situations are the same.
Be careful about what type finish you use if you resort to some type of flame heat. I don't like forced air because no matter how much you clean the dust still travels. Can ruin a finish.
Al
What about propane?
Here near Houston, I rarely have to heat my shop, but when I do, I use a $40 infrared propane heater unit that mounts on top of a 5 gallon propane can. I had to use two 5 gallons cans of propane last winter. That just gets it up to temperature then I turn it off when I'm in the shop working. There are propane wall heaters available that are 'vent less'. i.e. they do not cause a build up of carbon monoxide gas.
Or, you could get a forced air propane unit that that suspends from the ceiling. Those kind will require a vent pipe.
Is electric resistance heating out of the question?
PlaneWood by Mike_in_Katy
PlaneWood
Propane is certainly an option, but since I can run the gas line in myself, I am leaning towards natural gas. I would be concerned about the carbon monoxide just using an unvented propane heater.
I have used electric resistance heaters for the last thirty years, but electricity is getting pretty expensive around here and I would like a better system.
Lots to think about. Thank you for your help.
Jim
I have a direct vent Monitor furnace (kerosene) which I pulled from my home in Maine to heat the shop. The combustion chamber is sealed so no worries about a fire or CO2.
However since you have access to gas, another company which is also very good is Rinnai. Check out their link.
http://www.rinnaina.com/Main_Frames.htm
Jim:
I have a shop aproximately same sq. footage. Fortunately have 1/2 basement for wood rack and storage. I tried electric heaters but too costly as I am in the shop a lot. I went to kerosene and heated nicely but the smell drove me crazy and the price of kerosene here in Ga. is outrageous. Ahhhh.. I had a 1/2 gas pipe running across shop to a fireplace starter. I tapped into and added a gas space heater found 40% off in summer season. Gas is less expensive this area than options. Some of the more expensive systems are fantastic but I could use the difference in money out-lay for a whole lot of better suited purposes. I have seen heated floor that previous poster mentioned.. I love it.. Just to expensive my case.
I have not regretted the gas space saver. Be cautious with sawdust and finish fumes with any heater. Vacuum out frequently and I made a cover for warmer months from a cotton paint tarp I cut and sewed with nylon fishing line. Then reinforced with duct tape along seams. It would be a wise move to get a carbon-monoxide sensor $30-$40 as a extra pre-caution. You don't mess with the Lone Ranger and best to be a little over-precautious with CM also..
Good luck and Keep Warm..
Sarge.
Jim...
I went through exactly the same conundrum when I built my 30x30 shop a few years ago. Wanted the hot water radiant but the costs were just too much for my budget. I finally decided on a overhead gas radiant heater by these folks. http://www.easyradiantworks.com/ezdoz.htm
The unit I used was the straight 40k btu. lp gas version and it does a terrific job. I was really surprised at the gas usage only averaging less than 9-10 gal. of lp gas/mo. especially living here in Libby, Mt. with our long winters! Glen, the owner at EZ Radiant is a very nice guy and will answer any and all questions you might have. Three years ago the unit ran me about $500 including shipping from their facility in Canada which beat the hell out of all the mfr's in the states. They have both natural and lp models as well.
Might want to check em' out!
Jon
"Knot's to you"
http://www.wood-workers.com/~jonweis
Jim,
I have a 672 ft. sq. shop, attached to my house, well insulated, concrete slab. I used hydronic heat, natural gas powered. After two winters in upstate New York, it has exceeded all my expectations. I don't know the exact cost, since it was a part of the overall building contract, but the contractor said that it was slightly more than forced warm air and less than hot water radiators. The components are the PEX tubing, a small manifold, a 40 gallon domestic water heater, a small pump, and an expansion tank. There were 8 man days labor involved. If the plumber charged $60 per hour, that's about $3840 plus materials.
Keep in mind the efficiency of such a system. I have tried to determine the additional fuel consumption, and with variations in weather, I have actually used slightly fewer cubic feet of gas than before the system was installed. Obviously, I haven't invented the perpetual motion machine, but it is quite evident to me that there is very low gas consumption.
Go for it!
Regards,
Bob Powers
Here's a solution. Move. I can't believe that someone would tell you that you can't burn wood. I guess thats why they call it the left coast, it's certainly not right!!
My first thought when I read "can't burn wood", another way to prevent folks from using trees. Send those people a corn cob!
I once spent a couple of weeks in a condo in the BC rockies. Above the fireplace there was a red light and a green light. The red light meant you could not burn wood in the fireplace. The entire time we were there, the green light never came on.
I don't think Tracy CA allows wood fires either. All their track homes there come with gas fireplaces. Lotsa places like that now.
PlaneWood by Mike_in_KatyPlaneWood
I hate to throw a monkey wrench into the gears, but has anyone considered what happens to the tubing in a hydronic system set in a slab if/when the concrete cracks or settles? One can usually prevent settling through proper site prep, but not always. I don't think I've ever seen a slab that didn't develop cracks in time.
Jeff
> ...has anyone considered what happens to the tubing in a hydronic system set in a slab if/when the concrete cracks or settles?
Jeff -
Concrete cracks for two (primary) reasons - Shrinkage and settlement.
Shrinkage is virtually impossible to eliminate since it's due to the evaporation of the water in the concrete. Much the same as with wood only much less for given thickness or area, of course. Shrinkage cracks can be mitigated through proper use of control joints. The intent of control joints being to localize shrinkage cracks along predetermined lines. The amount of water in the concrete beyond that required for proper hydration of the cement also affects shrinkage; the more water, the more shrinkage. Unfortunately limiting the amount of water to the mix to that required for hydration makes for a very stiff and hard to work material. So there has to be some compromise made there.
I don't think, and I stress "think" the amount of shrinkage is enough to damage the kind of tubing used for in-slab hydronic heating systems since it appears somewhat elastic. The bigger factor would be setlement.
The safest bet here is to properly reinforce the slab so if there is localized settlement the slab can bridge it. Commonly used reinforcement in floor slabs is welded wire mesh, 10ga, with 6" x 6" spacing of the wires. This is pretty much worthless in my opinion. I've seen slabs demoed out of buildings where the mesh was lying on the ground and in some cases exposed on the underside. Better, again in my opinion, would be to use standard 3/8" reinforcing bar spaced 12"oc which can be "chaired" with small block such that it ends up being in the center of the slab where the reinforcing belongs. Wire mesh is much harder to control in order to get it where it should be.
Given a properly reinforced slab and control joints located on 20' x 20' max centers, I don't think there should be any problem with in-floor hydronic heating. At least I hope not since that's how I intend to build my shop floor.
Dennis in Bellevue WA
[email protected]
Dennis,
I think you are on the right track. I had much difficulty finding somebody who really understood proper procedures for installing a hydronic heating system in a concrete slab. I, too, had questions about the possibility of settling, shrinking, etc. I was assured that in the unlikely event of a leak after the concrete hardened that there was a procedure for dealing with it. The use some sort of infra-red heat detector to spot the leak, dig out the surrounding concrete, cut the leaky spot out and use standard connectors to repair it. It doesn't sound easy, but it does sound logical.
At any rate, after two years, I have had no leaks, no cracks, no settling. I also have no expansion joints in my 24X28 foot 4" thick slab.
The installation was as follows:
1. Put down several inches of crushed stone.
2. Out down 2" pink styrofoam over the crushed stone.
3. Put down 4" of pink styrofoam on the inside of the foundation wall. I don't know how far down it went.
4. Install 6X6" mesh over the styrofoam. Attach PEX tubing to the mesh with tie-wraps. The PEX was in two zones, each succeeding strip about 8" from the next one.
5. Pour the concrete. As the concrete was being poured, a man with a rod with a hook on the end pulled the mesh off the styrofoam so that some of the aggregate got under the mesh, suspending it roughly 1 or 2 inches above the styrofoam.
As I say, two years later and all's well.
Regards,
Bob
Hi Bob -
WW mesh works if, as in your case, they take the trouble to lift it off the bottom. It's a lot easier to install than standard rebar, that's for sure - I've done both. The back paid for it the next day after the rebar job (grin).
Here in the Pacific NW we have a very real problem with underground moisture. While the insulation board serves as a vapor barrier, true, crushed rock doesn't provide very good drainage so in my case I'll be using 3/4- gravel instead. I'll probably put the perimeter insulation board on the outside of the foundation wall instead of between the slab and the wall since in my case I've got a 3' retaining wall situation on two sides of the structure.
Sounds like you got a quality installation, Bob. You shouldn't have any problems. But in the unlikely event you do, if they have to tear out a patch of concrete be sure to insist that they saw cut ~1" deep around the area to be removed to create a clean joint between the old & new slab patch.
Dennis in Bellevue WA
[email protected]
Now that you remind me, the contractor installed styrofoam on both the inside and the outside of the foundation, then parged the exterior wall so that the 6-8" exposed looks like stucco. I am also reminded that there is a layer of polyethylene between the styrofoam and the crushed stone.
I am fortunate that we have no drainage problem in that we live on an alluvial plain and have about ten feet of sandy soil under our property, the product of one of those rivers left when the seas receded from Upstate New York and before the glaciers left our Finger Lakes.
i'm currently in almost the identical situation, but the 4-car/ 850 sq ft garage was already built so in-floor systems were never an option. the climate here in western north carolina might be similar to yours.
after weighing the costs of pulling natural gas from the house line ($1000) against having new 200 amp service buried from the pole out back ($0, which the shop will need anyway and might be able to get 3 phase at no extra charge), i've decided on an electric heat pump w/ 2 ton air conditioner unit. comparing the size of the space to the house, it should cost only about $25- $35/mo to operate. it will run about $6,000, installed. the ac will also serve as a dehumidifier in the summer. NOW IF I CAN ONLY GET A G**D*** CONTRACTOR TO CALL ME BACK!!!!
depends on the cost of power in your area whether or not this might work for you.
mitch
I heat my shop with a couple of old radiators I pulled out of my house. They get the hot water from the house furnace. My house was over-radiatored so I could spare them. I put one on each side of the garage door and ran copper pipes around the the three walls to connect them. It works great. I insulated my shop very well with fiberglass between the studs and foam board over that.
Jim,
There have been many good suggestions here. I have gone through this myself and done lots of back and forth. I have found that if you have ceiling height the cheapest (btus per dollar over time) is a hanging unit heater running on natural gas (certainly gas is cheaper in my area - you'll know for your area). You need a good ceiling height so the unit will neither eat up your available space nor be so close as to be a hazard. The units are available through Grainger, but I suggest you have a heating company size the btus for your space, window surface area, doors, insulation, etc.. Do blow the thing out regularly.
Of course if your space is divided in smaller rooms you'll not get good circulation.
Direct vent counterflow units seem to be a logical choice, but I've found that they are rather pricey (even coming close to the cost of forced air) and don't heat a larger space as they only heat from one source on the floor.
Many people balk at the idea, but forced air works quite well in a shop if the system is designed properly with adequate numbers and locations of registers and air returns. When a system is well designed it will be bery comfortable and not "blow" the shop around at all. Go with a sealed combustion unit (maybe even a two stage) and I'd save the money and only get an 80% unit, not a 90+% (unless your local utility gives you a rebate as many do for the super high effeciency units). Also, get a crate of cheap filters (certainly not the HEPA 3M ones) and replace them weekly if you making lots of dust. If you're not in the shop regularly then let them slide a while.
Propane? Why? You've got natural gas. It's easier and there
Wood burning stove? Very romantic but not practical for colder weather. Overnight glue ups can be a disaster and do you want to bring your finishes in the house everynight?
Yeh, radiant flooring is nice, but you can get the place totally usable for a quarter the money for installation and the unit and probably beat the utility bill too.
That's my two cents worth.
Good luck.
Seth
mistake. There is no win
and there is no fail . . . there is only
make."
John Cage
I thought he said that he did NOT have natural gas. If you got it, USE IT! Lot cheaper than propane. Of course, I own some oil co. stock, so what else would I say?
PlaneWood by Mike_in_KatyPlaneWood
Seth,
It sounds like you've got all the options identified. If you want a rough estimate of BTU's needed for space, assuming a normal insulation (eg. r15 in walls, r25 in ceiling)..here are the numers I used many years ago out here in the CT area.
7 BTU's loss for every square foot of wall space
9 BTU's.........................................ceiling, assuming one stroy building
80 BTU's for every square foot of glass.
the last measurment is air exchanges in the room, usually around 1.5 to 2, which means you multiply your totals by 1.5 to 2
Hey Jim. I have often wondered why California just doesn't outlaw forest fires :).
But to your ?. I live in Southern Va. We don't have too many cold days, but it does snow and the temp drops to then teens every year. So when I was setting up my shop, (600 sq ft) the best thing I did was insulate. I found that two small electric space heaters running for maybe an hour even on the coldest mornings was sufficient to get me going. Then body heat and machining heat took care of the rest. Gluing was more of an issue, so when I had assembly work I would place the pieces and the glue in front of the space heaters for a while.
For dust control I bought a jet dust collector and equipped it with a 5 mu bag. This allows me to discharge the collector into the shop so there is no heat loss from that source.
I also keep a dehumidifier going. That has eliminated the need for rust prevention. The biggest disadvantage is that I keep the shop closed up all the time unless the outside RH is less than 50% so it does get stuffy at times.
This works for me and it's cheap.
Dave
You might want to get the current issue of WOOD magazine. They have a good article about heating the shop. Rightly, they warn strongly against open flame heaters and electric units with exposed radiant heating elements. Use a system that has shielded electric elements or, if gas powered, chose a system that uses outside air for combustion rather than shop air.
With propane, a system that uses shop air will also produce great quantities of water vapor as part of the combustion process. This water vapor will contribute quite a bit to machine rusting.
Having recently spent two weeks in July in Dublin, CA, coming from the midwest I must admit I was surprised at how cold it can be at night with that continuos wind and zero humidity. Anyway, I don't know how far north you are located or how cold it can be in the winter, but I would probably insulate the walls with fiberglass insulation (R-11 or up) and possibly consider a unit heater. That would be a gas fired heater suspended from your shop ceiling. It would probably be cheaper than a full furnace but still very effective. Unit heaters are pretty common here in the midwest and they work great. I have found that lights and machines in the shop once up and running give off a fair amount of heat too so, with insulated walls, my heater would be off most of the time.
Good luck with your new shop!
In my earlier reply I said that labor to install my hydronic heating system was 8 man days. Turns out that included installing a sink with hot and cold water, water and gas for future washer/dryer, and roof vent, so labor for heating system was more like 4 1/2 days.
Since others have mentioned it, the average body creates 300 BTU's per hour, that's about 75 calories. If you shiver you double that amount. Have you thought about inviting over friends and showing scary movies...lol.
Bob,
Thank you for the update on the time involved in your hydronic heating project. I have been checking into what the materials would run on a website since so many people are so positive about the hydronic system.
It looks to me like the materials will run between $1500 and $1800 (including the hot water heater). If I can handle the installation, which looks likely. that may be my best bet. I will only have 8-9' ceilings so hanging a gas heaters may not work all that well. I am also still considering a direct vent gas heater.
I am very appreciative of how helpful everyone has been.
Thanks again,
Jim
You are most welcome to the info.
I have a couple of other suggestions if you intend to use hydronic heating in a concrete slab. I had the mason contractor make the finish as smooth as possible, unlike many who prefer a granular surface. I then sealed it with two coats of latex sealer and two coats of industrial liquid wax. I have had no trouble with traction when hand planing, etc. The smooth surface makes it very easy to keep clean. Some suggested to me that I would slip and slide, but I wear sneakers in the shop and have no problems that way. Best of luck in your project.
I would also suggest that you pressurize your tubing before you pour the concrete, in case of leaks. (Pardon me if I suggest the obvious.)
By the way, I think your estimate of materials for your project is quite accurate.
This has been an interesting topic, but I have noticed that what tempatures your shops are being kept at has been left out, and if the heat is constant or only while you are working in the shop. I'm curious of what balances are being met between comfort zones and the monthly bills for fuel.
Don
I'm in Anchorage Alaska. My building (shop, display, office) is 3400 sq. ft. I keep it a various temps during the heating months (most of the year) with all areas comfortable 24 hours a day. My average gas bill is about $50. Not bad I think. I have hydronic heat througout the building which is very well insulated. The old space I used to rent (1500 sq. feet) had neighbors on three sides so was also "insulated well." The gas bill there was nearly $70/mo. with cieling hung gas fired unit heaters.
By the way, at the old shop, the unit heaters did the job very well although I found that cieling fans were essential. I don't have any cieling fans in the new building.
In my Ct shop which is 700 SF I have a ceiling hung gas Modine heater. I leave the heat on 50 F when I am not in the shop and turn it up when I work. I am in the shop 3+ days in the winter and the I estimate the gas bill about $25-30 dollars. Also ceiling fans are a must set on low speed to move the warm air around, the shop has a 11 foot ceiling.
MikeD
Don,
I keep the heat in my shop at about 62 degrees in the cooler seasons. I had been told that radiant heat systems enable you to be comfortable at lower temperatures than convection systems. I find this to be true, although I have no idea why. I turn the heat completely off from early June to late September, since the insulation in the building seems to keep things comfortable. I installed a 24 inch fan in the gable end of the shop which I turn on if it gets too warm.
I don't know what the heating costs are, but my natural gas consumption has changed so little that I can't tell whether differences come from heating the shop or outside temperature changes. A not very precise indicator of fuel consumption comes from observation of the hot water heater that heats the shop. It is a direct-vent 40 gallon domestic water heater with a small blower, located in the basement of my house. I virtually never hear it running when I am in the basement. Once you get that 24' X 28' X 4" concrete radiator warmed up, it doesn't take much to keep it there.
Regards,
Bob
I appreciate the temp. information. My shop has been a detached 2 1/2 car garage at a house a I bought to renovate, but last week I accepted an offer on the house. I found a 25x40 cinder block ex-warehouse, but the roofceiling is 16 foot. It currently has the suspended Modine gas heater, but the height has me worried about heating a lot of empty space and the price of gas here has skyrocketed in the last year. My delema which has forced me to consider this building is my spray booth. Albeit small, this creates zoninginsurance problems outside of industrial zoning. Industrial zone leasing for anything worth while begins around $20 a square foot which is just out of the question. I have a feeling I'll be working in around 50 deg. temps this winter. thanks again.
Don
I posted early in the topic that I was using a gas hanging space heater low profile type (33k BTU) made by Armstrong in a 24'x30' shop with a insulated two car overhead door. Don C. asked about shop temperature, I keep my shop around 65 to 68 f deg. in the winter, that's about right for me.
Paul
very interesting topic indeed. those of us that don't have dedicated space yet just love to read about it and plan (dream). one thing that's always concerned me, though, is what kind of toll does the temp rising and falling (for those of you that don't heat 24/7) take on your tools? how about your wood supply? i would think the extra money spent on keeping it in the ballpark would pay off in other ways than comfort. i'm in wisconsin, and winters can be less than forgiving, although we've had it pretty mild lately.
Hi,
I think it is a given that in floor radiant heat is the best way to go if you can afford it. This company will sell you everything you need and do the system planning for you as well.
http://www.radiantec.com/
If you have high ceilings it certainly keeps the heat near the floor.
But no matter what system you choose it is a good idea to plan for some ceiling fans to circulate the air and get the warm air off the ceiling if it is high.
I have ofter wondered how well hanging radiant heaters work.
They supposedly heat objects and not air.
Does that mean the air temp could be quite cool but a piece of wood that you need to glue up would be warm?
Would be interested to know if anyone uses one of those!
Thanks,
Tom
I can't believe how many times I've heard "it heats objects not air" or something similar! Heat is heat when it leaves the heating appliance, period. What are these "object heating" people saying? Do they have some kind of heat-beam that directs the heat only at objects - skipping the surrounding air all together? Get real.
Having said that - Hydronic heating works so well for one of many reasons - it heats a concrete slab which gives up it's BTU's slower than air. So it REALLY is heating an object by inherent design. Put that in your pipe an smoke it.
Radient heat transfer is real. It can be measured, calculated, and felt. If you doubt that then you've probably lived your entire life in a cave and never felt the sunlight on your skin.
Obviously you've lived your pathetic little life without having the common courtesy to READ and COMPREHEND the written word. My post SUPPORTED the radiant properties of materials that store and give up their stored energy. My post DIDN'T support those marketing types that say their products heat objects (like a table saw, wood, plane, etc.) over the air between the source and the object.
"Do they have some kind of heat-beam that directs the heat only at objects - skipping the surrounding air all together? Get real."
Radiant heat transfer does indeed affect only the object radiated upon. It does not rely on the surrounding air as does convected heat transfer. Thus my reference to the sun. (There is no air between the earth's atmosphere and the sun.)
In a building heated by hot water pipes buried in a concrete slab there will be multiple forms of heat transfer. The hot water convects heat to the inner wall of the pipe. The pipe material conducts the heat through it to the outer wall where heat is again convected to the surrounding concrete. There a combination of radiant, convection, and conduction that gets the heat through the concrete to the surface where it is both convected to the air and radiates to any object in sight. If there were no air in the shop, the surrounding objects would be warmed anyway (although slower). Now, I do not contend that radiant heat transfer is the main method at work here, but it does exist and can be calculated.
Sorry if I was a bit testy in my first reply, but your "get real" got to me.
No sweat! I just have never heard a satisfactory explanation to the "object/air" thing. There are sooooo many factors involved in heat gain/loss that it's easy for the "salesmen" to find some way to sell their product.
I'm just jealous of the guys that do have hydronic heat!
> ...I can't believe how many times I've heard "it heats objects not air" or something similar! Heat is heat when it leaves the heating appliance, period.
Not really;
The human body is a heat radiator in any situation where the surrounding envirionment is lower than the normal human body temperature. Meaning you, your body, radiate heat to the surrounding object in your shop and your home. Sit next to a window (closed, of course) on a cold day. If your right side is next to the window it will soon feel the chill while your left side will remain warmer.
Raise the temperature of the surrounding walls, floor and/or ceiling and the amount of body heat lost to these surfaces goes down. You can actually feel more comfortable in a fully radiant heated space at a lower *air* temperature than you can in a space with cold walls, ceiling and floors in spite of a higer *air* temperature.
Dennis in Bellevue WA
[email protected]
Aha!
So some of you have actually used radiant heat sources and found that it works?
It is definitely a mysterious phenomena. How do those photons (which according to physics have no mass!) actually cross 93 million miles of cold space from the sun and bring us heat and light???
Incredible.
Now I guess the next question is more down to earth. ;-)
Is it cheaper and more efficient to use a radiant heat source instead of a big hanging gas blower?
BTW- you can often see these radiant tube heaters hanging up in the ceiling near the exit at your local Home Depot ( assuming you don't live in florida).
> ....Is it cheaper and more efficient to use a radiant heat source instead of a big hanging gas blower?
I'm not a heating/vent engineer so take comments with a grain of salt.
I'm currently in the process of getting info on changing out the heating system in a new (to me) home. First cost for hydronic heating (floor coils and radiators) appears to be quite high. Operating costs (propane in my case) appear lower. Some of the first cost is, in this case, due to working on an existing structure. New construction would be less.
For new shop construction -
I've priced PEX tubing on the web - 1000ft coils can be had in the $500-$600 range. It's not that difficult to install especially in a new concrete slab. Heating water to circulate trough the coils allows several options: gas, propane or natural; wood; electricity (suspect this would be relatively expensive). A simple waterjacketed wood stove would serve quite well in my area. Also considering solar.
Depending on your talents re: scrounging, one might locate some old cast iron radiators in the scrap pile at some building demo site. I have two in my basement office (otherwise unheated) that are heated by a home made coil in my basement fire place.
I personally feel that hot water heating offers many options for fuel (heat source). But I like to tinker with this kind of stuff.
Dennis in Bellevue WA
[email protected]
I'm not too sure about heating with wood, because it seems to imply that the heating would be sporadic. That is...heat in the morning to take the chill off, sort of thing. If so, then hydronic probably isn't the way to go. There is a definate lag time between turning up the thermostat and feeling warmer. Once temp. has been reached, one should resist touching the thermostat at all. The beauty of hydronic is the consistency one gets. I don't use a set-back thermostat because I don't think it would save me any gas costs.
I haven't done any studies but I believe that my hydronic system costs less to operate than unit heaters. The comfort it affords me is something I realize all winter. To me, the initial cost was worth it.
The only downside to hydronic that I've encountered is that one can't go drilling holes into the slab willy-nilly to bolt down machinery.
I can't answer all your questions, but have a few thoughts about hydronic heat.
1. It's nice to walk into my shop on a cold winter's day in my sock feet.
2. I suspect that gas convection heaters inject a lot of moisture into the room. When my heating system is operating, relative humidity runs around 23%-25%. Makes for dry wood.
3. Although I have dust collection, a few operations create dust that doesn't get collected. Hydronic heat doesn't blow it around. I just turn on my 24" fan for a few minutes and blow it into the neighborhood.
4. One of life's pleasures is silence.
5. I still don't know how much it costs me to operate my shop heat, since one gas meter serves my house and my shop, but the difference since I added the shop isn't great enough to noticeably reflect in my heating bills. I am sure there's a difference, but not much. The rest of the house uses a forced warm air system.
6. There are those who suggested to me that hydronic heat by nature is slow to warm up and slow to cool down. True. Once you get a room such as my 24X28 shop up to temperature (about 24 hours), leave the thermostat alone. Don't set it back at night. If I have warm days during the heating season, I have other devices I use to cool things down. They are called windows.
7. Don't use a boiler. Use a domestic hot water heater as your source of heat. Mine is set to come on when the water temperature drops to 110 degrees, and turns off at 120 degrees.
These are just a few of the less obvious advantages to hydronic systems. (Are all warm water systems, tubes-in-slab or radiators, called hydronic? I am speaking only of tubes-in-slabs. In case you wondered, I like my heating system.
Regards,
Bob
"7. Don't use a boiler. Use a domestic hot water heater as your source of heat. Mine is set to come on when the water temperature drops to 110 degrees, and turns off at 120 degrees."
Bob, is that a 40 gal. water heater, about 40K BTU?
Paul
Paul,
Yes, it's a 40 gallon heater, 50,000 BTU Powerflex made by American Water Heater Co., Johnson City , Tennessee, 37601. There are also an Amtrol Model 30 Expansion Tank, a small circulation pump about the size of my fist whose name I can't read, a temperature gauge and a pressure gauge. Pretty simple stuff.
The are two zones of PEX tubing.
Regards,
Bob
I've used a gas radiant heater in my 900 s/f shop for the last 3 years and really like it. It's on an insulated slab and the walls are 6" Sip (structural insulated panels). The ceiling is a 10' cathedral with 8' side walls and insulated to r39. As in my earlier post in this thread I average less than 10 gal of propane per month during the heating season which here in Mt. runs from the first of Nov. to the end of April. I have the thermostat set at 65 deg and that's exactly what the air temp stays at basically year round. In summer the shop seldom get's any warmer than about 70-75 deg even when it's at or close to 100 outside! As long as I keep the low-e windows closed. Gotta love those sip panels and the high insulation they provide.
As far as the radiant properties of the heater, all the objects in the shop absorb the radiant heat and in turn I guess you could say they heat the air as well. If you stand directly under the heater while it's running (which isn't really very often) you do feel the warmth from the heater but there are really no cold or hot spots anywhere in the shop and all the objects around the shop feel the same as in the summer when the heat's not running. I like it mainly because it's very clean and even heat plus the fact that it's a sealed burner that uses external combustion air and also exhausts to the outside, hense no dust worries. Just an occational blast from the air hose blows any accumulated dust from the top side of the reflector of the unit. Now I'm no heating expert but I dam well know when I like something and this unit has met and exceeded all my expectations.
There are some pictures of my setup in the "changes to the shop" portion of my web site. The pic's of the heater aren't that great but it may help to visulize what I am talking about.
Jon
"Knot's to you"
http://www.wood-workers.com/~jonweis
Jon,
Thanks for the good report!
Very good description of how it feels, which is the most important criteria.
I think I'll look into changing my big blower unit to a gas tube infrared.
Regards,
Tom
Here's the url to the outfit that I got mine from. Their in Ontario, Ca. and super folks to deal with. I got the 40k btu straight unit and it ran about $5-550 delivered to Mt. Probably a little higher now I would suspect but they were much lower than any I could find stateside!
http://www.easyradiantworks.com/default.html
Jon
"Knot's to you"
http://www.wood-workers.com/~jonweis
Maybe I missed it, but didn't see a response to tschmaling's question in #41:
I'm especially interested in the effect on lumber. Any responses??forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Within the temperature range your shop is likely to experience, I don't think you'll get any observable effect.
The time it takes for moisture to diffuse into and out of wood means you're also unlikely to see any effect from daily changes in relative humidity, except maybe in veneer.
thanks, forrest_girl. i've been watching waiting for a response, but thought it just got lost.
if i'm heating my shop from freezing (or below) to something comfortable just to let it cool back down every night, i would think there would be some change... but then again, my gut feeling is hardly scientific. all of the reading i've done about wood movement has got me almost too paranoid about the topic.
I remember your question awhile back, way back there ... I keep the heat on all winter, I was getting condensation on all metal parts in the shop during warm up so it was better to keep the heat on, and I was starting to store finishes out in the shop that could freeze. As far as wood goes, yes you are better off with your shop at a constant temperature. I keep my shop around 68 deg., in the winter.
Paul
Edited 9/3/2002 5:39:24 PM ET by PAULGEER1
With regard to your tools, I think it's the cooling off that causes problems -- condensation onto the surface. That's where keeping the tablesaw, jointer bed, etc., clean and waxed is important. For hand tools, some people who's shops really go through extremes daily, or are just plain cold and damp, keep their hand tools in a cabinet warmed somewhat by a lightbulb or whatever.
Brother! I'm not looking forward to winter. Lows tonight are in the high 40's and it's barely September. whine whine Thank heavens for the wood stove!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Jim,
I recently put in a radiant system in an addition to my house. It would be the perfect solution for a shop. I also ran the system from a conventional hot water heater. The system I used was Onix by Watts Radiant, check out their site, wattsradiant.com. In my case I installed the tubing and water heater and had my plumber do all of the manifold work. In my case the material cost for the system was under $800 including the water heater, my guess is you are looking at $1,000 - 1,200. If you contact the manufacturer their engineering group will design the system for you and let you know if a water heater will give you enough heating capacity to handle the shop. You can also purchase the materials from one of their local distributors so all you are in for, with your plumber, is time.
I am not sure but I would bet that there is an article about installing radiant slab systems in Fine Homebuilding.
Good luck with your new shop.
Michael Blutt
I assume that many of us have our "shop" in the garage or basement and share space with the washer and dryer.
Is it an option to use the dryer exhaust as a supplemental source of heat? Are there any concerns with the humidity produced?
Just wondering?
RR
> Is it an option to use the dryer exhaust as a supplemental source of heat? Are there any concerns with the humidity produced?
Well, woodworking environment aside, I bought a silly little device once that wa supposed to let you exhaust your dryer into the interior thus saving money (read capture the dyring heat indoors). Every window in the basement looked like someone had hosed them down with a garden hose by the time the clothes were dry (grin) .... well, maybe not *that* bad but certainly there was enough moisture in the air by the end of the drying cycle that any raw cast iron in the vicinity would have surely taken on a lovely shade of burnt umber.
Guess what I'm saying is .... I wouldn't do it myself.
But that's not to rule out some sort of efficient heat exchanger that might work without the humidity problem.
Dennis in Bellevue WA
[email protected]
It also depends on where you live. In a dry climate, the air in the house can get painfully dry in the winter. I've known people who vented their dryers inside in the winter and welcomed the moisture.
If you wake up in the morning with a stuffed up nose and it's so dry you can't get it cleared out till after you shower, you may be a candidate for indoor venting.