Best Heat for my Shop ? HELP

OK, I justput up a 40X56X12 ft sidewall shop. Now it is time for the heat and cement work. I had my mind set on radiant floor heat because of it efficency. But after speaking with my heatin/cooling guy I am thinking twice about it. He said that it is efficient IF you keep it turned up all the time and work in it 8 hrs a day. But he also told me the recovery time for it , is a long time. He is telling me to think about it, as I won't be out there everyday. In houses I guess it is efficient. But he brought up the point of heating it all the time vs turning on another type of heat for 3 times a week. Then what do you think is more "efficient" ? I am just wondering what you guys find as in personal prefences and what you find "efficient" for the person that will be out in his shop an average of 3-4 times a week ? Or maybe called a classic tinker shop. I think he is trying to push me into forced air because of the recovery time and the amount of time I will spend out in it. What do you think ? Thanks, Iowa883

If it was me I'd use a couple of blue-flame propane units that hang on the wall, and maybe a woodstove. Or maybe both.... The propane to heat the air quickly and the woodstove for radiant heat in case you're going to be in there for a long period.
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But find out if your insurance will cover you if you have a wood burning stove. One of the guys at work was all ready to install a woodburner in his shop. The insturance agent was looking over his shop and said if he installed a woodburning stove then the company would not cover him. He then called around and found his premium went through the roof (when he finally found a company to cover him. This is in the midwest, so it may be different by you.
Just a thought.....

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This is really something you'll have to answer for yourself. Ie: how cold does it get? How often will you use it? Would several hours of preheat to working temperatures be a PITA? What temperatures can you tolerate while working? Do you want T-shirt and shorts working temperatures? Do the things you're working on/with need to be heated?
Etc.
He's right. Slab heating is _slow_. So, if you expect it to be _warm_, unless you're willing to keep the thing turned on all the time, or _long_ pre-heat delays, you're not going to be very happy with it.
The best unit for walking in, turning on the heat, and being comfortable almost instantly is ceiling radiant IR heaters. Especially gas-powered (for economy of operation).
IR heaters don't warm the air. They warm the solid objects they impinge upon (especially _you_) up quickly.
They "feel" a little funny - the air can be quite cold, but you're just fine.
If IR radiant doesn't do the trick for you, forced-air is the best. One of the most expensive to install, but much cheaper to operate for getting warm quickly than slab heating.
In my shop, (32x24x8 - much smaller than yours) I have two 4800W 240V construction fan heaters (often called "cube heaters"). Brings the garage up 30C (from -25C) to useable temperatures in an hour or two, and I can sustain it with just one heater.
But my idea of "useable" is probably different than yours (I'm happy with 5-10C working temperatures most of the time). I have a small 1500W electric IR heater mounted on the ceiling near the workbench to keep _me_ warm for "I need to do this now!" jobs.
Purchase and installation of my heating equipment was _very_ cheap. Operation is _quite_ expensive, but, the duty cycle is so low the operational costs are okay.
In our area, IR radiant is very popular in repair garages, warehouses and other places that need lots of heat for working, yet have to open their doors a lot. And restaurants trying to extend their "patio season" ;-)

Forced air and a woodstove would be best. Radiant will take to long a time to recover.

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I'd vote for the forced air heat. You don't say where you are, but if it's a feeezing area, the on/off of radiant floor can, as I've had it explained to me, create a lot of stress on the heating parts inside the cement. I got to watch some of the work at our local SPCA where they used readiant floor heat. Took it over a day to get the place up to temp when it was first turned on, but it was also below zero outside with a wind. Nice, even, well-enjoyed by the animals heat now though! The kittens especially love it!
I couldn't get a run to my garage-shop, so I've settled for using a Reddy heater of 55,000 btu/hr output. Runs on kero, use about a gallon a day in coldest weather, but best of all, with the ceiling fan I put in (garage also insulated), the place heats up on no time. In the worst weather I have plenty of heat to work in less than half an hour, long before that danged steel tools warm up! <g>
Fer wat it's woit, 'nyway
Pop

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My experience from having a shop ............
Heating is not an issue unless you are in a very cold place. You can wear a coat until it warms up a bit. You can set the thermostat so that it stays 50 degrees inside, or some low temperature where it won't work a lot when you are not there, and won't have to work as hard to warm it up from say, 30 degrees. Whatever you do, when the HVAC is running, just picture yourself throwing $$ bills into a fire. Heating and cooling a shop will co$t.
Cooling is something else. I called the AC guy when mine wouldn't cool the shop. He said that in order for it to work, I would have to leave it on all the time. He said it would probably take three days for everything to cool down in the shop, as I had a lot of metal and metal machinery in there. And then, when you open the door, whoosh, you gotta start over again.
Heating and cooling a shop is an unique thing in the HVAC trade. Some shops don't generate a lot of heat. Some do. Some don't have the doors thrown open very often. Some do.
I would try to heat/cool it for a couple of hours before using it. I would check out cheap alternatives, like swamp coolers (if they work in your locale) and wood stoves. Dress for it, too.
HTH, but it is difficult to give you specific advice.

I woud buy a Monitor heater, that burns K-1 fuel oil. It has to be placed next to an exterior wall, and vents through a tube within a tube (about 4 inches wide, total). It **draws in** air from the outside, and vents back out in the tube within a tube. So, there is no "infiltration" of air.
It is oderless, safe, and very very efficient.
We have a cabin in the mountains, and it gets real cold in the wintertime, and the Monitor heater is the most efficient source of heat that we could find, after trying electric central/ baseboard heaters/ wood stoves. It would heat your shop from a cold temp, in a short time.
The model 2400 has btu rating of 43,000. Here is a link:
http://www.monitorproducts.com/index.html
I have no stock in Monitor heaters, just a happy customer.
--James--

OK Guys, I forgot to mention my area, I live in South central Iowa , with temps getting below zero . Also another thing to consider in your recommendation , is that I live on top of a hill out in rural Iowa . Does this help on your recommendations ? Please respond ASAP, As my loan on the shop needs to be wrapped up by Wednesday . Thanks so much for the replies, Iowa883 ( Hence location :-) )
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http://pages.cthome.net/edhome

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Piece of cake... See
http://users.montanadsl.net/~reysa /
NREL says 930 Btu/ft^2 of solar heat falls on a square foot of south wall on an average 24.4 F December day in Des Moines. Rotate the shop so one 56'x12' = 672 ft^2 side faces south, if needed, then apply a single layer of Dynaglas corrugated polycarbonate "solar siding" (which comes in 4'x12' sheets) over a 6" air gap with vent holes through the south wall to collect 0.9x672x930 = 562K Btu of sun on an average day.
With R20 wall and ceiling insulation and a 2240 ft^2 ceiling and 1632 ft^2 of non-south walls and heat storage under the ceiling, the air coming out of the upper vents on an average December day might have temp T (F), where 562K = 8h(70-24.4)672/R1+8h(70-24.4)1632/R20+24h(T-24.4)2240/R20, so T1 F.
If the ceiling store has an average (130+80)/2 = 105 F temp over 5 cloudy days, the shop needs 5(8h(70-24.4)2304/20+24h(105-24.4)2240/20)) = 571K Btu for 5 cloudy days in a row. This might come from 571K/(130-80) = 11,424 pounds or 178 ft^3 or a 1120ft^2x2" or 2240ft^2x1" of water in overhead flat plastic film ducts cooling from 130 to 80 F, with a slow ceiling fan and a thermostat to bring down warm air as required.
Nick

snipped-for-privacy@ece.villanova.edu wrote:
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Hi, The barn collector (referenced above) is still working well. It is starting to make the garage too warm on sunny warm days, so I plan to add the outside collector vents, and seal off at least some of the vents going to the garage soon.
There are some small (but maybe important) things I would change in the construction. I'll add these to the write up when I get some time, but briefly:
1) I would add light weight horizontal supports to the glazing at around 2.5 ft intervals -- i.e. two supports for my 8 ft panels. This would control the tendency of the glazing to bow inward or outward. When the wind blows from the North, it creates a negative pressure on the South side of the barn and causes the panels to bow out. This hasn't caused any failures, but I think over time it might. I plan to add these to mine sometime during the summer. I think that something like a 3/4 inch by 3/4 inch would be enough. Maybe painted white to reflect sun further into the collector?
2) If you can get the 4 ft wide glazing panels this is a real plus, in that it eliminates the intermediate vertical panel supports, and makes it easier to add the horz supports mentioned in 1.
3) I would use two layers of black screening for the absorber instead of one. The one bay I have that has two layers does better.
4) I am about to add the summer vent openings to keep the collecters from getting too hot during the summer when the vents to garage will be closed off. I am going to try using a couple of the cover plates that are used on outdoor electrical outlets. These can just be fliped open or closed easily, and they have foam gaskets that seal well. I will install 1 or 2 of these per 4 ft bay in the upper sill, and the same in the lower sill. I'm not sure if this will provide enough area or not -- I will add the results to the writeup.
------- I have some thoughts on an even simplier collector for garage/barn/workshop situations that I'll try to gather together and post in a few days.
Gary

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I missed the original post. My shop is in DeSoto, Iowa (16 mi west of Des Moines on I-80) and occupies a 2500 ft² aircraft hanger. I managed to keep the otherwise unheated and somewhat drafty shop above freezing all winter with the 6'x12' collector pictured near the bottom of http://www.iedu.com/DeSoto/pix.html - I plan to rebuild this one and add two more before this next winter.
Stop out for coffee next time you're in the Des Moines area.

Hi,
My climate is similar to yours and we also get wind with the colder weather. I might qualify my statements with the fact the energy costs in this area are probably lower than many areas so I lean towards the luxury side of the issue. Floor heat is luxury. Nothing feels better than when you walk in an out of the cold and get to walk onto a warm floor. You are going to get some thermal lag even with forced air heating, especially if you have a 6 inch floor. It is darn near impossible get warm and feel comfortable until the floor is warm. A thick slab of concrete tends to stabilize temperature so your ability to adjust temps quickly will be limited either way.
I have both floor heat and the fan type heaters that hang from the ceiling and are thermostatically controlled. That gives me a lot of flexibility. One nice thing about the floor heat is the heat starts at the floor and of course drifts upward, while my blowers blow it at the floor and I assume very quickly its back on the ceiling. Next, two doors are open at opposite ends of the building are open and the wind carries all the heat away. I doubt that it has any scientific justification but it seems that the floor heat is a bit more immune to loss.
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