# Safe Heat Sources for the Shop



## Jjb777 (Nov 17, 2021)

HI all.
We have a well insulated 20 ish by 30 ish shop. We just started using at a shop recently and plan to install a wood stove but won't be for another month or so.
Right now the shop has a fan forced wall heater that does an outstanding job heating.
I have a laser in the shop and cannot let temps drop below 40.
I am so nervous about leaving heaters on during overnight hours.
For now I just turn the heater on at night before I go to bed to bring up temp and then heavily blanket the laser and turn heater during overnight. So far this is working but we have only gotten temps down into the 20s so far this season.
We certainly will get lower temps at some point.

Are these fan forced wall fans used in shops safe if I ever need to keep on over night? If not, is there something safe I can pick up at HD or Lowes?


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## HokieKen (Apr 14, 2015)

What kind of laser are you talking about? Like a CNC? I assume you've already considered removing the head to take it inside at night and that's not a possibility. I'd say that what you have is about as safe as anything for what you need. A portable oil radiator is probably also safe but not likely to heat the size building you have. Assuming your forced air heater is properly installed and is on a properly functioning circuit and is from a reputable company and has redundant safety mechanisms, I wouldn't hesitate to let it run overnight.


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## Jjb777 (Nov 17, 2021)

Thank you for your reply.

It is a Glowforge laser. 
CNC laser … hopefully someday.



> What kind of laser are you talking about? Like a CNC? I assume you ve already considered removing the head to take it inside at night and that s not a possibility. I d say that what you have is about as safe as anything for what you need. A portable oil radiator is probably also safe but not likely to heat the size building you have. Assuming your forced air heater is properly installed and is on a properly functioning circuit and is from a reputable company and has redundant safety mechanisms, I wouldn t hesitate to let it run overnight.
> 
> - HokieKen


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## hotbyte (Apr 3, 2010)

While you should certainly be concerned about safety of your heating method, that seems like a lot of space to heat just for the laser. I would try to isolate the laser somehow so you only need to heat a smaller area…maybe a smaller insulated room inside the shop.


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## controlfreak (Jun 29, 2019)

This reminds me, I think I will put a remote temperature sensor in my shop for the fun of it. I can never remember what dial setting I left the electric heater on.


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## bigblockyeti (Sep 9, 2013)

Have you considered getting a furnace, even if for just one area it'd be hard to touch on safety and efficiency (assuming a 96% unit).


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## RClark (Jun 1, 2012)

A standard 1500 watt space heater puts out about 5K BTUs of heat. I'd have to run five of them to keep my shop at 40 degrees when it's 20 degrees outside. Heck, we have weeks when we don't get to 20 degrees outside for the daily high temperatures, and I'm not even in the "cold" part of Iowa.

I think I'd hook a thermostat to that wall unit to control heat during off hours. You'll save energy and the cost avoidance of not buying a small heater. I also wouldn't underestimate our human tendency to grow weary, very weary, of a drill EVERY NIGHT of heating up the shop and putting a blanket over the CNC. If your shop is well insulated, your existing heating unit may not actually not actually even run on many nights depending on your location. Basic programmable thermostats are cheap and available at any big box store.

What powers your wall mount heater? Electricity? Gas, and if so, is it a sealed combustion unit?

I think there's more risk to your shop from a wood stove than there is from a wall mounted heating unit, particularly if you're going to leave it burning overnight unattended. I'm not certain if this is your plan, just going by what you put in your post.


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## Jjb777 (Nov 17, 2021)

I GREATLY over estimated the dimensions! Thats our barn … the shop is more like 20 by 30. Foggy brain this morning. Revised original post.

In any case … love the idea of isolated our laser. Thanks.


> While you should certainly be concerned about safety of your heating method, that seems like a lot of space to heat just for the laser. I would try to isolate the laser somehow so you only need to heat a smaller area…maybe a smaller insulated room inside the shop.
> 
> - hotbyte


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## Jjb777 (Nov 17, 2021)

I have considered a furnace, yes.
At one point it had gas and has a very nice gas heater in the shop … but the gas tanks always smelled like they are leaking and company could not identify the leaks so we had them removed.

I like the idea of wood as we lose power a few times throughout the winter and shop is not hooked up to generator plus we have an abundance of wood on our land.



> Have you considered getting a furnace, even if for just one area it d be hard to touch on safety and efficiency (assuming a 96% unit).
> 
> - bigblockyeti


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## hotbyte (Apr 3, 2010)

So, I can stop drooling over your shop size    Grab another cup of coffee…it'll help clear the brain fog 

Still, 20X30 beats my 13X24…



> I GREATLY over estimated the dimensions! Thats our barn … the shop is more like 20 by 30. Foggy brain this morning. Revised original post.
> 
> In any case … love the idea of isolated our laser. Thanks.
> 
> ...


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## Mosquito (Feb 15, 2012)

I had similar concerns, if not just because of being paranoid about shop dust and heating elements. I ended up with a natural gas 96% efficiency furnace hung from the ceiling with a duct across the back wall. I have no regrets at all on it. It was only $500 more than a similarly efficient dual vented garage heater, but I run the fan often, to help with dust filtering, and just get some air movement in the summer months.

If a different heat source is not an option, I would agree with trying to isolate the laser somewhere that you can heat separately. Maybe even since it's just a Glowforge and not that big, you can have it in an enclosure with an incandescent light bulb (like many of the home/diy kilns that many woodturners use)


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## RClark (Jun 1, 2012)

A 20 X 30 shop…that size makes me "double-down" on a programmable thermostat controlling a heater. I don't know if the current heater is capable of accommodating a thermostat, but even if it meant replacing it with another unit, I think you'll be ahead in the long run.

A wood stove will require floor space that will have to be kept clear of combustibles. My shop is 25 X 44. When I moved in 7 years ago, I thought it was all the space in the world. But, Stuff Expansion happens…


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## Albert (Jul 28, 2008)

This is the heater I've been using, seems to work without a fire so far, my shop is about 20×40 but our temps are probably not as extreme as yours.

Check this out at Amazon.Com

Comfort Zone CZ230ER Digital Fan-Forced Ceiling Mount Heater with Full-Function Remote and 12-Hour Timer


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## CaptainKlutz (Apr 23, 2014)

+1 make a smaller enclosure for CNC laser.

That is a small table top unit, only 38W x 20.75D x 8.25H. Don't super size the problem. Make a simple hinged plywood box, 1" foam lining the interior; using a electric heating mat and thermostat like found on reptile cages or chicken coop. Open lid to use the machine, close lid when done for day. Can also buy 120v heating mat/tape separately and buy a thermostat switch from Amadud to use on floor of box.

If consistent electric power is not available, you have a compound problem; and need a back up power source, or different heating method; maybe both.

Best Luck!


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## Woodmaster1 (Apr 26, 2011)

I have a 50,000 btu bigmaxx gas furnace hanging from my ceiling. I heat the 30×33 shop at 68 degrees 24/7 in the winter. The budget only increased $10 a month.


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## ajosephg (Aug 25, 2008)

I have an 18,000 BTU mini-split heat pump in my 27×27 garage shop (well insulated, including door) and it does a great job.


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## controlfreak (Jun 29, 2019)

I guess this is the only time I like the size of my 10' x 16' shop. I am not in a vary cold climate and run a 5000 watt electric heater in 3000 watt mode. Try to keep it warm enough for tools but cool enough not to sweat if I start planning stock.


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## ibewjon (Oct 2, 2010)

Personally, I would never have a wood stove in my shop.. Mini split works great for me, and it cools in the summer. A wood stove won't do that.


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## Jjb777 (Nov 17, 2021)

Thank you.
We have had a chicken coop years and I could never adding any sort of heating element due to my same paranoid safety concerns. (ventilation and keeping moisture out is healthier for birds anyway)


Thank you for the two links … I think I will get both items you posted and build the enclosure. This helps me a lot!
They have the carpeted and rubber mats. I am guessing the rubber would be better?

Incidentally, I was looking at the heaters on the McMaster site and I think this is (or at least very similar to) the heater that is in the shop now. It works extremely well.












> +1 make a smaller enclosure for CNC laser.
> 
> That is a small table top unit, only 38W x 20.75D x 8.25H. Don t super size the problem. Make a simple hinged plywood box, 1" foam lining the interior; using a electric heating mat and thermostat like found on reptile cages or chicken coop. Open lid to use the machine, close lid when done for day. Can also buy 120v heating mat/tape separately and buy a thermostat switch from Amadud to use on floor of box.
> 
> ...


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## Jjb777 (Nov 17, 2021)

Yeah … I have been thinking about those too.

The reason I was thinking stove is
1. We have an awesome one already that we are not using.
2. We have so much wood on our property.


> Personally, I would never have a wood stove in my shop.. Mini split works great for me, and it cools in the summer. A wood stove won t do that.
> 
> - ibewjon


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## Jjb777 (Nov 17, 2021)

After giving it more thought, think we will not use the stove.


> Personally, I would never have a wood stove in my shop.. Mini split works great for me, and it cools in the summer. A wood stove won t do that.
> 
> - ibewjon


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## Jjb777 (Nov 17, 2021)

Thanks.
Is there a unit you recommend?
Right now the one I have is run by electricity.

I think I have given up on the idea of a wood stove.



> A 20 X 30 shop…that size makes me "double-down" on a programmable thermostat controlling a heater. I don t know if the current heater is capable of accommodating a thermostat, but even if it meant replacing it with another unit, I think you ll be ahead in the long run.
> 
> A wood stove will require floor space that will have to be kept clear of combustibles. My shop is 25 X 44. When I moved in 7 years ago, I thought it was all the space in the world. But, Stuff Expansion happens…
> 
> - RClark


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## RClark (Jun 1, 2012)

I don't really have a recommendation for brand.

For gas-fueled units, I think the Mr. Heater brand shown above is probably pretty reasonable. Modine's Hot Dawg units also seem to be well thought of. The unit in my shop is a 100K BTU unit my HVAC guy got at the local supply house. Key to a gas unit is sealed combustion. These units will be easily supported by a simple 110V outlet. Also do some research on noise. My unit is somewhat loud.

For electric units, I would look for certain characteristics: UL listing, output, voltage/amperage requirements. Be prepared to need 220V and higher amperages for much more than just a 1500W heater.


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## CaptainKlutz (Apr 23, 2014)

> They have the carpeted and rubber mats. I am guessing the rubber would be better?


depends on mounting method.

Not to trigger your paranoia, but to help keep you safe: 
Heating mat is nothing more than resistance wire bonded to a membrane. It comes in many shapes and sizes , and is used in 1000's of applications. 
Long term contact direct to wood is not recommended, as described in this reptile heater description They are designed to be bonded to surface that will not burn exposed to high heat, such as metal/glass/concrete. When attached to bottom of glass aquarium, they recommend an open bottom for air circulation to avoid hot spots.

If I were creating a hot box, would attach the mat to underside of 12-16AWG thick aluminum/steel plate, sitting under your machine. Then add an insulator between plate and wood box. Insulator examples include: Polyisocyanurate rigid foam, rock wool, paver bricks, or an air gap with stand offs.

PS - McMaster link was easiest source to find with many options, but is usually most expensive.  
Can find better value at other sources.


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