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Thread: Vent Free Propane or Natural Gas Heater

  1. #1
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    Feb 2010
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    Illinois
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    Vent Free Propane or Natural Gas Heater

    Does anybody use a vent free gas heater in their shop? I'd like to get away from my wood stove and I'm considering one of these. Do they create a lot of condensation on surfaces in a climate controlled setting?
    Teaching grandchildren the hobby is rewarding. Most of the time

  2. #2
    Avoid them like the plague unless your shop is basically wide open and leaky. Natural gas ventless heaters will produce nearly 100% moisture when they are running. A bit less with commercially processed and stripped natural gas but the output from these heaters will still be wet and you will basically be working in a enclosed space with your lawnmower silently running in the corner. You will be breathing the byproducts of combustion every minute the heater is running. This is tolerable with a kitchen stove or range because the use is minimal, often times the range hood is running, and so on.

    Heating any type of reasonably constructed space (if you have insulation, a vapor barrier, modern windows and doors) is asking for trouble.

    I have been a GC in a rural area that nearly all the homes in this area run off gathering lines (not commercially cleaned and stripped gas) and these heaters are the death of a home and anyone who has finally come to their senses and gotten off of them has had nothing other than the response of why didnt they listen sooner. On commercial gas, in a loose, airy, or rarely used, situation I could see them as a safety backup as they most generally do not require any electric to run.

    Do yourself a favor and spend the money on a Mr Heater or someo other powered venting unit that you can hang from the ceiling. They can be had for 600 bucks or so and you can punch a 6" hole in the wall to vent them.

    Dont waste your time.

  3. #3
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    Feb 2014
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    Another issue besides the moisture is that they don't burn 100% of what's in the gas with no waste, so they also leave a film on everything in the room. It doesn't accumulate really fast, but it does continually add to the layer, and it's hard to get off of some things.

  4. #4
    Been running an infa-red vent free propane for years in my shop. Never had any problems with moisture. Keep shop at 57 degrees all the time. Got tired of freezing my buns off waiting for heat to come up. Use about two 20# (filled full) cylinders per month. Have thermostat connected to air cleaner, so when heater is on, air cleaner circulates heat over whole shop.

  5. #5
    Join Date
    Sep 2016
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    Modesto, CA, USA
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    Propane produces about one pound of water vapor for one pound of fuel burned. NG should be similar. Vent free are outlawed in California for good reason. CO will kill you since it has no taste or smell. You body senses CO2 levels but CO is not noticed buy your body systems. Your face turns a nice healthy red like you have been exercising. I understand internal organs look the same with a nice "healthy" glow
    Spend a little extra and get a direct vent heater. they are more efficient and they will not kill you, unless the vent gets plugged.

  6. #6
    It probably depends on how often you need the heater to run, but as others have mentioned, moisture can be a problem. The byproducts of burning natural gas or propane are carbon dioxide and water, neither of which are particularly good for a shop (assuming you have enough combustion air, if not you'll get carbon monoxide, definitely bad). I friend put in a vent free one here in MN, he ended up avoiding running it when it was really cold out and it had to cycle a lot; it put too much water on his machines.

    Your location says Illinois, not quite as cold here, but definitely not warm in the winter. If there is any way you can put in a Hot Dawg (or similar) instead, I'd say do that.

  7. #7
    Join Date
    Sep 2013
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    Wayland, MA
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    They are illegal most places, for very good reasons, as outlined above.

    Unless your shop is exceptionally clean I'd want a sealed combustion unit that draws combustion air from outside as well as vents outside. Running sawdust through the combustion chamber can't be good. I have a Hot Dawg that uses one 4" concentric pipe as both supply and vent.

  8. #8
    Join Date
    Nov 2011
    Location
    Tacoma, WA
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    236
    I am wondering if cost of electricity in your area precludes the use of something like a King heater. I have used these in two shops and like them. I rewired with a King line voltage thermostat mounted remote from the heaters. I bought at least one of them at a box store. Internal wiring can be set for different wattage outputs.


  9. #9
    Join Date
    Feb 2018
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    Vent free heaters are one of the safest designs as they have the ability to shut themselves down. The infra-red type burn more cleanly than the blue flames as they run at a higher temp. Any odor that is airborne will go through the heater and I guarantee it will not smell better coming out. My vent free runs 0% CO as read on my digital combustion analyzer. I run it for temporary heat or if some one is in a jam. Air is 20.9% oxygen. The Oxygen Depletion Pilot system on these heaters is usually the pilot assembly. They are precisely set and not adjustable. With the 20.9% 02 the pilot can reach the thermocouple to prove flame and allow the unit to fire. In a confined space as the 02 level drops the pilot flame will feather off the t-couple causing it to drop out. That usually happens in the 18.5-19% O2 range. That is a hard lock-out. Customers would call me. My heater is out. I'd say open a window. That would solve the problem. I've sold and serviced a couple tens of thousand VF heaters. They are listed only as a supplemental heater and should be used as such. Where I have seen folks get into trouble is when they run them continuously in a tight home. it is the worst possible use for them. Personally, I am sensitive to them. I can tell if there is a VF working in a building when I'm 2' into the building. Most people are not. A gallon of LP or a therm of NG will produce approx 1 gallon of moisture. Given that cold air cannot hold moisture I have has some people tell me that a bit of moisture improves their comfort. Where is that line? Every system, building, owner, heater chosen has a personality. A very important point in VF heaters, especially in a shop is that they MUST be kept clean. Blow out the plaques regularly and pay attention to the pilot. Keep all dust, lint or whatever out of the pilot. Be careful blowing the plagues off. Some of the cheaper infrareds can't take 50# of pressure. You can destroy the entire assembly with to much air pressure. Stay away from the cheap chinese units. I spoke with a distributor in the SE (vent free country) who had over 35% failure. If you buy an infra-red today I would go with an Empire. If you choose to go direct vent, look at the Rinnai Energysavers.

  10. #10
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    Nov 2003
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    Central North Carolina
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    Jack,
    I accept that vent free heaters are safe from a flame stand point, but they are still not a good idea in a wood shop because of the huge amount of moisture that the propane or natural gas burn creates. That alone makes me not want it in my wood working shop. A mechanic shop or other kind of shop doesn't need low humidity, but a fine wood working shop does.

    I also don't want a radiant type heater that sits at floor level because it's too easy to accidentally place wood too close to it. A friend almost lost his shop due to this. I went with a heat pump and internal resistance booster heat for my shop because 1. I live far enough South that it is effective. 2. Because there is no worry about it setting any wood on fire. 3. Because it cools and de-humidifies as well as heats my shop. 4. Because with a high quality filter it also serves as my shop air filter.

    Charley

  11. #11
    Join Date
    Feb 2018
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    N CA
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    1,279
    Understood and I agree, Charlie. I wanted to point out how they work. With the exception of the gas range, I will only have sealed combustion direct vent appliances in my home or shop. Happy Heating!

  12. #12
    My hvac techs are instructed not to re-light vent free heaters if we shut the gas off for any other appliance repair. I refuse to install one or hook up the gas to one either. I have been involved in an insurance settlement where we were held liable for vent free heater damage, just because we hooked up the gas line. The homeowner installed it , we hooked up the gas line. It won’t happen again. DONT INSTALL ONE

  13. #13
    Join Date
    Feb 2018
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    N CA
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    That is the way it goes. You had insurance. You are in business. You are a target. The insurance companies trade clients and pay-offs. Ah, the joy! Mine was when a 92 yr old ship fitters family was angry that he had died so young and filed a mesothelioma suit. My partners Uncle had represented a company which made products which had asbestos in them in the 50’s. My partners last name was the same so we were named in the suit. It took us 6 yrs to be written out of the suit. The real issue is that we have created a situation where a customer no longer has any responsibility. I knew a guy who would buy a heater in October run it all winter, return it and buy a lawnmower in the spring and return that for a heater in the fall. He was upset when someone caught on. Great world we live in

  14. #14
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    Sep 2009
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    Medina Ohio
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    It depends on where you live if you have low humidity then a ventless heater is a good option.

  15. #15
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    Quote Originally Posted by Jerome Stanek View Post
    It depends on where you live if you have low humidity then a ventless heater is a good option.
    I completely disagree. No space occupied by people or animals should be heated by a ventless heater unless there are huge holes in the walls. Sure, there will be all kinds of people that have used them for decades & were OK, but there's just too much risk of something going wrong where the result will probably be death.

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