Ventless Heater In 300 Square Foot Garage

[LeGaCyGiAnT124]

Hey guys, I am looking at getting a ventless heater for my attached garage in our home. The garage is around 300 square foot give or take. My daughter's bedroom directly above is nearly 10 degrees colder in the winter, and we are hoping this will help heat it too. I keep reading about moisture. Is there anyway to avoid this? This is the model I was looking at. Thanks!!

https://www.homedepot.com/p/Dyna-Gl...VzJ6zCh3OAQp7EAQYASABEgKQvfD_BwE&gclsrc=aw.ds

 

[Git]

No, there is no way to avoid moisture, it is a by-product of the combustion of natural gas.

Although ventless heaters are supposed to be 99.9% efficient, they still produce carbon dioxide and other contaminants and are not to be used as a primary heat source. I think you will find that most of these heaters suggest you only run them for a maximum of 4 hours at a time and require fresh air source

Doesn't sound like a good fit for what you want to do

 

[LeGaCyGiAnT124]

No, there is no way to avoid moisture, it is a by-product of the combustion of natural gas.

Although ventless heaters are supposed to be 99.9% efficient, they still produce carbon dioxide and other contaminants and are not to be used as a primary heat source. I think you will find that most of these heaters suggest you only run them for a maximum of 4 hours at a time and require fresh air source

Doesn't sound like a good fit for what you want to do

Thanks for the honest answer. I think you might be right too. Here is something else I am hoping to resolve by heating the garage. The intake/ exhaust for the furnance runs through the garage (about 10 feet), which is uninsulated. When the temperatures outside are below 0, the exhaust tip gets ice/water build-up so bad that it shuts down the furnace in the middle of the night. Either the pitch of the pipe is wrong, or due to the fact of it not being insulated is causing the issue.

If I was to run this heat source, I would want to run it atleast through the night for the room to stay at temps close to the rest of the house.

 

[pbon]

The OP linked a model with built in 02 depletion sensor and shutoff. If it’s in a garage that is used daily, meaning the garage door gets opened and closed, it gets enough fresh air. If it is uninsulated or drafty, it probably gets enough fresh air. I’d recommend vented but the linked ventless heater should be fine.

 

[LeGaCyGiAnT124]

The OP linked a model with built in 02 depletion sensor and shutoff. If it’s in a garage that is used daily, meaning the garage door gets opened and closed, it gets enough fresh air. If it is uninsulated or drafty, it probably gets enough fresh air. I’d recommend vented but the linked ventless heater should be fine.

In the winter months, we typically don't open the garage door very often.

From looking at this picture, the longest wall on the left, and the very back wall are not insulated. The ceiling is, and the walls on the right are against the laundry room/ down-stairs bathroom, which are.

 

[HoosierBuddy]

A vented unit heater would be a much better investment. Lots of guys on this forum have them. Modine hotdog or similar.

Phil

 

[Randy in Maine]

Can you just run heat from whatever central heat system you probably have now? An additional duct or radiator zone with a thermostat might be a better long term choice and may be cheaper to boot.

 

[pbon]

Does code allow garage and house to share same heat source?

 

[pbon]

What about just insulating the pipe? And making sure it slopes slightly upwards?

 

[LeGaCyGiAnT124]

Does code allow garage and house to share same heat source?

Nope. I thought of doing that myself when I re-did the garage back in the Fall, but decided it would cause more of a headache, and technically not be allowed.

I honestly think the slope of the pipe is more the problem than the un-insulated pipes in the garage, but my furnance issues are a whole other problem. I just want to get my daughter's bedroom as warm as the rest of the house.

I just figured heat rises, and it would be nice to have heat in the garage too.

 

[LeGaCyGiAnT124]

Can you just run heat from whatever central heat system you probably have now? An additional duct or radiator zone with a thermostat might be a better long term choice and may be cheaper to boot.

It's illegal in my state to do that. I thought of that already.

 

[The Cobbler]

since a lot of your garage is not insulated, I think it it would be very inefficient to heat the garage to get more heat into your daughters bedroom. a good portion of the heat would escape thru the non insulated walls

 

[Randy in Maine]

Well my house and detached garage share the same heat source (a condensing propane fired wall boiler). I just run 120º warm water out to the shop (via pex tubing and the radiant floor) and it comes back to the house boiler to get reheated. Cheap and efficient to do and no operational issues.

I would work on improving the insulation first and then consider getting more heat into the equation.

 

[Jackfre]

The moisture generated will depend upon how much you run the unit. You don't indicate location. The difference in moisture between Maine or S CA while the same per unit of fuel will behave differently due to the climatic difference. In the North, due to the cold everything drys out. The VF can actually improve the comfort by providing a bit of humidity to the very dry air. Remember, vent -free are supplemental heaters.

 

[Dagny]

I'm in the business and will not hook these up. Big box sells them but it is illegal to install them in Wi.

 

[HoosierBuddy]

Well my house and detached garage share the same heat source (a condensing propane fired wall boiler). I just run 120º warm water out to the shop (via pex tubing and the radiant floor) and it comes back to the house boiler to get reheated. Cheap and efficient to do and no operational issues.

I would work on improving the insulation first and then consider getting more heat into the equation.

Pretty sure your system is fine with code, Randy.

What isn't allowed is running air ducts from the living space into the garage. I'm not sure if the concern is allowing a path for flames to make it through the firewall, or the possibility of exhaust fumes making it back into the house...but one of those or maybe both I think led to the code. Simply running hot water pipes to heat both areas off a boiler wouldn't cause any problem I can think of. My garage hydronic boiler also heats the bonus room above the garage and the attached breezeway. Can't see any issue there myself.

Phil

 

[Jackfre]

I'm in the business and will not hook these up. Big box sells them but it is illegal to install them in Wi.

Having sold them nationally many contractors won't install them. They are legal to install everywhere in the United States except CA, which most would expect
They are definitely the red-headed step child of the heating business. I am a vented heater guy by training and inclination, but when VF are used properly they are fine. The case can be made that they are actually safer than most vented heaters. They have the ability to shut themselves off in an unsafe condition. CO deaths by vented heating equipment are to common. There are none with VF heaters that I know of.

 

[Git]

Having sold them nationally many contractors won't install them.

In the back of my mind, they are the cheapest way to get heat. A basic 30,000 btu ventless heater costs around $150, but when you go to a vented heater of the same size, like the Modine Hot Dawg, the heater alone is around $800. Then you need to add some sort of vent which can easily be another $300 just in parts.

As you pointed out, a ventless heater has an oxygen sensor that will shut the heater off, yet a lot of the vented units, water heaters, etc don't have one. Just google carbon monoxide deaths:

"In the United States, approximately 200 people die each year from carbon monoxide poisoning associated with home fuel-burning heating equipment"

So what is someone to do, when they want to work out in their garage when it is cold and they don't want to spend $1,000 on a heater? They usually end up using a kerosene or torpedo type heater which is even worse.

Lastly, I don't buy the 'contractor won't install them' line because the contractor is looking out for the customer. I think it is because they want to upsell them on a vented unit where they can make more money. Scare Tactics...

 

[HoosierBuddy]

In the back of my mind, they are the cheapest way to get heat. A basic 30,000 btu ventless heater costs around $150, but when you go to a vented heater of the same size, like the Modine Hot Dawg, the heater alone is around $800. Then you need to add some sort of vent which can easily be another $300 just in parts.

As you pointed out, a ventless heater has an oxygen sensor that will shut the heater off, yet a lot of the vented units, water heaters, etc don't have one. Just google carbon monoxide deaths:

"In the United States, approximately 200 people die each year from carbon monoxide poisoning associated with home fuel-burning heating equipment"

So what is someone to do, when they want to work out in their garage when it is cold and they don't want to spend $1,000 on a heater? They usually end up using a kerosene or torpedo type heater which is even worse.

Lastly, I don't buy the 'contractor won't install them' line because the contractor is looking out for the customer. I think it is because they want to upsell them on a vented unit where they can make more money. Scare Tactics...

Of course on the vented heaters, water heaters, furnaces, etc, any carbon monoxide goes up the flue (or through the vent) along with the other products of combustion (water, CO2, and anything else that gets produced by combustion).

About 400 people die in the US each year because of CO poisoning. If you are concerned about the risk, a CO detector can be bought for well under $100. I prefer the type with a digital readout.

Phil

 

[DFB]

We put 3 "direct vented" wall mount gas heaters in our new 2 level barn store down at work. Only way to go...

 

[Git]

We put 3 "direct vented" wall mount gas heaters in our new 2 level barn store down at work. Only way to go...

So the OP with the 300 sq ft garage should install 3 direct vented heaters to solve his problem?

 

[pbon]

Probably one; I think the point was direct vent.

 

[fteufert]

I have a non vented 18K heater on a wall in my kitchen. 10+ years, no issues in the house.
No extreme moisture, no smell,

I do use my steam NG furnace for those really cold days (10F or less).

The humidity is higher in my house when the steam is on.

I use a propane heater in my garage, and I don't have issues out there either.

If I could get a gas line to my garage, I'd have a nice vented heater to keep it 50 all winter.

I have a ledge a foot down, so a line can't be buried deep enough.

 

[DFB]

So the OP with the 300 sq ft garage should install 3 direct vented heaters to solve his problem?

no...just one should suffice

They are well worth the money spent