# Attached garage-heat? or not heat?



## jargey3000 (Jan 25, 2011)

Looking for some feedback. current home, 6 yrs old, is the first I've had with an attached garage. I'm noticing a little mold around the window & door frame, and a few areas on the concrete walls. Not too serious, but its there. In winter I also notice continuous condensation on the window in garage. 
Checking with my neighbors on either side -whose houses were all built same time by same builder- they dont seem to have problem to the same degree. 
I tend to leave the heat on a bit in garage in winter ( maybe set a 5-8 degrees) , whereas they say they always keep the heat off. Could this be the cause of my mold problem?
Bear in mind that we live in a mainly cool, damp climate where humidity is likely over 80 most of the year, and the temperatures hovers around the freezing mark for maybe 6? months of the year.
Would appreciate any feedback from those with similar experience, or any suggestions. t'anks all!


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## like_to_retire (Oct 9, 2016)

jargey3000 said:


> I tend to leave the heat on a bit in garage in winter ( maybe set a 5-8 degrees) , whereas they say they always keep the heat off.


How do you set the heat in a garage to 5-8 degrees? Does it have independent thermostatic control? Is this electric heat?

ltr


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## Prairie Guy (Oct 30, 2018)

Unless you're working in a garage there's no reason to heat it and plenty of potential pitfalls. For one your vehicle will undergo daily freeze thaw cycles which may accelerate rust. Your also wasting heat for no reason. You're going to have melt puddles all winter long. And there's the potential for mold as you are starting to see.


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## Beaver101 (Nov 14, 2011)

^ By an attached-garage, I'm presuming it's next to the house so if jargey doesn't keep the garage heated abit, the house will be colder. 

Anyhow, I would put a dehumidifier in there to get rid of the moisture. Even a small one helps. Of course, a bigger one can do a better job.


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## AltaRed (Jun 8, 2009)

An attached garage will remain above freezing most of the time in a maritime climate (as compared to inland) simply because of heat loss from the house. I think Jargey's issue is that he is creating the ideal climate for mould, i.e. growing temperature but not high enough to reduce relative humidity. I'd shut the heat off entirely as a first attempt to eliminate mould (but won't help the condensation problem) to the more expensive choice being what is already suggested, a dehumidifier to take the moisture out. Need a drain though unless one loves to manually dump the water each day.


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## ian (Jun 18, 2016)

Never had this problem. In Calgary we have never heated our garage. It does not freeze. I agree with others. Shut the heat in the garage off....you are just burning money. 

Perhaps the seal in the garage window has gone. It does happen.


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## AltaRed (Jun 8, 2009)

A humid maritime climate especially in NF is quite different than prairie dryness. It is hard to get humidity out of houses as well, even at room temp... a damp feeling a lot of the time. 

Humidity can be an issue anywhere with right conditions. My bro in Southern AB has issues with his garage door freezing to the concrete floor sometimes.


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## prisoner24601 (May 27, 2018)

Some detective work to do! So clearly you have a source of moisture and some cold surfaces like the concrete walls, window and frames. First I'd try to isolate where the moisture is coming from. If a wet or snowy car is parked in a heated, closed space that could generate a lot of water vapour. Is that a possibility? Another source might be warm moist air from your house escaping into the garage. Is the common wall completely sealed off floor to attic, any new penetrations line vacuum, electrical that messed with the vapour barrier on the house side of the wall? Do you keep the door between the garage and house closed and is the seal in good condition? If you have moisture coming up from your garage slab that could be another source. How about your bathroom and dryer vents are they routed into/through the garage? If so the ducting may be leaking.

Is the garage vented through attic and soffitts? Putting an exhaust fan in may help in the winter (drawing in relatively cold, dry air and exhausting warm humid air).

You mention concrete walls. Is the garage insulated and sealed?


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## AltaRed (Jun 8, 2009)

An exhaust fan could be the best idea of all..if it can operate at freezing temps


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## Prairie Guy (Oct 30, 2018)

AltaRed said:


> An exhaust fan could be the best idea of all..if it can operate at freezing temps


But if it's 80% humidity like the OP states then a fan will only replace humid air with more humid air, and although it will be fresher air I'm not sure if it would help. A dehumidifier might be the most practical solution.

Also, as prisoner stated...parking a wet snowy car in a heated garage will only make it worse.


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## AltaRed (Jun 8, 2009)

Vehicles often come into garages wet. It is that water content that worsens the situation, especially snow and slush that has accumulated. Even have that occur in the dry Okanagan.

A key success factor is air circulation.


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## jargey3000 (Jan 25, 2011)

like_to_retire said:


> How do you set the heat in a garage to 5-8 degrees? Does it have independent thermostatic control? Is this electric heat?
> 
> ltr


basic electric heat. wall thermostat.


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## jargey3000 (Jan 25, 2011)

Beaver101 said:


> ^ By an attached-garage, I'm presuming it's next to the house so if jargey doesn't keep the garage heated abit, the house will be colder.
> 
> Anyhow, I would put a dehumidifier in there to get rid of the moisture. Even a small one helps. Of course, a bigger one can do a better job.


by attached i mean...attached? like a zillion other houses.....
heating or not heating garage has no impact on rest of house.


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## jargey3000 (Jan 25, 2011)

i have tried the dehumidifier on & off & it does help.
but i left the heat on a crack cause i was afraid it wouldnt work, or maybe freeze up, with the temp of??


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## jargey3000 (Jan 25, 2011)

AltaRed;2031502
A key success factor is air circulation.[/QUOTE said:


> would leaving the window open help?


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## jargey3000 (Jan 25, 2011)

....so, the consensus would be...leave the heat OFF....?


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## AltaRed (Jun 8, 2009)

i'd leave it off. Never had heat in my garage even in Calgary.


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## Beaver101 (Nov 14, 2011)

jargey3000 said:


> i have tried the dehumidifier on & off & it does help.
> but i left the heat on a crack cause i was afraid it wouldnt work, or maybe freeze up, with the temp of??


 ... what wouldn't work? the dehumidifier? Since the heating has no impact to the rest of the house, then would make sense to turn it off, even in your winter. Unless water does freeze up in your attached unheated garage which is highly unlikely because your car then wouldn't start either.


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## Prairie Guy (Oct 30, 2018)

Beaver101 said:


> Unless water does freeze up in your attached unheated garage which is highly unlikely because your car then wouldn't start either.


Why wouldn't a car start in an unheated garage? Most cars are fine to as low as -30, garage or no garage, as long as they have a good battery and are properly maintained. In fact, most block heaters on newer vehicles have an energy saving feature and won't even trigger until -15 or so.


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## lonewolf :) (Sep 13, 2016)

The cement floor where car is parked should not be flat it should be sloped to allow water to flow out the drain holes in the floor. Would insulate the garage if in a cold climate & would not heat. The larger the garage the warmer the garage will be in the winter. A garage on the North side will help keep the house warmer esp when wind blows from the North.

With the government going crazy with carbon tax would not be surprised if @ some point heated garages will have even an extra tax added on.


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## prisoner24601 (May 27, 2018)

I'd leave the heat off. In the winter warm air can hold more moisture. Once it hits those cold surfaces you get condensation. And if wet and warm enough for enough time you get mold.


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## prisoner24601 (May 27, 2018)

FWIW I'm a no heater in my garage in Maritimes. Even though it has electric heat


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## jargey3000 (Jan 25, 2011)

OK....I think I will try NO HEAT this winter...
I will let you all know how it went next spring...I KNOW you'll all be waiting with baited breath...:smiley_simmons:


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## Beaver101 (Nov 14, 2011)

Prairie Guy said:


> Why wouldn't a car start in an unheated garage? Most cars are fine to as low as -30, garage or no garage, as long as they have a good battery and are properly maintained. In fact, most block heaters on newer vehicles have an energy saving feature and won't even trigger until -15 or so.


 ... IDK, I was just shooting a dart out there ... I was guessing jargey's vehicle is a buggy???


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## jargey3000 (Jan 25, 2011)

Beaver101 said:


> ... IDK, I was just shooting a dart out there ... I was guessing jargey's vehicle is a buggy???


no....I traded it in for a Model T recently....


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## like_to_retire (Oct 9, 2016)

jargey3000 said:


> no....I traded it in for a Model T recently....


My understanding is that an electric starter was offered as optional equipment commencing in 1919. No more cranking required.

ltr


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## ian (Jun 18, 2016)

The only people we know who heat their attached garages are those that have a workshop in the garage. Otherwise it is money down the drain. And it sometimes gets very cold where we live.


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## Longtimeago (Aug 8, 2018)

Agreed, no need to heat a garage and as is obvious, doing so is causing you to have mold grow. Heating a garage is not for the benefit of the car, it is for the benefit of a person. In other words, when you use a garage as a workshop it makes sense to be able to heat it. When you only park your vehicle in it, heating it is of no benefit and may be detrimental in various ways including mold on the walls and rust on the vehicle. The only exception would be if you get a VERY cold night where a battery might freeze but I'd rather have to buy a battery than have a vehicle rust out sooner or have to deal with mold, which don't forget is a health hazard, you can't just casually wipe the walls down with a damp cloth you know.

What does make sense is to have an insulated garage door and an insulated wall between the garage and the house itself. Also, an area often overlooked with an attached garage is roof insulation. Insulation isolates the garage from having any affect on the house itself. Without insulation it will affect the house temperature obviously.


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## Longtimeago (Aug 8, 2018)

Some additonal comments on insulating the wall between the garage and the house itself. 

'Inside' walls are not insulated by a builder and with many attached garages, the wall in question is between the kitchen and the garage. It may or may not be insulated depending on local building codes at the time the house was built and whether or not that wall was considered an 'inside' wall. The easiest way to check for insulation is often to remove a wall outlet in that wall and see if there is insulation in there or not. If not, insulating that wall from the inside would be a major job, so the way to go is to insulate it from the garage side by simply putting up a 2x4 stud wall and adding insulation with a vapour barrier on the garage side. It's a relatively easy DIY job. Adding drywall or plywood sheeting to the garage side is optional.


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