Garage Dehumidifier

[armascott]

Good Day, I have about a 1000 sqft heated garage. Having a bit of a humidity problem in it. Mostly on the overhead doors. They kinda freeze shut. Looking to install a dehumidifier, any suggestions on what works? Thanks

 

[papajake]

thats a problem because most dehumidifiers will only work if the temp in your garage is over 50 degrees,tried one and it would only work when i heated the garage over 50 and i find thats to warm and a waste.try putting some of that 3/8 reflective blanket material one the inside of the door i put on the header and works and my door is insulated so only get frost on the seams.

 

[zal]

I have a dehumidifier from Crappy Tire. Like the above post says, you have to keep the garage at above 10C for it to work properly. Mine sits at 12C. They say they work at 5C, but they don't at all. They freeze up.

 

[Beels]

Only real way to fix it is a heat recovery ventilator.

 

[doorfx]

Good thread as I am building a garage in the spring. What type of heat are you guys using ?

 

[pete gads]

I have a big 3 car garage heated to about 15c with in floor. get lots of moisture, so bought a dehumidifier from crappy tire, on these last snowy days was get about 2 gals a day of water to dump out. works great.

 

[YamaDad]

A HRV is the best way to control humidity, but the garage must be heated. There is condensate that will freeze in them.

As for heat I vastly prefer radiant tube heat with combustion air from outside. That way the air burned is unheated and free of whatever is in the shop, sawdust or whatever. Cost is much cheaper than a boiler and works at least as well. The only drawback is you need room underneath them or risk melting paint off your hood.

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[Keith Brown]

Your humidity problem is very common in well built well sealed shops and garages that have vehicles coming in with slush/snow on them. It is particularly bad when the floor is heated either by a boiler or low intensity radiant tube heater because when the slush/snow fails on the floor there is more evaporation due to the temperature rise. The HRV (air to air heat exchanger) is by far the best way dealing with this problem. However there are alternatives you can use in the mean time that are very effective. #1 You can prolong your over head door opening while entering and leaving the shop or open it for short periods while the snow is melting and the humidity is high. #2 you can leave a small gap in your seal on one of your door seals.I realize that these two solutions may seem to be waste of energy but if not over done they are really not bad. The law of partial pressure states that each gas exerts its own pressure as if the other gas's do not exist so when there is a gap or an opening it is much like letting the water vapour/humidity out of a ballon. Humidity is a problem that is common and it requires energy to manage. A dehumidifier uses mechanical refrigeration to condensate the moister and requires large amounts of electricity to run. An HRV does the same thing as opening the door or leaving a gap only it recovers some of the heat in the air that is being removed and it is self regulating via humidistat but it does use electricity. As you may or may not know over 90% of the electricity we use in Alberta is from coal fired generation. Most likely if your garage is sealed well enough to have a humidity problem it is heated by high efficiency natural gas or passively by the vehicles them selves so it very well may be that the carbon foot print of opening your over head door for a minute longer from time to time is smaller then even the HRV. It may also cost less (electricity is very expensive gas is cheap).

 

[J-Roc]

I have a 32x 28 with in floor heat and use an exhaust fan on a humidistat. Works great. I basically leave the fan running all summer to help control dust.

Are your door seals freezing to the floor? If so maybe spray some white grease spray on them?

 

[YamaDad]

An exhaust fan is the cheap alternative to an HRV. The problem is that the air you are exhausting has to be replaced one way or another. It will enter the building at its weakest point, which may be the chimney, which wreaks havoc with the heater. If the fan is small it may not be noticeable but a large fan defiantly will be. I use a large fan for occasionally clearing the air, and Crack the overhead door a few inches. It works good but cools the building quickly.

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[Absledder]

A HRV is the best way to control humidity, but the garage must be heated. There is condensate that will freeze in them.

As for heat I vastly prefer radiant tube heat with combustion air from outside. That way the air burned is unheated and free of whatever is in the shop, sawdust or whatever. Cost is much cheaper than a boiler and works at least as well. The only drawback is you need room underneath them or risk melting paint off your hood.

Sent from my SM-G900W8 using Tapatalk

X2 on the paint thing. I've seen some wall mounted before. To me that would be better than a ceiling mounted heater.

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[zal]

I have a Natural gas ceiling heater. Radiants are nice, but too damn hot to work under when they are on IMO.
My doors would freeze to the cement until I put in the dehumidifiers. Also, my tools were starting to rust. Bringing in two vehicles full of snow into a heated shop, the water has to go somewhere. Tried the window open, but that wasn't working.

 

[ZRrrr]

I drilled a couple holes in the concrete, middle of garage along the water flow paths. Working well so far. Also do the door opening thing once in a while as mentioned above.

I have looked into this in past:

Home Hardware - Garage Unit Air Extractor Dehumidifier

Garages

 

[armascott]

Thank you, I really appreciate all the great info.

 

[rknight111]

A conventional dehumidifier will only effectively work good to 40-45% RH. An LGR has 2 coils and has the capacity to dry down to a much lower RH and this won't run as long, more efficient, and it generates heat. The best way of dealing with this problem is ventilation. LGR is Low grain refrigerant, Drieaz Evolution