Hot Garage Ventilator


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Old 07-25-18, 03:05 PM
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Hot Garage Ventilator

Problem: Heat of Georgia summers makes for very high temperatures in closed garage.

I'd like to install a thermostatically controlled ventilator in my 20x20 garage. Has someone done this really well and can advise me or direct me to resources?

My house is standard vinyl sided construction. Figure I can use the rear wall to mount a fan?
 
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Old 07-25-18, 04:37 PM
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There should be a lot of exhaust fans on the internet but there are decisions you need to make before you shop.
1. Is this garage attached to the house and if so is the attic space common with the house.

2. To blow hot air out you will need a lot of open vent area for incoming replacement air.

Also describe the house and garage more.

Bud
 
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Old 07-25-18, 07:47 PM
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The garage is attached to the end of my 1200 sq ft ranch style house. Double solid steel rollup door faces north, 2 windows face due west. Interior is completely sheetrocked. 40 gallon gas fired water heater is in garage. No current source of incoming air other than opening windows or door. Garage attic space is open to house attic. Regular asphalt shingle pitched roof.
 
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Old 07-26-18, 04:35 AM
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So you are looking to ventilate just the garage and not the attic above.
How is the gas water heater vented, side wall, chimney through roof, or pvc direct vent?
If the water heater requires combustion air then any type of large exhaust fan is going to be a problem.

Bud
 
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Old 07-27-18, 03:27 PM
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H2O heater has a 4" sheet metal exhaust pipe goes through the ceiling and through roof. Combustion air is just garage air. Any kind of ventilation should improve the high temps I have now out there in 90+ degree summer heat?
 
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Old 07-27-18, 03:50 PM
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Since your combustion air is coming from the garage you cannot operate a large exhaust fan which would depressurize the garage below the mfgs safety requirements. Even if you say you will not run the boiler at the same time that doesn't count for codes and it doesn't count when someone forgets.

Bud
 
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Old 07-27-18, 07:37 PM
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Depressurize? I would expect I would need to add adequate intake vents for the exhaust vent with the fan?
 
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Old 07-27-18, 08:34 PM
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For air to enter the intake vent you suggest it needs a pressure difference across that opening. To keep the pressure low enough so the combustion appliance can still function I'm guessing a 4' x 4' opening with a screen over it. I had a rather large new boiler installed and just for the air it needed it required a 3' x 3' opening.

But, to do it right you should have someone test how leaky that garage is and determine how much air the current appliance needs and its limit on negative pressure. Then you can determine how much additional venting you will need for your exhaust fan.

Bud
 
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Old 08-14-18, 02:39 PM
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My house faces due west and gets the brunt of the PM sun. What benefit might be expected by using tint on west facing windows? Currently I only have plantation blinds on these windows.
 
 

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