Should I install an exhaust fan in a new garage?

Question

I'm having a new garage built in my home and I'm wondering if it's a good idea to have some sort of ventilation/exhaust/fan system installed while they're at it? I'm thinking of doing some spray painting in there so I figured having a vent in there would be a good idea. I mean if I had to install one in an existing garage, I probably wouldn't bother but since it's being built from the ground up, I figure it shouldn't take much effort to install it?

The builder said it won't do much of anything/pointless and that I shouldn't bother. Any opinions on what I should do?

Answer 1

I would completely disagree with your builder. Since it is a new garage, I do see merit in the "build it in" approach. There are two important considerations:

1. how many CFM do you need and what kind of noise level is tolerable? Are you using anything flammable? Water based paints should not be a problem but solvent based paints require special attention. This will drive your fan selection. Of course you want to make sure that the way the fan is turned on is convenient to you. Would you want to have more than one switch? Perhaps a motion detector controller would be even better? Now is the time to choose.

2. you must have a supply of "make up air".

How will new fresh air come in to replace the air you vent? Venting will be most effective if you can arrange a cross flow through your work area instead of a short circuit or whatever might happen without a proper design.

It may be worth it to run a duct just to force the air to flow across. If you wish to get fancy, you could incorporate some degreee of filtering as well.

This is outside the scope of your question but I always like to make sure a work area is well lighted with plenty of lumens and as little glare as possible. Since you are painting, a good (high) CRI is probably important also.

Answer 2

Well, you could put a whole house fan in the wall if you will be painting so often. At the same time, be VERY careful about fans and potentially combustible vapors. If these fumes have ANY explosion potential, then running them through a fan motor is a bit insane.

Personally, I agree with ratchet freak - I'd open the garage door, and not paint on days when this is a problem.

Answer 3

Typically if the garage has ventilated soffet then the garage attic will get appropriate ventilation without the need for a fan, where proper attic ventilation is typically the primary concern.

When it comes to spray painting however that is a seperate concern entirely, and wholly dependent on what type of spray painting you intend to do. If it is typical consumer based spray enamel then opening the garage door should provide sufficient ventilation, however if you plan on doing any automotive painting (especially with the older non-water based enamels) then it is critically important that you have a custom ventilation system installed as well as wearing a ventilator.

The paint fumes from some automotive paints have been linked to certain types of cancer so proper precautions are necessary in this case, however any other type of paint then a ventilation system would be overkill.