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citizenzen

macrumors 68000
Original poster
Mar 22, 2010
1,543
11,786
Actually laundry room to be more precise. We had a very old exhaust fan with two lights that helped to vent our laundry room that died recently. I bought a fan at the local hardware, brought it home, and discovered that the old fan vented vertically, while the new fan vented off the side.

The problem it that the existing ceiling opening is oriented so a side vent goes straight into the ceiling joist. I could recut the hole and reorient the opening 90º, but I'd prefer to find a rectangular bathroom fan that fits the existing opening and vents vertically like my old one.

A little exploring on the web indicates this isn't so easy to find. It appears that vertical discharging fans have circular housing and are smaller than the existing hole I'm hoping to fit. So does anybody know of a rectangular bathroom fan with lights that vents vertically? Or am I just going to have to bite the bullet, recut the hole and patch it up afterwards?

Thanks for any help.
 

citizenzen

macrumors 68000
Original poster
Mar 22, 2010
1,543
11,786
The more I think about it, the more I'm convinced that I just need to recut the opening and reorient the fan. Whoever put originally installed it didn't do it correctly. But to continue trying to accommodate that mistake just compounds the error.
 
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dk001

macrumors demi-god
Oct 3, 2014
11,141
15,493
Sage, Lightning, and Mountains
Actually laundry room to be more precise. We had a very old exhaust fan with two lights that helped to vent our laundry room that died recently. I bought a fan at the local hardware, brought it home, and discovered that the old fan vented vertically, while the new fan vented off the side.

The problem it that the existing ceiling opening is oriented so a side vent goes straight into the ceiling joist. I could recut the hole and reorient the opening 90º, but I'd prefer to find a rectangular bathroom fan that fits the existing opening and vents vertically like my old one.

A little exploring on the web indicates this isn't so easy to find. It appears that vertical discharging fans have circular housing and are smaller than the existing hole I'm hoping to fit. So does anybody know of a rectangular bathroom fan with lights that vents vertically? Or am I just going to have to bite the bullet, recut the hole and patch it up afterwards?

Thanks for any help.

Did that in an old work shed. I cut and molded a sheetmetal mount cover and mounted the circular fan assembly into it. I was fortunate that the old square cut was larger that the circular new fan footprint.

If you can do sheetmetal, it's not hard.
 
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Tomorrow

macrumors 604
Mar 2, 2008
7,160
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Always a day away
Assuming you need just a typical light/fan (that is, the room you're ventilating is small), you can use a side discharge fan and simply turn the duct upward with a 90° fitting. Look at this PDF, page 2, bottom left corner detail.

It is true that the majority of these fans are going to be side discharge, but that shouldn't keep you from routing the duct vertically, I see it all the time.
 
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Huntn

macrumors Penryn
May 5, 2008
24,019
27,099
The Misty Mountains
My two cents, you probably know this but....

Buy a good fan, the typical fans that often come with a house can be cheap and don't move much air. Replaced our original and cheap bath exhaust fans with Panasonic, something like this. Of note If I did not have access to the attic, they would have been difficult refits. The builder had vented them into the attic, which is not the best. I had vents put into the roof when we had our shingles redone. Both are side exhaust fans.
 
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MacNut

macrumors Core
Jan 4, 2002
22,998
9,976
CT
Assuming you need just a typical light/fan (that is, the room you're ventilating is small), you can use a side discharge fan and simply turn the duct upward with a 90° fitting. Look at this PDF, page 2, bottom left corner detail.

It is true that the majority of these fans are going to be side discharge, but that shouldn't keep you from routing the duct vertically, I see it all the time.
This is my thinking as well.
 
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citizenzen

macrumors 68000
Original poster
Mar 22, 2010
1,543
11,786
Assuming you need just a typical light/fan (that is, the room you're ventilating is small), you can use a side discharge fan and simply turn the duct upward with a 90° fitting. Look at this PDF, page 2, bottom left corner detail.

It is true that the majority of these fans are going to be side discharge, but that shouldn't keep you from routing the duct vertically, I see it all the time.

That one could work.

The one that I have discharges off the short side of the rectangle ... the side butting up against the ceiling joists. But your version discharges out of the long side, where there is plenty of room to vent up.

Genius!

Thank you all for helping a brother out.
 

dk001

macrumors demi-god
Oct 3, 2014
11,141
15,493
Sage, Lightning, and Mountains
That one could work.

The one that I have discharges off the short side of the rectangle ... the side butting up against the ceiling joists. But your version discharges out of the long side, where there is plenty of room to vent up.

Genius!

Thank you all for helping a brother out.

One last thought ... increase the flow capacity of your fan if possible. Angles take a good bit away from it.
 

vrDrew

macrumors 65816
Jan 31, 2010
1,376
13,412
Midlife, Midwest
The builder had vented them into the attic, which is not the best. I had vents put into the roof when we had our shingles redone. Both are side exhaust fans.

I'm surprised that passed building inspection. Venting humid bathroom air into an attic space is a recipe for disaster.

Vertically venting bathroom fans is usually the preferred way of doing it. Hot air rises, and a straight path cuts down on the chances of condensation forming in the ductwork. That said, a vertical vent also means cutting a hole in the roof fabric. And it's critically important that the vent be properly flashed and sealed to eliminate the chances of wind and rain pushing water under the shingles. There is also the issue of the duct offering an ingress point for rodents, birds, and other critters.
 
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0388631

Cancelled
Sep 10, 2009
9,669
10,824
I did the same with Hunt. Buy a quality fan with low noise but good CFM. I replace my unit ever three years to keep it efficient. Also because I enjoy home improvement. I've torn up and redid our driveway about 20x in the last 15 years.
 

Tomorrow

macrumors 604
Mar 2, 2008
7,160
1,365
Always a day away
Vertically venting bathroom fans is usually the preferred way of doing it. Hot air rises, and a straight path cuts down on the chances of condensation forming in the ductwork. That said, a vertical vent also means cutting a hole in the roof fabric. And it's critically important that the vent be properly flashed and sealed to eliminate the chances of wind and rain pushing water under the shingles. There is also the issue of the duct offering an ingress point for rodents, birds, and other critters.

Vertical venting may be preferred for NATURAL ventilation, but with a fan, it's actually preferred to go sideways. A hole in the wall is much easier to build, it's more leak resistant, and can be used with a backdraft damper. A fan is forcing the air, so "hot air rises" plays no part in the equation.
 

vrDrew

macrumors 65816
Jan 31, 2010
1,376
13,412
Midlife, Midwest
A hole in the wall is much easier to build, it's more leak resistant, and can be used with a backdraft damper. A fan is forcing the air, so "hot air rises" plays no part in the equation.

Good to know. Thanks!

Bathroom fan venting became a (reluctant) hobby of mine. An acquaintance had his bathroom ceiling fall in on itself due to a (very) leaky ceiling fan. When I pointed out that simply squirting some caulk around the vent flashing was unlikely to solve the underlying problem - he wasn't very happy.

Six months later his house was condemned by the city building department due to the fact that the unchecked leak had filled virtually his entire living space with toxic mold.
 

Mind37

macrumors newbie
Mar 4, 2022
1
0
That one could work.

The one that I have discharges off the short side of the rectangle ... the side butting up against the ceiling joists. But your version discharges out of the long side, where there is plenty of room to vent up.

Genius!

Thank you all for helping a brother out.
I have the exact same issue that you had! What fan did you end up going with??
 
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