[valcarmo72]

I have a microwave oven/ Exhaust fan that is currently set to recirculate the air...which does absoloutley nothing at all. I wanted to flip the fan on the unit but the kitchen is located almost in the center of the house. Therfore I would have to run 18 feet of rigid duct to exhaust the hot air. Is there a max amount of length you can run and also is the normal single wall tin exhaust good enough...? I can't go up because it is on the first floor...only straight across in the cieling with one 90 at the begining of the run...

Thx for the help....

 

[TarheelTerp]

...but the kitchen is located almost in the center of the house.
Thx for the help....

What is UNDER the kitchen?

 

[valcarmo72]

Basement...thought of that but I thought u can only go up and out and not down..

Don't know?...ask someone...

 

[md2lgyk]

I suspect that like dryers, exhaust hoods have a maximum length for the exhaust run. Probably varies by manufacturer and/or model. But I have a gut feeling that 18 feet is much too long. The exhausted air really isn't very hot, so I see a big potential for grease condensing in the pipe.

 

[TarheelTerp]

Basement... I thought u can only go up and out and not down..

I suspect that like dryers, exhaust hoods have a maximum length...
a gut feeling that 18 feet is much too long.

Correct.

Which is where the supplemental exhaust fan comes into play.
LINK

 

[valcarmo72]

What do mean supplemental...? Like a fan on the closest exterior wall type...?

Don't know?...ask someone...

 

[valcarmo72]

Inline fans in the duct work? Will it not build up with grease?..

Don't know?...ask someone...

 

[md2lgyk]

I would've thought so too. But based on the info at TarheelTerp's link, it's apparently OK.

 

[valcarmo72]

Wow totaly missed the link....LOL. Thx

Don't know?...ask someone...

 

[GBrackins]

length of vent is determined by the manufacturer. they determine this by the size of the vent and the amount of air the exhaust fan can move per minute. Go on the manufacturer's website and see what they have listed.

Good luck!

 

[hand drive]

the best exhaust that we used was a roof fan mounted version. totally quiet at the hood when on full blast and pulling all kinds of air, really neat! if trying to pull to much air over a long run of space a supplemental blower will be need to pull the air, grease is part of the system in a kitchen and the fan filters are for the grease- change the filters when needed