Installing Ductwork for a Kitchen Exhaust Fan
LESLIE: Now we’re going to talk to Mike in New York who’s having an exhaust fan issue. What happened?
MIKE: Well, the … I thought it was just the filter and that the filter may be clogged. This is a house that …
LESLIE: Where is the fan?
MIKE: It’s the exhaust fan over the stove.
MIKE: And when I took the filter out, discovered that the exhaust fan goes nowhere.
TOM: Ah, well it’s a recycling fan.
MIKE: (chuckling) Yes. So that’s why it wasn’t exhausting.
TOM: Yeah. See, that solves the problem. (laughing)
MIKE: If I’d laid the duct work in there, does it … can I put just a 90-degree turn after the fan or do I have to do this gradually with a curve or a couple of 45s?
TOM: Well, it’s a good question. Every 90-degree turn, in duct work, is … has the resistance equal to about 20 feet of straight duct. So, you …
LESLIE: Wow. Can you put a fan inside the duct work to sort of conduct it along?
TOM: (overlapping) No. No. I mean the fan might be strong enough. And if it’s a kitchen exhaust fan that’s designed to be ducted, the fan’s going to be a little stronger than the kind that are not designed to be ducted. I hope you’re not thinking about using the same one; because you probably can’t. You probably want to get a new one.
MIKE: Well, I wasn’t thinking of that but if that’s what I have to do, that’s what I have to do.
TOM: Yeah. I would. And you want to try to put in as few turns as you possibly can. So just good duct design would involve you putting in as few bends into that run as you can so you get the hot air out as quickly as possible.
MIKE: Okay. I was only anticipating one 90-degree turn. But am I better off with a … with a curved duct work or maybe a couple of 45 bends?
TOM: Well, if you’ve got the room, go with two 45s. Yeah, less resistance. You know, if you’ve only got to put one 90 in and that’s just going to get you right out, then go ahead and do it. But just in general, the less turns … the fewer the turns the better.
MIKE: Okay, great. That’s what I needed to know, then.
TOM: Alright, Mike. Good luck with that and thanks so much for calling us at 1-888-MONEY-PIT begin_of_the_skype_highlighting 1-888-MONEY-PIT end_of_the_skype_highlighting.