Can I use microwave ducted vent for recirculation exhaust venting?
Jill Coopersmith
6 years ago
last modified: 6 years ago
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Comments (14)
barnaclebob
6 years agolast modified: 6 years agokaseki
6 years agoRelated Discussions
How can I tell if I have venting to the outside or recirculating?
Comments (8)Uh oh, that is NOT good news. It does have a grill along the top front, and the fan is loud and pretty ineffective. However, there is no air that comes out of that top grill....just the faintest, tiniest, almost non-existant whiff of air coming out of one tiny little section of the grill (like a 1/2" section of it). It is not butted against an exterior wall - the other side of the wall is our formal living room. Would there really be no air coming out of a recirculating vent? How hard is it to install venting? Can I do a wood hood that is basically like an extension of the cabnetry with a recirculating hood? It almost seems a waste - yes, it is mostly for asthetics that I want it, but it would be nice to have it functional too, and almost seems frivolous to install a non-fuctional (ie recirculating) vent. I am going to check out the exterior walls and roof right now to look for something....See MoreExhaust Vents - I Can't Be The Only One....
Comments (12)All the volume of air that the hood vents outside must enter the house from somewhere. In older homes, some of it will come from poor sealing around doors and windows. The rest will be pulled into the house from other openings, and these openings are usually the vents on gas-fired (and oil-fired) equipment (furnace, water heater, clothes dryer,etc). If enough MUA is needed, it can actually reverse the flow of the flue gas leaving the appliance and essentially bring the fumes into the house ("backdrafting"). Obviously, this is a very dangerous situation due to CO concerns. In newer highly-sealed homes this is an even greater problem. Every house and vent setup is different so it has to be handled on an individual basis. One way is to run the vent with all windows and doors closed and check the airflow at all gas appliance vents to ensure there is no backdrafting. Any MUA system will bring in outside air, which will be cold in winter and hot in summer. In some cases, a heat exchanger could be used to save energy costs. There is no easy or cheap answer if you find you need MUA. You can't count on always remembering to open a window when you run the vent. It really needs to be a foolproof system such as an automatic vent to let in MUA as needed. Steve...See Morehiding OTR microwave vent duct
Comments (10)So to answer questions back from you all... Re photos - in the top photo you see the empty space where the microwave should be installed, and the upper cabinets above it that were supposed to house the vent/duct into the wall to run outside. The contractor ran the venting to come in from the ceiling instead of into the back of the upper cabinets above the microwave. The second photo was one attempt at a solution- to stack a 2nd cabinet on top of the uppers. Not a great fix in my opinion. The microwave is existing and was less than 1 y/o so no need to replace it. This is a remodel not a new build and all the electrical etc was set up there for a stove/microwave combo I guess short of buying another upper cabinet w/ different dimensions, or custom building some sort of surround for the vent, I don't really have any other ideas. But at least you guys validated what I had already researched as options. Thanks....See MoreShould bath exhaust fan be vented to roof RIDGE VENT through attic?
Comments (11)Happy to help. I've had a bit of this work done myself, in two different houses. In one, I had a Fantech BFRK 100 installed. There was an existing bathroom exhaust fan that worked poorly but I didn't want to put in a new grill. With the BFRK, you take out the guts of the old fan, keep the housing in place, and then connect ducting that runs first to the Fantech unit located a few feet away up in the attic and then from it to the roof passthrough. I had that done by an HVAC contractor who was on site replacing HVAC equipment. I'm not sure they would have done the work otherwise, it was like a favor to me. The second one was the replacement of a 20 year old exhaust fan with light in a WC closet that was noisy and ineffective. I had that done by an electrician who also was doing other work. He needed to go into the attic to remove the old unit, connect the new one to the framing, put in a new duct and connect the power. It made a huge difference. That one also vents through a roof pass-through, important because we use it to vent the bathroom of moisture from showers and baths. Good luck and keep your BS detector handy. If other exhaust vents terminate in the attic, it's time to fix those too. Each duct run needs its own roof passthrough unless you're using a Y setup with one fan at the base of the Y for two locations. Be careful if so, those can be tricky if the duct runs from the rooms to the base of the Y aren't of equal length. As far as duct run distances go, the unit will specify the maximum distance. For my most recent job, the ceiling unit with light that was 110 CFM, I want to say the spec for the duct run was something like 60 feet. I wrestled with putting a wall vent on a gable end but decided to stick with the existing through-roof vent....See Moretjmwine
6 years agojwvideo
6 years agolast modified: 6 years agoJill Coopersmith
6 years agoJill Coopersmith
6 years agotjmwine
6 years agoJill Coopersmith
6 years agoJill Coopersmith
6 years agoJill Coopersmith
6 years agokaseki
6 years agoJill Coopersmith
6 years agoM Coviello
2 years ago
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