Seen that happen a lot. The biggest problem Ii se isThe biggest problem Ii se is the use of flexible duct. Great stuff! Bath fans are great at exhausting humid or smelly air, so (in spite of the code loophole) every bathroom should have one. Danko: Ha!Danko: Ha! The intention is to discourage the practice. I’m really at a loss and frustrated, I’m tired of having to wipe the walls down after every shower! Here are some of the most common reasons, and how to fix them: Check to see if something tripped the circuit breaker. Air flow can be restricted on the front end of the fan, too. Would this small difference be the reason for poor air pull or do I have a blockage somewhere. If the fan is not turning the wrong way I suspect your exhaust ducting or outdoor vent is blocked. Why Do We Need Exhaust Fans? Great info. There are several reasons why your exhaust fan might have stopped working. I am also glad to see that E.T. A stiff vent pipe is better because it does not snag. Nice big outdated bathroom that is not very functional. You can revoke your consent to receive emails at any time by using the SafeUnsubscribe® link, found at the bottom of every email. Minimal back pressure. #6 – the fan hasn’t been#6 – the fan hasn’t been cleaned in years, leading to dust and lint buildup. Don’t forget privacy concerns. I’ve seen them installed poorly by both trades, but you’re right that it really should be the HVAC contractor’s job because they’re more likely to understand air flow. Turn on the exhaust fan and hold a thin piece of paper, such as toilet paper, over the grille. Great post and excellent blog. Looks like i'll be in the attic making fiberglass snow angels. My guess is the bathroom fan exhaust pipe is located in a cold attic space. What have you seen? Yeah, I caught that alien lurking in an attic about 3 years ago. Thanks. They’ll be lucky to get half the rated flow out of that fan. The old ductwork is about 5′ and straight, but it’s only 3″ around while the new fan has a 6″ opening with a 6″ to 4″ adapter. If it doesn’t, there might be a blockage in the duct connecting to the exhaust fan. Maybe he’s not coming back. A bathroom exhaust fan works by pulling moisture out of the air before it can cause harm. Mike E.:Mike E.: That’s another good one. Despite all my research it was a mistake. There are plenty of nice timer switches available for this purpose. Here are 5 reasons why this happens. Danko:Danko: Great points! Then it goes into a piece of rigid duct that goes right up to another ceiling joist. It sounds like maybe the fan flow is hitting an obstruction that’s deflecting part of the air back into the bathroom. : Regarding undercut doors as return air pathways, Section 2.8 of the HVAC System Quality Installation Rater Checklist, Energy Star version 3, (Rev. The warm air will exhaust out the duct and enter back into the attic through the soffit vent or ridge vent. There is a limit to the number of turns the vent run can have to be effective, as well as the length. Realistically though, undercutting bathroom doors is probably the only viable option for these typically small rooms that have the doors open most of the time anyway. Whenever you look for the flow rating of bathroom fans, do not forget to look at what pressure conditions they were rated for. A typical bath fan is rated to move 50 cubic feet per minute of air when it’s operating, but most actually move about half of their rated air flow. HVAC Design Protocols The usual culprit here is that the house is built too well without adding the necessary counter measures. Open each a little bit so it doesn't get too cold in one room. A quick way to catch a blocked duct w/o going into the attic is put a piece of paper over the running fan and see it it can hold it. Reasons to run the bathroom exhaust fan. Any advice or ideas would be appreciated. Except when it doesn’t, of course, as in in this case. The included bracket, nails or screws to the ceiling joist allowing the fan housing to "Snap - In". I think I now understand myI think I now understand my situation in our bathroom which I’ve been trying to solve in my own but I might be calling a home service to fix it for me. Allison,  Allison,  A thousand thanks for doing this blog. And one thing not to forget. Given where I determined it exits in the soffit and the location of the fan I would say there are minimal turns if any as it is a straight shot. Avoid venting through a soffit vent or ridge vent. I always like to tell people when laying out the ducts in craziest possible manner to imagine that they were soldiers who need to crawl throug these ducts to the end, and figure out which layout will exhaust them more. Keep your kitchen clean and your home's air fresh by understanding all the options for ventilating via a hood fan, The Hardworking Home: We weigh the pros and cons of washing your clothes in the basement, kitchen, bathroom and more, Ridding your bathroom of excess moisture is vital for indoor air quality. Please Help, I have threePlease Help, I have three vents, two in the bathrm. You can see from the dark spot on the fiberglass that some air does escape, but it won’t be much here. These were both residential grade just more CFM on the new fan. That duct needs to go all the way to the outside to do its job. The problem is when wood surfaces in the attic are colder than the exhaust air dew point… you get condensation. I realize this question is over a month old but wanted to share my experience. 10 Bathroom Trends From the Kitchen and Bathroom Industry Show, Where to Splurge, Where to Save in Your Remodel, Where to Store the Towels When You Don’t Have a Linen Closet, How to Choose the Right Hood Fan for Your Kitchen, Green and Clean: Ventilate for a Healthy Bathroom, 8 Narrow Bathrooms That Rock Tubs in the Shower, how do i figure out the amount of tiles i need toile the bathroom. A working fan will grasp it t ightly. Wonder if anyone can help with a problem I’m having: I’m replacing a small bathroom fan which didn’t work well with a higher cfm version. Wonder if anyoneGreat info. Keep your ducts and grilles clean to have a good runnig power of your fan (the same as with your car). If your bathroom fan is not able to pull in air, it could be the fan is not clean and air gaps are blocked by dirt. Don’t just turn the fan off when you leave because it probably hasn’t done enough yet. It’s a small bathroom. ACCA Manual D (3rd edition),Appendix 1, para. Here's how to do it best, Not a fan of shower-tub combos or of ditching the tub altogether? Or does that carry energy problems of its own? Remove the grille and try to find and clear the clog with a brush, preferably one that’s specifically for cleaning ducts. Bill H.: That’s good to hear. Don’t Confuse Design Temperature With Degree Days. Bathroom exhaust fan make-up air requirements for tight buildings: this article explains why we need to provide make-up air in to bathrooms to permit the exhaust fan to operate effectively and safely.