Bathroom exhaust fan

[Walter Cohen]

My main bathroom does not [yet] have an exhaust fan and I'd like to install one. There is a ceiling light fixture that has two flood bulbs in it, one regular and one heat bulb which we use when coming out of the shower. I was thinking of replacing this light fixture with perhaps a combo light-fan unit but I don't think they make one with a heat lamp in it. So I could either purchase what I find on the net or in HD or keep the existing light fixture and mount the fan between the fixture and the outside wall.

Main question: I could exhaust the fan straight out horizontally through the outside wall. However, my kitchen is right next to the bathroom and a kitchen ceiling fan, with duct work, leads straight up through the attic and roof for venting. This kitchen fan duct is relatively close to the bathroom and I'm wondering if instead of venting the bath fan horizontally out the side of the house wall I could connect it up to the kitchen fan duct which runs up through the attic to the roof.

Any thoughts on if this is advisable or might cause problems? I hardly ever use the kitchen fan, by the way.

Thanks, Walter

[RBM]

They do make heat lamp-vent units, but the vent cfm tends to be so low that they're pretty worthless. You must vent the unit to the outside and you cannot connect it to a kitchen exhaust unit vent

[bamboo]

[websurf1]

I'd check my local codes. That sounds like it could be one of those "don't" things.

Also, backdrafts from the bathroom to the kitchen might be unappetizing....

[nicksanspam]

Who sez? Why?

Nick

[Todd H.]

That'd be my pick.

In this situation, kitchen fumes could be easily pushed into the bathroom, and vice versa. As such, I'd be surprised if local codes would allow it particularly given the grease-laden kitchen air's likelihood of getting in contact with a bath exhaust fan that will have large furry labels saying "not designed for kitchen use."

I *think* the reason for the labels is that unless a fan is electrically designed to be moving greasy air, you can end up with a fire hazard in a hurry, which I learned anecdotally:

Some exhaust fan specialist company in Chicagoland brilliantly installed a bath fan in the ceiling over my stove which had lacked any ventilation previously. A couple years after I had this fan added, I started hearing arcing and fan stuttering. I powered it off, popped the cover of the fan, and was immediately greeted by a big yellow warning label "not designed for kitchen use." Ironically it was coated with grease. I promptly wanted to throttle the company for installing a big steaming fire hazard in my kitchen ceiling.

To their credit, all it took was one phone message to the company explaining my discovery, my desire to have it corrected, that the estimate contract specified a kitchen exhaust fan, and a subtle friendly mention of the words "looming fire hazard" and "liability."

So in short, I'd play it safe and vent that baby out the side wall or to its own dedicated roof cap.

Best Regards,

-- Todd H.

[buffalobill]

requires separate venting to outdoors. most heat/light/vent fans are a noisy idea. look at remote fan if you can mount in attic.

Walter Cohen wrote:

[Rick]

sure they make that. NuTone-9427P-Two-Bulb-Heater-Ventilation-Exhaust-Fan

| So I could either purchase what I find on the net or in HD or keep the | existing light fixture and mount the fan between the fixture and the outside | wall. | | Main question: | I could exhaust the fan straight out horizontally through the outside wall. | However, my kitchen is right next to the bathroom and a kitchen ceiling fan,

never saw a ceiling fan with ductwork before. I always thought they had blades for air.

| with duct work, leads straight up through the attic and roof for venting. | This kitchen fan duct is relatively close to the bathroom and I'm wondering | if instead of venting the bath fan horizontally out the side of the house | wall I could connect it up to the kitchen fan duct which runs up through the | attic to the roof.

you can not connect bath exhaust fan with kitchen hood fan (not ceiling fan). illegal

| | Any thoughts on if this is advisable or might cause problems? I hardly ever | use the kitchen fan, by the way. | | Thanks, | Walter |

the shortest run of ducting possible bathroom exhaust fan ducting tend to create mold inside on long runs. unless you are taking cold showers.

NuTone-9427P-Two-Bulb-Heater-Ventilation-Exhaust-Fan

[Rick]

not to mention the combustible gases (methane) and grease are not compatible.

[RBM]

Aside from the possibility of backflow from either source, the duct attached to the kitchen exhaust would have been sized for the CFM flow of the kitchen unit, not the combined flow of both the kitchen and bathroom fans, so it would be to small to carry both at the same time without reduction in air flow

[Joseph Meehan]

Most local building codes. You don't want the bath to smell like frying fish and you don't want the kitchen to smell like .....

[Rick Blaine]

Most codes. Because they do not want cross venting to occur.

[nicksanspam]

We use the ICC. What does it say?

Nick

[Rick Blaine]

You need to check with your local building inspector. Most localities in the US use the ICC as the foundation for their codes, but then tailor it. Your local building inspector has the final say.

[nicksanspam]

We use the ICC. What does it say?

Nick

[Joseph Meehan]

Frankly I don't care what the ICC says. Around here the local code rules and it says don't do it. I might add that I think is is a really stupid idea anyway and I would not do it even if the code allowed it.

[Walter Cohen]

Ok all...thanks for your comments. I'll probably just get a fan-only unit and mount it exhausting straight out the back of my home (only about a 3 - 4 foot run).