Our builder talked us out of a remote blower, claiming it would be just as noisy as an internal unit. He was flat wrong, and now we are going to have to retrofit a remote blower at additional trouble and expense.

Remote blower = quiet.

Blower in hood = loud.

It's that simple.

Apparently our builder was unaware that intake silencers can be mounted in the ductwork between the hood and the remote blower. The cost is under $100.

Fantech Click on attenuators on the left after arriving at the site.

I accidentally posted a link to the wrong Fantech site. The correct one is below. Scroll down to "Silencers For Round Duct."

Fantech USA Site

The drawback to the remote blower is that if it's mounted on the roof it will be much harder to service if something goes wrong. Some people have found that people who repair such things refuse to deal with one on the roof. Most of the noise comes from moving air, not the motor, so while a remote blower will be a little bit quieter it may not be worth the hassle and expense.

Remote blowers are usually mounted in the attic. If the attic is accessible, serving it should be no problem.

There are at least 3 components to the noise:
(1) The motor noise (hum/vibration/etc)
(2) The sound of air rushing through ductwork.
(3) The sound of air rushing through baffles or filters

A remote blower allows you to move (1) away from the kitchen *If* you effectively isolate the metal ductwork so vibration is not conducted back to the hood.

You will never get rid of (2) and (3).

"Most of the noise comes from moving air, not the motor, so while a remote blower will be a little bit quieter it may not be worth the hassle and expense."

We also have an ERV (Energy Recovery Ventilator) which has a 150 CFM remote blower, which moves much less air than the average kitchen hood blower.

The ERV's installation instructions explicitly call for the installation of a silencer in the duct between the inside blower's intake and the wall grill. The instructions warned against leaving the silencer out due to the intake roar of the blower.

Our mechanical contractor, of course, left it out. The noise level in the house was so high the ERV was unusable. Once I prevailed upon the builder to get the mechanical contractor to install the silencer, the sound abated almost completely.

Researching the ERV sound problems lead me to the Fantech silencers and the knowledge that intake roar is the real problem with blower fans. Some types are worse than others, but the real cure is to put a silencer on the intake side. That requires a remote blower.

cherylkla
You asked about "remote blowers and internal blowers".
What about inline blowers?
These are what get installed in attics.
I have one installed in a soffit / header / box / at the ceiling over the kitchen counter.
The same header / soffit / box / whatever-you-call-it that has the overhead lights in it.

I bought it from fantech.net
I found fantech after coming to this forum.

My installation may be atypical for many reasons so I'll describe it here.
It's an FG6 installed in-line, i.e. the vent duct itself.
This FG6 fan / motor / blower is about 5 feet away from the kitchen exhaust opening that I built as a huge recess or alcove ( or "niche in the wall" ) behind the cooktop. My countertop jogs into it this niche - alcove - recess, and jogs out. It's great to have more counterspace. More room to put things there when cooking. I even use that counter area to dry stuff when I want to be sure the moisture will go outdoors and not stay indoors.

I love my custom setup. There is always noise when on high, for any fan, but this one makes a nice little rushing noise, not irritating. At medium or low it is real quiet. So it turns out that I didn't need a silencer. At any rate, I didn't have enough duct length to have room for it. The duct is initially a flat rectangular shape as it slides up the wall in the stud cavity.

Your CFM may be higher than mine (the FG6) and other factors apply, so you might like a silencer...

Definitely Yes, the farther you put the blower from your ears the less audible its turbulence will be. The only noise left is a normal rushing noise. Large duct and large surface area for grilles can make that moving air noise very reasonable.

"""Remote blowers are usually mounted in the attic. If the attic is accessible, serving it should be no problem"""

Remote blowers or not in the attic. In-line blowers are in the attic and are quieter than remote or internal.

Silencers can be added but these don't affect the sound of the air at the point of entry into a hood and there is no way this can be muffled.

If you want a quiet hood, use these criteria,
-In-line or Remote blower as large as possible. The larger the blower, the quieter it is on a low setting. This is basic mechanics. In-line blowers are not internal blowers.
-larger ducts are quieter than small ducts. Minimize turns (90 degree angles and such).

An inline blower is a remote blower by definition, since it is not mounted in the vent hood.

That is true by definition but not for the industry. Wolf, among others, classify theirs as either remote, in-line, or internal.
Similar to the word "stove" People ask appliance retailers for stoves all the time. By definition a stove requires wood to be it's heat source. A stove wouldn't be an appliance, but a "range" would.
I only make the point because kitchen ventilation is an afterthought to the general public and can be confusing.

This industry source has a different view. :-)

I have a Kobe CH27 vent hood that I installed last week. I bought this hood because (among other reasons) it was supposed to be quite. I also have a Radio Shack sound meter and just measured the sound pressure level with the baffle filter in and out. On the "Quiet" setting which is supposed to be 280 cfm, with the baffle filters it measures 65db at the cooktop. Without the baffles filters it is below the 50db limit of the meter. And in reality I can barely hear it a few feet away. I've not been happy with the performance of this hood and I'm trying to work it out with Kobe. They have actually been very helpful. It just doesn't pull much air and I realize one problem is the baffle filters. They really obstruct the air flow (which I guess is how they work) but is also reflected in the added noise.

I'm thinking about an in-line fantech blower in the attic to supplement the pull but I'm wondering how to activate it. I think I can use their air pressure switch to automatically turn it on when I turn on the hood. Has anyone done this?

sorry creek side but Futuro is not exactly a well regarded "industry" source for anything in the vent market.

They make cool looking products but have not been here that long, have very little market share and no bricks and mortar distribution that I can tell.

However , Wolf, their partner Broan, have been.

For people in the business it is as aprince laid it out.

Thanks, everyone, for the replies. Our cooktop is located on an exterior wall and we have a two story house, so the dealer said an in-line blower is not a possibility. He suggested the remote blower because it is quieter than the internal blower. I think I'd like to go with the remote blower, (I hate all the noise our current hood makes, and it's not even that big!) but I like to know all the pros and cons before making a decision just based on what the dealer says.

exterior wall ; two stories : so you would send the exhaust out the wall and up a duct on the wall, and the remote blower would be up high. ( Y / N ? )

forget the noise for a minut. When the blower motor or fan breaks (when not if), an internal blower and fan usualy has to be ordered from the manufacturer and may or may not be available and will take somewhere between a week and 6 months to get if it's not discontinued.
a repairman will have to work in your kitchen make a mess on your stove, and probably scratch up your hood to replace the unit.

An inline blower just hooks between two pieces of duct. doesn't need to be the exact same brand or model or capacity. It just has to fit the duct size, and if it doesn't adapters are cheap. and the repair man is in the attic, not messing up your kitchen.

a roof or sidewall mounted blower is a little more dificult, but not much.unless you have a two story house with a steep roof.

I took the guts out of a brand new Monogram Hood and connected a fan tech wall mounted blower in the attic. with a homemade silencer it's pretty quite. works great.

And i know I can get a replacement within a week 20 years from now.

>>forget the noise for a minut. When the blower motor or fan breaks (when not if), an internal blower and fan usualy has to be ordered from the manufacturer and may or may not be available and will take somewhere between a week and 6 months to get if it's not discontinued.
a repairman will have to work in your kitchen make a mess on your stove, and probably scratch up your hood to replace the unit.

COMPLETE BS

Hey, chery -- I recommend that you talk to the Broan folks, preferably with your computer up and connected to the internet. I found their customer service and product specialists particularly helpful and they actually know a lot about the Wolf-branded ventilation systems since Broan makes them for Wolf.

It helps if you understand that for commercial applications, hoods come in pieces that are put together in a package for hoods marketed for residential use, although you can definitely mix and match, like the Broan and Best by Broan parts.

The Wolf/Sub Zero folks I found much less helpful and a couple were downright difficult to deal with. Maybe it was because they don't actually make the ventilation products?

qwertyui is right, and his use of illustrative language is OK in my book. Separate the hood shape from the fan placement and fan type.

californiagirl is right about calling the manufacturer.

You're not in love with Wolf, just considering it. So know this. One big holding company owns several exhaust vent companies, but instead of having a single one of these companies take the lead and gradually take over the newly acquired company, this holding company keeps the acquirees in the dark for many years, still operating separately. Consumers are not told that these companies are all related and that they are now beginning to buy motors and parts from each other. Sooner or later you'll find knowledgeable people to talk to. Try Nutone. Nutone and Broan have been operating together as sister companies for the longest time. Best (Wolf) Venmar and others are more recent acquirees. Try the Canadian technical support numbers too. Sometimes the employees at the US tech support lines have the least amount of access to the kind of information that would let you build your own system.

You might be stunned to find out that a powerful remote or inline fan costs far less than what you are planning to spend for a packaged product that can be displayed in a showroom, sold as a boxed product, and then delivered as a single box... There are several manufacturers; fantech.net is only one of them. Your builder might love you for introducing you to the fan makers. If the fan guys only sell through distributors and some of their distributors only want to sell to knowledgeable people who appear to be custom manufacturers themselves, that makes sense since they cannot go through all the hassle of dealing with average consumers. Hint.

Any canopy captures rising air. Any blower takes that and exhausts it.

Showrooms need to have a product they can show you, so its blower is right in front of your face where you can be shown it. Hint.