The main job of the baffles is to act as a surface to which the grease collects. I don't think having them angled or flat will affect how they collect. The grease adheres to a cooler surface regardless of orientation.

Quiter depends on the whole system (airflow, duct size, shape of hood, fan speed &c&c) so I can't comment on that aspect--you'd have to compare hoods side-to-side.

I suspect they are at an angle to increase the capture area, as I have seen in Modernaire/eurostoves literature stating that the 'recessed lighting bar increases the capture area'. Having the baffles angled instead of flat across would also increase the capture area of the rising smoke and help prevent it from "spilling" out the sides.

In commercial hoods, the baffles have to be above a 45-degree angle to meet code. I believe this is to ensure that collected grease particles will migrate to the grease cups, thereby reducing fire hazard.

No residential hood that I've seen has the baffles at such a steep angle. Presumably, home owners will clean them before they reach the level of being a fire hazard.

Another factor may be containment. Steeper angled baffles could improve the chance for effluent reflected off of a baffle on the first bounce to be pulled past the baffles rather than curl down and escape the hood. Residential hoods with shallow baffle angles need a bit more cfm to compensate for this.

kas

we have an abakka and it works great. would do it again! Here it is:

A baffle filter installed at an angle will allow the grease to run down into a trough. When cleaning the trough is emptied and placed in the dishwasher along with the filters. This is the way commercial hoods are designed.

A horizontally installed filter will "rain" straight down onto the cooking surface when too much grease accumulates. One is not more efficient or quieter than the other.

The angled one may provide more surface area than the flat one. Hence more grease collection.

Baffles collect grease by impingement from moving air being forced to change direction abruptly. This also causes turbulence and noise. The noise from baffles will depend on their aerodynamic design and the air velocity. I don't think I could look at two different production residential baffle designs and choose which would be quieter for the same velocity. You would need an aerodynamicist for this.

An unusually quiet baffle would probably cost a lot more to make than the stamped designs that are affordable, even as parts of "high-end" hoods.

I haven't deliberately done this experiment, but my impression from memory is that wok cooking or vigorously boiling a pot of water will make more noise than the baffle hiss from my Wolf Island Pro hood on full power.

kas

I spoke with Abakka. There reasoning for flat baffles were as follows:

- True commercial hoods have angled baffles that are much larger and a much greater angle than can be done on a residential hood.

- The volume of CFM and grease in a commercial kitchen is exponentially higher then one would ever see in a residential setting. Thus, the steep angled baffle are needed to allow grease to drip down the baffles into a drip collection tray and have to be maintained daily.

- The flat baffles on the Abakka have more surface area then an angled style - residential baffle.

- The flat baffles were specifically designed for use with there blowers. The are designed for maximum baffle surface area, air flow, noise reduction and ample grease collection for the variable speed range on their blowers. i.e. more a total system design approach.

You can see the angle on the baffles on my Thermador hood. The angle must be 30* or more; not a true 45* however, but the grease will run down into the collection trays if I ever let it go that long (yukk).

As to sound, I doubt there is any difference. Certianly none that you can hear.

As to efficiency, it's just a matter of surface area. I think for the home it comes down to aesthetics and personal choice.

Can you make a commercial hood to ductless/recirc?

I recall recently (past year) linking to a commercial recirculating hood. These may require some extra ceiling height and will have significant filtering mass.

From UL:

"These systems capture the cooking effluent from a cooking appliance, process the captured air through various filters and vent the filtered air back into the room where the appliance is located. These systems can be either portable or permanently installed, and include an integral fire extinguishing system to protect the hood system and appliance area. Recirculating hood system requirements were originally introduced in the 1994 edition of National Fire Protection Association (NFPA) 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, and have subsequently been introduced in the International Fire Code (IFC), the International Mechanical Code (IMC) and the Uniform Mechanical Code (UMC). They were previously investigated in accordance with requirements in UL 197, Standard for Safety for Commercial Electric Cooking Appliances. Requirements covering these appliances were later updated and moved to UL 710B, Standard for Safety for Recirculating Systems."

Here are some examples: https://www.webstaurantstore.com/56229/ventless-hood-systems.html

https://kitchenventilation.com/2021/09/27/recirculating-systems-for-kitchen-ventilation/

https://wells-mfg.com/product-category/ventless-cooking-systems/ventless-hoods/

Has anyone ever had any trouble with condensation on stainless steel baffles? I have a vent a hood (M34SLDSS) with a 625 CFM blower and within minutes when we boil water (for pasta, for example), there is water dripping on my range. The blower is also soaked very quickly. No one can figure out what is going on... any thoughts?

Don't ask the same question on two threads. It can lead to broken trains of thought. Ideally, you should have started a new thread for this topic as it wasn't part of either thread.