Oh, and regarding the the idea for venting through a chimney -- building codes prohibit venting range hoods into a chimney if the chimney is used for anything else or even has unused connections elsewhere on it. Codes also prohibit sharing range venting ducting with anything else.

Now, if that existing chimney is otherwise unused and sealed off, and in good condition, your locality might or might not allow you to call that chimney a chase and use it to run sealed vent ducting to the roof.

I've seen that pass inspection in a couple of instances in my town. Both were old houses built back around the turn of the 20th century with half-chimneys that exclusively served a kitchen's coal-burning range. The chimneys had been sealed off since the 1940s when the homeowners replaced their old coal stoves with electric ranges. In both instances, the flues were in good shape and large enough to run the ducting for the hood vent. My vintage-1910 house had a similar set up (central chimney for heating appliances and a separate chimney in the kitchen for a coal stove) but found the kitchen chimney was in near derelict condition. The brick mortar and the flue lining were crumbling and needed to be removed. So I did that and found another way to vent the range hood to the outside.

If you are mostly boiling water or you have windows open daily then a recirc is fine. Otherwise you should vent to outside. And, given the health implications of poor indoor air quality, I would not shirk on proper ventilation to avoid MUA.

More: https://bamasotan.us/range-exhaust-hood-faq/

My husband and I went with a Broan recirculating hood. Pleased as much as could be expected. Our choice was made on CFM vs sone, user interface and looks,. The VAH may be the Rolls Royce of them, but it’s still a recirculating hood. And the upkeep, yipes the replacement filters $$ on top of its $$$ sticker price. We just don’t cook enough fragrant and greasy foods to warrant it.

We were steered toward rhe Miele; but in comparing it with the Broan we coild not see any real difference (other than styling, possibly). We took the risk not hving seen it in person and were very happy with its lines and proportions when it was delivered. After three months of cooking, I noticed slight yellowing of the screens indicating it is working to trap airborne grease. Good enough for me.

And you can‘t beat its price. Less than half of a comparable Miele.

At a minimum, a recirculating hood needs charcoal filters as well as grease filters. Else odors and potentially irritant chemicals will be recirculated.

Slight yellowing after three months of use sounds as if it doesn't really do much at all.

Our externally-venting hood has baffles. So, it can't clog if I forget to clean it. But if I don't wash the baffles monthly, I have big drips of oil coming down from the hood. That's all the liquids that it stripped out of the airflow, and that a recirculating hood has to remove as well or otherwise will deposit on the walls. And that's just the stuff that got removed as opposed to vented to the outside.

If you only see some yellowing, then go figure where the rest of the contamination ended up.

The VAH might have expensive consumable items, but that's exactly because you actually need filters of that size you be effective

M -

Apples to oranges. My hood is in a typical Manahttan apt. setting where there is no venting option (the small vent in the photo is not an option to attach to). Where does the ”contamination” end up? Ask 90% of New Yorkers dwelling in apts. built before 1985. So very happy for your vented hood, though, but it doesnt quite address the OP, does it?

The extent of any yellowing and clogging largely deoends on the amount of greasy foods one cooks. if one is primarily boiling water, there will be minimal grease in a lifetime of use. I dont recall having invited you for dinner… how are you to judge the efficiency of my hood? If you are regularly clogging your baffles, however, oh my, now that is cause for concern—as relates to your diet, not your hood. Please post a photo of your hood. I am curious!

Most people seriously underestimate just how much grease is aerosolized during normal operations of their stove. We see the splatter of big droplets that needs to be cleaned up from counters next to the stove when frying a steak, but we never make the connection that even more grease finds its way up into the air; and this even happens if you don't pan fry. Just normal steam distillation carries fat particles with it. So, unless you literally don't use your stove for anything other than boiling plain water, you will have grease that needs to go somewhere.

Have you ever cleaned the top of cabinets in a house that uses a recirculating hood (or even an externally-venting hood that is undersized). It's a thick filthy layer of built up grease. And that's just whatever got deposited up there. The rest circled back around into your living space.

And no, none of this requires that you operate a fry kitchen. It just needs you to use your kitchen for two or three meals every day. Small amounts add up over time. Humans are just really bad at estimating quantities for things that they can't see.

Properly sized baffle filters can do an amazing job at removing the bulk of these fat particles. Mesh filters are frequently undersized, are much less effective by design, and clog over time. So, you get fooled into thinking that there is less grease in your cooking effluents than there really is.

I used to live in a place that had an Asian-style centrifugal vent hood design. It flings the fat particles to the side and then requires you wash them off later. It would stop and request a clean cycle ever 8 hours of use. I thought that was crazy frequently, as I had no way to actually see the internals and verify how much fat had built up. But now that I have a hood with baffles, I can actually look at the separated fat. It's a lot more than you'd imagine, no matter what was cooked that week.

The elderly couple we purchased the unit from resided in it since the building’s residential conversion in 1970. They never had a hood, vented or not (both are alive and very healthy). I chose to add the recirculating hood, so I am pleased that there is at least something doing something to help, whether it’s 10% or 50% trapping of grease. In my past mid-century home I put in a Kobe vented hood where there was only recirculating. Yes, I understand venting is the optimal choice. But what does one do in a dwelling with no option to vent outdoors? Will they risk lung cancer if they don’t choose a VAH?

At some point for most people there is a cost-benefit determination that a VAH just isn’t worth it. Perhaps there won’t be much cooking at home, maybe they’re turned off by the recurring expense of their $$$ filters. Or..maybe because the thing is a behemoth and would look absolutely ridiculous in most apts with a postage stamp footprint.