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In a perfect ventilation world I would have a 27" deep and high powered hood fan that sits as close as possible to the stove (18"?). Unfortunately, this would be tricky as the hood fan would be so deep and low that I'd have trouble seeing the whole stove and I could hit my head on it.

This leaves me with two options:

  1. A low (18" above the counter) and shallow (e.g., 18" deep) hood fan, or;
  2. A high (e.g., 32"-36" above the counter) and deep (e.g., 27") hood fan.

Which of these two options would be most effective at eliminating unwanted odors and gases? Let's assume in both cases that the hood fan extends beyond the edges of the stove on both sides (e.g., a 46" hood fan over a 36" stove).

Behacad
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  • Wouldn't a fan only 18 inches above the stove be really annoying even if it were only 18 inches deep? I can't imagine dealing with that – Kat Dec 06 '20 at 22:34
  • The strength of your fan is also a factor....and you definitely do not want it low enough so that you hit your head. 18 inches is way too close. Also consider the occasional flair up. You do not want flames being sucked into your hood. – moscafj Dec 06 '20 at 22:58
  • Also...quick google search yields 24 - 36 inches above depending on fuel and hood. – moscafj Dec 06 '20 at 23:03
  • @moscafj 24-36 is an absolutely huge range though and 36" won't nearly be as effective as 24. – Behacad Dec 07 '20 at 00:06
  • @Kat 18" is the typical height of cabinets above the counter, isn't it? If so, this is certainly not that bad since most folks have cabinets or a microwave over their stove. – Behacad Dec 07 '20 at 00:07
  • @Behacad depends almost entirely on the strength of your exhaust fan. – moscafj Dec 07 '20 at 01:32
  • @moscafj I don't understand what you mean. Are you suggesting that the optimal placement and size of the fan depends on its power? So weak fans work better in some configurations and strong fans work better in others? That doesn't make sense to me. Good placement would benefit any fan, regardless of strength. – Behacad Dec 07 '20 at 01:53
  • @Behacad I have cabinets over my stove but they are much higher than the ones over the counter. I just tried putting a tall pot on the counter and using a spoon to stir it and I hit the bottom of the cabinet. So yeah that seems likely to be aggravating to me. – Kat Dec 07 '20 at 22:01
  • @Kat maybe some of the measurements I mentioned are incorrect but certainly having a cabinet at standard height is not unusual and doesn't get in the way – Behacad Dec 08 '20 at 15:04

1 Answers1

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This is going to be dominated by ergonomics.

The perfect fan for exhaust isn't so perfect if you're always banging your head on it, or can't see in the pan. Some unusual devices are rather tall and wouldn't even fit in your 18" (I can't strain jelly on the worktop because of the cupboards so do that on the cold stove).

In catering, where kitchen air quality is a concern, the fan hoods are normally high, well over head height for the tallest users, but powerful.

The stuff you want to get rid of, whether steam, oil aerosol, or smells, tends to be carried upwards by convection, which gives a push to complement the fan's pull. You also have to consider the source of replacement air - if the house was sealed completely tight there wouldn't be one and the fan would be largely useless. Airflow from the rest of the house into the kitchen to replaced the exhausted air can be effective in controlling the flow of smells, despite not increasing or even decreasing (for the same total inlet size) the amount of airflow.

Chris H
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  • In commercial kitchens the fans are usually located outdoors...on roofs or exterior walls. – moscafj Dec 07 '20 at 11:41
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    @moscafj that's true, but the hood itself is in the kitchen, and the OP seems to be asking as much about hood placement as the placement of the actual motor (or assuming little or no ducting between them) – Chris H Dec 07 '20 at 11:43
  • My questions is not ergonomic in nature, but rather refers to the effectiveness of hood fans. A low shallow hood fan and a high deep hood fan are both ergonomically fine – Behacad Dec 08 '20 at 15:03
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    I guess what I'm saying is that a low shallow hood often *isn't* fine. If you try to idealise out the ergonomics, it becomes a question of fluid dynamics not cooking IMO. – Chris H Dec 08 '20 at 15:07
  • yes it becomes a question of fluid dynamics, similar to how a ton of other questions on here relate to physics. How long to cook a turkey? Physics! Basting? Physics! Presumably I'm not the first person to ever ask the optimal design of a hood fan. Certainly a low and shallow high powered fan would be very effective because it is closer to the point of the gasses and they cannot escape to the room. Many kitchens have fans like this and they work well. but do they work better than very high and deep ones? That is the question – Behacad Dec 08 '20 at 19:31
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    great answer. a word of caution, if you use an induction stove convection won't be as strong and you lose that additional push – Agos Dec 10 '20 at 13:39