ᐅ Safety switch for range hood with mechanical ventilation system
Created on: 7 Mar 2018 09:56
R
Roppo
Hello,
this year we are building a KFW 55 house and are currently planning the kitchen. We would like to install a range hood because we consider it the fundamentally better option, and there is basically nothing speaking against it. We do not have a chimney!
However, our company just informed us that in our case, a safety switch still needs to be installed because we have a controlled residential ventilation system. The exhaust hood causes such a high air exchange that the ventilation system cannot handle it and therefore must be deactivated during the operation of the exhaust hood.
The cost for this switch is, I believe, around 300 euros, but that is not the main issue.
What it sounded like to me, and this is also my question, is that with controlled residential ventilation, the recirculation mode might be the better option. Not because it is cheaper, but because it does not affect the functionality of the ventilation.
What do you know about this topic, and what would you do if you had the free choice—and why?
Best regards
this year we are building a KFW 55 house and are currently planning the kitchen. We would like to install a range hood because we consider it the fundamentally better option, and there is basically nothing speaking against it. We do not have a chimney!
However, our company just informed us that in our case, a safety switch still needs to be installed because we have a controlled residential ventilation system. The exhaust hood causes such a high air exchange that the ventilation system cannot handle it and therefore must be deactivated during the operation of the exhaust hood.
The cost for this switch is, I believe, around 300 euros, but that is not the main issue.
What it sounded like to me, and this is also my question, is that with controlled residential ventilation, the recirculation mode might be the better option. Not because it is cheaper, but because it does not affect the functionality of the ventilation.
What do you know about this topic, and what would you do if you had the free choice—and why?
Best regards
So, we have now decided against a ducted range hood. It seems counterproductive to have to disable the mechanical ventilation system while cooking just to use a ducted hood. After all, we already have ventilation in the kitchen through the mechanical ventilation system—although certainly not with a comparable airflow rate... But overall, I think our system is good, so a recirculating hood should be sufficient.
Now comes the next problem: which one?
Especially in low-energy house standards, most hoods are recirculating, but strangely this isn’t really reflected in my Google search results. It’s hard to find recirculating hoods (also known as canopy or wall-mounted hoods) with more than just a handful of reviews or reliable tests that arrive at the same conclusion... Can you provide any recommendations?
Best regards
Now comes the next problem: which one?
Especially in low-energy house standards, most hoods are recirculating, but strangely this isn’t really reflected in my Google search results. It’s hard to find recirculating hoods (also known as canopy or wall-mounted hoods) with more than just a handful of reviews or reliable tests that arrive at the same conclusion... Can you provide any recommendations?
Best regards
S
Steffen809 May 2018 09:32What nonsense... we have a mechanical ventilation system with heat recovery (comfort air q450) and a Bora exhaust (1200 m³/h (700 cfm) air flow). Of course, we don’t turn off the mechanical ventilation when using the Bora. What could possibly happen? The mechanical ventilation only runs two simple fans anyway.
Steffen80 schrieb:
What nonsense... we have a mechanical ventilation system with heat recovery (comfort air q450) and a Bora exhaust (1200 cubic meters per hour!). Of course, we do not turn off the mechanical ventilation when using the Bora. What could happen? The mechanical ventilation just runs with two simple fans...Well, I have the problem that our home builder tells me it is required by regulations and they will not install it any other way. I lack the basis to argue against this...C
chand19869 May 2018 10:58It’s not entirely unreasonable: if the kitchen’s mechanical ventilation exhaust is releasing air, and an additional 1000 cubic meters per hour (about 35000 cubic feet per hour) is also being extracted, this air must be replaced somewhere in a modern, airtight house.
Of course, it is possible to smartly link the mechanical ventilation system with the exhaust air to achieve proper regulation. Otherwise, more crude methods include turning off part of the exhaust or leaving window seals open.
By the way, as soon as the exhaust in the kitchen is cleverly positioned at the rear part of the living/dining and cooking zone, the high-power mode of the range hood is almost never necessary—maybe only when frying oily fish like green herring.
Of course, it is possible to smartly link the mechanical ventilation system with the exhaust air to achieve proper regulation. Otherwise, more crude methods include turning off part of the exhaust or leaving window seals open.
By the way, as soon as the exhaust in the kitchen is cleverly positioned at the rear part of the living/dining and cooking zone, the high-power mode of the range hood is almost never necessary—maybe only when frying oily fish like green herring.
Well, you have to look at this realistically:
If you install an exhaust hood without providing adequate make-up air, a negative pressure will first develop inside the house. This is then either balanced by forced make-up air (e.g., through the mechanical ventilation with heat recovery system) or the exhaust hood cannot maintain the airflow, and its efficiency decreases.
So either the exhaust hood does not operate optimally, or the ventilation system does not function as intended during that time.
If it’s the latter, it’s actually not a big deal since it should balance out again shortly after cooking.
If it’s the former, then you have to question the purpose.
That’s why — especially when combined with a fireplace — forced make-up air systems are installed.
The truth probably lies somewhere in the middle (you can’t generalize). The mechanical ventilation system is somewhat disrupted, and the exhaust hood doesn’t perform at 100%.
I also thought about this a lot and ultimately decided on a recirculating hood. For me, all the extra effort wasn’t worth it.
We installed the Berbel Formline. It wasn’t cheap at nearly 2000€ (about $2200), but it looks good compared to most ceiling-mounted hoods and, most importantly, fulfills its purpose 100%. We’re absolutely thrilled with the hood and would buy it again anytime.
Also, the expensive replacement of activated carbon filters is avoided because you can simply refill activated carbon granules, which are much cheaper. It costs around 50€ (~$55) and lasts 2–3 years.
With a good recirculating hood, cooking odors are removed quickly by the mechanical ventilation system. When we make schnitzel at lunchtime, you don’t smell anything from it by late afternoon.
If you install an exhaust hood without providing adequate make-up air, a negative pressure will first develop inside the house. This is then either balanced by forced make-up air (e.g., through the mechanical ventilation with heat recovery system) or the exhaust hood cannot maintain the airflow, and its efficiency decreases.
So either the exhaust hood does not operate optimally, or the ventilation system does not function as intended during that time.
If it’s the latter, it’s actually not a big deal since it should balance out again shortly after cooking.
If it’s the former, then you have to question the purpose.
That’s why — especially when combined with a fireplace — forced make-up air systems are installed.
The truth probably lies somewhere in the middle (you can’t generalize). The mechanical ventilation system is somewhat disrupted, and the exhaust hood doesn’t perform at 100%.
I also thought about this a lot and ultimately decided on a recirculating hood. For me, all the extra effort wasn’t worth it.
We installed the Berbel Formline. It wasn’t cheap at nearly 2000€ (about $2200), but it looks good compared to most ceiling-mounted hoods and, most importantly, fulfills its purpose 100%. We’re absolutely thrilled with the hood and would buy it again anytime.
Also, the expensive replacement of activated carbon filters is avoided because you can simply refill activated carbon granules, which are much cheaper. It costs around 50€ (~$55) and lasts 2–3 years.
With a good recirculating hood, cooking odors are removed quickly by the mechanical ventilation system. When we make schnitzel at lunchtime, you don’t smell anything from it by late afternoon.
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