Exhaust hoods like that are a really bad idea (and actually forbidden in some places) when you have a system which requires open fire like a gas stove, an oven or a gas heating system.
They transport air outside and depending on the age of the building not enough fresh air gets in while the fire is consuming all the oxygen.
Also the reason why it is a really bad idea to have a gas heater for warm water and one of the mobile indoor acs. We have some deaths in Vienna every year because of that.
Edit: nevermind, only somewhat true. The slight under pressure caused by exhaust hoods with outside vents pulls down exhaust fumes from the chimney in case of gas heaters. In case of ONLY a gas stove it is not the same problem (I threw them into one basket because most places with a gas stove also have gas heating around here, and in this cases it would be a big no-no).
Yup, very energy efficient buildings tend to be that way by restricting how much hot/cold air can escape and waste the energy used to heat/cool that air. On the flip side, the ventilation needs to be consciously designed to allow for makeup air for any exhaust systems, and to generally allow for the air inside the building to be replaced.
I have a heavy duty exhaust fan in well insulated house, and at maximum power it works best if I open a window as my “makeup” air. Not ideal to not have air conditioning or heat for that incoming air, but it’s not like I’m cooking for hours a day.
A mechanical ventilation system with heat recovery should take care of this completely adequately I imagine, if your home happens to be air-tight enough to encounter this problem
Exhaust hoods like that are a really bad idea (and actually forbidden in some places) when you have a system which requires open fire like a gas stove, an oven or a gas heating system. They transport air outside and depending on the age of the building not enough fresh air gets in while the fire is consuming all the oxygen.
Also the reason why it is a really bad idea to have a gas heater for warm water and one of the mobile indoor acs. We have some deaths in Vienna every year because of that.
Edit: nevermind, only somewhat true. The slight under pressure caused by exhaust hoods with outside vents pulls down exhaust fumes from the chimney in case of gas heaters. In case of ONLY a gas stove it is not the same problem (I threw them into one basket because most places with a gas stove also have gas heating around here, and in this cases it would be a big no-no).
In the US, builders have to calculate make up air for this specific reason. In very efficient houses, make up air units need to be installed.
Yup, very energy efficient buildings tend to be that way by restricting how much hot/cold air can escape and waste the energy used to heat/cool that air. On the flip side, the ventilation needs to be consciously designed to allow for makeup air for any exhaust systems, and to generally allow for the air inside the building to be replaced.
I have a heavy duty exhaust fan in well insulated house, and at maximum power it works best if I open a window as my “makeup” air. Not ideal to not have air conditioning or heat for that incoming air, but it’s not like I’m cooking for hours a day.
Oh interesting to know how this is handled in different places!
A mechanical ventilation system with heat recovery should take care of this completely adequately I imagine, if your home happens to be air-tight enough to encounter this problem