We are working on a 5-story residential project that is being certified v4 BD+C. The dwelling units are naturally ventilated and there is a continuous 30 cfm exhaust from the toilet and continuous 100 cfm Dryer exhaust from each unit. (Total 130 cfm exhaust). There is no separate exhaust for the kitchen, but the total exhaust cfm is high enough to meet the requirements of 62.1-2010 Table 6-4 for the toilet and kitchen combined. Does the kitchen also need to have an exhaust hood, or is it sufficient to exhaust it through the toilet/dryer exhaust? This seems to meet the intent of 62.1-2010 since the two spaces are part of the same zone/dwelling unit.
Any insights or experience on this would be appreciated.
Dionisio Franca
DirectorWoonerf Inc.
30 thumbs up
June 5, 2018 - 8:46 pm
Hi Premal,
Maybe you could certify this as LEED for Homes. I worked on a LEED for homes project that was certifying under Passive House and the original design didn't have exhaust on the kitchen, but a air cleaner device. The reason for this is due to the IH heater used for cooking, no risk of CO due to incomplete combustion. USGBC required us to have regular exhaust systems because the air can be contaminated by cooking. Depending on the type of cooking you are looking to do on the kitchen, my personal opinion is that it would be a great design choice to have regular exhaust systems due to spices used or deep frying. If you are looking to save energy, linking an air intake opening control to the exhaust operation may be interesting.
Larissa Oaks
Specialist, LEEDUSGBC
LEEDuser Expert
67 thumbs up
June 18, 2018 - 5:20 pm
LEED v4 considers kitchen exhaust in residences as an important (and required) design element to allow occupants to remove contaminants and extra moisture generated from cooking activities, directly to the outdoors. This is a requirement in both the BD+C (per ASHRAE 62.1) and Homes (per ASHRAE 62.2) rating systems. Note that recirculating hoods do not meet the ASHRAE definition of exhaust.
Transferring kitchen contaminants through the living space to exhaust via the toilet/dryer exhaust is non-compliant with the standard because the class 2 kitchen exhaust air (see Section 5.16.1 and Table 6-4 regarding residential kitchen exhaust air classification in ASHRAE 62.1-2010) in most cases must pass through other living space (class 1) before finding its way to the bathroom to be exhausted. It additionally would be challenging to claim that the required volume of air is transferred directly from the kitchen (as opposed other spaces within the unit) unless there existed a situation where the bath was immediately adjacent to the kitchen, and the path of makeup air for the bathroom exhaust pulled exclusively through the kitchen. That would be a case where the class 2 air transferred to a class 2 space.
Below are some links to research supporting the LEED/ASHRAE requirement for residential kitchen exhaust:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4050506/
https://eta.lbl.gov/sites/all/files/publications/lbnl-6547e.pdf
Santiago Avila
Junior Sustainability EngineerMay 15, 2024 - 10:53 am
Hello Premal, may I ask if you solved your problem? If so, how?