"Luke, the depressurization caused by an overpowered fan (e.g. 600 cfm) in a kitchen cannot be compensated by a relatively small passive duct. The fan is creating a high static pressure to drive the exhaust out of the house. The resulting house…"
"I've seen both work with success, really it comes down to duct design/placement. It would depend on the location of the supply duct's entry point as well as duct sizing, length, type, etc.
One emerging option is a passive opening (with…"
In many homes, cooking is the largest indoor source of air pollutants. Exposures can be higher in the kitchen compared to other places in the home. We can still enjoy the many benefits of cooking by installing and using range hoods that vent to the outdoors. This group will promote discussion about how to select effective range hoods, strategies to improve the efficiency of existing ventilation systems for kitchen pollutants, and what to do in homes that don’t have ducting already installed…See More
"It would be nice to prevent range hood manufacturers from recommending extremely oversized cfm rates. Often we see customers install 1000+ cfm hoods with no consideration of make-up air. I generally recommend customers use the lowest cfm rate…"
"I agree. For modest homes a specialist is not likely to be engaged unless the Building Official flags it during construction. If it is done after the fact (conversion from wood to gas) then the only knowledgeable person who could stop it would be…"
"I might mock up something in my own house as I currently lack a range hood. There is a (too small) 4 inch duct already built into the wall over the range. I could probably use a variable speed in-line fan on that duct and create a hood out of…"
"I agree that is a gap in combustion appliance certification testing. There is a logical disconnect between combustion appliance standards and ventilation/depressurization standards. Being the first on the block combustion appliance producers have…"
"That is good information, Dara. Too bad we were not able to establish real gas appliance depressurization limits before we defaulted to -50 Pa. I am confident that many gas appliances are good to -50 Pa but some will not be. Specific…"
Yes, we are still doing depressurization testing. We use the CSA F326 test criteria. Now-a-days (as opposed to the '80's), new homes do not have spillage susceptible combustion appliances so we apply the 50 pa limit. As larger…"
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