应该削弱多少门以允许HRV的空气移动？
How much should interior doors be undercut to allow air movement for the HRV?
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Courtney,
Ideally, a bathroom exhaust fan or HRV shouldn't create a big pressure difference between the bathroom and the adjacent room or hallway. A typical goal is that this pressure difference should be held at no more than 2.5 pascals when the fan is operating.
在饰面和30英寸宽的门之间的间隙为1英寸，可以在最大2.5帕斯卡压力差的情况下提供47 cfm的回流空气。对于大多数浴室来说，这是足够的。
Martin,
The supply air enters in the bedrooms and living room. Should those doors be undercut too?
Courtney,
Most homeowners don't close the door (if one exists) between their living room and any nearby hallway. Do you?
不，只是卧室（有时）。客厅没有门。这只是我担心的卧室门。
Courtney,
The fresh air supply rate to bedrooms is too low for you to have to worry about door undercuts. Relax.
Jump ducts can provide a bit more privacy for bedrooms than door cuts. It's pretty easy to convert a partition wall stud bay into a jump duct, with a small grille near the floor on one side of the wall, and near the ceiling on the other side, for a longer path, transmitting less light & sound.
One could use 4" x 10" or 4 x 12" HVAC vent grilles. In many cases 4"- 5" inch round vent grilles would do it, depending on the size of the existing door-gap (sharing the flow). Be sure to check for fire blocking or other obstructions in stud bays used as jump ducts BEFORE you cut in the big holes.
Courtney,
Jump ducts are used to address air flow from furnaces or central air conditioning systems -- they usually can handle 100 cfm or more.
The supply grille of an HRV usually only delivers 10 cfm or 20 cfm to a bedroom -- so you don't need a jump duct.
The closed door vent area you need to avoid excessive pressure changes with the cfm, but never goes away. About .6 square inches per cfm for a door cut. And more (ie, less pressure change) is better.
Most room pressurization/depressurization recommendations for undercuts and transfer grilles are theoretical and do not factor in airflow around door jambs and head (we've found a typical gap of 1/16" to 1/8" for pre-hung doors) nor other smaller, unintentional airflow pathways (via interior walls). We've done a good bit of real world testing of room pressurization and feel confident room pressure difference will remain under 3Pa with supply airflows to bedrooms as high as 75cfm when the door undercut is at least 1/2". See attached graph showing test results of over 60 bedrooms (3 different builders), with just door undercuts (no transfer grilles, jumper ducts or return ducts). Undercuts varied from 3/8" to 3/4", flooring was about 50/50 carpet vs. hardwood.
John,
基于测量的答案，而不是数学！太好了 - 各个方面都优越。