Airlock Entry in a Passive House?

[Jim Burton]

Has anyone designed (and/or modeled in PHPP) an airlock entry in a home? I have a client wanting me to look into doing one on his project, and I expressed some skepticism about the benefits. For one thing, with an HRV the pressure inside and out will be roughly equal (as opposed to a conventional house) so it won't tend to suck cold air in when the door's open. Also, assuming the airlock is part of the conditioned space, any cold air that does get in will ultimately mix with the rest of the house anyway.

Any thoughts or input would be appreciated - thanks!

Jim Burton
206.501.8746

[Adam Cohen]

Jim, we have modeled both with and without airlocks and in general find them to be a waste of money.  We have employed them in a commercial project when the client insisted, but an air lock in the PNW - waste of cash IMHO

Jim Burton
206.501.8746

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Adam Cohen
Certified Passivhaus Consultant - North America and Europe

Registered Architect, LEED AP, NAHB Green Professional

Design/Builder of the First US Passivhaus Public School Building

2012 VSBN Green Designer of the Year

Structures Design/Build, LLC
5104 Bernard Drive
Roanoke, VA 24018

Web site: www.structuresdb.com
Passivhaus information: http://www.passivehousedesign.us/

More Passivhaus info: http://www.viking-house.us/

540.774.4800 (office)
540.989.7062 (fax)

[John Semmelhack]

I'm with Adam on this...Here's a screenshot on the topic from the older PHPP manual…

____________________________________
John Semmelhack
Think Little - Small Solutions for a Big World

semme...@think-little.com
(434) 409-3970 - tel
www.think-little.com

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[Graham S. Wright]

You could maybe make a comfort argument for one in a cold climate - high elevation east of the Cascades?

But design wise it might make more sense to move it outside the envelope, enlarge it into a mudroom / laundry and put the exhaust air dryer in there.

-gw

On Dec 7, 2012, at 1:06 PM, John Semmelhack wrote:

I'm with Adam on this...Here's a screenshot on the topic from the older PHPP manual…

<Screen Shot 2012-12-07 at 4.04.33 PM.png>

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[Tad Everhart]

I agree with Adam in light of the fact that you can purchase virtually air-tight doors.  My Innotech door has a measured air-leakage of 0.004  cfm/sq. ft.  It is far more airtight than the rest of our air barrier.  I've attached the specifications.

Ted Nickell has an airlock entry in his home which is near-PH.  Ted built his house in 1991.  I believe Ted designed and built it primarily to avoid gusts at his front door since his home is located near the crest of a mountain where prevailing winds on his side of the mountain are funneled up a valley directly at his house.  His front door is on the gusty side of his house.  In addition, Ted may have been influenced in his design by New England designs for energy-efficient homes of the 1980s which employed double doors for air-tightness.  For more information, I'll put you in contact with Ted.

One argument in favor of an airlock like Ted's is that it provides a dry and semi-conditioned area for shucking and storing shoes and outdoor clothing.  Ted's vestibule includes a bench where you can actually sit comfortably to remove or put on your shoes.  It includes sufficient area for storing 10s of pairs of shoes and boots.  I understand that keeping shoes out of the house is one of the most simple ways to reduce toxics in you home.  And with warm passive house floors, you will be comfortable in stockings.

Tad