I live in Manitoba. Think cold and windy. How good are single insulated steel doors?
I would like to see GBA do an article on entrance ways to residential buildings.
Almost all commercial buildings have double door systems or revolving doors to reduce air exchange. I keep reading GBA and they spend a lot of time on sealing the building, but not the door “system”. GBA seems to rely on a single steel insulated door that has seals the very quickly become worn and begin to leak and most often on a door bottom seal that is very often so stiff that the door is hard to close. There are some door seals that are very good. These usually end up only on custom homes, not on any developers homes.
Lets take a look at refrigerator door seals. They normally only have to operate with a temp difference or delta 16 C or 40 F, where as the residential door has to operate over a temp diff of 40 C or 75 F and in Manitoba there are lots of days when the diff can be 50 C or 90 F. I think the energy efficiency drivers in appliances could be used in residential homes.
Look at the automotive doors seals. They often seal against strong wind and pressure differentials. They also strive to have doors that close almost effortlessly.
Are there pleasing home layouts that use double entrance ways?
What has Passivehaus done on this topic? Any drawings I have seen of Passivhaus, only one in Fine Homebuilding showed a double entrance way but not all doors. This was the last month issue featuring the home in Alaska.
Also why has so little attention been spent on insulated shutters?
Thank you for considering Bob Hamlin P. Eng,
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Replies
Bob,
Energy researchers have quantified the heat loss that occurs when exterior doors are opened in winter. In the average cold-climate home, the heat loss associated with door opening is negligible -- certainly less than an amount that would justify the cost of double doors.
That said, steel Therma-Tru doors are pretty lame. The Europeans are making some amazingly nice doors for Passivhaus projects. The doors have a double rabbet at the jamb, allowing for tight-fitting triple weatherstipping. So if you have an extra $2,000 to $3,000 burning a hole in your pocket, you can always order a German door.
Eventually, U.S. manufacturers will catch up.
Bob: Thorsten Chlupp is working on prototypes right now, and hopes to have "a good door" on the market next year.... if you can wait. In the meantime, a place up here that makes tilt-turn windows also makes tilt-turn doors. They seal with 7 pins around the perimeter. They recommend them only for patio doors (limited use) because there is a large lip at the bottom that would be awkward for a main entry door. With some planning, I think that could be worked out. Do you have any tilt-turn manufacturers around? j