Air Sealing Woes

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Permalink Reply by randy tolowski on April 30, 2012 at 9:40am

It appears the mail slot in the wrought iron goes through the solid wood door? Can you post the interior portion of the mail slot?

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Permalink Reply by Patrick Michaelyan on April 30, 2012 at 3:36pm

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Permalink Reply by Bud Poll on April 30, 2012 at 10:12am

Nothing constructive to add, but the idea of air sealing a home with an attic fan that large scares me.  Is it serving as a whole house fan or is there an intake area to supply air flow from just the attic?

Bud

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Permalink Reply by Patrick Michaelyan on April 30, 2012 at 3:35pm

Hello Bud.
It's something I would normally be concerned with as well, but this house is very leaky. 5,500 CFM50, with a BAS near 3,000. The majority of the leakage is concentrated in the basement and the attic. I concentrated all my efforts thus far on the basement (where there was also pest issues).
So, does a leaky house with a whole-house fan pose a problem with regard to safety? 
My sense is that all such questions can be eliminated with sealed combustion equipment, but, then again, what about gas ranges, ovens, etc?

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Permalink Reply by Bud Poll on April 30, 2012 at 3:50pm

First, the mail slot.  If the mail can drop into a pocket that has another sealed access from the inside, at least it would be air tight. 

The good news is that old homes can rarely get too tight, however, what size is that fan.  A BAS of 3000 would be a natural around 150cfm, if my thinking is correct.  And a fan that size could be 3 times that volume, driving the entire house negative.

I'm in north country and often hear the excuse that a whole house fan and a furnace don't need to run at the same time.  Well, they may not need to, but it could inadvertently happen.  A fan left on from a hot day and the stat picks up a call for heat and suddenly you have a house full of fumes or worse.  I always suggest an electrical interlock where the furnace or stat is locked out when the fan is running.  Applies to range hoods as well. 

You didn't mention where that fan is pulling its air from, the house, a window, or attic venting.

Is the hot water gas or oil?

Bud

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Permalink Reply by Patrick Michaelyan on April 30, 2012 at 3:55pm

The electrical interlock you speak of sounds promising (given the number of houses I have encountered with whole-house fans).

As for the size (capacity) of the fan I don't have that info handy.

The fan is pulling its air from leaks in the attic to the outside, as well as leaks between the attic and the rest of the house. As with most folks, they only run it in the summer (with a whole lot of windows open). 

The hot water is gas.

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Permalink Reply by Patrick Michaelyan on April 30, 2012 at 3:56pm

You raise an interesting idea thought about the pocket with sealed access. I need to think that one through a little.

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Permalink Reply by Bruce Navin on May 1, 2012 at 6:38am

Would it be possible to build a pair of bifold (closet) doors in front of the fan? I would install an interlock there as well so the fan can only run when the doors are open. Obviously, you will need to have a way to lock them open. This may not completely reduce leakage through the fan, but it should reduce it substantially. 

Do they have gas cooking appliances? 

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Permalink Reply by Patrick Michaelyan on May 2, 2012 at 4:36am

They have a gas range\oven.

The bifold doors complete with an interlock sounds very promising...if I can reduce the leakage substantially then I'm happy, as I sure the HOs will be as well.

Thank you Bruce.

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Permalink Reply by Paul D McGovern on May 1, 2012 at 11:37am

hey Patrick ...

I think the 1st thing I would do is to completely/ temporarily seal both the mail slot & whole house fan and do a blower door ... then do without sealing to see the implication ... if it is not all that significant, why worry ?

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Permalink Reply by Patrick Michaelyan on May 2, 2012 at 4:39am

That is also a route I thought about taking Paul. It is my sense that the attic fan is worth sealing up, but it is the HOs prerogative that the mail slot be sealed (they say it is drafty in the foyer and front hallway during the winter).

I will post the results of BD testing for the attic fan and mail slot after I get the chance to put together a temporary seal for the fan (and maybe the mail slot).

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Permalink Reply by Bruce Navin on May 2, 2012 at 4:50am

Regarding the storm door-is it an older one? It appears to be steel with single pane glass. Is that so? Could the HO's impressions be as much about the door being a thermal bridge?

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