If I'm not missing something, I seem to have come upon a sort of envelope sealing blind spot that is also a problem in another way.

I found a spot on the internet about sealing the bottom corners of exterior doors. 

I should explain that my chimney has an enviable draft as chimneys go. It is a masonary chimney on an interior wall, going up two stories, and has a 12" x 18" flue. Even with the damper locked closed, it just depressurizes my house, so I have a kind of endless blower door. Any leak and I can feel the cold draft. So I have been sealing a bunch of holes and leaks, and things are much tighter. Still the air has to come in somewhere.

So I am feeling about the exterior doors and I notice that cold air is coming from the latches which are inside the weatherstripping on the doors. The dead bold and door knob latches are leaking air. It occurred to me that there is nothing stopping air from coming between the metal bits of the door knobs and the key hole of the dead bolts. 

Once the air gets into the round hole through the door it can leak out the latch mechanisms which are inside the weather stripping.

So I go on the internet and look for advice on sealing door knobs and dead bolts.

Nada. Nothing.

Everyone is looking at air tight strategies for the edges of the door and the door sweep and where the weather stripping and the door sweep meet, but no one even thinks about the locks and door knobs which seem to be leaking air on homes everywhere.

The problem with a tight house where cold air leaks through the locks constantly is that the locks can freeze.

Any word on retrofit airtight door hardware?
 

Posted By foaf on 30 Nov 2010 11:02 PM
If I'm not missing something, I seem to have come upon a sort of envelope sealing blind spot that is also a problem in another way.

I found a spot on the internet about sealing the bottom corners of exterior doors. 

I should explain that my chimney has an enviable draft as chimneys go. It is a masonary chimney on an interior wall, going up two stories, and has a 12" x 18" flue. Even with the damper locked closed, it just depressurizes my house, so I have a kind of endless blower door. Any leak and I can feel the cold draft. So I have been sealing a bunch of holes and leaks, and things are much tighter. Still the air has to come in somewhere.

So I am feeling about the exterior doors and I notice that cold air is coming from the latches which are inside the weatherstripping on the doors. The dead bold and door knob latches are leaking air. It occurred to me that there is nothing stopping air from coming between the metal bits of the door knobs and the key hole of the dead bolts. 

Once the air gets into the round hole through the door it can leak out the latch mechanisms which are inside the weather stripping.

So I go on the internet and look for advice on sealing door knobs and dead bolts.

Nada. Nothing.

Everyone is looking at air tight strategies for the edges of the door and the door sweep and where the weather stripping and the door sweep meet, but no one even thinks about the locks and door knobs which seem to be leaking air on homes everywhere.

The problem with a tight house where cold air leaks through the locks constantly is that the locks can freeze.

Any word on retrofit airtight door hardware?
 

Yeah - you figured it out! When we first started doing air tight, people would come home and not be able to unlock their doors because the keyway was frozen. I don't have a perfect solution but one that helps a bit is to cut circles of bubble foam (similar to what they sell for sealing plugs and switches) and put one on each side of the door knob. They need to be thick enough to compress slightly when you tighten the screws. The other thing to do is put doors on the fireplace (assuming the chimney is for a fireplace or stove) and pipe fresh air inside the unit. That would let the air in someplace but not through the house.

Doors on the fireplace. 

I have a masonary open-through fireplace with doors on either side.

I did some measurments and calulations. When you add up all the bits of gaps around the fireplace doors, there are about 20 square inches of gap total between the doors and their frames. These sorts of doors do not seal air tight. They are much better than nothing, but are by no means a way to stop air leaking.

I have just installed a system to remotely close and seal the outside air intake for the fireplace, and I have installed a latch to hold the butterfly flue damper shut, since it wants to swing open a bit all the time when closed. The damper does not seal at all well, even when fully shut. It still leaks lots of air constantly. The doors aren`t going to stop it.

When the fireplace was built 27 years ago, nothing was exacting. Doors that reduce but do not halt air loss. Forced air heat registers used on the fireplace air intake, with the usual hinged flap that reduces air flow but does not stop it. A flue that closes but does not even come close to sealing.

All these things were better than nothing at reducing heat loss, but everything was a half measure that never really fully tackled the job. I used what was available at the time, but I was and remain unimpressed.

Now, because it is an open through fireplace, I cannot get a woodburning air tight insert, because no one makes an air tight wood burning open-through insert.

After owning three homes with masonry fireplaces, I'm convinced that they have no place in an energy efficient home. I now own a high-end Dimplex electric fireplace that avoids heat loss problems entirely, but still gives me a clean, fire in the hearth ambience at the flip of a switch. But, to respond to the originator's point, it really helps to install a storm door if you can tolerate the appearance.

I think companies should come up with the solution about door knob and locks problem. It really is a burdensome when you're having trouble with such.

Not really relevant, but 30 years ago I was a blacksmith making reproduction hardware. That included thumb latches for exterior doors. The guy i apprenticed to used to take special care fitting the thumb piece to the pul on the outside and to make sure the latch bar covered the hole through the door when the door was latched. He used to call that a "wind-proof" latch. I never figured out whether it was the draft or the rattle or both that he was fighting but your problem certainly predates modern locksets!

I think companies should come up with the solution about door knob and locks problem. It really is a burdensome when you're having trouble with such.

Hopefully,they can come up with the proper solution on this. It is really burden it such caused!

I'm sorta considering spray foam as the solution to every problem. 

If that's not the case someone better tell me quick before I start building.

FOAF...

Perhaps you should consider a "top-sealing damper" to minimize, or eliminate your leaky damper problem! You are correct in yoiur description of a blade type damper that most masons are accustomed to using. However, that type of damper is totally unacceptable in an environment such as yours.

Leymance is the brand name that comes to mind, also US Fireplace 'Seal-tite Dampers'

Both manufacturers use a stainless steel cable to operate the damper which sits ON TOP of the chimney.

The original style blade type damper (such as you have) allow the chimney to fill up with cold damp air, which is heavy, and coupled with negative pressure will create a "cold hearth" syndrome, introducing mega cold air into your home.

A top-sealing damper is a gasketed, nearly air tight replacement, which keeps the cold air and rain out of the flue. Over time, the collumn of air becomes somewhat conditioned, as it is within the envelope of the home. The next time you go to use the fireplace, open the damper and a smoke free start-up is easily accomplished due to instant draft caused by the bouancy of the conditioned air.

Also, as far as a fireplace insert for your see-thru fireplace, what I have done is simply install a fireplace insert (on either side of the fireplace; homeowner choice) and install a set of glass doors for the other side. You can get tinted glass to block the view of the 'back side' of the insert! (or paint the back of the glass black)

A modern wood burning insert will burn much cleaner than your fireplace, will use 1/4 (or less) fuel, and will provide 500% more heat.

Good luck with the project! 

Mark