For Energy considerations 35% of your heating requirements can be caused by air leaking!

So you want a very tightly built house. . . BUT

Some builders focus heavily on air tightness and forget that just because it is airtight, you need fresh air also.

Wrap yourself in a plastic bag to keep warm on a cold day. Where does the moisture go?

With a tight, energy efficient home, you get good energy efficiency. But how to you get rid of the humidity that can build up in the house? 

Especially when it is too cold to open a window but the mechanical ventilation provided by the furnace is not bringing in fresh air because the furnace doesn't run due to minimal heat loss from a very efficient home.

ANSWER: Active HRV (Heat Recovery Ventilator
It will run independent of the furnace constantly bringing in fresh air and preheating that air with the exhausted stale air.- NOW seal that house tight!
Testing for Air Leakage

A blower door test is a fan that is placed in an exterior doorway and removes some air, placing the house under a negative pressure.

Using a Manometer, the pressure difference created can be measured and calculated when entered into the software to determine the ACH or air leakage.

A blower door test will generally only take 15-20 minutes to collect the data.

We can also use this tool at the pre-drywall stage when you have just insulation and poly in place. This can be useful to identify and correct air leakage before drywall is installed.

When used with a thermal imaging camera you can literally "see" the leakage areas as air leaking back into the building is cold and cools surfaces that can now be seen with the infrared camera.

This openeing was through a dead area inside the wall and was open all the way to the furnace room, two floors below. The stack pressure would be considerable during cold weather, pushing significant amounts of humid air into the attic.

Frost in your attic?

95% of the time it is NOT poor ventilation
95% of the time it IS air leaking from the house into the attic space. That air condenses and freezes and over time accumulates

EXAMPLE (pictures of this example to the left)

My neighbour this winter had a huge accumulation of frost in his attic, to the point that when it warmed up to above freezing, water from dripping from several doorways on the second floor.

With a thermal imager we found several "pools" of water in the attic.

During our testing, the Attic access lid and several main plumbing stacks had significant air leakage.
These were all sealed with a material that would stay in place (Not Acoustical Caulk)

2 weeks later the frost returned. Upon further investigation we found another significant opening next to the furnace "B" vent that went 2 storeys to the basement.

Once sealed and after 3 weeks of significant cold weather - no more frost in the attic. 
Frost that melted ran from the attic and collected and dripped out of the doorways as can be seen here
Water collected all over the ceiling as a result of the frost accumulation
Bathroom fan also was leaking air into the attic and shows as wet. Tested with a moisture meter to confirm that iit was wet, not just colder
Second floor ceililng shows wet spots (confirmed by using a moisture meter) as a result of frost accumulations that melted during rapid warming
Air Sealing

Here are some of the areas to consider when looking at air sealing a home.
Wind driven rain entering the soffit area, running down the insulation stop and behind the building paper - then into the joint on the wall sheathing and eventually dripping from the windows inside.
Air leakage through insulation

Wind Driven Rain into Soffits causing leakage
The black area behind the poly is dirt that was filtered through the hole in the poly, then the the fiberglass insulation. If you see black insulation, 99% of the time you have air leakage through that area.
Results of air leakage into a cold attic space
Since 1986

Issues with Air Leakage
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