The Importance of Attic Air Sealing Before Blowing More Insulation.

Most customers think when they are too hot or too cold, that they only need more insulation only. This only fixes one way heat moves and is often not the only reason they are uncomfortable. Often people don't know about other ways heat moves. The insulation only takes care of conduction which is like having a sweater on you. The sweater like insulation, allows air to move through it easily. When you air seal it's like having a wind breaker before you put on the sweater.

We practice building science principles, and one is the stack effect. The stack effect happens in everybody's house all year round. The easiest way to understand this is the winter scenario. As you heat the home the heat rises to the highest level and it escapes through penetrations in the attic floor. These penetrations could be bath fans, ceiling registers, recessed lights, and top plates. The top plates are the top part of walls being interior or exterior. The top plates have gaps along side them where the drywall meets. The electricians drill through these top plates to run electrical wires down the walls. This allows the air to move up and down the walls and conditioned air escapes to the attic.

Some of the worst places for the air you paid to heat escapes is called open chases. A chase is a like a elevator shaft that runs from the basement to the attic. This is to run the chimney for the furnace and water heater in the basement to the roof. Or sometimes it's for the duct work to go to the upper floor. This is a direct connection from the attic to your home. These are the largest holes you could have in the attic floor. 

The next building science principle is hot always moves to cold. So imagine your outside attic is getting up to 100-140 degrees and you have all these penetrations in the attic floor. This is the division between outside and inside. The heat is going to try to move to your air conditioned home. This causes your air conditioner to work extremely hard and in some cases not keep up to the temperature you have set on the thermostat.

So when you are uncomfortable or want to improve efficiency of your home, don't forget the air sealing.