Gaines Group Architects
attic energy solutions

What Energy-Efficient Product Will Make Your Home Air Tight?

Air tightAir tight is the most critical element of green building design. The easiest way to be air tight in an existing home is using caulk at every gap and crack between building materials. The top and bottom plate of a wall, electrical outlets, doors and windows, all penetrations need to be sealed and air tight. The attic access should be considered as a door and weather stripped and insulated. The rim board (the place where floor joist meet the exterior wall) is always a huge air leak. This can be fixed in an unconditioned crawl or an unfinished basement.

There are many places where air leaks impact comfort and energy-efficiency in the average home. Ducts that are not sealed tight leak out air before it reaches the room it is intended to heat or cool. Double Hung windows have a weak air seal where the two window panes intersect. A finished wood floor will leak air into the crawl space below. The tongue and groove vaulted ceiling will leak air to the outside of the thermal envelope. Air always leaks around recessed can lights. Any penetration in the walls from outside for water lines, electrical panel, or dryer vents are consistently a place for air leaks.

Air tight   Air tight

Seal these gaps and cracks with a silicone caulk to stop air leakage before you take any other action. The next step, insulation, can also do the air sealing if you use spray foam.

Should my new house “breathe?”

Ask any seasoned carpenter (that does not understand building science) and they are likely to tell you “don’t build too tight, you want your house to breathe.” This is a tried and true “because that is the way we always do it idea.”



Early in the construction industry you did not build a home air-tight so that the walls could dry out. This is a leftover from days before we insulated or conditioned a home and wanted to air them out to keep them healthy inside.


However, now we have added insulation into our walls to increase energy performance.

Now we have heating, cooling, and ventilation systems to control indoor-air-quality and make the house comfortable and healthy.


So if your builder tells you they have done anything less than make your home as air tight as an igloo cooler, ask them if they will help pay your monthly electric bills. Ask them if they will come and dust your home once a week. Ask them why they continue to build as if the house is not insulated or conditioned.


Making your home air tight is key to a healthy, energy-efficient, and durable solution. Of course you do need a heating and cooling system that includes ventilation. This is how you bring fresh air into the house – through a filter – using an energy recovery ventilator. Making your home air tight filters the air reducing the need to dust. It also reduces energy consumption. It also filters the air improving indoor air quality. Making it air tight includes sealing every connection, joint, vent, penetration, window, door, roof, and hole.


Triple C Camp - NEST Rebuild, 2010