Attic Insulation

Chances are good that your home could benefit from added attic insulation. Many homes have inadequate insulation — some older homes have none at all.

Signs Your Attic Needs More Insulation

You'll usually benefit from additional attic insulation if you notice any of the following:

• Your air conditioner works extra hard to cool your home
• Your home heats up quickly after the air conditioner cycles off
• You have comfort problems, such as rooms that are too hot in summer or too cold in winter

Insulation Levels by Home Age

The age of your home is a good starting indicator of how much insulation it likely has:

• Built before 1985 — insulation is most likely well below current minimum standards
• Built between 1986–1995 — insulation is probably slightly below current minimum standards
• Built after 1996 — insulation most likely meets minimum standards for the time it was built

Even homes that met the minimum code standard when built can benefit from more. The U.S. Department of Energy recommends insulation levels above the minimum building code standard for most homes in our climate zone.

Air Sealing Comes First

This is the step that gets skipped, and skipping it is why some homes see far less improvement than the R-value on the bag suggests. Insulation slows heat moving through a surface. It does nothing about air moving straight past it — and an attic floor is full of paths for that: gaps around recessed lights and bath fans, the openings where plumbing and wiring pass through, the top plates of interior walls, and the attic hatch itself.

Blowing insulation over unsealed penetrations buries the leaks rather than closing them. Sealing first, then insulating, is what makes the insulation perform the way it is rated to — and it is also what stops warm, humid household air rising into the attic and condensing there, which is a mold problem as much as an energy one.

Adding to What's There, or Starting Over?

Usually adding. Existing insulation that is dry, clean and evenly spread can be topped up rather than removed, and blown-in material over existing batts is a normal way to reach current levels.

Removal makes sense when the existing material is wet or has been wet, when it is contaminated by rodents, or when it has been compressed or disturbed enough that it is no longer doing much. Wet insulation in particular does not recover — it has already lost most of its R-value and is a moisture problem sitting on your ceiling, which is worth tracing back to the ventilation or roof issue that soaked it.

Do not bury the soffit vents. Insulation pushed right to the eaves blocks the intake air the attic depends on, which is the single most common way a well-meant insulation job creates a ventilation problem. Baffles hold that channel open.