Heat rises, and in most homes it rises straight out through the attic. An underinsulated attic is like wearing a heavy coat with no hat, you lose warmth from the top no matter what else you do. Topping up attic insulation is consistently one of the best-paying home upgrades, often recovering its cost in just a few years of lower bills.
Check What You Have
Stick your head into the attic and look at the depth of the existing insulation. If you can see the tops of the wooden joists poking through, you are short. Most homes benefit from a total depth of 12 to 18 inches, depending on your climate. Colder regions need more.
Seal Before You Insulate
Insulation slows heat moving through surfaces, but it does not stop air leaking through gaps. Before adding any, seal the holes where warm air escapes into the attic.
- Around light fixtures, vents, and pipes where they pass through the ceiling.
- The attic hatch or door, which is often a bare, uninsulated panel.
- Gaps at the top of interior walls hidden under the existing insulation.
Use caulk for small gaps and expanding foam for larger ones. Skipping this step lets air carry heat right past even thick insulation.
Add the Right Amount
You can lay rolls of batt insulation between and over the joists, or rent a blower to add loose-fill on top of what is there. Loose-fill is faster for large areas and fills awkward corners better. Either way, do not block the soffit vents at the eaves, which the attic needs for airflow.
Know When to Call a Pro
If your attic has knob-and-tube wiring, signs of moisture, or mold, get a professional in before adding insulation. Trapping moisture or covering old wiring causes bigger problems than it solves.
Done right, a weekend in the attic delivers a warmer house in winter, a cooler one in summer, and a lower bill in every season.