Do I Need Insulation? Do I Need More Insulation?

Snapshot | Check your insulation | Insulation status | Rebates

Snapshot

We often think of insulation as something for snowy climates. In fact, insulation is an excellent protection against summer heat, and even in the mild Bay Area climate, insulation significantly improves winter comfort.

If your home feels too hot or too cold, consider boosting your insulation to improve comfort and energy efficiency. Adding insulation is like putting a blanket on your home. Insulation works best when it's fluffy, providing a multitude of tiny air spaces that create a barrier to outside temperatures. 

Insulation is rated by its "R-value," which measures how well a material resists heat transfer. The higher the R-value (usually listed on the packaging), the greater the insulating power per square inch. R-30, about 15 inches in depth, is the recommended level of attic insulation for the Bay Area. Rebates for insulation require R-30, which is about 10 to 12 inches of attic insulation.

Insulation moves. You may have been nicely insulated years ago but under-insulated now. Over time, insulation degrades, moves, and gets compressed. Your attic insulation might have gaps or there might be areas with no insulation.  

Insulation problems are not confined to older homes. In new homes, poor installation compromises insulation's performance. There might be high R-value in the attic, walls or crawlspace, but unless it is well installed, the results will be poor. 

If you have no insulation, installing insulation will provide immediate and sizable savings, as well as a big comfort boost. If you have insulation, adding to it will increase comfort and reduce summer air-conditioning load. Insulation also reduces noise, a benefit many homeowners appreciate. 

Check your insulation

Here's how to check to see if you have enough insulation. Look for the amount of insulation, its condition, and whether it's well installed. 

As the graphic below shows, insulation should be a wrap-around blanket for your home. It should cover all sides, from ceiling to crawlspace and all around the exterior walls. Kneewalls, cathedral ceilings, and overhangs are often uninsulated. 

Where to insulate your home. Graphic: National Association of Insulation Manufacturers

Walk around to check your insulation, or hire an energy auditor. Using an infra-red (thermal imaging) camera, an energy auditor can pinpoint your problem areas.

In addition to an infrared profile, you or your energy auditor should tour your home to check:

• The attic: Attics can leak out heat in the winter and collect heat in the summer. Measure the depth of your attic's insulation; if it's less than R-30—about 10 inches—consider adding more. Here's a check: If you can see the tops of ceiling joists (the horizontal beams in your attic) poking above the insulation, then you have less than 6 inches of insulation and you need more. Insulation should also cover knee walls (vertical walls with attic space directly behind them), skylight shafts, and attic trap and access doors.

A well-insulated attic, right? Wrong. Dislodged insulation leaks heat and the attic joists uncovered like this mean this insulation is 6 inches or thinner—not enough. Photo: Ennovationz

• Under the house: Your crawlspace or basement ceiling need insulation too. Bats of insulation should be right up close to the floor of the house, held in place by netting or cables. Look for the insulation to touch all the beams and walls—no gaps or sags!

• Garage walls: Look for insulation on garage walls that are shared with the living space. Without this layer of protection, the outdoor temperatures of the garage cool the shared wall in the winter, and heat it up in the summer, creating an uncomfortable room.

• Walls: Without opening the walls, it's difficult to check the insulation status. But here is some help:

1. Get a pro. Hire an energy auditor take an infrared profile of your walls. Thin spots and leaks in your walls will be revealed right away on the infrared camera's screen.

2. Take a peek. Unscrew an electrical outlet plate on the exterior wall. The wiring behind it should be enclosed in a metal case. Poke a plastic pen in between the wall and the case. From your opening you might see pink or yellow (standard fiberglass insulation) or gray rockwool batting.

3. Trust your feelings. If you are standing next to a well-insulated wall, it will be comfortable. But if the wall is cold in the winter and hot in the summer, it does not have enough insulation.  
 

Insulation status

Many homes have some insulation, but it has gaps and it's compressed, allowing air to bypass the insulation barrier. Here are 2 examples:

Left: Area of missing insulation around plumbing pipe. Right: Blackened insulation is evidence of air leakage around plumbing pipe. Photos: Ennovationz

Compression: Your insulation may have been fluffy once, but it might be settled or squished now. Without those tiny air pockets, insulation is really not effective. Consider pulling out the old insulation and replacing it with new or adding more insulation on top. 

• Gaps: Is your insulation touching all sides of the walls and surfaces it is insulating? Insulation should touch all surfaces it's protecting or it is not doing its job. Check ducts, pipes, and lighting fixtures: Insulation is often pulled away from these during installation and should be put back.
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• Heat and air leaks: Look where the pipes and ducts penetrate walls. If you see gaps or feel leaks, seal them! Use a caulk gun or hire a pro. Your insulation will work 30% better or more if air leaks are sealed. 

If your home is like most, you'll find it could benefit from additional insulation. Before you begin, do a round of air sealing. Closing up the points of airflow will improve your insulation barrier against outside temperatures.

Read more in our articles Sealing Air Leaks, Choosing Insulation and Eco-Friendly Insulation Options to learn about your options and quick tips.
 

Rebates and tax incentives 

Your insulation contractor will also have rebate forms. Make sure to keep your invoices and receipts for your tax records.