Frequently Asked Questions

Insulation works by slowing down the transfer of heat into and out of a home or building. In the winter, it stops heat from escaping your house, and in the summer it blocks heat out.

Heat moves in three ways: conduction (through materials), convection (through liquid or air), and radiation (in a straight line, heating anything solid in its path). Most insulation materials, like fiberglass, cellulose, and spray foam, slow conductive and/or convective heat transfer. Reflective insulation materials like radiant barriers reduce radiant heat gain and loss.

Air sealing reduces drafts and convective heat loss by closing up gaps and openings around chimneys, plumbing and wire penetrations, floor joists, recessed lighting, and other areas. There are several types of air sealing materials, including foam, flashing, and caulk.

In the typical home, significant volumes of air enter through cracks near the basement and exit through ceiling cracks and penetrations on the building’s top floor. Even with an adequate volume of attic insulation, without air sealing, you will still have significant air leakage. These leaks add up to waste a tremendous amount of energy, which is why it’s important to both air seal and insulate.

Cellulose and fiberglass resist heat based on the same property; the air pockets between the material act as the insulator, not the material itself.

Where they differ is that, unlike fiberglass, cellulose is a pest-repellant and flame retardant. Its flame-retardant properties are demonstrated by “The Big Burn,” an experiment in which three identical houses were built: one with cellulose insulation, one with fiberglass insulation, and one without any insulation. The house with no insulation collapsed at 40 minutes, the fiberglass house collapsed at 42 minutes, and the cellulose house at 67 minutes. The fire-retardant qualities of cellulose can save the roof structure of a house from caving in, allowing the fire department more time to put the flames out.

Cellulose has been the preferred material of many LEED-certified professionals and followers of building science for decades.

All of these claims are false. Cellulose has two ingredients: 75-85% recycled newspaper, and Borate, with Borate bringing pest-repellant and flame-retardant performance. It is completely non-toxic and is found in contact solution, laundry detergents, and many other common household products. Cellulose is indeed denser than fiberglass, but that means you actually need less of it than fiberglass (13.5” cellulose vs 18” fiberglass for an R-49). If your ceiling drywall is bowing, you probably have other issues to worry about.

At the end of the day, some homeowners simply prefer to use fiberglass, and while we recommend the performance of cellulose, we can always honor that wish and blow fiberglass instead.

Dense-packed cellulose is meant for enclosed cavities. It utilizes a dry material at a high pressure to prevent settling. Blown cellulose is the same material, but comes out at a lower pressure to maintain fluffiness and is ideal for insulating attics where there is room to blow high.

Initially, cellulose needs to settle down about 1 inch. When installing cellulose insulation, we blow an extra inch to compensate for this settling. After this, cellulose does not shrink quickly—it maintains the same height for 25 years.

Typically, no. Since insulation removal adds cost, we only recommend doing so when it’s absolutely necessary due to moisture, mold, animal infestation, etc. Usually, the insulation that is already there isn’t pretty, but is working to an extent, so there’s no need to remove it. Leaving it in place also means you can save money on the amount of new material needed. When the job does require insulation removal, we vacuum and remove everything, sanitize, then air seal and blow for a “brand-new” attic. One additional upside of extraction is that we can see all penetrations and air leaks and perform an extremely thorough air sealing job, since nothing is hiding under insulation!

The R-value you need depends on where you live and what climate zone you’re in. In Greater Cincinnati, we are at the top of climate zone 4, which means you need an R-49 in your attic and an R-13 to R-19 in your walls.

Depending on your home’s construction and level of insulation currently existing, this answer varies greatly. According to the Department of Energy, attics can be responsible for 25%-30% of heat loss, and walls 35%. The attic is generally the “low-hanging fruit” improvement that is the lowest cost with the highest impact. Sustainergy Cooperative offers free energy assessments to determine where your home would benefit the most from an insulation upgrade.

Proper attic ventilation is crucial for energy efficiency and healthy indoor air quality. We want to control the airflow between the conditioned/living space and the unconditioned/outside space, but also want to encourage air flow through your attic to move moisture, indoor air pollution, allergens, heat, and more. This can come in many forms of home ventilation including soffit vents, gable vents, roof box, and ridge vents.