What R-value insulation for an attic?

Author: Monica Wolf  |  Last update: Monday, December 8, 2025

The recommended R-value for attic insulation can vary depending on the climate zone in which you live. The U.S. Department of Energy recommends attic insulation levels of R-49 to R-60 for most homes in colder climates, and R-30 to R-49 for homes in warmer climates.

What R-value is best for attic insulation?

For example, homeowners in the southern United States can begin insulating their attic using materials that have R-values in the R30 to R60 range and R13 to R19 insulation ratings for the floors. Attic insulation should be R49-R60, while floor insulation should be R25-R30 for those in the north of the United States.

Is R19 or R30 better for an attic?

Yes, you can use R19 insulation in an attic, but whether it's suitable depends on a few factors: Climate Zone: R19 insulation is typically appropriate for attics in moderate climates. In colder climates, higher R-values (like R30 or R38) may be recommended to effectively prevent heat loss.

Can you have too high of an R-value insulation?

The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space.

Is it okay to use R19 insulation in attics?

You will want to bring up your attic up to R-38:

If your attic has 5-6″ of existing insulation, you'll want to install an R-19 to achieve a total of R-38.

How to Choose the Best Insulation for Your Home | DIY Home Renovation

Is R19 worth it over R13?

R13 insulation is generally more affordable, which makes it an attractive option for budget-conscious projects. However, R19 insulation offers better long-term advantages because of its higher R-value. Why? Because the R-Value translates to a greater energy savings over time.

How many inches of insulation is recommended for attic?

The higher the R-Value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.

Can I put too much insulation in my attic?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers.

What is the thinnest insulation with the best R-value?

The thinnest insulation material currently available on the market is the 10mm Aerogel blanket. Its manufacturing technology is highly interesting, and its appearance resembles frozen smoke. For some, aerogel is synonymous with time frozen and suspended in space.

Does doubling up insulation increase the R-value?

The thermal barrier of a home should consist of a continuous layer of insulation on all sides—including the lowest floor, the exterior walls, and the ceiling or roof. Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half.

Can you double up R19 insulation?

If the existing attic insulation is an R-19, you may choose to add another layer of R-19. Two layers of R-19 at 6¼ ” thick will achieve a total R-value of 38. So adding an R-19 batt to an existing R-19 batt will give you a total insulation value of R-38.

Is it worth upgrading attic insulation?

Heat naturally rises, and without proper insulation, it escapes through your attic, forcing your HVAC system to work harder. 💰 Upgrading insulation can reduce energy costs by up to 30%! ✅ Better insulation = less heat loss in winter and less heat gain in summer.

Is R15 worth it over R13?

R15 insulation offers slightly better thermal insulative properties than R13. Some of its formats are a fraction of an inch thicker than R13, making it more effective at helping with energy efficiency. However, the difference is minimal. R15 is slightly thicker than R13 for spray foam and blown-in cellulose.

Do I need faced or unfaced insulation in my attic?

Typically, you use unfaced insulation when you plan to add more insulation to your attic or between the walls and floors of your living spaces at home.

What is the best rated attic insulation?

If you're concerned about having a positive impact on the environment, fiberglass batt is probably the best insulation option for your attic.

What insulation board has the best R-value?

The best kind of rigid foam insulation is polyisocyanurate, also known as polyiso. It has the highest R-rating of any rigid foam insulation and comes with a reflective foil on both sides, allowing it to act as a radiant barrier as well.

How do I choose the R-value for insulation?

Depending on where you live and the part of your home you're insulating (walls, crawlspace, attic, etc.), you'll need a different R-Value. Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces.

What is the cheapest most efficient insulation?

It's essential to wear protective clothing and a mask when installing fibreglass insulation to prevent any health risks. Overall, fibreglass insulation is the cheapest and most effective insulation option available, making it a popular choice for homeowners and builders alike.

Should I use r30 or r38 for attic?

For homes located in colder regions, R-38 insulation is typically recommended for attics and ceilings. Its higher thermal resistance ensures compliance with updated building codes and reduces heat loss significantly, which leads to lower heating costs during winter months.

Is it okay to cover attic insulation with plywood?

Can I put plywood over insulation in the attic? Yes you can install plywood subflooring directly over the floor joists and insulation on your floor. You need to install rigid insulation boards on top of the attic flooring joists and then install plywood over the top.

Where should you not put insulation in the attic?

Also, when laying down additional insulation, work from the perimeter toward the attic opening. Never lay insulation over recessed light fixtures or soffit vents. Keep all insulation at least 3 inches away from recessed "can" lights, unless they are rated IC (Insulated Ceiling).

Should old attic insulation be removed?

The bottom line is the old insulation needs to be removed because it hinders the airflow into the attic, it can promote mold growth, and it is dirty.

Should I insulate my attic floor or ceiling?

Insulating your attic floor can create a vented attic, which is ideal for storage and not needing temperature control upstairs. Insulating the ceiling will make an unvented attic, which allows you to control the temperature for temperamental storage items, living space, and HVAC ductwork.

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