# Question: How Much Better Is R38 Vs R30 Insulation?

## Can I use unfaced insulation in attic?

When installing between the roof rafters of finished attic spaces, you can use either faced or unfaced batting.

When using insulation that has paper or plastic batting, that moisture barrier should face outward toward the attic space..

## Is a high or low R value better?

R-value tells us how well a particular construction material insulates. The higher the R-value, the better the insulation and the more energy you will save. An R-value only applies to specific materials, not to systems.

## Does r30 and r38 make a difference?

Example: R38 has a U of 1/R or 1/38=. 026 and R30 has a U of 1/30=. 033. So R38 is about 20% better.

## Can you use r19 insulation in attic?

Most homes only have R19 in attics. To give you an idea that’s only 5 1/2 inches of insulation. That’s ok for your walls. … So by adding another R19 “5 1/2 inches will give you an R38 value.

## Can you put too much insulation in attic?

But there may be a theoretical point of “too much.” If a home is over-insulated and is too tightly sealed, moisture can get trapped inside. Without proper ventilation, a home can build up too much moisture, especially in the attic (warm air rises), which can cause mold problems and, overall, lower indoor air quality.

## Does doubling the insulation increase the R value?

Doubling the thickness of insulation will double the insulation’s R-value, cutting heat loss in half. The energy saved per year by doubling insulation from R-10 to R-20, however, will be considerably more than the energy saved by doubling insulation from R-20 to R-40, because of the law of diminishing returns.

## Which is better insulation r30 or r38?

The U value is a direct value to use for heat loss. Example: R38 has a U of 1/R or 1/38=. … The bigger the R value, the better the insulation is at slowing down the heat transfer. So R19 is better insulation than R13, and R30 is better than R19.

## How many inches of insulation should you have in your attic?

According to the U.S. Department of Energy, it’s recommended that attics have an R-38 to R-49, or about 12” to 15” of fiberglass or cellulose insulation. Use unfaced insulation when adding more insulation to an attic that already has some insulation, laying the rolls or batts at right angles to the floor joists.

## What is the best insulation for attics?

Loose-fill fiberglass attic insulation still experiences convection, but not nearly as much as old fiberglass used to. If you check with the North American Insulation Manufacturers Association, they’ll assure you that fiberglass or mineral wool is definitely your best choice for attic insulation.

## How much does it cost to insulate a 1500 sq ft attic?

Attic Insulation Cost On average, most homeowners spend between \$813 and \$1492 or \$1.50 to \$3.00 per square foot to install attic insulation. Pricing depends on the size of your attic, the type of insulation material used, and labor rates.

## What is a good R value for an attic?

Insulation levels are specified by R-Value. R-Value is a measure of insulation’s ability to resist heat flow. 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.

## Should I remove old attic insulation before adding new?

According to ENERGY STAR®, you can put new insulation over old insulation, “unless it is wet. … “Faced” insulation should not be placed on top of existing insulation in the attic. Any new roll or batt insulation installed over existing insulation in the attic needs to be without a vapor retarder (face).

## What’s the best R value?

R-value (insulation)Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch. … Straw bales perform at about R-1.5 per inch.More items…

## How many inches of insulation is r38?

Cellulose ChartR-ValueMin ThicknessBags / 1000 Sq FtR4413.4”66.2R3811.6”55.5R309.3”42.7R196”24.81 more row

## Which is better blown in insulation or rolled?

The environmentalists in your family will likely favor it over the rolled kind of fiberglass insulation. Blown fiberglass insulation scores an R-value of 3.2 to 3.8, making it slightly less likely than rolled fiberglass to prevent the flow of heat into and out of your house.

## How much does it cost to insulate a 1200 sq ft attic?

How much does attic insulation cost? The pros charge \$1,500 to \$2,000 to do a 1,200-sq. -ft. house.

## What is better r19 or r30 insulation?

Insulation in your walls and ceilings slows down this heat transfer. … The bigger the R value, the better the insulation is at slowing down the heat transfer. So R19 is better insulation than R13, and R30 is better than R19. The larger the R value, the better the insulation value.

## How long does insulation last in the attic?

20 to 30 yearsThe typical lifespan is 20 to 30 years, with degradation beginning as early as 15 years after installation. As with other types of insulation, severe weather or outside interference can reduce the lifespan. Note: cellulose is often used as supplementary insulation.