Insulation R-Value Chart and Buyer's Guide (2023)

August 10, 2020 18:30:48

isolationconstruction science

Matt Power, Editor-in-Chief

6 minutes of reading

(Video) Understanding Insulation and R-Value | Ask This Old House

However, choosing the best insulation is not as simple as comparing the R value. Locate and seal any leaks for best results.(updated 12-22)

You strive to improve the comforts of your home, and R-value, as you've been told, is your first port of call. Here's the chart you've been looking for, but before you choose a product based on R-value alone, read on.

Insulation R-Value Chart and Buyer's Guide (2)

This chart shows the approximate R-value per inch of various insulation materials, but does not account for air leakage, which can drastically affect overall performance.

Almost any type of insulation can improve your home's performance. Some perform multiple steps at once. Let's take a quick look at the main suppliers of insulation products:

foam spray

The most well-known benefit of spray foam's high R-value per inch of 6.25 (for high-density foam) is that you can cram a lot of insulating power into a small space to create a well-insulated wall. But spray foam has other benefits too.

Firstly, it seals air leaks, especially in difficult places, e.g. B. near pipe penetrations and cable entry points.

Second, it adds structural strength to your roof or walls. For example, if you live in an area prone to hurricanes, spray foam on the underside of the ceiling box.increases your resistance to wind suction by 250 percent.

Of course, you pay up to six times more per square foot than some fiber optic products for this premium performance.

Spray foam is also used to seal basements from radon and has been shown to nearly double the hurricane resistance of older roofs. However, be sure to let spray foam insulation cure before reinstalling it in a room. They need 24 hours to harden and dry.

Cellulose: green filler

A big challenge in older homes is accurately filling all the hidden voids in the walls to improve energy efficiency. Using thermal imaging, cellulose can be "blown" behind walls through a series of small holes in interior or exterior walls. (These will be corrected when finished.)

(Video) Insulation Installation - R-Value In Walls, Attic, And Crawl Space (cost of material and labor)

Some pulp brands, such asgreen fiber, contain a high percentage of post-consumer recycled waste. This is currently the most sustainable type of insulation you can buy and as such has the lowest carbon footprint. With about the same cost as fiberglass, it is also a very suitable product for DIY. If you're intrepid, you can rent a blower from a big box store, buy lots of bags of compressed cellulose fiber, and blast it into the walls and ceiling voids. It's noisy and messy work, but affordable and effective. However, I would recommend an expert if you are looking for optimal performance.

Another benefit of cellulose is that now it can also be used in the cavities in the walls that separate a two-story. Not only does this dampen the sound between the two houses; It also stops most odors from cooking and other sources. When installed correctlyThis method provides a two hour firewallthat goes beyond the required building regulations and makes the building safer.

Fiberglass: Affordable and strong

Fire resistant, affordable, insect resistant and trusted by most contractors, fiberglass remains the most common choice for insulation. It's available as a blown product for walls and attics, and many manufacturers have changed their manufacturing method so that the tiny fibers are less irritating to the skin, easier to apply, and easier to make at home.

Perhaps the most common fiberglass retrofit is adding inch-by-inch insulation to your attic. Research has shown that you probably need a lot more insulation up there than you think. After about R-38, however, your return on investment for extra insulation starts to wane, so don't think you can just hoard it.

Insulation R-Value Chart and Buyer's Guide (3)

One reason why many regulations now recommend deeper insulation in attics is what is known as thermal bridging. By fully covering the ceiling joists, the product retards heat transfer through the wood or steel.

Lã mineral: Fire Plus

Mineral wool manufacturers such as Rockwool emphasize the fact that their product is virtually impervious to flame. It shares many of the same properties as fiberglass, with the added "superpower" of extreme heat and flame resistance.

For a home in an area prone to wildfires, this might be the logical choice. Note that the mineral wool industry has had some issues with mining practices to extract raw materials lately, but we hope they make adjustments towards sustainability. It is a good product especially for larger houses, fire hazard objects and commercial buildings.

Rigid Foam: Super Armor against extreme heat

In one of our recent VISION House display projects in Scottsdale, Arizona, we are testing the effect of applying an inch of itpolyisocyanurate foam boardon the roof deck (under the waterproof EPDM layer). The results were impressive. According to Steve Easley, the construction expert who masterminded the conversion, this single layer dramatically lowered the ambient temperature in the attics. With outside temperatures of 50 degrees Celsius, this type of "shielding" makes all the difference so that cooling devices can efficiently regulate internal temperatures.

New homes: Insulation options abound

When building a new home, you have several options for insulation.significant. Modern homes have a big advantage over those built 20 years or more ago. They typically have external "sleeves" that allow for fewer air changes per hour, so the wall "system" doesn't rely as heavily on insulation. New wall coverings with taped seams, taped inner film, sprayable inner film, and other innovations effectively reduce overall leakage and spot sealant application and foam joint penetration.

(Video) How to Choose the Right Insulation | Ask This Old House

This levels the playing field for different types of insulation and gives more weight to each product's R-value rating. In other words, you can get good performance out of any type of insulation.

The difference now is the cost and available cavity: are you building in 2x4" or 2x6" frames? Ready to consider building parallel walls to get super high R-values ​​on your walls? Of course, I'm assuming here that you've chosen traditional bar frames, not structurally insulated panels or insulated concrete forms, both of which are good alternatives.

Ultimately, building codes require a certain level of insulation for any new home. But you might want to go further - try to achieve net zero performance, where you can say your home is "carbon neutral".

Insulation R-Value Chart and Buyer's Guide (4)

Thermal imaging cameras can detect where energy is leaking in walls or ceilings. In this Arizona home, the red areas represent locations where warm outdoor temperatures are transmitted indoors.Foto: ReVISION House Scottsdale

common questions

How do I decide where to insulate my old house?

The most accurate way to find out is to do an energy audit of your home. This test usually involves a thermal imaging gun and a vent port and will identify where your home is leaking and poorly insulated. For most homes, the attic or basement is the best place to start insulating. But with the thermal imaging camera, you can discover entire sections of wall that aren't insulated or spots where old insulation has come apart.

Should I add insulation to my home if I replace siding?

If you're spending $10,000 to $14,000 to remove and replace your home's siding, adding insulation makes financial sense. and thatjustScenario where the deviation eventually becomespay for yourselfEnergy savings due to the tighter construction envelope of the house.

Your options include 1. Injecting cellulose or spray foam, or 2. Adding rigid foam board such as DuPont/Dow Styrofoam. Both methods significantly reduce air intrusion while adding some R-value.

Insulation R-Value Chart and Buyer's Guide (5)

Left image: progressive foam. Right image: DuPont

Are insulating attic covers worth the cost?

Accordinglygreen builderMagazine, some brands of loft door insulation can reduce air infiltration by 70%. Priced under $150, they can reduce a home's heating or cooling loss by 20% per year. For a home with a $3,000 annual heating bill, that's a savings of $600 in the first year alone. In other words, attic coverage can pay for itself in just three months through energy savings.

(Video) Styro Aircrete: a cheap way to insulate. R Value Testing

Editor's Note: This article was originally published on January 21, 2015. It has been updated and republished with new information to reflect changes in technology and products.

10.08.2020 18:30:48 ·

6 minutes of reading

By Matt Power, Editor-in-Chief

Veteran journalist Matt Power has been reporting on innovation and sustainability in housing for nearly three decades. An award-winning writer, editor, and filmmaker, he has a long history of asking tough questions and adding depth and context by revealing complex themes.

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