What insulation rating is best?

Author: Geovanny Sporer  |  Last update: Tuesday, February 3, 2026

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.

Should I use R13 or R19?

r19 just means its thicker insulation, made to fit into a 2x6 frame where the r13 is meant to fit in a 2x4 frame. the insulation is soft and will press in fine and won't offer as much of an air buffer in the insulation but will still accomplish the job just fine especially for a garage situation.

Is an R-value of 2.5 good?

The higher the R value, the more your mat resists heat loss and the better it insulates you from the cold ground. As a rule of thumb, an R value of 1.0 to 2.0 is fine for summer use but you'd need a rating of 4.0 to 5.0+ for winter camping.

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.

Is an R-value of 24 good?

Preferred wall insulation is R-24, because conductive heat transfer does not favor a direction. Convective heat rises, but heat conduction simply goes through solid objects: walls, floors, ceilings.

Understanding Insulation and R-Value | Ask This Old House

What is the highest R-value for a 2x4 wall?

Fiberglass and rock wool batts—2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products. Generally, batt insulation is the least expensive wall insulation material but requires careful installation for effective performance (see page 4).

Is R13 or R15 better?

R-value is a metric that tells us how well insulation performs at reducing heat loss. When comparing R13 to R15, insulation designated as R15 performs better at reducing heat loss than R13. R-values are generally cumulative, meaning that you can stack two layers of R6 insulation boards to achieve R12.

Does doubling insulation double R-value?

The dip from R10 to R4 seems odd, as one would expect more R as you travel further north through the zones. Thicker is not better! Doubling the amount of insulation will double the R-Value, but so what? Doubling the insulation from R-19 to R-38 does NOT cut the heat loss in half (50%) it cuts it by around 3%!

Is it OK 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.

What is the minimum R-value of insulation allowed in an attic?

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 best R-value for winter?

R-values 101

For winter camping, you generally want an R-value of at least 5, while three-season campers only need an R-value of 2 or more for most conditions. R-values are additive, so stacking two pads on top of each other provides an R-value that is more or less the sum of their individual R-values.

What is considered a bad R-value?

If we wish to label the strength of the association, for absolute values of r, 0-0.19 is regarded as very weak, 0.2-0.39 as weak, 0.40-0.59 as moderate, 0.6-0.79 as strong and 0.8-1 as very strong correlation, but these are rather arbitrary limits, and the context of the results should be considered.

Do sleeping pads keep you warm?

Sleeping Pad Warmth

A sleeping pad's insulation is crucial to a warm night's sleep because you lose body heat to the cold ground beneath you. To counteract this, pads use a variety of materials and construction techniques to prevent heat loss.

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.

What is R13 good for?

R-13 insulation has become a standard choice for many homeowners, and for good reason. This medium-grade insulation offers substantial thermal protection while remaining cost-effective. It's particularly well-suited for: Standard 2x4 wall cavities in most homes.

Is R19 enough for a garage ceiling?

By our rough estimate, for a garage heated consistently throughout the winter, insulating four walls, garage doors, floor, and ceiling to R-19 would result in about $1050/year in energy savings!

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.

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).

Can I use a higher R-value insulation?

As mentioned above, you can always increase your R-Value simply apply an extra layer of insulation over your initial layer.

Can insulation be too thick?

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 are the disadvantages of double insulation?

Because its structure is more complex than single-layer insulation, the cost is relatively high. Additionally, in some cases, double-insulated cables may fail due to spalling between the inner and outer insulation layers.

Which insulation has the highest R-value?

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.

Can you use R13 in a ceiling?

R13 batt insulation is typically used to attenuate sound in interior wall cavities. It is akin to a large blanket, designed specifically to fill a wall, floor, or ceiling cavity.

Is R15 worth the extra cost?

R15 insulation offers slightly more thermal resistance than R13 insulation, but it also costs more. Ultimately, it's difficult to justify paying a significantly higher price for R15 when R13's insulative properties are only slightly lower than R15.

Is R15 uncomfortable?

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