What R-value do I need for a garage?

Author: Dr. Ricardo Greenholt Jr.  |  Last update: Friday, August 8, 2025

Exterior Garage Walls Typically these will be constructed from standard 2-by-4 studs which will define the amount of insulation that you can have installed. You should be targeting an R-Value of R-13 or R-15 in these areas to properly maximize your insulation in this application.

What is a good R-value for a garage?

With an R-value ranging from 2.9 to 3.8 per inch of thickness, it provides an optimal balance between insulation performance and material thickness. This means that it effectively helps regulate temperature and reduce energy loss, making your garage more comfortable and energy efficient.

Is 6.5 R-value good for a garage door?

So Which Level of R-Value Should You Choose? To get a decent R-Value: R-Values in the range of 6-8 are decent, respectable R-Values that are leagues above non-insulated (R = 0) or wood (R = 2) doors.

Is R-19 insulation good for garage walls?

R19 is fine for walls. Just remember that fiberglass wont do a thing to stop cold air--and even that air flowing thru it will also reduce its R value. What you need to do is get out the caulk gun and sprayfoam to seal all gaps and cracks allowing the cold air in first.

Is R12 insulation good for a garage?

Insulation needs to have enough room to fluff up. If it's compressed, it won't insulate. In other words, if your walls are 2x4 construction, use R12. If they're 2x6, it's up to you whether or not you think it's worthwhile to spend the extra money on R20.

Understanding Insulation and R-Value | Ask This Old House

Should I get a R12 or R16 garage door?

If the insulation and the look of your garage door take a back seat because the price of a quality door is your top concern, we suggest going with an R12 door. Otherwise, if insulation and appearance are very important, an R16 or a fully glazed door could be a better fit to pick the right garage door.

Is R13 or R15 better for garage insulation?

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.

How much insulation for a 24x24 garage?

The average cost to spray foam insulate garage wall insulation is $500 to $3,000. A 24x24' 2-car garage wall has a dimension of 576 sq ft. The cost of insulate the walls with R13 - R21 depends on the type of insulation installed. The labor cost for insulating the 2-car garage wall is $1,500 - $3,500.

Can you put R19 in 2x4?

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.

Does it make sense to insulate an unheated garage?

Attached garage insulation can reduce the cost to heat or cool your home. Creates more comfortable living spaces. An insulated garage makes it easier to control the comfort in adjacent spaces.

What is the minimum R-value for a garage door?

For a detached, uninsulated garage – in this case, an uninsulated door or an R‑6 rating should work. For an attached garage – since these spaces are typically well insulated you'll want to make sure you've got at least an R‑value of R‑12, as well as ensure that the door itself has good resistance to cold temperatures.

How much clearance do I need for a 7 garage door?

Most garage doors are available at standard heights of 7 and 8 feet, so ceilings should be 12 to 15 inches higher than your garage door.

How much of a difference does garage door insulation make?

Yes, insulating a garage door can make a significant difference by acting as a barrier between the outside and inside temperatures. Insulating your garage door can keep your garage 10-14 degrees warmer in the winter, and 22-26 degrees cooler in the summer.

Do you need a vapor barrier in a garage?

The primary function of a vapor barrier is moisture control. In the garage, like other spaces in the home, condensation results from moisture in the air. Excess condensation and humidity levels in your garage can damage your garage's foundation and cause tools, vehicles, and cabinets to rust faster.

Can insulation R-value be too high?

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. While you might think that too much insulation can't be bad, there are some significant consequences to consider.

How to insulate a garage cheaply?

What's the Cheapest Way to Insulate a Detached Garage? In most cases, fiberglass batts/rolls are still the simplest and all-around cheapest option for detached garage insulation.

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.

What R-value is best for soundproofing?

The Higher R-Value the Better The higher the number the better job the insulation will do at keeping heat and sound in or out of your home. Cellulouse Insulation has a R-value rating of 3.6-4.0 cubic inches, which is one of the highest ratings in the industry.

Where do you put R19 insulation?

The most common application of R19 Insulation is in a vertical wall framed by 2×6 studs. As mentioned above this is a common code requirement in some parts of the United States.

What is the best insulation value for a garage?

What R-value insulation should I use in my garage? Generally, insulation with an R-value between R-13 and R-21 is recommended. Adding insulation to exterior walls (including garage walls attached to living spaces) can help increase R-value and create a more powerful thermal boundary for your home.

Will insulating an unheated garage cause mildew?

Insulating an unheated garage alone may not necessarily cause mildew, but the risk of mildew increases if there isn't proper ventilation. Insulation can trap moisture in the garage, especially in humid climates, creating a perfect environment for mildew growth.

Is R30 insulation good for a garage?

Here, the level of R-Value you apply is largely going to depend on whether or not you have a finished room over the garage. If you do, this is going to be resting on joists and will give you roughly 10 inches of play in which you can apply high-density R-30 style insulation.

Is R15 worth the extra money over R13?

You can use both in similar places and climates. 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.

What is the best insulation for a 2x4 garage?

For standard 2x4 walls, which are common in older homes, an R-value of R-15 is considered good, while R-21 is excellent. This can be achieved with high-performance fiberglass batts, dense-packed cellulose, or a combination of cavity insulation and continuous insulation.

Can I use R13 for 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.

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