How many inches of insulation is good?

Author: Andres Yost DDS  |  Last update: Saturday, February 7, 2026

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.

What is the recommended thickness of insulation?

For insulation rolls and batts, the recommended thickness level is 270mm. This is what you will have to insulate to in a new property, and what you should be aiming to insulate to in an older one. If starting from nothing, you will probably have to buy and install two rolls or batts.

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.

What is a good level of insulation?

If you live in the Southern part of the U.S., the recommended insulation level is a minimum of R-38 or about 13-14 inches of insulation. If you live in the Northern part of the U.S., the recommended insulation level is a minimum of R-49 or about 16-18 inches of insulation.

Can you put too much insulation in your attic?

Mold and Mildew Growth

Having too much insulation in your attic can allow for the accumulation of moisture. This leads to mold and mildew growth, which can be extremely bad for your health.

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

How many inches of insulation is good in the 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.

Does extra insulation really help?

Unless your home was specially constructed for energy efficiency, you can probably reduce your energy bills by adding more insulation. Many older homes have less insulation than homes built today, but even adding insulation to a newer home can pay for itself within a few years.

How to tell if an attic needs more insulation?

7 Ways To Know If Your Home's Attic Is Under Insulated
  1. Schedule an insulation inspection. ...
  2. Safely access the attic and take a look around. ...
  3. Insulation is unevenly layered. ...
  4. Evidence of leaks or water damage. ...
  5. The attic has mold or mildew growth. ...
  6. You haven't replaced attic insulation in more than 10 years.

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.

Is it better to insulate a ceiling or roof?

The answer to these issues may be adding insulation, but that still leaves the question of where to apply additional thermal protection to see the most benefit. While both ceiling and roof insulation will increase your home's resistance to outside temperatures, insulating the ceiling should be your priority.

What R rating should I have in my attic?

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.

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 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.

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 is the most effective insulation per inch?

Insulation R-Value Chart
  • Closed Cell Spray Foam: R-6 to R-7.
  • Foam Board: R-4.5 to R-5.
  • RetroFoam Injection Foam: R-4.6 to R-5.
  • Open Cell Spray Foam: R-3.6 to R-3.9.
  • Cellulose (Loose-Fill): R-3.1 to R-3.8.
  • Fiberglass (Batts): R-2.9 to R3.8.
  • Fiberglass (Loose-Fill): R-2.2 to R-2.9.

How do I choose insulation thickness?

Choosing the right thickness for your insulation depends on various factors such as climate, location within your home, and type of material used. It's crucial to do thorough research, consult with professionals, and ensure proper installation for maximum efficiency.

What is good insulation cheap?

Fibreglass insulation is considered the cheapest and most effective UK insulation option. It's made of glass fibres and is available in batts, rolls, or loose-fill form. Fibreglass insulation is widely used in residential and commercial buildings due to its affordability and effectiveness in reducing heat transfer.

Do I need faced or unfaced insulation?

For example, if you need extra soundproofing or don't want to spend time installing a separate vapor barrier, then face may be the best option for you. However, if cost savings are more important than convenience, then unfaced may be the better choice in this case.

What blanket has the highest R-value?

Aerogel insulation offers the highest R-value of any insulating material at less weight and thickness—ideal for construction, refineries, pipelines, and thin-gap thermal barriers. Browse our superior selection of superinsulating aerogel blankets below.

Is 6 inches of attic insulation enough?

However, the DOE recommends that attics in Southern homes be insulated with 13 to 14 inches, or R-38, of insulation at minimum. Northern homes should have attics with 16 to 18 inches of insulation or R-49. If your home isn't insulated to the recommended thickness, you likely want to consider adding more insulation.

How often should attic insulation be replaced?

However, due to its construction with natural materials, eventually the product will lose effectiveness. Fiberglass insulation typically needs to be replaced 15-20 years into it's life, as it can easily become dirty, wet, moldy, and ineffective if there's a roof leak or water damage of any kind.

Can an attic be too insulated?

Too much insulation will leave humidity and moisture to accumulate in your attic space. This can lead to mold growth on your walls and insulation. There might also be water damage to the support beams in your home's roof.

Where should you not put insulation?

Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.

How much does it cost to replace attic insulation?

Attic insulation costs anywhere from $1,680 to $3,125, depending on the size of your attic and the material used. On average, most homeowners shell out around $2,380. These costs include the insulation materials and installation by a professional.

Is blown in attic insulation worth it?

Blown-in insulation offers several advantages over other types of insulation. It is highly efficient and can significantly reduce energy bills. Additionally, because the insulation can be blown into difficult-to-reach spaces, it can provide more comprehensive coverage than other types of insulation.

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