Updated: Dec 26, 2022
When your attic insulation is not performing as well as it used to, it’s a sign of a problem in your home. You could be at risk due to various reasons. First being a rodent infestation. Also, a poor attic can lead to high energy bills because it interferes with a home’s ecosystem.
So how often should attic insulation be replaced? Well, there are different insulations used in homes. Follow through with the article as we sample replacement periods of varying insulation types.

Fiberglass
Fiberglass is effective and pocket-friendly. Unless damaged, fiberglass insulation can last between 80-100 years without the need to replace it. Nonetheless, attic insulation can fall from fiberglass batts in around 15-20 years. So attic insulation installed in batts should be checked and replaced often.
Mineral wool
Mineral wool is getting popular due to its durability when it comes to attic insulation. However, durability depends on which wool you use, either slag, glass, rock wool, and many others. Mineral wool can survive for decades before replacement.
Similar to other attic insulation, when damaged, mineral wool insulation cannot last for long periods. Mineral wool is majorly used to supplement existing attic insulation. Mineral wool should also be replaced when its functional period is over, even with other types of insulation in place.
Cellulose insulation
Cellulose insulation is safe for the environment and blocks air effectively compared to other types of insulation. Furthermore, cellulose has also been linked to protecting homes against fire.
Cellulose is made of recycled materials but is not easily degradable. Cellulose can last for 20 to 30 years. Degradation can start after 15 years of installation. Interference or bad weather reduces the lifespan of cellulose insulation.
Just like mineral wool, cellulose insulation is used to supplement other forms of insulation. Though a home may contain primary insulation from different materials, with cellulose present, signs that the insulation is aging are seen. This is because when cellulose starts aging, it degrades.
Spray foam
Spray foam is among the most durable attic insulation. It is practical, durable, and popular among many homes. Spray foam can last for a lifetime or more extended periods. Its ability to resist mold and moisture makes it stay put for long periods unless you move it physically.
Spray foam insulation is rarely replaced. But if bad weather, construction, or other damaging factors affect your spray foam insulation, then you need to repair or replace it.
General factors that determine how often you should replace attic insulation
Insulation has different lifespans. However, there are general factors that determine how often you should replace them.
- Roof damage: A damaged roof causes water leaks that drip down to your insulation.
- Mold: growing mold can damage your insulation and significantly reduce the lifespan of your attic insulation, and it is hard to detect unless you do an inspection.
- Punctured insulation: animals or a storm can puncture your attic insulation, damaging it and forcing you to replace or repair it.
- Dust: dirty and dusty insulation makes it less effective as days go by.
- Severe weather: if your house has survived extreme weather conditions, you may need to check out your insulation.
Signs that you should replace your attic insulation
Change in temperature: temperature changes can indicate that you need to check out your attic insulation. Difficulties in maintaining a specific temperature are a sign that you have problems with your insulation.
Draft in your rooms: drafty rooms indicate that you should replace your insulation immediately.
Increased energy bills: this can be a result of air conditioning. Damaged insulation means that no heat is being repelled, which requires you to control the air condition within your house.
Allergies or illness: damaged insulation provide the best conditions for mold and allergens which could affect you.
Leaks and moisture issues: if you are getting leaks from your attic or dampness, it means that your attic might require replacement.
Rodent infestation: rodents can make unvisited rooms their living areas, and your attic is just one of them. If you are struggling with rodents in your home, consider inspecting your attic insulation.
Conclusion
When moving in, you should know the background of your home. Old houses often have old insulation, which might be damaged or of low quality. Also, the insulation might be poorly insulated. The longer the house has existed, the more likely it does not have the proper insulation in place.