How Do You Know When Your Attic Insulation Needs Replacing?

Time, Humidity, and Critters destroy your home's insulation and cost you money.

How do you know when your attic insulation needs replacing? You’ll definitely get a lot of telltale signs that your home needs new insulation, but some may be easier than others.  For example, can you see the rafter in your attic? Or does your insulation look matted down like this? 


insulation removal


Insulation is an investment that saves you money year over year, but, like anything, it does wear and lose its effectiveness over the years. In theory, attic insulation can last decades depending on the insulating material. But several factors can shorten the lifespan of the insulation to about 15-20 years in general.

It’s always best to consult experts through an evaluation. In the meantime, read this article for signs your attic insulation needs replacement.

Signs your attic’s insulation is no longer effective  

High energy bills 

This could be simply due to time, or there may have been a critter up there walking around.  Either way, a home with poor quality or compacted insulation cannot regulate temperature efficiently. Just like a down jacket, insulation works efficiently when it’s “puffed up” creating thousands of air pockets that increase the resistance value, and therefore, fluctuations in temperatures or transfer of energy. Hot and cold air escapes in air leaks, making your A/C/heating systems work harder to cool/heat your home. This results in higher energy bills and overworked cooling/heating systems. 

fiberglass insulation

Drafty room or home 

Drafty rooms or hot and cold spots in homes can be caused by air leaks from which the attic or home air is drawn, creating a vacuum effect. As your conditioned air is escaping your home it is replaced by unconditioned air. This makes your HVAC system constantly run, creates varying temperatures room to room, possible condensation problems, and much more.  Old, deteriorated insulation and lack of proper air sealing will only contribute to this problem.  

Water leaks, condensation

If your ceiling or wall has water leaks coupled with signs of condensation, then you need to check your insulation. Chances are, your insulation is damp, damaged by a leak or heavy storm, or is insufficient in heavy humidity areas.

Aside from these, there are many other signs that your home is not properly insulated.

Other factors that negatively impact insulation

Wet insulation

It could be from water leaks after a rain.  Once an insulation gets damp or wet, it isn’t as effective anymore because it loses a portion of its R-value and thickness even if you dry it out. The trapped moisture within the insulation material can cause mold growth and advance decay of joists and rusting of metal or steel pieces.


Do you have mice living in your attic space? Or have you seen their little droppings in places? If yes, your insulation is at risk of damage. Even more so, you could be living in a health hazard.  As critters are running around your attic and leaving their droppings and urine everywhere, they are doing so right next to your HVAC unit, or right above the place where you sleep.  These leftovers don’t go away.  Furthermore, as they are running around, they are trampling your fluffy insulation into a matted down pancake!   


Insulation removal

You should call a pest removal expert at the first sign of critter issues in your attic. You might be able to save your insulation if you catch it quick enough, but there is a good chance a full removal and disinfectant should be completed once the critters have been removed or eradicated.  This will save both your energy bill and possibly your health. 

Severe weather or incident

If your home has experienced harsh weather conditions or events like flooding or fire, the more the insulating materials are prone to wear.  Houston is known for its flooding.  If you get just a few inches of water in the house, your lower drywall and insulation will most likely need to be replaced.  As soon as the drywall and insulation get wet, they will soak up the water and retain it for weeks or even months if not properly removed and dried.  This creates a breeding ground for mold and other bacteria.  

insulation flood damage

Old Home = Old Insulation

Many older homes were made without insulation while others may have insulation but are probably in need of replacement by now. Or at minimum, a top-off.  Simply put, if you can see your rafters, you are losing money and need more insulation. Homes built before the year 2000 now have insulation at least 20 years old.  If built in the 80’s, it is now 40 years old or nearly twice the life expectancy of cellulose insulation.  Some houses before 1978 have vermiculite insulation which contains asbestos. If you suspect that your attic insulation has asbestos, contact an asbestos removal expert immediately. 


Cellulose Insulation Removal

Batt insulation and loose-fill (blown-in) insulation (settles over time)

When was the last time you inspected your attic insulation? If you have batts or loose fill (blown-in) insulation installed a decade ago, it’s probably time to check it now.

Batt insulations like cellulose and fiberglass have a tendency to sag within 15 years. While loose fill (blown-in) insulation has the tendency to settle and can sag especially if it is wet.

insulation removal

How long do insulations last?

Spray foam insulation

This type of insulation material is durable and doesn’t hold moisture. If undamaged, it can last a lifetime.

Spray foam insulation is great against mice since it isn’t an attractive food source for them. 


This material is popular for being lightweight and less costly than other materials. In ideal situations where it has experienced zero-damage, it can last about 80-100 years.

However, fiberglass needs to maintain its fluffiness to retain its insulative properties. Once compressed or filled with moisture, its R-value decreases.  Having to constantly deal with humidity and other external factors, the typical life expectancy for blown-in fiberglass is around 20-25 years.  Or by this time, if still of good quality, it would have settled enough where a top-off may be required.

Due to different circumstances, fiberglass batts tend to sag from the ceiling after 10-15 years. If the fiberglass is exposed and loose, particles can scatter in the air and pose risks to respiratory health.


Cellulose insulation is a sustainable and effective air-blocking material.  Ideally, this material should last around 20-30 years but due to different factors like moisture and damage, it can deteriorate as early as 15 years.  Houston’s humidity strikes again here. 

The material is made up of 75-85% of paper, making it more susceptible to moisture and mold growth.

As long as you have cellulose in your insulation, whether it’s the main insulating material or just an additive insulation, you need to inspect whether it needs to be changed. 

Mineral wool

Another type of material that is not critter-friendly.

Depending on if it's slag wool, rock wool, or glass wool, this insulation material typically lasts for several decades. Mineral wool does not absorb moisture within and hence does not promote mold growth. If it is dried after getting wet, it would not lose its thermal resistance.

However, if it stays wet for a period of time, it can cause moisture in the attic.

Replacing the insulation

If the insulation in your attic is wearing thin, it doesn’t mean you have to replace it. You can add another layer of insulation material as long as your old insulation was not damaged by water, mold, or pests like mice, rats, or even cats! 


Insulation Removal

Making changes or replacements to your insulation depends on many factors like your house’s age, the age and type of the insulation material, and external factors that affect the insulation.

Want to get an expert’s opinion on your attic’s insulation?  Book a free attic evaluation with one of our consultants today!


Koala Insulation of Northwest Houston

Delivering Efficiency. Improving Comfort. 

Koala Insulation is an insulation contractor providing high-quality insulation services to homeowners, contractors, and property owners. We work with new construction, retrofit applications, and properties affected by natural disasters or that have suffered significant damage. 

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We Provide Insulation Services to the Following Northwest Houston Areas

Houston, Spring Branch, Jersey Village, Willow Brook, Copperfield, Cypress, Mason Park, and Cinco Ranch

Counties Served

Harris County, Waller County, & Fort Bend County

Zip Code

77040, 77041, 77080, 77043, 77055, 77070, 77069, 77066, 77065, 77449, 77450, 77433, 77429, 77095, 77084, 77064

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