While it has a long lifespan, it does not last forever. With time, your insulation settles and loses its thermal resistance or R-Value depending on the material.
Insulation, depending on the material used, can last for decades if properly cared for. Some insulation materials are composed of natural materials and will eventually degrade. Others are made from synthetic material and can last for nearly a century before needing replacement.
Over time, older insulation can become less effective due to settling, moisture damage, or degradation. Removing old insulation and replacing it with newer, higher-quality materials can substantially improve your building's energy efficiency.
Studies conducted by the Department of Energy's Oak Ridge National Laboratories show that as outside temperatures drop, the R-value of fiberglass insulation decreases.
Fiberglass can hold moisture, which puts it at risk. Moisture will cause fiberglass insulation to deteriorate over time and lose its effectiveness. Not only will this affect its integrity, but it also promotes mold growth.
What causes cold walls? Poor insulation is the main reason why walls feel cold, especially in older properties with solid walls. Roughly 35% of heat loss is through walls and gaps, in and around windows and doors. Walls transfer heat and the warmth from your home will escape outside if your walls are poorly insulated.
In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.
Fiberglass insulation can potentially last 80 to 100 years if it is undamaged, but bits can start to fall from fiberglass batts after 15 or 20 years. If shouldn't need to be replaced after such a short time, but it's worth an inspection.
As a general rule, however, home insulation should be inspected once a year to check for signs of damage, mold, and more. If you see signs of degradation and/or you are experiencing issues such as uneven heating, cold spots, etc., it may be time to upgrade or replace the insulation.
In reality, fiberglass insulation (whether batts, rolls, or blown-in) is very long-lasting. Under ideal conditions, it can insulate a home for 80–100 years. However, it is worth checking the quality and efficiency of the insulation at the 15- to 20-year mark.
The thermal barrier of a home should consist of a continuous layer of insulation on all sides—including the lowest floor, the exterior walls, and the ceiling or roof. Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half.
Moisture and allergens can be get trapped inside fiberglass
It doesn't happen often but when it does it may cause serious damages to the resident's health. People who suffer from allergies are more affected. Dust, allergens, and moisture can be trapped inside fiberglass and lead to mold growth.
Expert contractors that specialize in insulation advise that removing old fiberglass insulation is best before installing new cellulose insulation because of possible mildew, mold, or rodent excrement.
In fact, adding too much insulation to your walls can lead to problems such as poor ventilation, mould growth, and condensation. This is because thicker insulation can block airflow and trap moisture, leading to indoor air quality issues and even structural damage.
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. To determine whether you should add insulation, you first need to find out how much insulation you already have in your home and where it is.
Any reputable insulation installer will thoroughly remove old insulation before putting in the new. However, as a homeowner, you should double-check that they remove all of the old insulation as a first step.
How heat escapes from your home. If you're asking yourself Why is my house so cold even with the heating on? or Why is my house not staying warm?, the truth is that air leaks—along with insufficient insulation—cause heat to escape directly from your home.
When snow accumulates on your roof after a storm, especially when there are several cold days in a row, it's a good indication that heat is not escaping through your attic, meaning your insulation is doing its job.
Unlike exterior walls, which must meet local and state codes for insulation, interior wall insulation is rarely required. This is because interior insulation has much less impact on your home's energy efficiency – but it can still play a role.