Unless damaged, it can last 80 to 100 years in most houses before it needs to be replaced. However, insulation can start falling from fiberglass batts after 15 to 20 years, so if your insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.
If you're experiencing high energy bills, uncomfortable rooms, and other problems like moisture it's likely time to replace the insulation in your existing home. If you have traditional insulation in your home, like fiberglass or cellulose, those materials have a tendency to sag, settle, and shift over time.
Look at your energy bills
That's a sign that something is amiss in your home. Energy could be escaping through the insulation in your attic or crawl space. There could also be energy leaks in windows and doors.
Over time, insulation wears down. Weather, critters and general age can degrade your home's temperature protection. That said, you can find out how long your insulation will last before a swap-out is needed. Depending on your home's insulation type, you'll be protected for a few decades.
If you see mold growth on the insulation material in your attic or surrounding surfaces, such as the framing around the ceiling plane, you'll definitely need to consider attic insulation removal and replacement. Mold grows where moisture occurs. Without moisture, mold won't grow.
Yes! You can absolutely new insulation over old insulation… as long as it isn't wet. Energy Star advises as follows: “If it… appears that the insulation [is wet or] has previously been wet, you should look for the cause and repair the problem to prevent a reoccurrence.
Unless damaged, it can last 80 to 100 years in most houses before it needs to be replaced. However, insulation can start falling from fiberglass batts after 15 to 20 years, so if your insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.
Wall and Floor Temperatures
Here's another great way to tell if your home is well insulated. Use your hand to check the temperature of interior walls, floors, and ceilings. If they feel warm and dry, you are in good shape. If they feel cold or damp, then you have an insulation problem.
Cellulose insulation usually lasts 20 to 30 years before it starts to degrade, and mineral wool also lasts decades as long as it is not damaged. Spray foam insulation is one of the longest-lasting. Many homeowners never have to replace it in their lifetime.
Mold can grow on the fiberglass insulation backing, which is made of paper and is a mold food source. Fiberglass insulation without backing may be the best choice. Cellulose insulation is constructed of ground paper, which is an ideal food source for the growth of mold if it becomes wet.
That's because insulation performance decreases dramatically. A 1.5% increase in moisture content in fiberglass insulation can reduce its R-value by up to 50%, according to Rastra. That's not a typo.
Overall, if you are looking for the best long-term solution, foam insulation products will create the air seal in your home that will make it more comfortable while saving you money on your monthly energy bills. Foam insulation doesn't settle or sag and it fills all the nooks and crannies where it is installed.
Rolled fiberglass insulation scores an R-value of 3.7. So overall, rolled fiberglass insulation is slightly more effective at blocking in and out heat than its blown counterpart.
Insulating older homes is an all-or-nothing proposition. Just blowing insulation into the walls can create moisture problems that will rot the wood structure from the inside out. Wood has only a few enemies. An encounter with termites, fire, or a weekend warrior is almost always fatal.
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. That's when mold starts to grow.
To calculate the IR value, apply the voltage, measure the steady-state leakage current (after the dielectric absorption and charging currents have decayed to zero) and then divide the voltage by the current. If the insulation resistance meets or exceeds the required value, the test is successful.
Black Spots on Insulation caused by Air Leakage
Particulates released by combustion appliances, such as wood stoves, boilers, furnaces, diesel heaters or auto exhaust, can produce very fine soot that can build up over time in insulation. Tobacco smoke can also contribute.
If you notice any discoloration on your insulation such as brown, black, or even pink or orange particles, you are dealing with a dirt or mold problem. Insulation sheets are a solid color, so any discoloration will be obvious.
It's possible to over-insulate an attic as too much will cause moisture buildup and eventually result in mold. Eventually, adding more insulation leads to diminishing returns in trapping heat as well.
Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half. Each time the insulation layer is doubled in thickness, this rule applies.
Many people consider fiberglass batt to be the best attic insulation. It consists of plastic reinforced by small glass fibers. The batt version comes in blanket form — i.e., small, pre-cut sections that you can lay down wherever you need to.