You can assess if your home insulation needs replacement by observing signs like increased energy bills, uneven indoor temperatures, drafts, and visible damage to insulation materials. Additionally, if your insulation is over 10-15 years old or has been exposed to moisture or pests, it may require replacement.
Look for drafts in your home
If you can feel a draft, that means that warm air is escaping from your home, which means your insulation isn't doing its job properly.
But how long does loft insulation actually last and how often should you replace it? Loft insulation usually lasts 40 years or more if properly maintained and pays for itself many times over its lifespan. However, this greatly depends on how well it was installed and the type of material used.
Insulating your loft, attic or flat roof is an effective way to reduce heat loss and reduce your heating bills. Installed correctly, loft insulation should pay for itself many times over in its 40-year lifetime.
Removing old insulation is generally recommended if it's damaged, contaminated with mold, or infested with pests. However, if the insulation is in decent shape and just needs a boost, adding a new layer on top can be a cost-effective option.
The answer is yes, you can put new insulation over old. But there are some circumstances that would require insulation removal first, such as in the case of contaminated insulation from pests, water or smoke. Moisture is the biggest culprit, as it can lead to mold and mildew, as well as ceiling and roof rafter rot.
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.
Since most common insulation types (fiberglass, cellulose, mineral wool) have an R-value of about 3 – 3.5 per inch it is easy to estimate how much R-value the insulation your attic currently has. Just take the depth in inches x 3 to get an estimated value.
Looking across your attic, if the insulation is level with or below the attic floor joists, you probably need to add more insulation. If you cannot see any of the floor joists because the insulation is well above them, you probably have enough, and adding more insulation may not be cost-effective.
If you experience roof leaks resulting in moisture damage, wet insulation will need replacement. Moisture damage can accelerate the settling of your insulation. Once moisture and mould will form on your glass wool insulation, it becomes stringy as the fibres start to separate.
New insulation can make a huge difference in your utility bills. According to ENERGY STAR: “… homeowners can save an average of 15% on heating and cooling costs (or an average of 11% on total energy costs) by air sealing their homes and adding insulation in attics, floors over crawl spaces and basements.”
You can easily detect areas of missing insulation by walking around your house with a thermal imager and looking for temperature differences. For best results, you'll want at least a 20 degree temperature difference.
Conclusion. Attic insulation can last 80 to 100 years, though it loses its energy efficiency benefits with time. Certified attic specialists' professional advice is to upgrade it every 15 years to ensure that it is still performing the job.
Regardless of the cause, the unfortunate reality is that attic insulation does not last forever. Instead, it eventually needs to be removed and replaced for adequate home temperature control. Removing old attic insulation has these added benefits: The costs associated with heating and cooling your home go down.
Increased Humidity and Moisture
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.
Fiberglass Insulation--The actual lifespan of this commonly used attic insulation is from 80-100 years. However, due to its construction with natural materials, eventually the product will lose effectiveness.
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.
One important thing to remember is that insulation should never be pushed right into the eaves because it will interfere with airflow. If you're going for a warm loft then you'll need much more insulation to be able to cover the underside of the roof along with the gable and party walls.
Fibreglass Loft Insulation Disposal
You can take it to a household waste recycling centre if you are replacing the insulation yourself. If a contractor is replacing it they will need to privately dispose of fibreglass, which they can do for a small fee.
Too much Insulation with a minimum amount of ventilation will result in condensation forming as the warm air has nowhere to escape to. It can also result from insulation being improperly installed such as too many layers being laid on top of each other or if it is too tightly packed.