The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space. While you might think that too much insulation can't be bad, there are some significant consequences to consider.
The answer is yes! Past a certain point, insulation in a vented attic will do more harm than good. In most of the United States, achieving an R-Value of 38 is more than sufficient. In the temperate Southern California region, an R-Value of 30 tends to be ideal.
Mold in the Middle
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.
The higher the R-Value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.
Yes, it is possible to put too much insulation in a loft or attic.
(R303. 1.1. 1) Blown-in or Sprayed Roof and Ceiling Insulation | UpCodes.
The Short Answer
If your house has too much insulation, it becomes too tightly sealed, and moisture becomes trapped inside. If there isn't proper ventilation, especially in the attic where the warm air travels when it rises, mold will grow, and your home's air quality can decline.
If you're looking for a solution to enhance your home's comfort and energy efficiency, blown-in insulation offers a reliable and cost-effective option. It seals gaps that other insulation types miss, helping to lower energy consumption and create a more stable indoor environment.
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.
Can cause mold and mildew – Because blown-in cellulose is made of paper products, it soaks up any and all moisture in the insulated area. A roof leak, pipe leak or high humidity can cause water to infiltrate the insulation, and insulated areas take a long time to dry back out.
The short answer, yes, insulating the attic is an effective way to keep your home cooler during the summer months. While it's a given that the insulation in your attic will keep the home warmer during the winter, it isn't immediately obvious that insulation can also help to keep the home comfortable during the summer.
The depth of loft insulation in some new-build homes is being increased above the government-recommended 270mm to 300mm. That said, the amount of insulation needs to be balanced with levels of airflow and ventilation. Too much insulation without sufficient ventilation can cause condensation, dampness, and mould.
Depending on where you live and the part of your home you're insulating (walls, crawlspace, attic, etc.), you'll need a different R-Value. Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces.
Divide the square footage of your ceiling joist cavities by the square footage covered per bag of insulation. Round up to the nearest whole number. The result is the number of bags of insulation you need to buy.
Cellulose Insulation
The best kind of blow-in insulation comes from cellulose. Products such as Nu-Wool cellulose insulation are made of recycled newspapers. There are no microscopic bits of dust from minerals, rocks, or glass that might get into your or your family's lungs.
The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space. While you might think that too much insulation can't be bad, there are some significant consequences to consider.
Your walls or floors are always cold. Your home is drafty, especially in certain areas. You notice water leaks or moldy insulation, especially in attic spaces.
Common Over-Ventilation Problems
Too much ventilation can work against the airflow of your attic because having too many vents can cause them to start to work against each other. If the wrong types of vents are installed, these can also work against each other in a way that moisture or frost can regrettably develop.
Do I Have To Remove Old Insulation? Unless your insulation is wet, moldy or infested with pests, you don't need to remove it before adding insulation on top of it. ENERGY STAR® recommends that you inspect your insulation for signs of mold, mildew, moisture and pest infiltration before making this determination.
On average, you can save up to 20% on your home's heating and cooling costs or up to 10% on its total energy costs by adding insulation to attics, floors, crawl spaces, and accessible basement rim joists, and by reducing unwanted air leaks all around your house.
Blown fiberglass insulation scores an R-value of 3.2 to 3.8, making it slightly less likely than rolled fiberglass to prevent the flow of heat into and out of your house. That being said, though, blown fiberglass insulation isn't meant to cover huge areas like rolled fiberglass insulation.