How Much Attic Insulation Is Too Much

Measure your attic s square footage.

How much attic insulation is too much. Even with grid supplied resistance heating that s perhaps 10 15. Adding an inch of insulation to a wall that has 30 inches of insulation makes sense nowhere. Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation. Having too little insulation can cause all these same problems and more.

When it comes to insulating your homes attic there are usually no safety concerns regarding having too much. This is not to say that if you have mold in your home too much insulation is the culprit. How much to buy. The passive house standard requires a peak heating load of no more than 3 17 btu hr per sq.

The long term payoff of insulating an attic is impressive too. The worst thing that could probably happen when you have too much insulation is that your home may become too warm. For loose fill read labels. Each bag lists the required depths for a range of r values and the number of bags needed to cover 1 000 square feet at those depths.

Without exception you should talk to a professional to determine what your home requires. If you think you re among the 90 of us homes that are under insulated 1 performing a simple insulation inspection will help you determine your insulation needs. For batts or rolls calculate the number based on the width and length of the product you re using. That said air resistance and interference such as vent grates reduces the area of true ventilation.

On the contrary most homes have too little insulation not too much. Insulation generally helps you prevent heat from escaping and since preventing heat loss is the main goal here then clearly it is a good thing. The energy savings that would flow from hitting this target are too low to justify the extremely high cost of the insulation needed to achieve it. Even yoda won t live long enough to get a return on investment for that much insulation so it s pretty much pointless.

Without proper ventilation a home can build up too much moisture especially in the attic warm air rises which can cause mold problems and overall lower indoor air quality. I realize the focus was on too much insulation and found it very interesting and instructive that for example increasing roof r from 60 to 90 yielded a measly 89 kwh savings. Having the correct amount of attic insulation can help you maintain a comfortable temperature throughout your home and help save money on your energy bills plus prevent major issues like ice dams in the winter. And you may also qualify for a tax credit on the blown in attic insulation cost check with the irs or at energystar gov.