The varied weather in Baltimore and throughout Maryland means you need to weatherize your home carefully if you want to keep your energy bills low all year. There are dozens of home improvement jobs you could do to boost your home’s efficiency, such as sealing air leaks, installing energy-efficient windows and upgrading your appliances. Few of these jobs, however, give you as much benefit for as little effort as improving you attic insulation.
Why Attic Insulation Matters So Much
Because your attic spans your whole house, its quality influences the conditions in all your rooms. A home with a poorly insulated attic is vulnerable to whatever the weather brings in both summer and winter, making it much harder to maintain a comfortable temperature indoors.
Worse yet, lack of insulation in the attic leaves this space open to attack by mold and pests, which can eventually do serious damage to the wood structure of your house.
Even in mildly warm weather, the direct sunlight hitting your roof can raise the temperature in the attic to well over 100 degrees. Without good weatherization, that built-up heat will seep through air leaks and radiate through the attic floor into your air conditioned rooms. Your air conditioner then has to use more energy to remove this additional heat from your house. Installing attic insulation is the most effective way to hold back this heat so your attic ventilation can remove it, taking the load off the air conditioner.
Winter brings even more problems. Warm air naturally rises, meaning the warm air your furnace supplies rises toward the ceilings. If there isn’t enough insulation in the attic, the warm air will enter the attic and move out of the house through the roof.
In winter, the job of attic insulation is as much to keep the attic cold as it is to keep rooms warm. Warm room air hitting the cold surfaces in the attic creates condensation. When it’s damp from condensation, what insulation you do have in the attic will be less effective. Damp insulation, wood and drywall are also prone to rot and mold growth.
A warm attic releases heat near the peak of the roof, causing uneven temperatures across the roof. When this happens, snow near the roof peak melts and runs down toward the cold roof edges, where it re-freezes. The resulting block of ice, known as an ice dam, prevents further snow melt from draining off the roof, causing it to pool. Pooled snow melt can damage your roof and eventually cause leaks. Icicles on the eaves are a clear sign your roof is forming ice dams and the attic needs more insulation.
Does Your Attic Have Enough Insulation?
If your attic only has a plywood floor and you’re using the space for storage, you’re doing a serious disservice to your home. Even in mild climates, some attic insulation is necessary for a comfortable house and reasonable energy bills. Maryland’s hot summers and cold, snowy winters mean we can’t forgo attic insulation.
If your attic does have insulation, take some precautions before you inspect it. A home built before the mid-1970s could have vermiculite attic insulation that contains asbestos. Vermiculite looks like gravel and is usually a shiny beige, grey or off-white. The tiny fibers it releases cause lung damage, so if you find this substance in your attic, don’t disturb it. Call a heating and cooling professional to have the insulation assessed safely.
Fiberglass batt insulation, while much safer than vermiculite, also releases fibers that can irritate your eyes and skin. If you plan to handle this material, wear protective clothing and eyewear.
To determine whether or not you have enough insulation, check the type and thickness. Regardless of the type of insulation you have, if you can see the attic floor joists, you need more insulation. The 3- to 4-inch layer that fits between the joists but doesn’t cover them isn’t enough in our climate.
An insulation’s efficiency is indicated by its R-value. A higher R-value means greater efficiency. If your attic has fiberglass batts, you should have an R-49 layer of insulation at minimum, which is around 12 or 13 inches thick. If you have cellulose insulation, you’ll need an inch or two less.
While measuring your insulation’s thickness is a fairly accurate way to decide whether or not you have enough, it won’t tell you exactly how much heat your attic is losing and from where. To find that out, consult with a heating and cooling technician for an energy audit. During one of these home assessments, the technician will take photos of your home using an infrared camera. The images clearly show points of heat loss that can be improved through air sealing, insulating or other means.
While you’re inspecting your insulation, also check for signs of moisture, mold and pest problems in the attic. These should be corrected before you lay new insulation.
If you find damp or moldy insulation, your attic may have air leaks that should be sealed with caulk or spray foam insulation. Streaks of dust are another sign of air leaks. A leak in the roof or around your ventilation fans is also possible. Droppings, hair and dead bugs suggest a pest infestation that may require an exterminator.
Optimize Attic Insulation and Save
Even if you don’t find any obvious signs of air leaks in your attic, it’s still important to air seal the attic before you install new insulation. Air leaks waste energy, contribute to moisture problems, and reduce indoor air quality.
Locations to seal include the point where the attic walls and floor meet, kneewalls, dropped soffits, recessed lighting, and penetrations for utility lines and vents. All-purpose latex acrylic caulk is sufficient for small leaks, but foam spray insulation is better for leaks of 1/4 inch to 3 inches.
Due to the heat they produce, furnace flues and recessed lighting rated non-IC require special air sealing techniques that ensure they don’t come in contact with the attic insulation.
The joints of your air ducts should be sealed with mastic to prevent air loss and excess moisture in the attic.
Once the attic is sealed, you can begin installing new insulation. There are several types of insulation suitable for use in the attic and each has its pros and cons.
- Batt insulation – These long strips of insulation are manufactured in widths that fit between standard floor joists and wall studs. Because you can simply lay them into place, you can install them without help from a professional. The drawback is that they leave small air pockets that let warm air pass, reducing their effectiveness. Fiberglass is the most common material for batts, but you can also find batts made from cellulose, cotton, sheep’s wool and other material.
- Loose-fill insulation – Also called blown-in insulation, this insulation consists of small chunks of material. The loose pieces fill in small crevices, providing more efficient insulation coverage. To install it, you’ll need a blower machine, which you can rent from home improvement store if you prefer not to hire a professional. Loose-fill insulation is most often made from cellulose, but other materials are also available.
- Rigid panels – These solid panels are made from polyurethane foam or rockwool. As with batts, they can be simply laid between the attic floor joists. Foam provides an R-value of between R-4 to R-8 per inch, higher than both fiberglass and cellulose. This means you’ll need a thinner layer than you would with batts or loose-fill. Because rigid foam resists water better than fiberglass or cellulose, it reduces the risk of mold growth, protecting your attic from damage. On the downside, foam panels are one of the more expensive types of insulation.
Loose-fill is ideal for attics with a lot of irregular spaces, utility line protrusions or non-standard joists. In an attic with little overhead space, it’s often easier to blow in loose-fill insulation than to lay batts. Loose-fill is also a good choice if you already have almost all the insulation you need and you want to add just another few inches.
Rockwool offers R-values similar to those of fiberglass, but unlike fiberglass, it’s an effective acoustic insulator that can help cut back on the noise entering your home from outside.
Because the attic hatch is highly prone to energy loss, this area requires some special attention. You can buy an attic hatch insulation kit from a home improvement store or simply use foamboard adhesive to attach a square of rigid foam insulation to the top of the hatch. To prevent air leaks here, attach weatherstripping to the inside edges of the bottom of the attic hatch.
Learn more about attic insulation solutions from the pros at Griffith Energy Services, Inc., or contact us today at 888-474-3391 to schedule a home energy audit to get you started!
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