Top 4 Tips on How to Insulate your Attic

Most of us learn in elementary school that hot air rises. However, unless we take up hot air balloon riding as a hobby, applying that fundamental physics principle to our everyday lives might seem like a bit of a stretch. If you have ever gone up into your attic in the middle of summer to rummage around for some lost photo album or an extra mattress for an arriving guest, the principle of hot air rising is undoubtedly (and tangibly) easy to understand. That same basic principle that makes your sweat like crazy on a hot summer day in your attic might also be contributing to a more expensive (and wasteful) heating bill in the wintertime.

Because hot air rises, if your attic is not well-insulated, the heat in your home from your furnace, fireplace, and even the natural sunlight shining through the large bay window on the south side of your home will quickly escape out of your ceiling before dissipating into the cold air of your attic. Learning how to insulate your attic adequately will not only save you money during the cold winter months. Still, it will also drastically reduce the carbon emissions associated with heating your home.

Most homes in mild climates spend anywhere between 5,000 and 30,000 kWh per year on heating their homes. Each kWh of electricity use averages around 1.22 pounds of carbon dioxide emissions, meaning that by heating your home, you´re placing anywhere between 6,000 and 36,000 pounds of CO2 into the air. Reducing the amount of energy you use through proper insulation of your home will go a long way towards making your home more sustainable and eco-friendly.

Tip 1: Cover up the Cracks

Before you get to actually replacing the insulation in your attic, the first thing you will want to do is to check for leaks. While many people spend much time sealing their windows and doorways, much more heat generally escapes from a home through the ceiling. Cracks can occur due to the typical settlement of a home and building errors might contribute to leaks, especially around corners where your walls meet your ceiling. 

Most homes also have several holes that have been drilled through the ceiling to facilitate the passing of wires, cables, and pipes. Sealing those holes with caulk or silicone is essential to help avoid heat escape through your roof. Not only do these holes in your ceiling cause heat loss in your home, but the high-pressure system that builds up in the top of your attic will also actually pull in cold air from the outside through openings in the foundation or slab of your home.

Tip 2: Find Where Your Insulation is Scarce in your Ceiling

After you have sealed up all the holes and leaks in your ceiling, you will want to search for places in your attic and ceiling where insulation is thin or non-existent. If your attic or crawlspace allows you to see the insulation without having to pull things away, look for gray or black smudges, which signal air leaks that you might have looked over. Also, some places might be visibly thinner than other places due to settling or improper installation. 

If the insulation in your ceiling and/or attic isn't readily accessible, you can use an infrared heat gun to quickly identify places where heat is escaping through your roof or attic.

Tip 3: Choose a Natural Insulation Product

Since most homes do not have insulated attics, you will have the opportunity to choose an insulating product that is as natural as possible. There are reports that typical fibreglass insulation (the pink, cotton candy looking stuff) might very well behave similarly to asbestos, releasing microscopic particulars into your home that you breathe in and then are lodged in your lungs. Fortunately, there are several natural insulation products on the market today.

• Blown-in cellulose insulation can often be obtained locally and is usually made from recycled newspaper.
• Straw insulation is a natural insulation alternative that has been used for hundreds of years by rural peoples around the world.
• Hemp insulation is another natural insulation method that has recently hit the market. If you want a DIY option, sheep wool is naturally flame retardant due to the high level of lanolin and might be readily available in your region if people raise sheep for meat production.

Tip 4: Ensure Proper Ventilation

Why would you want to ensure ventilation in a space that you are insulating? Confirming proper airflow in an insulated attic is essential for several reasons. Firstly, by allowing colder air to enter your attic through vents will keep your attic cold enough to prevent ice damming. Ice damming occurs when your warm attic melts snow accumulated on your roof, which then refreezes at the gutters (where the warmth from the attic doesn't reach). This can lead to expensive roof damage in the short term.

When insulating your attic, then, you want to make sure to never wholly cover up or block the airflow at the eaves of your roof. Rafter vents and soffit vents are essential to maintain proper airflow in an attic space, which will protect your roof from the above-mentioned issues. Rafter vents are best placed between the rafters where the attic ceiling meets the floor of the attic. These vents essentially create a channel where colder air from the outside can enter into attic space through the soffit.

Article by:

Tobias Roberts

Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.