How to Improve the Energy Efficiency of Your Roof
If your house were a human, the attic and roof would be its head—that part of the human anatomy that loses the most heat. Just as you would wear a hat in the winter, you want to make sure your attic and roof are protected against the elements.
By improving the energy efficiency of your roof, you prevent the “stack effect” from stealing your expensive heated air. The stack effect happens when warm air escaping through the roof draws cooler air up from the basement and lower level windows.
How do you know if your roof is losing heat?
You can start with what you know about your roof. Do you notice melt zones after a light snow or frost? Do you have lots of long icicles or ice dams on your eaves, even if it isn’t a particularly sunny winter day? These are signs that your roof is struggling to keep heat inside.
Just like you wouldn’t have surgery before you knew exactly what was wrong, you need to get a home energy checkup before you can resolve your roof’s heat-loss issues. To do this, you can hire a professional energy auditor to perform an energy “audit,” or evaluation on your home. This likely will include an inspection of your attic, basement, windows, exterior, heating system, combustion appliances, and diagnostics (like a blower door test). You’ll then receive an audit report with recommendations for improvements, and you can work with your contractor to prioritize the improvements based on the benefit, cost, and complexity of each suggestion. You may even find that if you’re handy, you can do some of the improvements yourself.
What are some simple steps to prevent heat loss?
Air seal the attic
The best place to start improving home energy efficiency is with air sealing. Think about how cold you are on a windy winter day if you wear a heavy sweater. You find that you also need that windbreaker shell to keep the cold air from blowing right through the knit. Your home needs the same thing. By sealing all the leaks, you can make a big impact on the amount of cold air finding its way in and warm air escaping.
If you’re a DIY enthusiast, you can talk to your contractor about tackling some of the improvements on your own. A good internet search will uncover a bounty of resources that can show you step by step how to accomplish this. Here is one I found, which covers most of the basics, but there’s a lot out there, so look around for articles and videos that address the specific needs of your attic.
Don’t forget to air seal the attic entry hatch while you’re at it. There are several ways to do this, from weather-stripping to sealing it up completely if you have just a crawl space or an alternative access to the attic. Another opportunity to reduce air flow is the chimney chase. By installing heat-resistant air-sealing material to block the air from flowing around the chimney, you will feel a noticeable reduction in drafts.
Are you looking for more energy efficiency projects? Read our eBook for more suggestions.
Control your ventilation
Air sealing your home is a great first step, but don’t forget about ventilation. You may wonder why we tighten up and then add ventilation, but there is an important distinction. Once the “accidental” air leaks are gone, a building can feel stuffy and trapped toxins can reduce the air quality. This is where the services of your energy auditor/contractor are needed. They can help you choose the right ventilation for your home, whether it may be a couple of good-quality bathroom fans, or a whole-home air exchanger. These controlled ventilation techniques will provide ventilation with minimal energy loss, so don’t miss out on this important step.
Insulate the ceiling
After you’ve addressed the air-sealing and ventilation needs, take a look at the insulation you already have in the attic and determine its R-value. The R-value is the insulation’s capacity to prevent heat flow. In Vermont, your ceiling insulation R-value should be at least R-49. Start by determining which type of insulation you have and do some simple math. This article offers some helpful information about the different insulation types and their R-values.
There may be areas of the roof, where there isn’t enough space to properly insulate the area. Your best bet in these areas is to use a loose-fill or blow-in insulation. Check out this article for a step by step guide to determining whether your attic needs to be insulated, whether you should do the job or not, the best tools for the job, and how to do it. Remember that your energy auditor or contractor can offer guidance if you are taking on the insulation improvements yourself.
Replace or repair your roof
Ideally, this final step won’t be necessary, but we all know that while roofs last a long time, eventually they need replacing. Here are some conditions that indicate that you should consider a roof replacement:
- It is outdated (shingle roofs, 20 to 30 years old; metal roofs, 40 to 50)
- The shingles are curling, bloating, cracked, or simply missing
- You can see sunlight coming through when you stand in your attic
- It’s leaking
- It’s sagging
- Your roof has turned green (with moss)
Occasional roof inspections and some maintenance will help you learn about your roof. You can repair small leaks, cracks, and shingle issues as you inspect your roof, and as you keep up on maintenance, you will get a sense for when you may need to do a major replacement. Though roof replacement can be costly, you will save money in the end by protecting the integrity of your home and improving its energy efficiency. You may also consider making your roof “solar-ready” at the time of replacement, to improve your future energy savings.
Looking for other ways to improve the energy efficiency of your home? Read our eBook!
About Laurie Fielder
Laurie directs VSECU’s statewide VGreen energy savings loan program. Previously, she worked for the weatherization program at the Central Vermont Community Action Council (now Capstone), and for a successful residential solar installer. She enjoys helping Vermonters learn about efficiency and renewable financing options that maximize the savings of these smart investments. She lives in Woodbury with her family and enjoys the outdoors, walking the dog, and tackling home improvement projects.