In the United States, 9 out of 10 homes are under-insulated and therefore not energy-efficient. Many homes neglect to apply proper insulation, air sealing, and ventilation, especially in the attic.
But why the attic? How can insulation, air sealing, and ventilation improve energy efficiency?
In this article, we’ll be looking at those methods – air sealing, insulation, and ventilation – and outlining how they contribute to an energy efficient attic.
We start at air sealing, which is basically sealing any air leakages in your home. Air leakage happens in practically every home, old or new, and accounts for anywhere between 25% and 40% of the energy lost when cooling and heating a typical home.
Attics are equally as susceptible to leakages. An under-sealed attic has huge implications for your energy bills and overall spending. Let’s take a look at why air sealing your attic is so important.
Why is Air Sealing an Attic Important?
Homeowners tend to believe that air leakages just have small negative effects on your home temperature. If there are a few air leaks, that just means cranking up your AC or heater, right?
Not necessarily. Air leaks, regardless of size, have a similarly deleterious effect on your home temperature. The more leaks you have in your attic, the more hot or cold air you let in.
This leads to utilizing your heater and AC units more often, leading to expensive energy bills.
A study by the Minnesota Department of Energy Resources found that air leaks in your home’s building envelope account for up to one-third of your home’s total energy loss. Envelope refers to the barriers that keep your home dry and energy-efficient, such as your walls, ceilings, and roof.
As such, air sealing your attic means improving your home’s envelope and reducing your total energy usage and costs. Most homeowners use insulation, caulk, or spray foam insulation to plug most air leaks.
Areas in Your Attic to Air Seal
If you’ve got all the equipment you need to air seal your attic, it’s time to identify where it is you need to seal. While this is different for every home, here are the most common areas in your attic that typically needs to be air sealed:
- Attic hatch or door
- Attic floor holes
- Fireplace and furnace holes
Before Sealing Your Attic
Identify all of the gaps and cracks in your attic. Schedule a free attic inspection.
You’ve now identified where in your attic needs air sealing. Before you start, there are a few things that you need to consider. The Department of Energy suggests that you take care of these items before air sealing your attic:
- Make sure that adequate combustion air is available for furnaces and heaters
- Ensure that there’s adequate fresh air in your home before sealing the attic
- Make a plan for whether or not you’ll install insulation and other material after air sealing for maximum efficiency
However, 90% of American homes are under-insulated. This likely means that homeowners aren’t properly insulating their attics despite it being one of the most effective ways of improving your home’s energy efficiency.
Why is Insulating an Attic Important?
But why is that the case? What’s so special about attic insulation and how does it improve home energy efficiency?
For starters, insulation helps keep certain types of heat inside your home while keeping others out.
Heat often travels upwards to the attic because of convection, and insulation makes sure that the warm air generated by your heating systems don’t escape through the roof. In the summer, heat from the sun tends to collect in your attic. Insulation not only keeps that heat from entering through the roof, but it also prevents the warm air from passing through the attic floor into your living space.
This results in you using your air conditioner less in the summer while reducing your reliance on gas and electric heat in the winter. All that translates to greater energy efficiency and lower bills.
The EPA estimates that air sealing and insulating your attic floors, walls, and ceilings allow homeowners to save up to 15% on their annual energy bills. This is on top of less wear-and-tear on your HVAC system and an overall improvement in home comfort.
Areas in Your Attic to Insulate
Choosing where you insulate your attic is key to getting maximum energy efficiency. Here are some key attic areas that homeowners typically insulate:
- The entire attic floor
- The ceiling
- Your hatch or attic entrance if you’re using reflective insulation
- Between ceiling joists
Before Insulating Your Attic
If you’re thinking about installing attic insulation or calling a contractor to do it, here are a few key things to consider:
- Examine your attic thoroughly – are there any structural issues? Are there any damp or moist areas? What about mold and other irritants?
- Air sealing your attic beforehand is key. Make sure your attic temperature is about the same as the outdoor temperature before installing insulation.
- Purchase the right insulation based on your attic surface area as well as your region’s R-value.
- Fix any roof leaks that you might have.
- Make sure you aren’t blocking any air vents with insulation
While you don’t hear ventilation in the same conversation about energy efficiency as you would for insulation, it’s just as vital for your attic as anything we’ve discussed so far.
Ventilation improves your roof’s lifespan which improves your home’s overall envelope. More importantly, it affects how your home retains and blocks heat during the summer and winter.
Why is Ventilating an Attic Important?
Most attics have intake vents down low among the soffits and exhaust vents up high at the peak of your roof ridge. These two vents allow for a continuous flow of air throughout your attic.
Cooler air gets drawn through the soffits while warm air migrates upwards and exits through the vents along the roof ridge.
Proper attic ventilation makes a big difference during the winter when your roof is covered with ice or snow. When warm air is generated by heaters and rises up to the attic, a poorly ventilated home can experience a lot of condensation.
Bonus tip: add active ventilation with a high-efficiency solar attic fan.
This causes moisture in your attic, which can ruin your attic insulation as well as other structural elements.
Warm air entering your attic also melts the snow and ice on your roof. This causes ice dams to form, which prevents further runoff. This means melted water has nowhere to go and ends up backing up the shingles.
This means water can enter back into the attic and saturate the attic insulation you’ve installed there.
Creating moisture in your attic and potentially botching your attic insulation means your energy efficiency will go down and you’ll be paying higher energy bills as a result. Proper roof and attic ventilation prevent that from happening.
Learn more about how to remove hot air from your attic.
Areas in Your Attic to Ventilate
If you want to avoid ice dams or condensation from happening, you need to identify areas in your attic that need ventilation. Here are the most common areas:
- Your roof’s overhang, where you can install soffit vents or drip edge vents
- The ridge of your roof where you can install ridge vents
- Near the roof ridge if you’re installing a static vent
- The side of the roof near the gable
- The rafters where the ceiling of your attic meets the floor
Before Ventilating Your Attic
Now that you know where you need to install attic ventilation, here are a few more tips before starting your project:
- Determine the square footage of your attic and compare that to your net free area to calculate how many vents you need
- Choose the right kind of vent you need depending on where you want to install them
- Remember that you typically need one square foot of roof vent for every 300 square feet of ceiling space
Make Your Attic More Energy Efficient
Schedule a free attic inspection to see how efficient it is.
Most homeowners tend to ignore their attic, leading to poor energy efficiency and higher energy bills. You don’t have to be one of those homeowners.
Whether it’s air sealing, insulation, or ventilation, there are plenty of ways to improve your attic’s energy efficiency. Use this guide to find the best option for your home and start saving on your energy bills today.