You have spent some big bucks for your high-end air conditioning and heating systems to get you ready for the hottest of summers and harshest of winters. And yet, these home comfort experts say you need to air seal your home AND insulate it. You ask, “Which do I really need? Air sealing vs insulation?”
Air sealing and insulation are two of the most effective ways to ensure that your home has excellent indoor air quality, is energy-efficient, and comfortable. Sealing is the solution to air leakages that let conditioned air out while letting outdoor air into your living space. Meanwhile, insulation resists heat flow that drives up the time your cooling or heating devices run to maintain a controlled temperature inside your house.
It is equally important to ascertain that your home is airtight and properly insulated. Leaks undermine your air conditioner and furnace’s ability to keep the temperature at a desirable level. Sealing them by caulking and weather stripping is an essential way to start, but with poor insulation, the natural movement of heat can still reduce your comfort and increase your energy consumption at the same time.
In terms of importance, sources say air sealing is more critical for energy efficiency than insulation as the former deals with air leakages more directly. Insulation is a great support measure to defy the movement of heat and improve comfort. Sealing unwanted holes, cracks, and gaps should also come first before installing insulation materials.
For the best possible energy-saving measures and ideal comfort level inside your home, air sealing and insulation should always be performed and installed together.
Even before the pandemic hit and most people spent more and more time indoors, a large percentage of Americans had already started to spend a sizable amount of money on home improvements. However, in the past year up until the recent months, people’s splurging on residential comfort took a bigger leap.
Bank of America did a survey and found that “over 70% of respondents have taken on home improvement projects during the outbreak of pandemic and plan to do more in the next year.” CBS News backed up this data by discussing the change in the spending behaviors of Americans towards minor to major house renovations as these provide a measure of control to homeowners in an otherwise out-of-control global situation.
Expensive purchases such as modern HVAC systems do not seem extravagant when you are forced to stay inside through quarantines and adjusting to the new work-from-home setup. But when the electric bills come at the end of each month, you are left wondering what else can you do to save on energy but still maintain a cozy home?
The answer is two-fold: Air sealing and insulation.
Is Air Sealing Necessary To Save Energy?
Your house’s first line of defense to natural elements such as wind, heat, and rain is called the “envelope” of the structure. It mainly consists of the exterior walls, windows, exterior doors, roof, and subfloor. This envelope can either be “loose” or “tight,” depending on how much air movement is allowed to pass through the building.
For places with cooler climates and even those that have a variety of hot and cold weathers, a tight envelope is preferred so you can better control the indoor temperature with cooling or heating devices.
The most notorious enemy to a residence's airtightness is air infiltration. Gaping holes, cracks, and openings no matter how small can compromise the performance of any state-of-the-art air conditioner or furnace. How so?
HVAC equipment measures the overall temperature of any given room against the desired level set in the thermostat. The equipment will then start to bring the temperature up or down to your preferred level of temperature by filling the space with cooled or heated air.
If all gaps and crevices around your home were combined, you may be looking at a huge hole the size of a basketball. This unwanted opening lets out the tempered air from the inside and in turn, untreated air from outside enters in the form of drafts.
Air sealing is a sure-fire way to combat air infiltration or leakages in your home. By caulking and weather stripping, you stop the unwanted air exchanges and will be able to maintain the right level of cool or warmth in your living space.
Why Do I Have to Insulate My Home?
A natural phenomenon called heat flow is all around us and it can directly impact your home comfort.
Heat moves from a warmer to a cooler area until there is no more difference in the temperature. Hence, in the summer, the heat from the outside will do all it can to invade your cool and shaded living space. Meanwhile, during winter, the heat produced by your furnace will try its hardest to evade your home to the chilly snowy outside.
If left untreated, this heat transfer will put a heavy strain on your HVAC devices because the indoor temperature will be hard to maintain. This will inevitably result in higher energy consumption month-on-month and potential early wear and tear to your cooling and heating devices.
Insulation, if done right and in a sufficient amount, can resist the heat flow by slowing down its movement or reducing radiant heat gain. The way to determine if you have enough is to first know the mandated R-value in your specific location.
R-value is the "temperature difference between the warmer surface and colder surface of a barrier.” This is the standard rating for insulation material. The higher the R-value of your chosen insulation, the better is its resistance to the movement of heat.
Next, measure the existing R-value of your house’s insulation and compare it to how much it needs to be based on your local climate. Fill the gap by choosing an appropriate type of insulation material for the specific area in the house. Lastly, decide if you will install the insulation yourself or hire a professional to do it for you.
Which Saves More Energy: Air Sealing or Insulation?
Both air sealing and insulation contribute to home comfort and improved indoor air quality. But the question remains: Which is more important?
If you will ask the opinion of the Green Building Advisor (GBA) and Orcas Power & Light Cooperative (OPALCO), air sealing is a weightier process because it confronts air infiltration or leakages head on. Air leaks are said to be responsible for more than 33% of your utility bill, according to GBA and OPALCO.
Meanwhile, Energy Star shows a more modest estimate on savings by saying “that homeowners can save an average of 15% on heating and cooling costs (or an average of 11% on total energy costs) by air sealing their homes and adding insulation in attics, floors over crawl spaces and basements.”
Other sources such as House Energy are also balanced in comparing the significance of air sealing versus insulation when it states that “Airtightness and high levels of insulation are both critical for efficiency and energy improvement.” Their statement is based on the following grounds: 1) Air sealing and insulation have distinct purposes and yet complement each other, and 2) air sealing and insulation make use of different materials.
Should I Seal Before I Insulate?
This is where the sources come together in the same conclusion—air sealing must always come first.
To illustrate: If you are heading out to a cold night, you first COVER yourself with basic clothes, leaving no exposed skin as much as possible. But to keep yourself warm and comfortable to walk around outside, you wear EXTRA LAYERS of a vest, jacket, or coat.
This is the same with air sealing and insulation. You have to make sure first that there are no holes, gaps, cracks, crevices, or unplanned openings that will let outdoor air in nor indoor air out without your control.
But to increase and maintain a level of comfort, heat that would want to invade or evade your space without permission can be stopped by the appropriate amount of insulation properly installed.
If you try insulating first before air sealing, your efforts might go to waste, and you might have to remove critical portions of your insulation material if you, later on, realize you need to cover up a huge gaping hole in the basement or attic.
So, air seal first, insulate next.
Is Sealing Air Infiltration Without Insulation Recommended?
“Note that air sealing alone doesn’t eliminate the need for proper insulation to reduce heat flow through the building envelope,” the Department of Energy says without reservations.
If you perform air sealing without completing it with insulation, you will rob yourself of many benefits. You will miss out on better indoor air quality, increased comfort, and a better maintained temperature in your home. Finally, your savings will be less on electric bills.
It is not recommended to install insulation without testing your home’s air tightness first and then sealing the air leakages around your house.