Home Sealing and Insulation Reduce Cooling Costs

Identifying Problem Areas

A Professional Audit

The best place to start identifying the places in your home where you’re gaining heat is to have an energy audit by a licensed HVAC contractor or energy auditor. They use various tools and gauges to measure the places where air leaks are located, as well as vulnerable areas that lack insulation. Most energy audits start with a blower door test that measures the amount of air leakage and where it occurs.

The blower door test also uses thermographic devices or harmless smoke pencils to pinpoint air leaks. When infrared still or video cameras are used, they also can identify where your home has inadequate insulation throughout its envelope. Using an HVAC contractor for the energy audit will ensure that the auditing team will check your home’s ductwork for airtightness. Leaks in the ducts can contribute to significantly higher cooling bills since the cooled air doesn’t reach its proper destination.

Duct leaks also degrade indoor air quality and can backdraft carbon monoxide into your home if you use any vented gas appliances in the summer. An HVAC contractor has the tools to find the leaks and seal them properly using metal tape or mastic, a type of adhesive that makes a permanent seal. Duct tape is a temporary solution for loose ducts since its adhesive is not durable.

At the end of the audit, you’ll receive a report that tells you where you need to do home sealing and insulation to improve your home’s energy efficiency. This report will be helpful for any contractors you invite to help you with the improvements. It also will provide a roadmap for you if you decide to do the work yourself.

Doing the Audit Yourself

You can conduct an energy audit yourself by closing your home tightly and turning on the exhaust fans in the kitchen and bathrooms. Walk along with the interior of your outer walls with a burning candle or incense and look for places where the flame or smoke wavers. The movement indicates an air leak. You can note the location for later air sealing. Pay particular attention to areas around doors and windows, and places where plumbing or other utility lines or pipes penetrate the home’s envelope.

Hidden Air Leaks

A DIY audit of your home may not show all the hidden air leaks, but you can head to the basement, attic, and crawlspace to look for problem areas, also noting their sizes and locations.

Specific places to inspect for obvious and hidden air leaks include:

In the Attic

  • Attic hatches
  • Top plate
  • Dropped soffits inside the home
  • Recessed lights
  • Chimneys, vent pipes for fans, plumbing, and flues
  • Wires

In the Basement or Crawlspace

  • Sill plate
  • Holes around the foundation for pipes and wires
  • Foundation cracks

Around the House

  • Electrical outlets and switches on exterior walls
  • Dryer vents
  • Open fireplace dampers
  • Windows and exterior door frames

You’ll run across built-in ventilation areas in the attic that you shouldn’t cover. The attic needs adequate ventilation to lower its temperature in the summer and prevent moisture from condensing in the winter.

Sealing Air Leaks

As you go about home sealing and insulation, choose caulk and other sealing materials with durability and safety in mind. If you have to seal around flues and chimneys, use metal flashing or silicone caulk that resists heat better than latex caulk. Silicone caulk also shrinks less than latex or acrylic products.

You might want to use a qualified electrician to stop leaks around recessed lights and add insulation to them since these lights can get hot, and there may be a fire danger if the wires are exposed. Expanding foam is a good method for home sealing and insulation, but read the instructions carefully, since some types are highly flammable. Once the foam has dried, you can use a knife to shape it, and then paint it.

If the air leak or gap is excessively large, consider stuffing it with insulation. Place the insulation in a plastic bag to prevent air from flowing through it. If the weatherstripping on the attic hatch and exterior doors needs replacement, note the type of original weatherstripping on the door. It may be simpler to use that type to replace it. You can also improve your home’s energy efficiency by cutting a sheet of insulation to cover the inside of the attic hatch.


Home sealing and insulation go hand in hand when you’re improving your home’s ability to resist thermal change. The U.S. Department of Energy suggests that homes in our area have 16 to 20 inches of attic insulation for R-values that range between R-38 and R-60. The “R-” refers to how long the product resists temperature change. Each digit represents an hour, so theoretically, R-38 resists thermal change for 38 hours.


The most common types of insulation for attics are fiberglass batts and blown-in insulation. Both have an R-value of about 3 for each inch of thickness. Less common types include rigid foam board, foam insulation, and reflective products. Foam has a higher R-value than fiberglass or loose cellulose blown-in insulation, and it’s a good product to use when space is limited.

Reflective insulation uses shiny foil that reflects heat back to its source. It’s a space-saving option for our climate since summers are warm and winters fairly mild. It will block heat gain in the summer and prevent heat from leaving your attic in the winter.

When choosing fiberglass batts, read the labels carefully. Those that have a paper coating on one side need to be covered with drywall or a nonflammable surface. Although fiberglass is made from spun glass, use care when touching it since it can irritate your skin. If you install it yourself, wear long pants and a long-sleeved shirt, and use a dust mask to cover your nose and mouth.


Wall insulation isn’t as critical as having adequate insulation in the attic because walls don’t have the same intense exposure to the sun that the roof does. However, home sealing and insulation in the walls do have an important effect on the energy efficiency of your home. To check the wall insulation, turn off a circuit breaker to an electrical outlet on an exterior wall and remove the cover plate. Look inside to see how much insulation is present. Spot check throughout your home to see where it’s lacking.

The easiest way to insulate a wall is to hire a contractor who can blow loose insulation inside it. You can use either blown fiberglass or cellulose. Installers drill holes in the walls with a special drill bit, pump the insulation in, and reseal the wall once finished. After it’s been painted, the sealed holes won’t be visible.


Insulating a basement is somewhat more difficult because of the moisture content in the masonry material. The best product for interior basement walls is rigid foam board, since it’s unaffected by moisture, unlike fiberglass and cellulose products. If the basement ceiling isn’t finished, you can use fiberglass batts to improve first-floor insulation.

Logan Heating, Air Conditioning & Electric can help you with your home sealing and insulation. We provide exceptional services in the Winston-Salem, High Point, and Greensboro areas.

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