Understanding Air Conditioning in Arlington: Sealing Air Leaks

Understanding Air Conditioning in Arlington: Sealing Air Leaks

Summer has arrived in North Texas and Arlington homeowners have invaded home improvement centers to load up on plants, fertilizer, mulch, and anything outdoorsy they need. But did they remember the caulk and spray foam?

Say what?

What do caulk and spray foam have to do with summertime in Arlington and North Texas?

Not as much mowing the lawn and trimming the hedges, but while you’re at the home improvement center gathering supplies — and while you’re engaged in summer maintenance — you might as well address those pesky air leaks that waste money and expensive energy.

In this post we look at materials to seal air leaks, where to start, and what to do. You can do much of this yourself, but if you’d prefer not to mess with the mess, then your Arlington air conditioning repair or service tech (or a good handyman) can do these for you.

Rather than run around the house like a caulk-wielding gunslinger looking to fill every nook and cranny with sticky, messy goop, there are places you want to attack first. Since basements are uncommon in Arlington and North Texas, you’ll want to start in the attic.

Quick Heat Refresher

Cold air infiltrates the base of the home, then rises through the house (creating drafts) and exits through the attic. It’s the chimney effect.

In order to minimize this effect, Arlington air conditioning repair and service techs, as well as energy specialists, recommend you seal the attic first.

Needed Materials

Caulk, spray foam, and weatherstripping are the basic materials you need. These are inexpensive and readily available at any Arlington home improvement center or hardware store.

How efficiently you seal air leaks depends on the size and location of the leaks and choosing the right material for the job.

  • Plug larger holes with pieces of drywall or cardboard.
  • You can also stuff holes with plastic bags filled with scraps of fiberglass insulation.
  • For most openings, caulking, sealants, and weatherstripping are the best solutions.


Caulk is a semi-solid, toothpaste-like substance you apply into gaps no wider than 3/8 of an inch where different building materials meet.

For the job at hand, you’ll want to use tubes and a caulking gun. Caulk is also available in card or rope form and put into place with your fingers.

For the Arlington climate, choose a caulk that seals well in both the cold and heat. If you are unsure of the right caulk for a specific application, make note of the location to discuss with a customer service or sales rep at a Lowe’s, Home Depot, or favorite local hardware store.

You’ll need different caulk for different surfaces, inside and outside. Some caulk is weatherproof, some not. Some can be painted, some cannot. Some expand, some do not. Generally, high-end caulk seals better, lasts longer, and isn’t much more expensive than the cheap stuff.

Air sealing is one area where you don’t want to scrimp on materials because a poorly sealed crack is still a crack.

Weatherstripping Options for Doors

Foam sealants are commonly used for large gaps up to one inch. Once applied, the foam expands to fill and seal the space and, like caulk, hardens when it dries.

The two most common types are urethane and latex foam. These are readily available at Arlington-area hardware and building supply stores. If you are unsure of the differences between them (mostly due to drying time and cleaning requirements) ask someone in customer service to help.

Weatherstripping eliminates gaps between movable parts when they are closed (around the perimeters of exterior doors and operable windows. It can be made of metal, foam, rubber, vinyl, or felt and is often sold by the foot or in pre-packaged kits.

If possible match the product that originally came with the door or windows. The finished result will look its best and be the most effective. Some materials are nailed or tacked into place, others are applied with self-adhesive tape. Well-installed weatherstripping will be slightly compressed when the doors and windows are closed.

As with caulk and foam sealants, if you have questions regarding weatherstripping and installation ask a customer service rep in building supplies.

Start at the Top

Attention to the attic will save the most on your energy bills. Every opening in the ceiling is a potential “chimney” for conditioned air to escape. Check around electrical wires, light fixtures, recessed can lights, chimneys, stove flues, ductwork, plumbing vent pipes, and along the tops of walls.

Attic Culprits

If you have a finished attic you may have knee walls (side walls under eaves). In many cases the insulation and air barriers behind the walls and under the floor are inadequate to minimize air flow.

There are three steps to effectively sealing attics with knee walls:

  • Seal air leaks between the heated and unheated space. This includes rigid foam insulation blocks between the joists and sealing them with spray foam or caulk.
  • Adding more insulations above the flat ceiling.
  • Adding more insulation batts behind the knee walls (the vapor barrier is toward the heated side of the wall).

Attic Access

If you have an attic door, attach fire-coded rigid insulation to the back, then weatherstrip around the sides and top and add a door sweep.

If you have an attic access panel, insulate the back with a minimum R-20 rigid insulation, then add weather stripping around the perimeter. Make sure the latches provide a tight fit.

If you have pull-down stairs, create an insulated overhead cover that will fit above the stairs and can be hinged or slid to the side when you go into the attic. Install weatherstripping around the perimeter of the door.

Recessed Lights

Recessed lights can be a source of significant air leaks. The most energy efficient (and also the most expensive) option is to replace them with ceiling mounted lights or airtight fixtures.

If you want to continue using your old fixtures and minimize air leakage, experts recommend installing a box built from wallboard and sealed with caulk around each fixture to stop the air leakage. If you go this route, be sure each box is constructed to prevent insulation from contacting the fixture and creating a potential fire hazard (3″ minimum clearance is recommended).

Soffits, Bulkheads and Dropped Ceilings

Cover any large open holes into the attic space with plywood that is caulked into place to minimize air infiltration, then lay insulation over the plywood.


If you have a metal chimney, check the condition of the metal collar where it meets the roof and repair if necessary.

If you have a brick chimney, check for gaps between the chimney and the wood framing around it. Fill any gaps with a minimum of 26-gauge metal/galv metal or other fire rated material flashing, then sealed with fire rated caulk or sealant.

If you have a two-story home with high or severely pitched roofs, you will want to call an Arlington-area roofing company and have a service professional come to the home and do the work for you. Working on a roof as an inexperienced homeowner is dangerous to your personal safety and, because of your inexperience, you may do more harm than good.

Plumbing Vent Stacks

Seal any gaps around the pipe with an expanding foam sealant.


Before you put your caulk and foam away, seal around any utility penetrations that pass to the outside (including dryer vents or other ductwork, dog fence and other wiring, and electrical, phone, gas, cable or water utility related pipes).

Seal and Insulate Ductwork

If you have a forced air heating system, it pays to seek out leaks in both the supply and return ducts in attics and crawl spaces. Make sure all the pieces are properly connected. With the furnace fan operating, run your hand over the duct seams/joints to feel for air leaks. Holes in supply ducts will blow air out of the system, and gaps in return ducts will suck air into the system. Plug any leaks you find with foil duct tape (not gray Duct Tape), or better yet, use water-based mastic coupled with glass fiber mesh tape. Once the leaks are fixed, insulate ducts located in unheated areas with foil- faced glass fiber duct insulation. Just wrap the insulation around the duct and secure it into place.

Products to seal and insulate ductwork are readily available at Arlington-area home improvement centers. Ask a customer service rep for help on what products to use.

Quick Fixes

Here is a short list of things that you can do on a dull Saturday that will have a great impact on the energy efficiency of your home.

  • Weatherstrip and insulate attic doors, access panels or pull-down stairs
  • Seal (using an appropriate expanding foam) around plumbing vent stacks
  • Caulk or foam along sill plate, rim joist and rim joist cavities

Best Handled by Professionals

You can do many of these yourself, but it probably will take you much longer and cost possibly more money than if you just hire a professional to:

  • Replace, augment or install insulation in hard to reach places (such as behind kneewalls or above attic ceiling). A pro will be able to tell you about alternatives and the cost of each.
  • Repair and seal the chimney exterior.
  • Insulate behind soffits, bulkheads and dropped ceilings.
  • Install boxes over recessed lighting fixtures.
  • Install rigid foam under attic floor boards and seal it in with foam or caulk.