It’s officially down-to-the-bone cold, Houston. Where better to seek sanctuary and guaranteed warmth than your own home, right? Wrong!

Air leaks in the envelope of the home – windows, doors, ceilings, etc- are a major cause of heat loss in most homes. According to Energy Star, if you added up all the leaks, holes, and gaps in a typical home’s envelope, it would be the same as having a window open every single day of the year. That’s the last thing you want when it’s getting below the 50’s. Think about how much energy that wastes and how much that will cost you in the long run. Before you get “It Will Never Happen to Me Syndrome,” the fact is that most homes in the United States don’t have enough insulation and have major air leaks.

Green Building Advisor, a website that provides information for building, designing, and remodeling green homes, estimates that a whopping one-third of the energy you pay for ends up leaking through holes in your house’s windows and cracks. Along with rain and other weather factors, air leaks through walls, roofs and floors can have the largest effect on the resilience of a home. Uncontrolled air flow through little open spaces you can’t see can not only carry moisture into pockets within the frame causing mold and rot, but it can also be the cause of excessive energy use and cause indoor air quality problems.

What’s the problem?

Air leaks around windows don’t cause that much discomfort during summer months. But in the winter, drafty windows can make an entire room chilly, forcing you to spend extra money on heating and wondering what the heck is going on.

“The most common reason for air leaking in a window is probably old caulking that gets worn away over time and comes out,” Charles Griffith said, a John Moore HVAC technician. He also said that it could be the shim space that was left a bit too loose and open by your home’s builders.

Many homeowners incorrectly assume that if they have drafty windows, they need to have replacement windows installed, but that’s not really the case. The truth is, replacement windows will improve your home’s comfort and energy efficiency, but they don’t always get rid of drafts. When it comes to windows, many times the gap between the framed window opening and the frame of the window, called the shim space, is usually the culprit. You can’t see the “shim space” underneath the interior and exterior trim that’s been nailed to the window jambs and to the wall framing, but you can feel the effects of an open shim space when it’s cold. Chilly outside air will find its way around the exterior trim outside, into the shim space, and then around your window’s exterior inside trim and into your living space, and poof – the comfort is gone.

Feel it or see it? Seal it!

According to Energy Star, a knowledgeable homeowner or skilled contractor can save up to 20% on heating and cooling costs – or up to 10% on their total annual energy bill – by sealing and insulating.

When checking your home windows and doors for air leaks, start with a detailed visual inspection from both the interior and exterior parts of your home.

Outside: Griffith said to look for areas where the old caulking has failed, revealing the gap between the window or door frame and the side of your home. If your home has old single-paned windows, be on the lookout for damaged glazing, which is the hard putty that holds the individual panes of glass in place. If the entire perimeter of each window and door is not sealed tight against water and air infiltration, then your home is vulnerable to heat loss and expensive bills.

Inside: Inspect the sill under each door, looking for daylight or other obvious signs of an opening that is too big and needs to be sealed. Make sure that the weather stripping around the windows and doors is in good condition, making note of any damaged weather stripping that needs to be replaced. Holding your hand by possible leaky areas and feeling a draft will tell you if there is a leak, but that isn’t always so easy and obvious. Another more accurate way to check for air leaks is to conduct a “smoke” test.

Smoke Test: First, on a very cool day, depressurize your home by closing all windows and doors, turn off the furnace, and turn on all fans that blow air outside, such as bathroom fans or stove vents. Then, hold a lit candle or incense stick (something long-burning) close to the spaces around the edges of your home’s windows and doors, looking for a noticeable change in the smoke rising from the lit incense stick. If there is an air leak, the smoke will waiver and be drawn inwards by the outside air that is finding its way into your home. If the smoke remains undisturbed, then you can assume that there are no air leaks in that specific spot.

Get it Done Right

Sealing leaks with caulk, spray foam or weather stripping will have a great impact on improving your comfort and reducing utility bills.

In some cases, an experienced energy technician will have to carefully pry off your interior trim to reveal the shim space. In other cases, the tech may be able to drill holes through the window jambs and inject spray foam into the shim space through the holes using a special spray foam applicator. In addition to plugging air leaks, caulking can also prevent water damage inside and outside of the home when applied around faucets, ceiling fixtures, water pipes, drains, bathtubs and other plumbing fixtures, so it’s a great, inexpensive tool to have on hand at home.

Many homeowners are often concerned about sealing their house too tightly. However, this is very unlikely in older homes. A certain amount of fresh air is required to have good indoor air quality. Did you know that there are certain specifications that set the minimum amount of fresh air needed for a house? If you are concerned about how tight your home is, experts can use diagnostic tools to measure the actual leakage in your home. If your house is too tight, they may even recommend a fresh air ventilation system.

It’s also important to remember that after any home sealing project, you should have a heating and cooling technician check to make sure that your combustion appliances (gas- or oil-fired furnace, water heater, and dryer) are venting properly.

Reap the Benefits

You may be thinking about all the effort you need to put in to get the process for air leak detection going and ultimately getting it all fixed. We get it; the information above may seem a bit overwhelming. Usually, fixing the entire problem isn’t quick and it isn’t necessarily easy, but the benefits that will come from sealing up air leaks are well worth it, and that’s a promise! Sealing leaks and adding insulation can improve the overall comfort of your home and help to fix many of these common problems:

Reduced the amount of outside noise
Less pollen, dust and insects (or pests) getting into your home

Better humidity control; keeps things from rotting and molding which pollute your home’s air
Keep your home warm during the winter (you need this right about now… Brrrr)
Lower your energy bills (this one’s our favorite!)

No matter what you do, don’t attempt to seal your windows or doors alone unless you are highly experienced. Taking on some of these projects without proper training and knowledge can cause bigger problems in the long run and cost you even more money. Also, make sure someone experienced takes a look at your work to make sure everything checks out and is safe. Call our John Moore experts for help with any aspect of energy efficiency, or even just to answer any of your questions about a small, quick-fix project. Once you see your energy bill lowered and feel warm and toasty in your home, you’ll be really glad you did.