Finding and sealing off cold air flowing into your building is one of the most effective ways to save money on your heating bill. Finding the source of cold drafts can be frustrating. We often know it is there but can’t feel it well enough to pinpoint the source.
The engineering word for air leaking into a building is “air infiltration.” Sealing off the air infiltration can cut the energy cost of heating by as much as 30 to 40% in industrial, commercial and residential buildings.
Locating and sealing air leaks saves money during both the heating and air conditioning seasons. Finding drafts is much easier when you use something to make the airflow visible.
Smoke Can Help
Over the years, I have used many different tools to locate the source of drafts that cause expensive energy waste. They range from low-tech cigarette smoke to high tech electronic ultrasonic listing devices.
Way back in the olden days, 40 years or so ago, cigar, cigarette or pipe smoke was one of the best ways to make air movement visible. It was cheap, available and effective. Now days, tobacco smoke is banned in most facilities and is considered a health and fire hazard.
Making a cloud of smoke and watching how it moves helps you to “see” where that cold draft is coming from. Slowly moving a smoke source around the frame of a window will quickly show you exactly where the air is flowing in or out at the window.
Inexpensive smoke sources may not be as effective as ultrasonic listening devices or infrared cameras. But, they are cost effective when you consider that the high tech tools can cost $1,000 or more.
Note the photo above is and older smoke pencil product, not the new pro model.
The name “Smoke Pencil” is descriptive of what it does, but not how it looks.
First, you put some of the magic liquid in the unit. Then you squeeze the trigger. In a few seconds, a column of smoke flows out the top of its smoke stack.
The smoke flows out in a lazy cloud that reminds me of the smoke from my childhood Lionel Train locomotive. Except this smoke is sweet smelling and there is plenty of it.
The liquid in the supply tank does not spill, even when you hold the unit upside down and shake it. Good design.
I had trouble finding air leaks when I first started fussing with it because our house is well sealed. Out on the sun porch I made some air leaks by opening windows just a crack. The Smoke Pencil did a great job making the airflow visible.
Using the Smoke Pencil, I actually did find a draft around the back door that I need to fix.
You can use the smoke pencil just about anywhere, as the liquid is non-hazardous. The liquid is a blend of food grade chemicals so the vapor it produces is non-hazardous. A Material Safety Data Sheet is available so it can be used in buildings where the owners are fussy about safety paper work.
Other Trade Secrets
Some of the more unusual items I have used to find leaks are, incenses sticks, baby powder, candles, soap solutions and shaving cream.
Incense sticks smell nice to some folks, and make enough smoke to do the job. I hate them because the smell is burned into my mind associated with that Crazy Asian War.
Making a cloud of baby power by squeezing a plastic bottle of the stuff works OK and smells much better than tobacco or incense smoke. It does leave a white dust trail showing where you have been. You get tired of it very quickly.
Soap solutions are good for safely finding compressed air or gas pipe leaks when they make bubbles in the applied liquid soap. It is a good way to find air leaks in your car tires.
Candles are great for jobs where you can safely use an open flame. They work best when you are doing a detailed search for small leaks.
By watching the candle flame you can see when it gets blown by the airflow.
Bring lots of matches or a lighter. Candle flames blow out easily. Dripping hot wax is a problem.
Candles really shine at finding vacuum leaks. I’ve used them in industrial situations where there are vacuum leaks at pipe flange connections and similar equipment. The air being pulled into the equipment makes the candle flame point right at the leak.
When you can’t use a candle due to safety concerns, the next best tool for finding vacuum leaks is spray foam shaving cream. You coat the area where you think the vacuum leak might be, with shaving cream from an aerosol can. Vacuum leaks will suck the foam into the leak revealing its location.
I think that the Smoke Pencil Pro is a great tool for finding air leaks.