When extreme weather approaches, having drafty windows and doors can be an annoyance that drives up your heating bills even when using an energy-efficient HVAC system.
Studies suggest that even just one drafty window can reduce your heating efficiency by up to 30%. Now imagine the impact on your energy bill if you have multiple windows allowing cold air in from outside—we doubt you’d be saying “the cold doesn’t bother you anyway.”
Sealing air leaks in your windows is usually an easy fix that can help eliminate cold spots in your rooms, which translates to increased comfort and energy savings. This guide covers how to detect drafty windows and the various ways you can fix them.
Let’s get started!
Checking for Drafty Windows
There are several ways to check for leaky or drafty windows. It is best to perform these tests on a windy day or when there is a substantial difference between the indoor and outdoor temperature.
Here are a few ideas:
1. Visual Inspection
Start with a thorough inspection of your windows from outside your home. Look for areas where the caulking has cracked or failed, revealing the space between the window frame and house siding. This could be a major source of cold air leaks.
If you have single-paned windows, also assess the individual panes of glass for damaged glazing at the edges. Inspect the caulking on each pane to ensure they are not cracked or worn out.
From inside your house, inspect the weatherstripping around the windows. Weatherstripping should be intact and firm in order to form a tight seal whenever you close your windows.
Lastly, check for cracks in the glass, frame, and sash. These could also cause large amounts of outside air to leak into your home.
2. Check for Loose Windows
To check if your windows are closing tightly, place a piece of paper on the windowsill and then close it. Try to pull the paper out. If it comes out easily without tearing or folding, it is likely that air can pass through as well. In such cases, it would be advisable to install weatherstripping or a new threshold.
3. Smoke Test
For air leaks that are not easily visible, you can conduct a “smoke test.” Follow these steps:
- To prepare for the test, close all doors and windows in your home.
- Turn off all combustion appliances, such as the water heater or furnace.
- Next, turn on the bathroom and kitchen exhaust vents to create an internal negative pressure that sucks outside air into your house through any opening.
- Now, place your hand in areas that are likely to have gaps to see if you feel the draft on your hand.
- You can try putting some water on your hand to make it easier to feel when air is coming through.
- Alternatively, you can tape a small piece of plastic wrap on a pen and then hold it next to your windows. Make sure that the plastic can move freely. It will be easy to detect any draft from your windows.
- For a more dramatic test, you can use smoke from a lit incense stick. Pass the stick close to the edges of your windows, looking for any noticeable change in the way the smoke rises. If there is a draft, the smoke should waiver and get blown inwards.
4. Technical Test
If you have the resources, you can try using an infrared thermometer to detect air leaks. This non-contact thermometer can measure ambient air temperatures around your window frames. Leaky areas letting cold air into the house should register a colder temperature than the rest of the room.
Fixing Drafty Windows
There are several easy fixes for leaky windows, including the following:
1. Apply Caulking
This soft and sticky substance can fill up a non-moving gap in your drafty windows. The best caulking to use for this is silicone caulking. This type can adhere to materials like glass, PVC, metal, and so on. It’s versatile, water-resistant, and long-lasting.
If you suspect that your drafty windows are caused by failing or broken weatherstripping, then replacing the worn-out material is recommended. Make sure to get weatherstripping that is compatible with your windows.
And if you have old windows in your home that do not come with grooves for weatherstripping, adhesive foam-type weatherstripping is recommended.
To learn more about replacing weatherstripping, check out this guide: How to Repair a Broken Seal on a Window.
3. Shrink Film or Shrink Wrap
Shrink film is a clear plastic sheeting that, when applied with double-sided tape and heated with a hairdryer, shrinks to form a tight seal that prevents drafts. To release the tape in spring, simply use rubbing alcohol. This is only recommended for small gaps.
4. Nail Polish
This is a great option for DIYers. However, just like most of the items on this list, it’s only a quick and temporary fix. This usually only works with really small gaps.
When carefully applied, the clear polish can fill cracks and form an invisible seal. Hardened nail polish can also stabilize single-pane glass—just enough to make it through the cold months.
5. Replace Loose or Leaking Glass
If you notice cracks in the glazing putty that seals the glass of single-pane windows, you can replace it. First, you will need to remove the old putty. Then, you can detach the pane and add fresh putty. Lastly, press the glass gently into the putty and add glazing points.
However, if you have multi-pane windows (e.g. double-pane or triple-pane), you can’t simply replace putty to fix the issue. Usually, these windows only leak around the glass when the insulated glass unit’s seal is broken. The only solution for this is to replace the insulated glass unit.
Get Durable, Energy-Efficient, and Weatherstripped Windows by Clera
This wraps up our guide on drafty windows. Please note that the above solutions will only work if the window itself is not severely damaged. If you are dealing with worn, rusted, or rattling windows, replacing them is the best option. This is recommended for both single-pane and multi-pane windows.
If you need a window replacement for your home, we’re here to help!
For over 40 years, Clera Windows + Door has been a trusted manufacturer of durable and energy-efficient custom windows. With our ENERGY STAR-certified windows, you can say goodbye to drafty windows and look forward to added energy savings and optimal home comfort.