A leaky window is a common problem many homeowners face. Not only is it a nuisance, but it also affects the overall safety and energy efficiency of your home, leading to increased energy bills and possibly the growth of mold. 

However, fixing a leaky window can be relatively easy and cost-effective if you catch it in time. In this article, we’ll explore some of the main causes of a leaky window and provide solutions to fix the issue.

Top 4 Causes of Leaky Windows

If you’ve noticed water seeping through your windows during rain showers or experiencing drafts on windy days, it’s time to address the issue. Here are some common causes and what you can do to fix them.

1. Old or Damaged Caulking

This is the most common cause of a leaky window. Caulking is a material that seals the gap between the window frame and the wall, keeping all the elements outside. However, due to weathering and age, it can crack, shrink or become brittle, leading to leaks. 

old or damaged caulking

The good news is that repairing it is easy. Simply remove the old caulk with a scraper or utility knife, clean the area thoroughly, reapply a new layer, and let it dry.

2. Worn Weatherstripping

Another cause of a leaking window is damaged or worn-out weatherstripping. Weatherstripping is a rubber or foam material that covers the gap between the window sash and the window frame, preventing air and water from entering inside. Over time, weatherstripping can lose its flexibility and effectiveness, leading to leaks. 

worn weatherstripping

Replacing it is simple and cheap, and you can do it yourself. Remove the old weatherstrip, clean the area, apply the new weatherstrip, and trim any excess material.

3. Damaged Window Frame

The third most common cause of a leaky window is a damaged window frame. Windows frames made of wood can rot over time due to moisture exposure. Metal frames can rust when exposed to water for extended periods. Both scenarios can lead to gaps or holes that let air and water into your home.

damaged window frame

Repairing a damaged frame is possible but may require professional help depending on the extent of the problem. If the damage is severe, simple repairs may be out of the question, and a full replacement project may be necessary.

4. Condensation Issues

Condensation forming on the inside of windows can sometimes be mistaken for leaks. While not directly a leak, it can still cause water-related issues.

condensation issues

When to Replace Your Windows vs. Repair Them

In some cases, repairing or replacing individual parts may not fix the issue, and it’s best to replace the entire window. Some signs that indicate the need for a replacement window are:

  • Condensation between the panes of glass
  • Difficulty opening and closing the window
  • Visible damage or decay on the frame
  • Excessive noise or drafts
  • Higher-than-usual energy bills

How to Choose Good Replacement Windows

When purchasing replacement windows, keep the following factors in mind:

Quality Materials

Opt for windows made from durable materials like vinyl, fiberglass, or wood. High-quality materials are more resistant to leaks and deterioration.

Energy Efficiency

Look for energy-efficient windows that can help you save money in the long run, such as options with a low U-factor and a high R-value. These ratings measure the insulation value of a window, meaning that a lower U-factor and a higher R-value will provide better insulation and help you save energy. You can also look for windows with ENERGY STAR® certification, indicating their energy efficiency and potential savings on utility bills.


A good replacement window should come with a solid warranty, demonstrating the manufacturer’s confidence in their product’s quality.

Proper Installation

Once you’ve chosen a new window product, choose a reputable contractor who has a track record of proper window installation to ensure a tight fit and prevent leaks.

Time for Window Replacement? We Can Help

Don’t let a leaky window be a problem in your home; tackle it with these easy steps and enjoy a more comfortable, energy-efficient space. If window replacement is in your future, get in touch with our team to talk about brand and product options. We stock top-name manufacturers — Andersen®, Marvin®, Jeld-Wen®, and North Star — that promise quality for years to come, so you can get the most out of your investment.

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