Energy Efficient Windows – How to Tell if You have a Leak

Living in the dry desert, window leakage may not seem like the type of thing that the average Phoenix, Arizona resident should have to worry about. It’s warm year-round and it rarely rains; why worry about maintaining energy efficient windows?

A substantial portion of your electricity bill each month goes toward heating and/or cooling your house, depending on the time of year. If there was a simple way to cut your energy bill by 20-30%, you’d probably want to hear some more about making that happen. Well, doing a quick walkthrough inspection of the windows throughout your home could actually give you some insight into how to make that a reality.

Simply identifying the energy inefficient windows throughout your home and taking steps to replace them can have a dramatic impact on your household carbon footprint. Some of the following questions may come to mind:
What are some things that cause window leakage?
How do I check my household for them?
What can I do to prevent leaky windows in the future?


Many common mistakes can be made throughout the installation process to cause window leakage. The three primary forces, that cause otherwise reliable, well-built windows to leak, are house design, installation, and maintenance.
Home improvement author, Kathy Price-Robinson has written that there are 9 causes for leaky windows; mistakes that are made during the design, installation, or maintenance stages of your window’s lifespan that can reduce the energy efficiency of the household.

1. Complex Window Layout with No Overhang
• Overhangs provide shade, block sunlight, but they also prevent wind-driven rainwater from pushing into the walls through the windows.

2. Angled Fascia

• A fascia is a board or band situated above a window. Angled inward, the fascia will direct running rainwater towards the house.

3. Poorly Installed Flashing

• Flashing is a material installed around the periphery of windows to waterproof them. Well-installed flashing tape is usually continuous, leaving now holes or overlapping material that might allow water to seep in through.

4. Misuse of Materials

• Some contractors have been known to use house wrap or building paper instead of special flashing tape. This can have consequences at a later time since house wrap is generally a less robust material more prone to ripping or tearing.

5. No Flashing

• Neglecting to use any type of material for flashing is a costly mistake which will inevitably cause you a headache down the road when leakage becomes an issue.

6. Inadequate Assembly

• Having an incomplete seal or leaving cracks between the caulking is a evidence of an inadequate installation.

7. No Shingles

• ‘Shingling’ not only refers to the process of adding shingles to your roof, but can also describe the layering of materials atop others to prevent potential fluid leakage.

8. Cracked Glazing Putty

• Best fixed by tearing out the glazing and refinishing it.

9. Lack of a Paint Seal

• It sounds counterintuitive, but the paint around your windows should actually slightly overlap the glass itself to create a slight paint seal.

For a more in-depth analysis into what causes leaky windows with descriptive photos, please see 9 Causes for Leaky Windows.


Checking for leaky windows is super simple and can be even easier if you know what you’re looking for. Energy efficient windows can’t exist without proper maintenance, and occasionally checking windows for inefficiencies is a part of the maintenance process. Here are some common methods:

Candle Trick
 -Use the common ‘match trick’ to test for drafts. Simply hold a candle or a match a few inches from the window and keep an eye on the flame for stuttering. It may be difficult to see or feel a cool draft in Phoenix, Arizona, but if you do, the window is probably improperly sealed. A fluttering curtain or blind can be a dead giveaway that the window has a sealant problem.

Condensation Relief- Condensation build-up on the window or in between window panes is a troublesome sign that should be dealt with as soon as possible. The excess moisture could be causing problems to the wood around the window.

Clearing a Blocked Weep Hole – A weep hole is a tiny hole typically found near the bottom of a window that drains moisture from between panes. Over time, the weep hole can be blocked by dust or debris, causing moisture to build up. Simply using a vacuum to clean out the window tracks is an easy fix to blocked weep holes.


In most cases, repairing and replacing windows is better left to the professionals. But here are some quick and inexpensive sealing solutions that any DIYer can use to properly seal their windows.

Stripping and Film – Self-adhesive foam weather stripping can be easily installed along the interior edges of a window to create a simple seal. Additionally, clear plastic window film can stretched over the frame,

Window Insulator Kit
 – Another simple solution is to purchase the Window Insulator Kit, a clear, plastic material that is applied with double-sided tape, creating a makeshift seal.

Expanding Foam
 – Foam and silicone can be quickly used to fill holes or gaps. A product called Great Stuff is an expanding foam sealant that dries quickly after being applied, leaving no room for gaps.

Use this page as a guide for your DIY home window replacement project. Your local window provider will have the experience to assist you in the installation process and a solid understanding of your local environment. Let the Phoenix window professionals be your go-to consultant when it comes to installing energy efficient windows. After all, energy efficient windows can only be energy efficient if they are properly designed, installed, and maintained.

Andy Akers is a professional blogger for XO Windows, Arizona's largest window distributor, providing complete, accurate and on-time delivery for your vinyl or aluminum windows and all of your window product needs. Follow him on Twitter

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