Drafty windows raising energy bills - Written Price Before Anything Is Ordered

Drafty Windows Raising Energy Bills

Drafty windows are almost always a sign that the seal between the glass unit, the frame, or the weatherstripping has broken down – letting conditioned air out and outside air in. The fix depends on which part has failed, and a trained eye can usually identify it in a single visit. Until that visit happens, your heating or cooling system is making up the difference on every utility bill.

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What you’re feeling as a draft is air moving through a gap. That gap might be microscopic – a failed perimeter seal around the insulated glass unit – or it might be visible, like a compressed weatherstrip that no longer meets the frame. Either way, the window is no longer doing the one job it was specified to do: hold the thermal boundary of your home. Left alone, the problem doesn’t stabilize. The seal or the frame material continues to degrade, and the energy loss compounds. Knowing which of the four causes below matches what you’re seeing will tell you whether you’re looking at a repair or a replacement, and roughly how urgent it is.

Why It Happens

Failed Insulated Glass Unit (IGU) Seal

Every double- or triple-pane window holds an inert gas – usually argon or krypton – between the panes. That gas is what gives the window most of its insulating value. When the perimeter seal around the IGU fails, the gas escapes and moisture enters. You’ll know this is the cause if you see fogging or condensation between the panes that you cannot wipe away from either side. The glass itself is still intact; the insulating cavity is not.

Deteriorated or Missing Weatherstripping

Weatherstripping is the compressible material that lines the contact edges of an operable sash – the part that moves when you open or close the window. It degrades with UV exposure, compression cycles, and age, and it’s the most common source of a draft you can feel with your hand near the edge of a closed window. Run your fingers slowly along the perimeter of the closed sash. If you feel air movement or see a visible gap where the sash meets the frame, the weatherstripping is the likely culprit.

Frame Warping or Frame-to-Rough-Opening Gap

Wood and some composite frames absorb moisture over time and can warp enough to break the airtight contact between the frame and the sash, or between the frame and the rough opening behind the trim. A window that used to close flush but now takes noticeably more force – or one where you can see daylight at the corners when you look carefully with the interior light off – is showing you a frame problem. This is less common than a seal or weatherstripping failure, but it’s also harder to address without a full replacement.

Glazing Compound Failure at the Glass-to-Frame Interface

Older single-pane windows, and some aluminum-frame units from the 1990s and early 2000s, use a hardened compound or tape to seal glass directly into the frame channel. That compound shrinks and cracks with age, leaving a thin air path around the edge of the glass. You’ll often see it as hairline cracking or visible separation at the point where the glass meets the frame material – sometimes with a faint dusty or chalky residue. It can look minor from a distance, but the gap it creates runs the full perimeter of the pane.

What to Do Right Now

• Check the panes for interior fogging. Look between the glass layers in daylight. If you see condensation or a hazy film you cannot reach, photograph it – that image is useful documentation when your technician arrives.
• Run a slow hand-check along every edge of the closed window. Move your palm along the sash-to-frame seam, the frame-to-wall trim, and the bottom rail. Note exactly where you feel air movement and take a short video so the location is recorded.
• Check whether temporary film insulation is in place. If you’ve added interior window film or shrink kits as a temporary measure, leave them in place – they are evidence of where the gap is severe enough to warrant a workaround, and they help your home until the actual fix is done.
• Do not attempt to re-caulk around the glass pane yourself if the frame is visibly warped or the window is original to an older structure. Caulk over a warped frame or a failing rough-opening connection can trap moisture and accelerate rot inside the wall cavity. Photograph it and wait for the assessment.
• If the window is a large fixed unit at height or spans a stairwell, do not lean out or apply pressure to test the frame. Document what you can see safely from inside and let the technician do the physical assessment from the proper position.

Before

After

How We Fix It

When your local Sightline Windows & Doors team arrives, the first thing they do is a measured survey – not a sales presentation. They check the IGU seal condition, the weatherstripping compression, the frame squareness, and the rough-opening fit. Every reading goes into a documented photo record you receive at the end of the visit, under the Haven Standard’s Evidence clause.

If the IGU seal has failed but the frame is sound, the path is usually a Window Replacement of the glass unit into the existing frame. If the frame itself has warped or the rough-opening connection is compromised, the correct fix is a full Window Installation – new unit, new frame, properly reset into the opening. Both services are available through Sightline, drawing from manufacturer lines including PGT, CGI, CWS, ES Windows, ECO Window Systems, and ViewLux, specified by what your opening actually requires.

Before any work starts, you receive a written price – that is Haven Clause 1, not a promotion. The job is covered by the 365-Day Done Right Promise. Most window assessments are completed in a single visit; installation scheduling depends on the unit specified and the scope confirmed in writing.

Frequently Asked Questions

Get It Fixed

Your local Sightline Windows & Doors team will assess the window, document what they find, and give you a written price before any work starts. Call (509) 265-6387 – a live person answers – or book online. No voicemail, no callbacks, no surprises.

Written by Sonia Raman, Owner at Sightline Windows & Doors, serving communities nationwide since 2012.