What’s Happening

Drafty windows that raise your energy bills almost always mean the seal between the glass and the frame has broken down, the weatherstripping has worn through, or the window unit itself has reached the end of its useful life. Your heating and cooling system is working harder to replace conditioned air that is quietly escaping around the edges or through the glass itself. This is a fixable problem, and the fix almost always pays for itself in lower monthly bills.

Call (562) 478-8017

When a window stops sealing the way it was designed to, outside air finds every small gap and pushes in. In summer that means warm, humid air entering a cool room. In winter it means cold air pooling near the floor and along the wall. Your thermostat reads the room average, not the cold zone near the window, so the system runs longer than it should to compensate. Most homeowners notice the bill going up before they notice the draft itself, which is why it helps to know exactly what to look for before calling anyone.

Why It Happens

Failed glass seal (fogged or hazy double-pane unit)

Modern windows use two or three panes of glass with an inert gas – usually argon or krypton – sealed between them. That gas layer is what gives the unit most of its insulating value. When the seal around the edge of the glass unit cracks, the gas escapes and outdoor air replaces it. You can usually see this as permanent fogging, condensation between the panes, or a faint haze that won’t wipe away because it’s on the inside surface of the sealed unit. If your window looks like that, the glass unit itself needs to be replaced.

Worn or compressed weatherstripping

Weatherstripping is the foam, rubber, or pile material that runs along the edges of an operable sash – the part that opens. Every time you open and close the window, that strip compresses a little more. After several years it loses its memory and stops returning to its original shape, leaving small gaps even when the window is fully closed. A simple test: close the window on a thin piece of paper and try to pull it out. If it slides easily, the weatherstripping is no longer doing its job.

Warped or settled frame

Wood frames absorb moisture and can swell, shrink, or cup over time. Vinyl frames in areas with extreme temperature swings can warp subtly at the corners. When the frame is no longer square, the sash can’t sit flush against the seal, and you get a gap along one side or one corner that no amount of weatherstripping adjustment will fix. If the window is hard to close, sticks on one side, or has a visible gap at a corner, the frame geometry is the likely cause.

Aging single-pane glass

Older homes sometimes still have single-pane windows, and a single layer of glass provides almost no meaningful thermal barrier on its own. You’ll feel radiant cold off the glass surface in winter even if the frame and seal are perfectly intact. If you hold your hand a few inches from the glass on a cold day and it feels noticeably cooler than the rest of the room, single-pane glass is working against you and weatherstripping alone won’t solve it.

What to Do Right Now

• Do a draft test on a calm day. Hold a lit incense stick or a thin strip of tissue paper near the edges of the frame and sash. Horizontal movement means air is moving through. Mark the windows where you see movement – your technician will want to start there.
• Check the weatherstripping by touch. Run a finger along the foam or rubber strip on the inside edge of the sash. If it crumbles, flattens without springing back, or has visible gaps, note which windows and which edges.
• Look between the panes, not at them. Fogging or haze that sits between two layers of glass – not on the surface – means a failed sealed unit. Take a photo with your phone so you have a record before anyone arrives.
• Check for daylight at the corners. Close the window fully, then look at the corners from the inside in a darkened room. A sliver of daylight at a corner points to a frame or sash alignment issue.
• Don’t rely on temporary caulk as a long-term fix. Rope caulk pressed into gaps will slow the problem this week but won’t address the underlying failure. It can also make it harder for a technician to assess the seal accurately when they arrive, so use it only if you need to protect a room for a few days while waiting for an appointment.

How We Fix It

When your local Lightwell Windows & Doors team arrives, the first thing we do is a full frame and glass assessment – measuring each sash opening, checking the frame for square, and confirming which units have failed seals versus worn weatherstripping versus structural frame movement. We’ll show you exactly what we find and explain the options before anything is quoted.

Depending on what we find, the solution is either a window replacement or a targeted window installation of a new unit into an existing opening. We carry products from eight manufacturers – PGT, CGI, CWS, ES Windows, ECO Window Systems, Mr-Glass, Therma-Tru, and ViewLux – so we recommend the product that fits your home’s specific needs, not whatever happens to be easiest for us to supply.

You’ll receive a written price before any work starts – that is how every Lightwell job works, without exception. The work is covered by our 365-Day Done Right Promise: if it’s not done right, we make it right. A typical window replacement takes a few hours per window, and we leave a photo of the clean-up before the crew leaves.

Frequently Asked Questions

Get It Fixed

Call (562) 478-8017 – a real person answers around the clock – or book online to schedule your free written estimate. Your local Lightwell Windows & Doors team will assess every window, show you exactly what they find, and give you a written price before any work begins.

Written by Keith Yamada, Owner at Lightwell Windows & Doors, part of the Cedarwell network since 2010.