Fixing Drafty Windows in a 1970s Home in Skagit, Island and Whatcom Counties

Updated August 2026 · Alpine Exteriors · WA contractor license ALPINI751OW

The Short Answer

In most 1970s houses around Mount Vernon, Anacortes, Burlington and Bellingham, the draft you feel at the window isn't a mystery — it's the original aluminum-frame windows themselves, along with weatherstripping and glazing putty that have simply worn out after fifty-some years. Caulk and rope weatherstripping can quiet things down for a season or two, but in almost every case we've looked at, the frames and glass are the actual problem, and full replacement is what permanently stops the cold air.

The Detail Behind It

Homes built in Skagit and Whatcom counties in the 1970s were almost universally fitted with single-pane aluminum sliders or aluminum-framed fixed windows, sometimes with a thin secondary storm panel added later by a previous owner. Aluminum is a poor insulator on its own — with no thermal break in the frame, the metal carries outdoor cold straight to the interior surface, which is why the frame itself often feels colder than the glass on a January morning. Single-pane glass adds almost nothing to that picture; it insulates barely better than a piece of cardboard in terms of R-value, which is why condensation and cold radiating off the glass is such a common complaint in these houses even when there's no obvious air leak.

The air leakage part comes from two places. First, the glazing putty or vinyl glazing bead that holds the pane in the sash dries out, shrinks and cracks over four or five decades, opening tiny gaps around the entire perimeter of the glass. Second, the fuzzy pile or foam weatherstripping between the sash and frame compresses flat or disintegrates, so the sliding sash no longer seals against the frame the way it did when the window was new. On top of that, most houses from this era have settled a bit over time — stud walls shrink, foundations shift slightly — and that settling can rack a window opening just enough that the sash no longer meets the frame square, even if someone replaced the weatherstripping at some point. Put those three things together — a conductive frame, single-pane glass, and failed seals — and you get a window that both loses heat directly through the material and lets outside air leak through the gaps around it.

What Makes This Region Different

A drafty window in a 1970s house isn't unique to this area, but a few local conditions make the problem worse here than it would be somewhere calmer and drier.

• Wind off the Skagit and Samish flats. Houses in and around Mount Vernon, Burlington and La Conner sit in open, flat farmland where wind off the delta hits window walls directly and steadily, rather than the gustier, more sheltered wind you'd get in a wooded neighborhood. A leaky window on the windward side of one of these houses will draft noticeably more than the same window on a calmer lot.
• Heavy winter rain, not snow load. Our winters bring long stretches of driving rain rather than deep snow. Failed glazing and worn sill weatherstripping don't just let air through here — they let water track in along the sill and down into the wall framing below the window, which over years can rot the sill plate and sheathing quietly, behind the trim, long before anyone notices a stain.
• Salt air on the islands and Camano. Homes on Camano Island, in Anacortes and along the water near Stanwood deal with salt-laden air that accelerates corrosion on aluminum window hardware — rollers, latches and the frame's own fasteners — faster than the same window would corrode inland. A window that's merely draft on the mainland can be seized or crumbling at the hardware on a waterfront lot of the same age.
• Occasional ice and hard frost in the foothills. Homes up toward Sedro-Woolley and the Bellingham foothills see harder overnight freezes than the valley floor. That freeze-thaw cycling stresses old glazing putty and caulk lines even more than steady cold does, which is part of why cracked exterior glazing shows up so often on these homes' east- and north-facing windows.
• Washington State Energy Code. Any window you actually replace today has to meet the prescriptive U-factor and, in many cases, the solar heat gain requirements set out in the Washington State Energy Code for the residential provisions in effect at the time of permit. That's worth knowing going in, because it rules out some of the cheapest big-box replacement units and narrows the field to windows rated for this climate.

What the Homeowner Should Actually Do

Start by figuring out whether you're dealing with a genuine air leak or just a cold, poorly insulating window — the fix is different for each, and it's easy to conflate the two. On a windy or rainy day, run a bare hand slowly around the window's perimeter, at the sash-to-frame joint and along the sill. A steady stream of moving air is a leak you can often address with weatherstripping, backer rod and caulk as a stopgap. A window that feels cold and clammy to the touch but shows no moving air is more about the glass and frame material itself, and no amount of caulking will fix that — only added glazing (a storm panel) or full replacement will.

For genuine leaks, cheap and reasonable interim steps include: replacing visibly compressed or missing weatherstripping in the sash track, re-glazing cracked putty on fixed panes, and running a bead of paintable exterior caulk where the window frame meets the siding or trim — that last one matters more here than in a drier climate, because it's often less about heat loss and more about keeping winter rain from working its way behind the trim. Interior plastic film kits or heavy curtains can also cut the felt draft through a cold winter without spending real money, though they're a seasonal patch, not a fix.

If the frames themselves are aluminum, single-pane, corroded on the hardware, or the sashes are visibly racked out of square, weatherstripping is only buying time. At that point the honest move is to budget for replacement — starting with whichever rooms take the worst of the wind or rain (usually the windward wall on flat, open lots, or anything facing the water on the islands) rather than trying to do the whole house at once. Vinyl and fiberglass replacement windows built to current Washington State Energy Code U-factor requirements will outperform the originals by a wide margin on both drafts and condensation, but it's a real expense, and it's fair to say the energy savings alone usually pay it back slowly — the bigger, more immediate benefit is comfort, less condensation on the glass, and stopping water intrusion at the sill before it becomes a rot problem. A full-frame replacement (removing the old frame down to the rough opening) also gives a contractor the chance to check the sill and framing underneath for rot from decades of rain intrusion, which a cheaper pocket replacement — where the new window is installed inside the old frame — does not; on a house with visible sill damage or a history of water staining, that difference is worth asking about directly. Alpine Exteriors walks Skagit, Island and Whatcom county homeowners through that assessment on-site, checking the sill condition and existing frame before recommending pocket versus full-frame replacement, and can quote either path depending on what's actually found once the trim comes off.

FAQ: Drafty 1970s Windows

Is caulking and weatherstripping enough to fix drafty 1970s windows?

It helps with airflow leaks around the sash and can buy a few more winters out of an old window, but it does nothing for the poor insulating value of single-pane glass and an aluminum frame with no thermal break. If the window still feels cold to the touch with no moving air detectable, weatherstripping alone won't solve that — you're dealing with a material problem, not a seal problem.

How much does window replacement cost in Skagit, Island or Whatcom County?

Costs vary a lot by window size, whether it's a pocket replacement or full-frame tear-out, and how many windows you're doing at once — a single mid-size vinyl replacement window typically runs somewhere in the low-to-mid hundreds to over a thousand dollars installed, with full-house projects scaling up from there. Full-frame replacements that involve fixing rotted framing underneath will run higher than a straightforward pocket swap into sound framing. Getting a firm number really does require an on-site look at the specific window and its condition.

Will new windows meet Washington's energy code automatically?

Not automatically — the window itself has to carry a U-factor rating (and often a solar heat gain rating) that meets the prescriptive requirements of the Washington State Energy Code residential provisions in effect at the time of your permit. Not every window sold at a retail store is rated for that, so it's worth confirming the NFRC label on any window before it's ordered, especially if you're sourcing materials yourself rather than through a contractor pulling the permit.

Can I replace just one or two windows at a time instead of the whole house?

Yes, and for most budgets that's the more realistic approach — prioritize the windows on the side of the house that takes the worst wind or rain, or any window with visible sill damage, and work through the rest over a few seasons. The only downside is you won't get the full comfort and condensation improvement until the whole house is done, and you may pay a bit more per window in mobilization costs across multiple smaller visits than you would doing it all in one project.

Get a Window Assessment

If you're feeling drafts through original 1970s windows anywhere from Mount Vernon and Burlington out to Anacortes, La Conner, Camano Island, Stanwood, Sedro-Woolley or Bellingham, it's worth having someone look at the actual frames and sills before deciding between weatherstripping and replacement — what looks like a simple draft can be sill rot or corroded hardware once the trim comes off. Alpine Exteriors, WA contractor license ALPINI751OW, serves Skagit, Island and Whatcom counties and can walk through your specific windows, check for water damage, and lay out honest options — patch, storm panel, or replacement — along with what the Washington State Energy Code requires for whichever route you choose.