Curious if anyone here’s tried full sash replacement instead of just the glass? I’ve heard some folks say it’s easier, but I’m not sure about matching the look with older trim.
Just went through this with a couple windows in my place (built in ‘82, so not exactly historic, but still enough old trim to make things tricky). Here’s what I learned the hard way:
Step 1: Try to identify which windows are actually worth saving. I wasted time fussing with a bathroom window that honestly should’ve just been replaced outright. If the wood’s soft or the hardware’s shot, swapping glass or sashes is kinda pointless.
Step 2: About sash replacement—yeah, it’s definitely less hassle than messing with just the glass. The kit I got came pre-assembled and slid right into the old frame. No fighting with sticky sealant or trying to get the IGU lined up perfectly. BUT... matching the old trim is a pain. My new sashes are a slightly different white, and the profile is a bit chunkier. Not super obvious unless you’re looking for it, but it bugs me more than I thought it would.
Step 3: If you go this route, measure everything twice. I mean *everything*. Height, width, depth, even how much play is in the old frame. The first sash I ordered was off by about a quarter inch and wouldn’t close right. Ended up shimming it, but now the lock doesn’t line up perfectly.
Energy savings-wise, I noticed less draft right away, but like you said, it’s not a miracle on the heating bill. Still, the house feels less “leaky,” especially when the wind picks up.
If you care about keeping that original look, you might want to refinish or repaint the trim after installing new sashes. Otherwise, be ready for a little mismatch. Personally, I’m calling it “character” and moving on... at least until I get around to painting.
Repair kits felt like putting a band-aid on a broken leg for me. Sash replacement was more satisfying, even if it’s not perfect. Just my two cents—hope that helps someone avoid my mistakes.
Repair kits felt like putting a band-aid on a broken leg for me. Sash replacement was more satisfying, even if it’s not perfect.
I get where you’re coming from, but honestly, I’d push back a bit on that. I’ve had mixed results with sash kits—sometimes they’re great, sometimes they’re just a headache—but I wouldn’t write off glass-only repair so fast. If the frame and hardware are solid (which isn’t always the case, granted), swapping out just the IGU can actually be pretty straightforward and way less intrusive. No messing with trim, no color mismatch, and you keep your original sightlines.
Had a couple of fogged units in my ’79 ranch, and after pricing out full sashes, I just ordered replacement glass panels. Local shop cut them to size, and popping them in wasn’t nearly as bad as I expected. Saved a few hundred bucks per window, too.
Matching the old trim is exactly why I hesitate on full sash kits unless the original wood is really shot. To each their own, but sometimes less is more if you want to keep things looking original—especially with older houses where every window seems to be a slightly different size anyway.
Matching the old trim is exactly why I hesitate on full sash kits unless the original wood is really shot.
I hear you on that. The trim is always the trickiest part—especially if you’ve got older casings or custom profiles. I’ve done both: full sash swaps and just IGU replacements. If the wood’s still solid, I’d rather keep the original frame and just swap the glass. Less mess, less risk of messing up the look. Only time I go full sash is when the rot’s too far gone or hardware’s toast. Otherwise, glass-only keeps it simple and usually cheaper.
Matching trim on old houses is always a rabbit hole. I ran into this exact headache last fall working on a 1920s bungalow—those chunky, detailed casings just aren’t something you can pull off the shelf at the box stores. I ended up going with IGU replacement for four windows because the sashes and frames were still structurally sound. The original wood had some dings and a bit of soft grain, but nothing that justified tearing everything out.
Where it got tricky was the stop moldings—some cracked when I removed them, and I had to mill a few new pieces to match. Still, it was way less intrusive than a full sash kit, and I didn’t have to mess with the plaster reveals or risk damaging that original trim detail. Honestly, if you’re even halfway handy with a chisel and a little patience, keeping the frame and just swapping glass is usually the best route for these old houses.
That said, I’ve gone full sash on another project where water infiltration had rotted out both the bottom rail and part of the jamb. At that point, patching would’ve been throwing good money after bad. But in my experience, unless there’s significant rot or alignment issues (think warped sashes or broken pulleys), IGU replacement is less disruptive and keeps costs down. Plus, you don’t end up in that endless hunt for matching trim profiles or dealing with paint lines that never quite disappear.
One thing to watch for: sometimes those old frames aren’t square anymore, so getting new IGUs to fit perfectly can take some measuring finesse—or even ordering slightly undersized units and packing them out. Not ideal, but still better than trying to replicate 100-year-old millwork.
All in all, unless there’s structural failure or major hardware issues, sticking with glass-only swaps has saved me a lot of headaches...and kept those original details intact.
Honestly, if you’re even halfway handy with a chisel and a little patience, keeping the frame and just swapping glass is usually the best route for these old houses.
Couldn’t agree more—trying to match old trim is a nightmare, especially when you’re dealing with those thick profiles and weird angles. I’ve seen folks spend weeks chasing down “close enough” molding and still end up with gaps or obvious patches. Unless the wood’s totally shot, just doing the IGU swap keeps everything looking right. Only time I’d push for full sash is when you’ve got serious rot or if the window won’t open/close at all. Otherwise, why mess with what’s working?
Unless the wood’s totally shot, just doing the IGU swap keeps everything looking right.
That’s been my experience too. I had a couple of sashes with fogged glass in my 1940s place—frames were still solid, just needed new IGUs. The trickiest part was getting the old glazing out without gouging the wood, but once that’s done, it’s pretty straightforward. I’d only bother with full replacement if you’re dealing with rot or major warping. Otherwise, keeping the original frames just looks better and saves a ton of hassle.
Yeah, I totally get wanting to keep the original frames if you can. I swapped out a couple IGUs last summer in my place—honestly, the hardest part for me was wrestling with the old glazing and trying not to swear every five minutes. My windows are from the late 50s, and the wood’s still in great shape, so it felt silly to rip everything out just because of some foggy glass.
If you’re handy with a putty knife and have a little patience, it’s not too bad. I did have one spot where I nicked the sash a bit, but a dab of wood filler fixed it up. The only thing I’d say is, check for hidden rot under the glazing—sometimes it sneaks up on you. If everything’s solid, swapping just the IGU saves a bunch of money and keeps that original look.
Full replacement feels like overkill unless your frames are really toast. Plus, matching old trim is weirdly hard... ask me how I know.
Full replacement feels like overkill unless your frames are really toast. Plus, matching old trim is weirdly hard... ask me how I know.
Yeah, replacing the whole window just for fogged panes is kinda nuts if your wood’s still solid. I’ve done a bunch of these IGU swaps—biggest pain is always getting that old glazing out without gouging the frame. Sometimes the putty fights back, y’know? But as long as there’s no rot hiding under there, it’s way cheaper and keeps the original vibe. Matching old trim is a lost cause half the time anyway... nothing ever lines up right.
Funny how the putty seems to have a personal vendetta sometimes. I had one window where it took longer to get the old glazing out than actually swapping the glass. But yeah, unless you’ve got drafts or rot, just swapping the IGU is way more efficient—and keeps your heating bill from going nuts. The only time I considered full replacement was when I found carpenter ants lurking under the sill... that’s a whole other headache.
That’s wild about the carpenter ants—I had a similar scare a few years back, except mine turned out to be termites. Never thought window repair could turn into a full-on pest control mission, but here we are.
On the IGU swap, I totally get what you mean about the putty. The last time I tried to salvage an old sash, it felt like the putty was welded in place. Ended up taking twice as long as I’d planned, and I was regretting not just ordering a new sash altogether. But you’re right, unless the frame is shot or there’s rot, just replacing the glass unit is usually all you need. Did you notice any difference in noise reduction after swapping yours? Mine seemed a bit quieter, but maybe that was wishful thinking.
Curious—did you try any of those defogging kits before going for the full IGU replacement? I’ve heard mixed things but never actually tried one myself.