Finding the right balance with insulation in older homes is a real art form. I’ve run into this exact issue on a few of my projects—especially with properties built pre-1940s. There’s this temptation to chase every eco label and max out efficiency, but sometimes it backfires.
You nailed it here:
Over-insulating can mess with moisture balance—seen plaster walls get moldy after folks went overboard.
I once bought a Victorian that had been “upgraded” by the previous owner with spray foam everywhere. Looked great on paper, but within a year, we started seeing bubbling paint and that musty smell creeping in. Turns out, the original plaster and lath needed to breathe, and sealing everything up tight just trapped moisture behind the walls. Ended up having to rip out sections and install a proper vapor barrier plus some discreet venting. Not cheap.
It’s funny how the green building world sometimes pushes for one-size-fits-all solutions, when these old places really need more nuance. I’ve found that sometimes less is more—like using mineral wool instead of foam, or leaving certain crawl spaces semi-vented rather than sealed up like a submarine.
Eco labels are great for new builds, but with historic properties, I always try to respect what’s already there. Sometimes you have to accept a little draftiness if it means preserving the structure (and avoiding mold headaches). It’s not always about chasing the highest R-value or ticking every box on an energy audit.
Honestly, half the battle is just knowing when to stop adding things. The best results I’ve seen come from combining modest upgrades with regular maintenance—think storm windows, targeted air sealing, and keeping gutters clear so water doesn’t sneak in where it shouldn’t.
Chasing certifications can be rewarding, but I’d rather have a healthy house than a plaque on the wall...
Had a similar thing happen with a 1920s bungalow—client wanted to go all-in on insulation, but after we sealed everything up, the basement started sweating like crazy. Ended up having to backtrack and add some vents. Sometimes those old houses just need to breathe a bit. I get the appeal of eco labels, but they don’t always fit these quirky old places. A little common sense goes a long way.
Funny, I ran into something similar with a 1915 duplex. Tried to chase every green certification, but after tightening up the envelope, we got condensation in places I didn’t even know could sweat. Sometimes chasing the eco label just doesn’t line up with how these old houses were built. I’ve found it’s a balancing act—improve efficiency, but don’t fight the original design too much or you’ll just create new headaches.
That’s been my experience too—old houses just don’t behave like new builds, no matter how much insulation or fancy windows you throw at them. I’ve learned the hard way that sometimes a little draft is actually part of the original “ventilation system.” It’s tricky, but you’re not alone in that balancing act.
Yeah, I’ve run into the same thing—old houses are just a different beast. Here’s what I’ve noticed:
- You can throw all the eco-label stuff at an old place, but sometimes you’re just fighting the original design. Those “drafts” are basically built-in air flow.
- Tried sealing up every gap once and ended up with condensation on the windows and a musty smell. Not worth it.
- Some of those eco products don’t even fit right in older frames or walls. Had to return a few “universal” window kits that were anything but.
Curious if you’ve found any eco-labeled products that actually work well with older homes? I feel like most of them are made for new builds, not 1920s bungalows with weird quirks.
