The Best Window Insulating Material For Older Windows

The Best Window Insulating Material For Older Windows

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Sarah Rae Smith
Jan 14, 2011

A few months ago when we started talking about winterizing your home, there weren't many snowflakes on the ground and we definitely hadn't seen any sub-zero temperatures yet. But the world has since turned cold and all winter long we've been keeping toasty with what we consider to be one of the best insulation products on the market. Forget that plastic sheeting stuff—this is where it's at!

So what is this magical stuff? Well, think of it as silly putty for your windows (one that kind of looks like Twizzlers Pull-n-Peel). It comes on a large roll and you can pull it apart as needed to fit the spacing between your windows. It's called Rope Caulk, but in our experience with 7 major hardware stores, most employees won't know what it is. But it's quite popular as evidenced by the fact that it was sold out many places we went. It's not expensive (few bucks a roll) so we suggest buying more than you think you'll need as larger gaps will require the full thickness of the rope.

During the day we keep our heat around 62, so this thermometer sitting right next to a vintage single pane window should show you how well this stuff keeps the drafts out! Before the install we were averaging around 40 degrees or so near the windows at any given time and that... that was just too cold!

In our case we had a large gap to fill as the old crank windows wouldn't close completely. The top of each window was also letting in air, but we do have a few windows that don't open and we were able to use the putty rope along each frame to keep the cold air out. We used the candle trick for this. The rope caulk worked like a champ — plus, we can still see out our windows!

(Image: Sarah Rae Trover)

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