We live in a 100-year-old apartment building whose exterior envelope hasn't been upgraded, so thermal comfort isn't one of the building's strong points. Heat is delivered through giant clanking radiators that are oversized for the rooms, so most of the winter we need to crack open a window in order to get the temperature down to something comfortable.
Except in the Master Bedroom. Where. We. Are. FREEZING. All winter long. For the past 12 years. So this is the year that I'm systematically reviewing the perimeter of our master bedroom to try to figure out how to warm things up a bit. What better place to start than the windows, where our lower sash seemed to be slightly out of alignment, causing a gap between the sash and the window frame, and resulting in a noticeable draft along the side of the lower sash.
I called my friend Bob Murray, Regional Sales Manager at Super Enterprises - distributor of Marvin Window & Door Products on Long Island - and asked for his advice. He set up an appointment for his colleague Ron, Super Enterprises' Field Manager, to come and take a look. Here's what I learned during our window checkup...
Our windows were manufactured and installed in 2003. They are Marvin MTO clad ultimate double hung (CUDH) windows, Marvin's most popular window. They are generally in good condition. However, while the windows are double-pane with insulating glass, they do not have a "low-e" coating - an optional feature that improves the insulating value of a window while also reducing the amount of the sun's heat that is admitted into the room. The insulating property of a window is expressed by its U-factor - and the lower the number, the better it insulates. But Ron says that the higher U-factor of our clear glass (absent the low-e coating) windows isn't the main reason why we're chilly in the winter in our master bedroom. He did, however, find - and fix! - a number of other issues with our windows.
One of the great features of these windows, which is particularly helpful in a sooty urban environment, is the ability to tilt the sashes into the room to clean them. We clean our windows two or three times each year. But it turns out that we haven't been careful enough when using the tilt mechanism to clean the windows - so we created two problems that Ron and his colleague, Emil, were able to repair.
First, because we hadn't lifted the lower sash up enough before tilting it in for cleaning, we managed to disengage the lower sash from its clutch...a part of the balance tube mechanism that sits on the side of the frame and enables the sash to go up and down. Ron felt that, after re-seating the window sash into its clutch, the sash was sitting a little straighter - which could help with the draftiness of the window.
Another result of our tilting the window in the wrong position during cleaning was a bent pivot pin on the side of the sash. The pivot pin enables the sash to tilt and engages the mechanisms on the side of the window so the window can go up and down. Ron changed out the pivot pins on the master bedroom windows and several others that were also damaged.
Bent pivot pin on the side of the window sash...
...replaced with a new - straight - pivot pin.
With the windows open, Ron pointed out another window maintenance issue that we needed to address. Our outside sill had accumulated a fine layer of soot, which is not uncommon in Manhattan. Ron recommends cleaning the exterior sills regularly (four times/year) to prevent the soot from getting into the working mechanics of the window. After cleaning the sill, he sprayed a little bit of silicone onto a rag and cleaned all of "the vinyls" on the windows - the weatherstripping, the outer ledge, and the channels inside the window. Seasonally lubricating and cleaning the windows is imperative in urban and coastal environments.
Soot on the exterior sill of the window...
...clean sill and window channels keeps the window operating smoothly.
As for the cold air leaking through the side of the windows? Ron examined our window's weatherstripping to see if a repair was needed. The weatherstripping was in excellent condition. But, he had one more "trick" to address the draft. He pulled the frame weatherstrip out of its channel ever so slightly, so more surface area would make contact with the sash.
I was hopeful that all I needed was a window tune-up to fix the thermal discomfort problem in our master bedroom. But Ron correctly pointed out that our master bedroom is on the corner of our building, where there are three exterior walls. And the architect who designed our original renovation had replaced the room's large radiator with a slim one, which is probably undersized for the space. I'll address these issues in subsequent posts...but for now - thanks to Super Enterprises - our windows are in great working condition, we know how to maintain them, and we're hopeful that when the really cold weather comes, we will have eliminated the draft alongside the window sash.