How to upgrade the windows in your co-op, condo, or brownstone

A major renovation is always a good opportunity for New York City homeowners to replace or upgrade their windows, particularly if they are drafty and performing poorly, which is not uncommon in aging NYC buildings. This is because changing your windows can make a world of difference in terms of acoustics, heat and cooling efficiency, and aesthetics.

“Basic performance issues can sometimes be addressed by re-caulking the frames or re-glazing the glass panes,” says Paul Capece, an architect with Bolster. “However, sometimes the windows aren’t installed properly in the first place, are of poor quality, or simply don’t meet the homeowner’s aesthetic or functional requirements.”

Homeowners might also be motivated by a desire to change the style of the window—from a double-hung to casement window, for instance, or vice versa—or they may want to upgrade the look of the window with new, superior products. In these cases, replacing or upgrading the windows is the best option.

Making changes to your windows, though, can entail some complications, particularly if you live in a landmarked building or historic district. And even if you don’t, you may need to go through an approval process with your building’s board.

The work itself is also fairly specialized, and there is a limited number of people who know how to replace windows in accordance with city guidelines and are familiar with all the materials involved.

“Having a team of experts on your side is essential to taking the guesswork out of complex projects like window updates,” says Bolster Founder and CEO Fraser Patterson. “We carefully vet each professional we work with so that NYC homeowners who hire us can rest assured their projects will be delivered on time and on budget.”

Here’s what you need to consider when replacing your windows in NYC.


Replacing windows in landmark properties

If you own a landmark apartment or house, or live in a historic district, you’ll need approval from the Landmarks Preservation Commission before you make any changes to your windows, to ensure that your renovation plans won’t interfere with the historic character of your home.

Note that for any project on landmarks that requires permits from the Department of Buildings—as most major renovations do—you will also need to go through the LPC.

“The LPC’s prime directive is to keep the historical profiles of buildings,” says Bolster’s Lead Project Manager, Chris Amplo. “They’ll want to see drawings of what you’re proposing, and know about the color, glass, and frames of your replacement windows.”

The LPC has jurisdiction over the appearance of windows of landmarked properties (as it does with other exterior features of these buildings), and will expect homeowners to maintain the glass-to-frame proportions of their windows. Depending on the building, the LPC might also require specific materials be used for the frame, and for decorative molding to be preserved.

“If you’re in an ornamental Art Deco building with elaborate molding profiles, the LPC often requires that to be replicated, and there’s a significant expense goes along with doing that kind of work,” Paul says.

The LPC could also require that you use specific materials—for example, wood rather than aluminum frames—on your replacement windows, though this varies on a case by case basis, depending on your building and district. The LPC’s website notes that the commission does take into account the needs of today’s homeowners.

“The LPC cares about materials, but not on every building,” Paul says. “They might give you the latitude to use aluminum windows since they are typically the best-performing.” 

That said, landmark property owners should anticipate additional expenses in replacing their windows. Some landmark buildings, for instance, have curved glass windows with wooden frames, which Chris says are the most expensive type in the city, starting at $10,000 to replace. For the more straightforward window, expect to pay up to $3,000 per unit.


Non-landmark properties

For non-landmark buildings, the process of replacing windows tends to be less complex, though there are still plenty of decisions homeowners need to make regarding products.

“If you own a townhouse, for instance, it’s very straightforward,” Paul says. “You just need to meet the energy code and follow standard practices that include proper installation.”

Co-ops, on the other hand, are likely to impose some limitations on shareholders. Many co-op boards have agreements with specific companies, and homeowners who are replacing their windows may be obligated to work with their preferred installers.

“They don’t want every unit in the co-op to replace windows over time with different companies, so that from the outside there’s a mishmash of styles,” Paul explains. “That does happen sometimes, and it usually does lead to an unsightly situation.”

Even if your building does not have preferred installers, your board can withhold approval of your plans if your proposed windows could create a mismatched façade or fail to adhere to other building guidelines. To avoid delays because of complications with approvals, it’s crucial to hire contractors who are well-acquainted with the process.

“It’s really a specialty business,” Chris says. “You need a contractor who has a good relationship with manufacturers and knows how to navigate the approval process.”  

You should also consider which products are appropriate for your particular situation, if you aren’t facing strict restrictions. At the high end, Chris says, many homeowners prefer the aesthetics of wood windows, which can cost between $2,200 and $2,600 per unit. Aluminum, on the other hand, is cheaper, with high-quality products available at about $1,500 per unit.

“The right product for you is important to consider. Think of your timetable—if you won’t be in the property for a long time, maybe you don’t need the most expensive product,” Chris advises.


Major renovations versus standalone window replacements 

If you’re upgrading your windows as a standalone project, you’ll likely want the work to be minimally disruptive to your life in the apartment. Many companies make replacement windows, Paul says, that can be installed without removing your window’s casings and other exterior components, a simpler process that can save you time and money.

However, there are some downsides to this type of work.

“The window function, material, and style options are typically more limited with replacement windows,” Paul says.

Furthermore, he adds, the frames for replacement windows are often thicker than window units designed for new construction, which can shrink the amount of glass in your window, and therefore reduce the natural light entering your apartment. For landmark property owners, these types of windows may not be an option, as they may not match the original style of the windows.

Homeowners who are replacing windows as one aspect of a larger renovation may opt instead to have the windows’ casings removed, which allows for more freedom in selecting materials. The best practice in these cases is to select windows designed for new constructions, Paul notes.

“With these windows, you can have any function, any operation, and many material choices,” he says.

Paul adds that removing the window casings makes it easier to install a new window with a better seal, which in turn means improved insulation and more natural light.

“You end up with a tighter, better performing, more beautiful window,” he says.

“At the end of the day, it’s about understanding the homeowner’s scope, budget, and vision–and ensuring we’re choosing the best materials that fit within the parameters of their building’s codes and regulations,” says Fraser.

About Us

Bolster is a data-driven team of experts on a mission to eliminate risk from major home renovations by being radically transparent across everything we do. We hire the industry’s best talent and use a continual improvement process to financially guarantee that your major home renovation is designed and built beautifully, on-time and on-budget. From the first sketch to the final handshake, our homeowners know the cost of every line item and have full visibility into project milestones.