Replacing Windows: DIY or Hire a Pro?

replacement window how to

If you just purchased a fixer-upper, you may be asking yourself one simple question: “Can I do some of this work myself?” Determining what is, and what isn’t, a good DIY project is usually the first order of business for a new homeowner.

Only consider replacing old wooden windows if you’re a skilled carpenter. The removal alone can be dangerous. The glass is almost never tempered or safety glass and can break into very dangerous shards.

If the line item you’re pondering at the moment is “new windows,” this is written for you!

Windows Are Not Created Equal

Size (standard or not), material (wood, vinyl, aluminum, steel) and the general condition of the existing windows and openings will help you determine if the project is something you can tackle on your own or contract out.

First step: Determine the type of framing material used to construction your current windows.

Handcrafted Wooden Windows

A historic home may come with some of its original wooden windows. You can expect wooden windows in houses that are more than 60 years old, generally pre-1950. An original early wooden window may be painted shut, or it may still work. Either way, replacing these bad boys is a chore you won’t soon forget.

Find Your Home on

Only consider replacing old wooden windows if you’re a skilled carpenter. The removal alone can be dangerous. The glass is almost never tempered or safety glass and can break into very dangerous shards. The window was often put together on-site, and much of the perimeter frame is often part of the window itself. Preparing the wall opening for replacement windows usually involves framing work, interior and exterior finish work and the window installation itself.

Factory Made Wooden Windows

Just because a window is made of wood doesn’t mean its historic and handcrafted on-site. If your wooden windows are factory made, you’re in luck. Manufactured wooden windows are much easier to remove, as they usually pop right out.

To remove windows, simply remove the screws and trim that holds them in place. For ease of installation, be sure to purchase replacement windows in the exact same size as originals. To install, pop new windows in place and fasten them securely and squarely.

Replacing factory made wooden windows is a moderately easy project that a skilled DIYer could tackle.

Aluminum Windows

Aluminum windows are “usually” the easiest to remove. Simply unscrew the window, clear away trim, caulking, stucco, etc. on the exterior flange and pull the window out. Sometimes this is easier said than done. Caulking is crazy sticky strong, so be sure the window is cut completely free from all interior and exterior surfaces.

Here again, appropriately sized replacement windows will save you a lot of headaches when it comes to installation.

Replacement of aluminum windows is a good DIY project in terms of skills required. Whether or not it makes financial sense is another question (read on).

DIY Window Replacement: Common Problems

Misfits: The most infuriating problem bar none? Replacement windows are almost NEVER exactly the right size. If the replacement window is too small, the opening has to be filled in. If the replacement window is too big … sheesh … you don’t want to know.

Removal: “Those old windows came out so smoothly and easily! It took half the time I had expected!” said no one, ever. Usually removal of existing windows is a mess. Exterior finishes get all messed up. If you’ve got a stucco house, the windows are often stuccoed in place and can’t be removed without chipping away the stucco around the edge. That’s no fun. Interior damage to drywall and window sills is also very common, so be prepared for some patchwork.

Fastening Points: Older building codes often allowed for windows to be fairly loosely installed. It isn’t uncommon to find old windows held in place by four screws or less. Newer building codes and newer windows generally require substantially more attachments, sometimes four screws or more per side! You may face a problem if you’re trying to attach windows to something flimsy, like a block wall with hollow core cells on the sides or a framed opening that was somewhat haphazardly built the first time around.

Expense: While it is kind of obvious, people often forget to ask themselves if they will actually save any money by installing windows themselves.

Even on the easy jobs such as straight-up aluminum window replacement, the answer isn’t always a clear “yes.” That’s because window replacement contractors often purchase the windows for so much less than you can. A window that retails for $200 might cost a contractor half that much. Windows plus installation may amount to about as much as the cost of windows alone.

If you’re considering replacing your windows, it’s probably worth your time to get a couple of estimates. You’ll get some solid professional feedback on your specific situation and might be surprised by what you find.

Is window replacement a good DIY project? At the end of the day, it’s a solid yes, no, maybe …