However before deciding to tackle the how to install replacement windows job yourself check the condition of your existing window frames.
Insert windows for existing vinyl windows.
Next measure the width at the top middle and bottom.
The extrusions of the vinyl windows would not allow that.
Push them into the opening inside your existing windows to create an insulating pocket of air.
This is a much bigger and more complicated job than installing a vinyl window insert and may require a pro.
An insert window is a great option when you re happy with the size shape and operating style of your existing window.
More advanced project because you have to remove interior and exterior trims and sometimes the siding.
Sliding windows slide open horizontally saving space while offering a clean modern design.
One solution that has been around for a while is the window insert an acrylic window that fits inside your existing windows often held in place with snap.
Necessary when existing window frames are old and deteriorating.
Keep the cold air out in the winter.
If you need to stick to a tight budget you may want to look into vinyl windows.
Replace the entire existing window down to the house frame.
Just to get it out there you could use them but only after you remove the vinyl window completely and install them like it was new construction.
You have two choices for vinyl replacement windows.
If they re rotten or badly out of square the whole unit including the frame may need replacing.
Your question if you can use replacement windows would be no.
Fix it with a replacement window to seamlessly match the existing windows in your home.
To do it that way would be a little counterproductive.
Add skylights to let in additional daylight.
Insert windows preserve the original frame exterior trim exterior siding and interior casing.
The window insert to the rescue.
Write down the measurements and use the smallest measurements for width and height to buy your new window.
Even relatively new vinyl windows less than ten years old can suffer from seal failures and degradation from exposure to weather and may need to be replaced.
Full frame windows and insert windows.
Energysavr window inserts are effective interior window insulation panels.