Window Dog Door Installation

Professional Pet Door Installation for Sash and Side Sliding Windows

Portal Pros installs pet doors into sash and side sliding windows — no cutting, no permanent modifications, removable at any time

Option 1

Sash Window Insert

For double hung and single hung windows that slide up and down.

• Insert sits horizontally in the sash channel
• Spring loaded end adjusts to window width
• Pet door on the left or right side
• 9 width ranges, 23" to 52.25"

See sash install details

OR

Option 2

Side Sliding Window Insert

For windows that slide left and right along a horizontal track.

• Insert sits vertically in the window track
• Spring loaded top adjusts to window height
• 4 pet sizes, up to XL for large breeds
• 6 height ranges, 30" to 73.5"

See side sliding install details

Not sure which one you need? The appropriateness guide below breaks it down, or call 855 DOG DOOR and we will tell you in about a minute.

Before You Begin

Window pet door inserts are the most renter friendly and damage free way to give your pet outdoor access. There is no sawzall, no drilling, and no hole in the wall to patch when you move. The entire assembly compresses under spring tension into your existing window opening, then expands to lock in place, and it comes right back out the same way.

Three things to sort out before you order: which window type you have, whether your window track is compatible, and the size range that matches your opening.

📋 Things to Consider

• Window Direction: Sash windows slide up and down. Side sliding windows slide left and right. These are two different products and are not interchangeable.
• Pet Size: The sash insert comes in Small (7"w x 11"h opening) and Medium (10.5"w x 15"h). The side sliding insert covers four sizes from Small to Extra Large (up to 15"w x 23"h) for large breed dogs.
• Window Size: The sash insert covers window widths from 23" to 52.25" across 9 ranges. The side sliding insert covers window heights from 30" to 73.5" across 6 ranges. Snap on 2 inch extensions add reach to either.
• Track Compatibility: Both inserts require specific channel dimensions. We cover the numbers below.
• Location: Basement windows, catio connection windows, and cat only side windows are common installs. Send us a photo and we will confirm compatibility.
• Renters: Zero cutting, zero drilling, fully removable. Confirm with your landlord if your lease has specific language on window modifications.

Compatibility Check Before You Order

Both inserts need specific channel and track dimensions to seat properly. Take these three measurements before you order.

For double hung and single hung sash windows

Purpose built for windows that slide up and down The SB Standard Sash Lockable Window Insert from Security Boss is a tempered safety glass panel in a heavy duty aluminum frame with a pet door built into the base on the left or right side. The lower sash is raised, the insert compresses under spring tension, and it locks into the sash channel without a single screw driven into your window. Starting at $298.31 with free shipping. Shop the SB Standard Sash Insert →

Key Features

Pet Opening Sizes

Window Width Ranges

Measure inside the sash channel from left to right, into the deepest part of the channel. Match your measurement to one of these nine ranges at the time of order.

Beyond 52.25"? Snap on 2" extensions add reach without tools. Multiple extensions stack.

Sash Insert Installation Process

1. Raise the lower sash. Open the window to the height needed to seat the insert.
2. Position the insert. With the pet door on the side you chose at order, set the insert into the sash channel horizontally.
3. Compress the spring end. Push the spring loaded end against the far side of the channel until the insert seats fully.
4. Lock the tension knobs. Both locking knobs on the spring end must be tightened. This is what prevents the insert from being compressed from outside.
5. Lower the sash onto the top of the insert. The sash rests on the insert to complete the seal.
6. Install the brace bar. The extendable brace bar immobilizes the sash so it cannot be raised from outside.
7. Test the flap and the lockdown panel. Confirm the pet flap swings freely and the security panel slides in and out cleanly.

For windows that slide horizontally

Purpose built for horizontal sliding windows The SB Standard Side Sliding Window Insert uses the same tempered glass and aluminum frame construction as the sash model, rotated for a horizontal slider. The spring loaded top adjusts to your window's track height across six ranges, and 2" snap on extensions extend the range without any tools or drilling. Available in four pet sizes including large and extra large for big dogs. Choose your rise (2", 4", 6", or 8") to raise the pet opening to your pet's shoulder height. Shop the SB Standard Side Sliding Insert →

Key Features

Pet Opening Sizes and Panel Widths

The panel width is the horizontal space the insert takes up when installed. Add this to your window opening math to make sure you have room to open the sliding sash far enough.

Large and Extra Large sizes are not available in Range 1 (30" – 37.25"). The panel would be too tall relative to the window.

Window Height Ranges

Measure from the very bottom inside track to the very top inside track of your open sliding window. Match your measurement to one of the six ranges below.

Windows taller than 73.5"? Snap on 2" extensions add reach beyond Range 6. Two extensions bring the total range to 7.25". Extensions stack indefinitely.

Track Compatibility Check

Before you order the side sliding insert, verify your window track dimensions:

• Bottom rail width: The bottom of the insert has a 5/16" wide base with a semi circle C channel that straddles the center rail on the floor track. If your center rail is wider than 5/16", this insert will not straddle it and will not fit. Standard residential windows are almost always narrower than this.
• Bottom channel depth: The channel that your sliding sash follows must be at least 1" wide to accept the insert.
• Top track: The spring loaded top of the insert is 11/16" wide and fits into most any residential sliding window top channel. If your top track has a center rail, the insert can straddle rails up to 9/16" wide.

Choosing Your Rise

The rise is the distance from the bottom of the insert to the bottom of the pet door opening. It raises the opening off the floor so it aligns with your pet's shoulder height. Available in 2", 4", 6", and 8".

Rule of thumb: the top of the pet opening should be 1.5 to 2 inches higher than your tallest pet's shoulders. Measure floor to shoulder, subtract the pet opening height, and choose the rise that gets you there.

Example: A 22" tall pet needs the top of the opening at 24". If you have chosen the Medium 10.5" x 15" opening, that puts the bottom of the opening at 9" off the floor, so you need a 9" rise. Since rise comes in 2" increments, order 8" and shim slightly, or 6" and add step over blocks. Call us for edge cases.

Side Sliding Insert Installation Process

1. Slide the window open to the position that gives clearance for the insert panel width plus a small margin.
2. Position the insert vertically in the track with the pet door at the bottom. Seat the bottom C channel over the center rail of the floor track.
3. Compress the spring loaded top until the insert seats fully into the upper track. The top floats on tension rods within a 3.25" adjustment range.
4. Lock down the top with the two thumbscrews. These are accessible from inside only. This is what prevents someone from compressing the top and removing the insert from outside.
5. Snap on 2" extensions if your window is taller than the range you chose. Extensions lock in with no tools. Add as many as needed.
6. Install the extendable brace bar between the closed sliding sash and the window frame. This immobilizes the sash so it cannot be forced open along its track.
7. Apply the 3" vinyl weather stripping to the back side of your sliding sash. This seals the gap that opens between the sliding panel and the fixed panel when the insert is in place.
8. Test everything. The flap should swing freely, the lockdown panel should slide cleanly, and the insert should sit tight with no rattle.

Advanced: Stationary Panel Mounting

On some sliding windows, the insert can also mount on the stationary side. Many windows have stoppers that prevent the stationary panel from moving. If those stoppers can be removed, the stationary panel can be repositioned to accommodate the insert.

This technique will not work on windows where the stationary panel is molded into the frame. Send us a photo and we will tell you which side to mount on.

💡 Measuring Tips

• Sash windows: Measure the interior width of the sash channel from left to right. Get the tape all the way into the deepest part of the channel on both sides.
• Side sliding windows: Measure the interior height of the open window track. Held vertically, floor of the track to the top.
• Photograph the channel: A photo of your tape measure held in place is faster to review than a written measurement. Send both if you can.
• Measure your pet: Shoulder height plus 1.5 to 2 inches for the pet opening. Widest point of the body plus at least 2 inches.
• Note the pet door side (sash only): For sash inserts, decide whether the pet door should be on the left or right as viewed from inside. Consider approach direction, furniture, and any interior wall obstructions.
• Choose your rise (side sliding only): Measure floor to your pet's shoulders and work backward to pick the rise that puts the top of the opening 1.5 to 2 inches above.

⚠️ Common Mistakes to Avoid

• Skipping the tension lock: Both locking knobs on the sash spring end (or both thumbscrews on the side sliding top) must be tightened. Without them the insert can be compressed from outside.
• Skipping the brace bar: The insert holds itself in the channel, but the brace bar is what keeps the open sash from being moved. Both matter.
• Wrong size range: Each range covers 3.25" of adjustment. Ordering the wrong band means the insert rattles or will not seat.
• Measuring at the edge of a range: If your measurement falls within 1/2" of the bottom of a range, call us first. We can build a small alteration into the unit for a tight fit.
• Ordering the wrong pet door side: Left or right on the sash insert is set at order and is not field changeable. Confirm before you buy.
• Missing the rise calculation: On the side sliding insert, ordering without a rise (or too small a rise) can put the pet opening too low. Do the math before you order.
• Ignoring the track compatibility check: The 5/16" center rail limit and 1" channel minimum are real. Skipping this check leads to returns.
• Assuming any window works: Casement, awning, jalousie, and fixed windows are not compatible. Send a photo if you are unsure.

Why Choose Portal Pros for Window Pet Door Installation?

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