Choosing a Pet Door for Sliding Doors

Everything You Need to Know Before Installing a Pet Door in a Sliding Glass Door

Sliding doors are one of the most popular places to install a pet door. They provide direct access to the backyard, patio or entertaining area, making life easier for both pets and their owners.

However, choosing a pet door for sliding doors isn’t as simple as buying the first model you see online. The type of sliding door, the glass, your pet’s size and how you use the doorway all influence which solution is best.

Whether you’re considering a removable insert panel or a professionally installed in-glass pet door, this guide explains the options, the advantages and what to consider before making your decision.

Why Sliding Doors Need a Different Type of Pet Door

Unlike a solid timber door, a sliding door is made up of several components that all work together.

These include:

• Glass panels
• Aluminium frames
• Sliding tracks
• Locks
• Weather seals
• Rollers

A poorly chosen pet door can affect how the door slides, reduce security or leave gaps that allow draughts and water inside.

Additionally, when glass is involved, there is another important consideration.

Toughened safety glass cannot be cut once it has been manufactured.

Instead, the existing panel must usually be replaced with a new Grade A Toughened Safety Glass panel manufactured with the correct opening for the pet door.

This is why choosing the right installer is just as important as choosing the right pet door.

🐾 Pro Tip: Sliding doors need slim-profile pet doors. Bulky pet doors can stop the sliding panel from closing properly or interfere with locks and handles.

 

What Are Your Options For Sliding Doors?

There are two main ways to install a pet door for sliding doors.

Option 1 – Sliding Door Insert Panels

Insert panels fit into the opening of an existing sliding door and contain a built-in pet door.

Many people choose this option because:

• Installation is relatively quick
• No glass replacement is required
• It can be suitable for rental properties
• The original door remains largely unchanged
• Can be significantly cheaper than a more permanent solution
• Some inserts require drilling into the frame to prevent movement

However, there are compromises.

Because the insert sits inside the doorway, it reduces the opening width of the sliding door. That may not matter for some homes, but if it’s your main entrance, moving furniture, prams or entertaining guests can become less convenient.

Additionally laundry door openings tend to be smaller than in main living spaces. And trying to carry a washing basket through a narrow opening can be challenging.

Secondly some insert panels also require additional locking arrangements depending on the door design so can be a security issue.

 

Option 2 – An In-Glass Pet Door

An in-glass pet door offers the cleanest and most permanent solution.

Instead of fitting a separate panel, the existing glass is professionally measured and replaced with a brand-new glass panel manufactured specifically for the chosen pet door.

The result is a pet door that:

• Maintains the full width of the doorway
• Looks like part of the original door
• Provides a neater finish
• Is ideal for long-term homeowners
• Works beautifully in modern homes
• Does not require drilling into the frame to secure the door

Because every glass panel is custom manufactured, professional measuring is essential.

Installing a Pet Door into Glass Sliding Doors

Many homeowners are surprised to learn that glass cannot simply be cut after installation.

If your home has:

• Toughened safety glass
• Laminated glass
• Double glazing

the installation process will usually involve replacing the existing glass panel with a new one manufactured with the pet door opening already included.

Attempting to cut toughened safety glass after manufacture will cause it to shatter immediately.

That’s why professional glazing knowledge is essential.

For more information, read our guide:

👉 Single Glazed vs Double Glazed Pet Doors

🐾 Pro Tip: Installing a pet door into double glazing doesn’t necessarily reduce your insulation. A replacement insulated glass unit (IGU) maintains the same thermal performance as your existing glass.

Choosing the Right Size Pet Door

One of the biggest mistakes homeowners make is choosing a pet door that is too small.

Importantly your pet should be able to walk through comfortably without crouching or squeezing.

Measure your pet’s:

• Shoulder height
• Chest width

Then compare those measurements with the opening size—not the outside frame dimensions—of the pet door.

Additionally, if you have more than one pet, always size the pet door for the largest animal.

Planning for a growing puppy? Choose a size suitable for its expected adult height.

For help, see our guide:

👉 How to Measure Your Pet for a Pet Door

🐾 Pro Tip: Bigger isn’t always better. Choose the smallest pet door your largest pet can comfortably walk through to minimise draughts and preserve the strength of the installation.

 

Security Matters

A pet door should make life easier—not create a weak point in your home.

Quality pet doors include features such as:

• Secure locking mechanisms
• Weather seals
• Durable flap systems

Professional installers also ensure the sliding door continues to lock correctly after installation.

If your sliding door opens onto a high-traffic area or street frontage, ask your installer which pet door offers the best balance between convenience and security.

Weather Protection

Sliding doors often face outdoor entertaining areas where they are exposed to wind and rain. 

So a quality installation is essential. This includes:

• Correct positioning
• Quality weather seals when exposed directly to the weather
• Professional fitting
• Suitable silicone sealing where required

Importantly these details make a significant difference over the life of the installation to cater for all seasons.

🐾 Pro Tip: Homes exposed to coastal conditions or strong prevailing winds benefit from premium pet doors with better weather sealing and stronger flap construction.

 

Is an Insert Panel or In-Glass Pet Door Better?

The best solution depends on your home.

Neither option is right for everyone. 

Why Professional Installation Makes a Difference

Sliding doors require precise measuring.

Importantly, even a few millimetres can affect:

• Door alignment
• Lock operation
• Weather sealing
• Glass manufacture
• Overall appearance

Professional installers understand both glazing requirements and pet door installation, helping avoid costly mistakes.

At Pet Doors Ontime, we install pet doors into:

• Sliding glass doors
• Single glazed glass
• Double glazed glass
• Timber doors
• Security screen doors
• Crimsafe® compatible security doors*

*Subject to suitability and installation method.

Related Articles

Continue your research with these helpful guides from the Pet Doors Ontime Advice Centre:

• How to Measure Your Pet for the Perfect Pet Door
• Single Glazed vs Double Glazed Pet Doors
• Can You Put a Pet Door in a Security Screen?
• Can You Install a Pet Door in a Timber Door?
• The 5 Best Cat Flaps for Glass Doors

 

Need Help Choosing the Right Pet Door for Your Sliding Door?

Every sliding door is different. The type of glass, frame design, pet size and security requirements all influence the best installation method.

At Pet Doors Ontime, we help homeowners choose the right solution every day. Whether you’re installing a pet door into a sliding glass door, replacing a double-glazed panel or looking for advice on the best product, our experienced team can guide you through the process from measure to installation.

Get an instant online quote today or contact our team for expert advice on the best pet door for your home.

Frequently Asked Questions