Here are the key points to consider in purchasing a patio pet panel:

1. Measure the height of your sliding glass door track-  Don't just assume that 'it's standard' as they do vary. Using a ruler, measure inside the track, very top to very bottom (see the illustration in the 'Patio Panel FAQ' section). Always compare your track height to the adjustment ranges shown for the various pet doors. Some manufacturers offer custom heights for the occasional odd size. Others don't.

2. Determine how wide the flap needs to be- Open your sliding glass door wide enough for your pet to come through comfortably. Allow room for growth as needed.  There's your minimum width. Don't buy a flap that isn't at least that wide.

3. Determine the flap height and 'rise' dimensions you need-  Ideally, the top of the flap will be at least as tall as the top of the pet at his 'withers' (top of his shoulders). That way he doesn't have to crouch to use the pet door. The 'rise' dimension is the height of the bottom of the flap above the base of the pet door.  That's how much he has to step over.

So, flap height plus rise is the height of the top of the flap.

Generally, the lower the rise the better. Especially when your pet is older or arthritic, less to step over is better. So you might prefer a flap 17" tall with a 3" rise to one with a 15" height and 5" rise. Both reach 20" at the top, but the taller flap yields a lower rise.

More flap and less rise can also be helpful if you've got a small pet that needs to share with a larger one.

A pet door that incorporates a 'User Adjustable Rise' makes it simpler and offers more flexibility for the future.

4. Check the color of your framing- Most brands are available in white, satin (aluminum color) or bronze (very dark brown). You can paint any of these to get a different color if you wish but the easiest to paint is the white. Check with your local paint shop for primer and paint recommendations.

5. See if you have dual-pane glass- You probably do and, unless you're in a Very temperate climate area, you'll want to choose a pet door that has dual-pane glass also. You can tell by placing a finger on both sides of your glass. If they look like they're touching, you have single pane. If they stop about ¹/₂" apart, you have dual pane.

6. If you want dual-pane glass, how about Low "e" also?  It performs much better than regular glass in insulating your home.

7. See if you've got vinyl frames- There is more standardization in the newer vinyl framed panel doors. We suggest the Ideal VIP Patio Panel for vinyl frame applications.