Trane GAT2A0B42 air filter size

Filter size20×20×1

The Trane GAT2A0B42 takes a 20×20×1 filter in its built-in filter rack.

Is this your unit?

The model number is on the label on the side of the unit or inside its front panel. It starts with GAT2A0B42. This page also covers GAT2A0B42S31SA. The same units are sold as American Standard.

Not sure? Take a photo of the label and we'll read it for you.

If your filter isn't in the unit

Many closets have the filter behind a grille on the door, wall or ceiling instead. That one is sized by the grille, not the unit. The size is printed on the filter's edge, or you can photograph it on our home page.

Size from Trane's product specifications. If it doesn't fit, our fit guarantee sends a new one free. Caliper isn't affiliated with or endorsed by Trane.