Does the current HVAC filter fit snugly?

Choose the answer that matches what you can see.

Help with this question

Look for the filter beside the furnace or indoor air handler, or at a large return-air grille on a wall or ceiling.
The location depends on your installation.
Once you find it, check whether it fits snugly.
If it is loose or does not fit, its size is not a reliable replacement guide.
Choose Not sure if you cannot find or check it.