I need to find a cold air return grill size 31 1/2 by 10 do you know where I can find one that size in southern California preferably near Anaheim?
Thanks you.
Christina

That sounds like it could be a special size. Any heating supply house or HVAC company will try to find one that fits. If not available get the next size up and spray paint the wall area that will be exposed under the grill. That way no one will see it is the wrong size. NOTE use flat black paint.