The middle of December I had Lindstrom install a new HVAC in my home. I had asked for a standard sized return so I could get replacement filters anywhere. They installed a 20x24 return. I have yet to find a single 20x24 filter in any Home Depot or Lowes. In addition, the year's supply of filters they provided are all 20x25 (which is a size they do sell in all the stores). When I inquired I was told 20x25 was not a standard size and they would have to order it. It is now 2/17 and they are scheduled to come out next Friday to install the new return. We'll see. read full review »