Excerpt: We recently swapped out the Aer1 Filter Replacement for Holmes Air Purifiers (HAPF30AT) and were intrigued by the combo of 2 True HEPA filters plus 4 carbon booster filters. What surprised us was just how much cleaner the air felt—the HEPA trapped microscopic particles, while the carbon lent a refreshing freshness even days after changing them. Maintenance was effortless, with the filters sliding in smoothly and the purifier’s pull-chain operation remaining intuitive. Our only mild reservation? The slight hum when running at higher speeds, though it proved faint in our room. All things considered, the cleaner air and ease of use made ours a worthwhile upgrade, defying our initial hesitations about such a multi-filter setup.