Holmes is one of the older players in the air purification game. They have a large lineup of older units from the ’90s, 2000s, and early 2010s. They don't update their designs very often, mainly because of there, “If it ain't broke don't fix it attitude”. Some of the newer style purifiers have been updated to a minimalistic, black, compact tower build with updated features. Some of the most popular units are the Hapf600 series, Hap625, Hapf222 series, and HAPF30 / HAPF30AT series purifiers. Most of their units include an auto-shutdown timer, multiple fan speeds, filter change indicator lights, and sleep modes. They come in multiple sizes ranging from large room purifiers down to desktop size purifiers. Holmes purifiers get the job done for a reasonable price, however, like most OEM manufacturers the replacement filters leave more to be desired. This mainly is due to the overhead that Holmes has to bake into their prices to stay profitable. Thankfully for the average consumer, Breathe Naturally doesn’t have this overhead cost and can offer the same or in most cases, better quality filters without the expensive price tag. Breathe Naturally MERV 17 HEPA filters stop harmful airborne particles down to 0.03 microns small at a 99.97% efficiency level. Capture mold spores, dust, dander, pollen, bacteria, virus carriers, and tons more airborne particles, leaving the air you breathe clean and healthy. Our filters are perfect for those with seasonal allergies, sensitive respiratory systems, and people who just want to Breathe Naturally. Breathe Naturally carbon filters are made from Bamboo carbon and are proudly made here in the USA, supporting American companies and jobs. We take pride in our specially designed carbon filters that are made to be thicker, last longer, and capture more odors and particles that ultimately lead to a longer lifespan on your HEPA filters saving you money and leading to less waste. We recommend changing HEPA filters based on use, usually every 4-6 months for normal use, and every 1-2 months per carbon filter, again with normal use. Those who put extra strain on the air in their homes, such as larger families, people with pets, and people who live in larger cities may want to change their filters more often. Most modern air purifiers come with a filter change indicator light that will let you know pretty accurately when you're due for a change. When changing your filters, dispose of dirty filters in the garbage. Reset filter indicator lights, and enable child lock if needed and available. Breathe Naturally firmly stands behind their filters and trusts them in their homes and the homes of their loved ones. We offer a 30-day money-back guarantee on all purchases. Satisfaction guaranteed or your money back. Our carbon filters are proudly made in the USA. All filters ship from Minnesota, a family-owned and operated company. Do not place the air purifier too close to your head, and refrain from having the air blow directly towards you. If you have any questions about Holmes air purifiers and replacement filters or any other questions please don't hesitate to drop us an email or give us a call. All of our contact information can be found in the About Us/Contact us section of the website.