Your Air Purifier — A Plain-English Guide

1 Picking the right size for your room

1. Look for the CADR rating on the box (Clean Air Delivery Rate). Higher number = bigger room covered.
2. Rough rule: CADR rating should be at least 2/3 the square footage of your room. So a 300 sq ft bedroom needs a CADR of about 200.
3. Most mid-size purifiers cover 200-400 sq ft well. Tower-style units cover 500-1,000+ sq ft.
4. If you're buying for the whole house, you typically need ONE in the main living area plus a smaller one in the bedroom — not one big unit trying to do everything.

2 Where to place the purifier

1. NOT in a corner. Air can't circulate around it. You'll filter the same square foot of air all day.
2. Middle of the room is best. Failing that, against a wall with 2 feet of clearance on each side.
3. Don't put it behind furniture — couches, dressers, bookshelves all block airflow.
4. For bedroom use, place it 3-5 feet from the bed (not at your head — the fan noise will wake you).

3 When the air-quality light goes red

1. Most modern purifiers have a built-in air-quality sensor (green = clean, yellow = OK, red = bad). Red means the sensor is detecting particles, smoke, or VOCs.
2. First: close all windows and doors. Outdoor air may be worse than indoor — this is true on smoke days, high-pollen days, and during nearby paving/painting.
3. Set the purifier to MAX or Turbo until it goes back to green. May take 30-90 minutes.
4. If it stays red after an hour with windows closed, look for the source: candles, cooking smoke, cleaning chemicals, a leaky garage door, or the bathroom from a recent paint job.

4 Filter replacement — when and what

1. Pre-filter (the foam mesh on the outside): vacuum or rinse monthly. Reusable.
2. True HEPA filter (the main one): replace every 6-12 months. Most apps remind you; if yours doesn't, mark a calendar.
3. Carbon filter (for odors): replace every 3-6 months. Some models combine HEPA + carbon into one.
4. Buy genuine filters from the manufacturer's website or Amazon (sold by the manufacturer). Third-party knockoffs often don't actually filter to HEPA standard.

5 Smart purifier with an app — should you bother?

1. Apps add useful features: filter-life tracking, scheduling, air-quality history graphs, and remote on/off (handy if you forgot to turn it on before leaving for the day).
2. Setup is the same as any Wi-Fi device — needs 2.4GHz network during pairing, your phone has to be on the same network.
3. Pick a brand whose app is actually good. Levoit's VeSync app is reliable. Coway and Dyson are also solid. Avoid no-name Amazon brands — their apps tend to disappear in 2-3 years.
4. If you don't want to mess with the app, every smart purifier still works as a manual button-press device. The app is optional.

⚠️ Heads up.

Two scams to watch for. First: "ionizer" or "ozone generator" air purifiers marketed as more powerful. They produce ozone, which is genuinely BAD for people with COPD, asthma, or any respiratory condition. Stick to pure HEPA-and-carbon models.

Second: doorstep salespeople offering "free home air-quality testing" who then sell you a $3,000 whole-house system. Real HVAC pros don't door-knock seniors. If you want a real air-quality test, call a licensed local HVAC company you researched yourself — or call me first at (330) 200-8042.