Rather than relying on someone else’s comparison, here’s how to build a chart tailored to your specific decision factors.
The reason a home-made chart beats a published ranking is that rankings have to pick a winner for an average reader. You are not average: you have a specific room, a specific noise tolerance and a specific willingness to pay for filters every year. A chart makes those weightings explicit instead of hiding them inside someone else’s verdict. Keep it to six or eight candidates, because past that the chart stops being a decision tool.
- Include CADR rating, noise level, filter cost/frequency, and price in your chart.
- Weight factors according to your specific priority — bedroom quiet use vs. ongoing cost management.
- Verify CADR and HEPA certification directly from manufacturer specifications.
- A personalized comparison chart beats a generic ranking for your specific room and priorities.
Key Columns to Include
CADR rating (matched against your room square footage), noise level (particularly important for bedroom use), filter replacement cost and frequency, and price.
- CADR, all three numbers. AHAM publishes separate clean air delivery rates for smoke, dust and pollen. Record all three rather than the single headline figure, since they differ.
- Rated room size, and the assumption behind it. Manufacturers convert CADR into a square-footage claim using an assumed number of air changes per hour and an assumed ceiling height. Two brands using different assumptions produce non-comparable room claims from similar hardware, which is exactly why CADR is the column that matters.
- True HEPA, stated explicitly. Record the exact wording. “HEPA-type” is a different claim.
- Filter cost and replacement interval, for every filter the unit takes, including any separate carbon stage.
- Annualised filter cost. Filter price multiplied by replacements per year. This is the column that most often changes a decision.
- Noise at low and at high. One number is not enough, because the quiet setting is the one a bedroom unit will actually run at.
- Power draw in watts, if the unit will run continuously.
- Certifications. AHAM Verifide for the CADR figures, any asthma and allergy friendly certification, and presence on the California list of air cleaners certified for ozone emissions.
- Warranty length and physical dimensions, the two columns people forget until the unit arrives.
One derived column is worth adding by hand: three-year cost of ownership, being the purchase price plus filter cost multiplied by the expected replacements over three years. It routinely reorders a chart, because an inexpensive unit with proprietary filters can end up costing more than a mid-priced one with cheap consumables.
Weighting What Matters Most to You
If you’re prioritizing bedroom use, weight noise level heavily. If you’re managing ongoing costs, weight filter replacement price and frequency instead.
A simple way to do this without pretending to be precise is to pick the two or three columns that would actually make you reject a unit, and treat everything else as tie-breakers. In practice most people land on one of three profiles.
- Bedroom. Noise at the low setting first, then CADR adequate for the room at that setting, then filter cost. A unit rated for a much larger room can be a good bedroom choice precisely because it hits your target while running slowly and quietly.
- Large or open-plan living space. CADR first, then power draw, then noise. Consider two smaller units in the rooms you use rather than one very large one.
- Long-term or whole-house cost sensitivity. Annualised filter cost first, then CADR, then everything else. Check whether filters are widely available or sole-sourced.
Sources for Filling In the Chart
Pull CADR ratings and HEPA certification directly from manufacturer specifications rather than relying solely on retailer marketing copy.
- The AHAM Verifide directory for independently verified CADR figures. If a model is not listed, its CADR claim is the manufacturer’s own.
- The manufacturer’s specification sheet or manual, not the marketing page. Manuals routinely state noise, wattage and filter part numbers that the sales page omits.
- The California Air Resources Board list of certified air cleaners, to confirm a unit is not an ozone emitter.
- Retailer listings for the replacement filters themselves, which is the only reliable way to get the real consumable price rather than a recommended one.
- Long-term owner reviews, filtered to the ones mentioning noise, filter availability and failures after a year. Treat these as evidence about durability, never about filtration performance.
Leave a cell blank rather than guessing. A visibly empty column is information: it usually means the manufacturer chose not to publish that number, and that is worth weighing.
FAQ
What’s the single most important factor when comparing HEPA purifiers?
CADR rating matched to your specific room size — an undersized unit won’t adequately filter regardless of other features.
Why record all three CADR numbers instead of one?
Because they measure performance against different particle sizes. Dust and pollen figures are the more relevant ones for allergen work, while the smoke figure reflects performance on the finest particles.
How many candidates should the chart hold?
Six to eight. Enough to see real spread between options, few enough that you will actually fill every cell rather than leaving the comparison half-done.
Verify specifications directly from manufacturer sources rather than relying solely on retailer product descriptions.
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.
