Filters, water & air — explained without the jargon
Every guide is written against the actual standards (NSF, ASHRAE, EPA contaminant lists) and tested against the filters we sell. No "replace every 6 months" folklore without the why.
How-to Guides
Step-by-step, per brand — with the reset codesHow to Change a GE Refrigerator Water Filter (Complete Guide for Every Model)
Twist, push, pull and flat-cartridge bays all work differently — and GE's filter location moved three times across model years. Covers XWFE swap without the cap tool, plus the 3-second reset per model family.
How-to · WhirlpoolHow to Change a Whirlpool Refrigerator Water Filter (Complete, NSF-Aware Guide)
EveryDrop bays in French-door, side-by-side and bottom-freezer layouts — base grille vs interior ceiling — with the air-lock trick that stops the sputter after a change.
How-to · HVACHow Often to Change Your HVAC Filter (an ASHRAE-Pressure View of the Schedule)
The 90-day rule assumes an average home. Pet loads, fan-ON settings and MERV choice move the real date weeks in either direction — here's how to read the pressure side, not the calendar.
Water Problems A–Z
Look up what's in your water →What's actually in your water?
Every entry follows the same structure: where it comes from, what it does, the EPA limit, and which filter technology actually removes it — sediment, carbon, RO, UV or softening resin. Start with the twenty most-searched:
Searches/mo shown are real, US. The other 28 entries — chloramine, chromium-6, radon, giardia and more — live in the full index, cross-linked by shared filter technology.
Browse all 48 entries →Certifications & Ratings
Read the label before you payNSF-42 vs NSF-53: The Real Difference (And Why Your Filter's Label Is Half the Story)
NSF 42 covers taste, chlorine and aesthetics. NSF 53 covers lead, cysts and the contaminants that hurt you. Many filters proudly carry only the first — here's how to read past the badge.
Rating · AirMERV Rating Explained: The Complete 2026 Guide to Air Filter Efficiency
What MERV actually measures, what each grade catches at particle sizes that matter (pollen vs smoke vs virus carriers), and the airflow trade-off your furnace manual assumes you know.
Rating · WaterWhat Is a Micron Rating in a Water Filter? (And Which One You Actually Need)
Nominal vs absolute ratings, why "5 micron" means different things from different factories, and the micron cutoffs that actually matter for sediment, cysts and lead.
Buying Guides
Sizing, comparisons, schedules — before you spendOEM vs Aftermarket Water Filters: The Honest 2026 Comparison
Same factory, different label, 4× the price — sometimes. And sometimes the cheap one really is worse. Where the differences are real (caps, o-rings, carbon source) and where they're packaging.
Buying · SizingWhole House Water Filter Sizing Guide: The Complete 2026 Formula
GPM demand, EBCT contact time, port size and the mistakes that quietly kill your shower pressure. Sizing a Big Blue system in five measurements — before you buy, not after.
Buying · ScheduleReverse Osmosis Filter Replacement Schedule: When to Change Each Stage
Sediment every 6 months, carbon every 6, membrane every 24, polish every 12 — unless your water says otherwise. Per-stage diagnosis: which stage is failing from the taste alone.
Filter tips, once a month.
One short email: what's coming due in your home, one thing worth knowing about your water or air, and any price drops worth acting on. Written by the same people who write these guides.