WhatSizeIsMyFilter.com exists because picking the right filter should not require a search engine rabbit hole, three manufacturer manuals, and a call to an HVAC technician.
What We Do
We publish plain-English guides for the filters that keep your home running — furnace filters, AC filters, whole-house media cabinets, air purifiers, and pool filters. Every guide answers the same core questions a real homeowner actually asks:
- What size do I actually need?
- Which MERV / HEPA / filter type is right for my situation?
- How often do I really need to replace it?
- Which brands are worth the money — and which are marketing fluff?
- What happens if I ignore it?
Why We Started
Most filter information online falls into one of two camps: manufacturer marketing (everything is amazing, buy the premium tier) or forum advice (one guy's opinion from 2014). Neither helps a homeowner standing in Home Depot trying to figure out whether a MERV 8 or MERV 13 is right for their house.
We sit in the middle: independent, readable, and honest about trade-offs. When a cheap filter is the right choice, we say so. When a premium filter is genuinely worth the markup, we say that too.
Our Editorial Approach
Every guide on this site follows a few simple principles:
- Plain English over jargon. If a term needs explaining, we explain it the first time it appears.
- Specifics over platitudes. "Check your filter regularly" is useless. "Hold it up to a light — if you can't see through it, replace it" is actionable.
- Cite the math. When we say a dirty filter raises your energy bill, we reference the Department of Energy's actual efficiency numbers.
- Honest trade-offs. Higher MERV filters capture more particles but restrict airflow — we'll always tell you both sides.
- Editorial independence. Commission rates do not influence which products we recommend. See our Affiliate Disclosure.
How We Make Money
WhatSizeIsMyFilter.com is supported by affiliate commissions (Amazon Associates, FilterBuy, and others) and display advertising (Google AdSense). When you click a link and buy a product, we may earn a small commission at no additional cost to you.
Full details are in our Affiliate Disclosure. In short: we only recommend products we believe are useful, and affiliate income keeps the site running without requiring subscriptions, paywalls, or email signups.
Who We Are
WhatSizeIsMyFilter.com is an independent publication operating out of the United States. We are not owned by any filter manufacturer, HVAC service company, or retailer. We are readers, tinkerers, and homeowners who got tired of bad filter advice and decided to write better.
The site is maintained by a small editorial team. Guides are researched from manufacturer specifications, EPA and DOE publications, industry trade resources, and direct product testing where practical.
Contact Us
Have a question, spot an error, or want to suggest a topic? We read every email.
Email: hello@whatsizeismyfilter.com
More on the Contact page.
WhatSizeIsMyFilter.com is an educational and consumer-guide publication. It is not a licensed HVAC service, a medical resource, or a substitute for professional advice on serious equipment problems. If your furnace is making bad noises, call a technician.