20×25×1 is a common residential return size. Order by the printed nominal size on the old frame — not the slightly smaller tape measurement. Caliza Home sells Aerostar 1-inch packs as 6-packs in MERV 11 and MERV 13.
Confirm the size before you buy
- Pull the old filter and read the frame (look for
20x25x1). - If the print is gone, measure shorter × longer × thickness, then round to the nominal size. A filter that measures about 19.5 × 24.5 × 0.75 is usually ordered as 20×25×1.
- Follow the airflow arrow toward the furnace / blower on install.
Full walkthrough: How to measure a furnace filter.
MERV 11 or MERV 13?
Match what your furnace / air-handler manual allows. MERV 13 is denser media on the same 1-inch footprint — useful when the equipment supports it, not a medical upgrade. Practical comparison: MERV 11 vs MERV 13. More answers: Filter FAQ.
Shop 20x25x1 packs
Swap cadence
Many homes change 1-inch filters about every 90 days (sooner if the pack looks gray or airflow feels restricted). A 6-pack keeps the next swap on the shelf.
About Caliza
Caliza Home is a small Southern California filter shop. HVAC packs use the Aerostar line with manufacturing tied to Orlando, Florida factory operations for this line — we state factory city carefully, not blanket “Made in USA” slogans. We don’t sell medical devices, water softeners, or 99.9% claims.