1-Inch AC & Furnace Filters

This is normal. Many HVAC systems are designed for filters labeled as 1-inch nominal, but the actual depth is typically 0.75 inches. Manufacturers round measurements for marketing consistency.
If your filter slot looks too tight for a full 1-inch filter, a 3/4-inch actual depth is correct and will fit properly.

For most homes, replace your filter every 30–60 days. You may need more frequent changes if you have:

• Pets
• Allergies
• A large household
• Construction or dust in the home

Yes. A handful of sizes (such as 16x25x1, 20x20x1, 14x20x1) represent most HVAC systems in the U.S. We stock every common size, plus hard-to-find or discontinued dimensions.

Yes. We manufacture custom filters in nearly any size. If your system uses an uncommon or discontinued dimension, we can build a filter to your exact specifications.

Fiberglass filters are inexpensive and allow maximum airflow but capture fewer particles — best for protecting equipment. Pleated filters offer higher filtration efficiency, improved indoor air quality, and longer service life.

Thicker filters have more surface area and can improve filtration and airflow consistency. However, you should only use the thickness your HVAC system is designed for. Never force a larger filter into the slot.

An incorrect filter size allows air to bypass the filter, letting dust and debris into your HVAC system. This can lead to costly repairs and lower energy efficiency. Always use the exact size recommended for your unit.

Not necessarily. While a higher MERV rating captures more particles, it also restricts airflow more. Some residential HVAC systems are not powerful enough to handle high-MERV filters, which can strain the system and increase energy bills. MERV 8 to 11 is the sweet spot for most homes.

Check your HVAC system’s manual or contact the manufacturer. As a general rule, most modern residential systems can handle up to MERV 13, but older systems may be limited to MERV 8. When in doubt, a MERV 8 filter is a safe and effective choice.

Washable filters can be cost-effective over the long term, but they require regular cleaning and offer lower filtration efficiency (typically MERV 1-4) compared to pleated filters. They are a good choice for basic equipment protection but not for improving indoor air quality.

“Nominal” size is the rounded, common number used for marketing (e.g., 20x25x1). “Actual” size is the precise dimension of the filter (e.g., 19.5" x 24.5" x 0.75"). Always check the actual dimensions printed on your current filter to ensure a perfect fit.