

Ships same day if ordered by 12 pm
Manufacturer pricing rules prevent us from advertising our discount — no account or email required to see it.
Secure Payments
Easy Returns
Expert Advice
Fast Shipping
The GLASFLOSS ZLP18251 is a MERV 10 pleated air filter designed for residential and commercial HVAC systems where reliable particulate capture and low airflow resistance are required. Sized at 18 inches x 25 inches x 1 inch, it provides 5.41 square feet of synthetic fiber media surface area across 14 pleats per lineal foot. Initial resistance is 0.21 inches WC and final resistance is 1 inch WC, keeping static pressure impact minimal throughout the filter's service life. The 1-piece die-cut frame is constructed from heavy-duty, moisture-resistant beverage board incorporating post-consumer recycled material. A galvanized expanded metal backing is laminated to the air-exit side to maintain pleat shape and integrity under sustained airflow. Manufactured in the USA and Energy Star rated.
The ZLP18251 fits ducted forced-air systems in residential, light commercial, and geothermal unit applications. The tapered radial pleat configuration maximizes media contact area within a standard 1-inch filter slot, making it a practical choice for return-air grille and air handler installations where filter changeouts are routine. Its 100% synthetic fiber media performs across a wide range of HVAC operating conditions, including systems that experience intermittent humidity exposure. Applicable standards include UL 900, ANSI/ASHRAE 52.2, USGBC LEED criteria, HARDI, and NAFA guidelines.
Designed as an OEM-style replacement filter for standard 18 inches x 25 inches x 1 inch filter slots in residential and commercial forced-air HVAC systems, including geothermal units. Verify nominal and actual dimensions against the existing filter slot before installation.
This filter is installed by HVAC technicians or qualified service personnel during routine maintenance. Power down the air handler or furnace at the disconnect or breaker before accessing the filter compartment. Install with the airflow arrow on the frame pointing toward the blower and away from the return air stream. Do not operate the system without a filter in place, and replace when final resistance of 1 inch WC is reached or per the service schedule.
Thanks for subscribing!
This email has been registered!