Filter Modification - Custom sized 3M filters are converted from standard sizes to meet the required length and width specifications. The filters are modified in a U.L. certified air filter manufacturing facility and continue to meet the original specifications with regard to filtration efficiency and pressure drop. Sizes with at least one length or width in excess of 30 inches and/or 20 inches, respectively, will be manufactured by combining two Filtrete filters to equal the required dimensions. If a dimension exceeds 30", the filter will need to be created using two custom filters assembled together. This is a limitation of the materials used to build your filter.
Before ordering a custom size filter, please measure the length and width of the current air filter being used. We will make the length and width to your specifications with a tolerance of 1/8". This means the product delivered will never be larger than your specifications, but may be up to 1/8" smaller. This tolerance is typical of all custom made air filters and is the result of the manufacturing process.
The easiest way to make sure you order the correct size is to measure your current air filter length and width with a tape measure. Additional Info:
- All orders (standard or custom) are sold in quantities of 6.
- Custom size air/furnace filters will be delivered within 9 business days of order. Business days exclude weekends.