Bosch BGS80M080B4A furnace filter size
This furnace takes a 16 x 25 filter (side or bottom return).
The maker lists width and height only. Most filter racks next to a furnace hold a 1-inch filter; a separate filter cabinet usually holds a 4- or 5-inch one. Check the thickness printed on the edge of your old filter before you order.
Every filter option for this model
Where the filter goes
external: field-supplied side filter rack, bottom-return filter box/rack, or return grille; not supplied
The maker does not ship a filter with this furnace. The size above is the maker's recommended size at the furnace; if your home has a filter grille in a wall or ceiling, that grille sets the size instead.
How often to change it
General guidance, not from the maker's table: 1-inch filters every 1 to 3 months; 4- and 5-inch filters every 6 to 12 months. Change sooner with pets, smoking or construction dust.
About this model
| Cabinet width | 17.5 in. |
|---|---|
| Airflow direction | multi-position (upflow/downflow/horizontal) |
| Heat input | 80,000 BTU/hr |
| Efficiency (AFUE) | 80% |
| Model number note | as printed |
How to read a Bosch model number
Source
- Bosch BGS80 Installation, Operation & Maintenance Manual 09.2018 (installation manual, page 18): document. Read 2026-11-03.
- Bosch BGS80 Engineering Submittal Sheet 09.2018 (spec sheet (engineering submittal), page 8): document. Read 2026-11-03.
Check that the model number on your furnace label matches, and compare with the size printed on your old filter. If they differ, go by the filter that fits your rack.