Carrier 58MTB100-20 furnace filter size
This furnace takes a 16 x 25 x 1 (3/4 in. actual) filter (side (upflow only) return) or a 20 x 25 x 1 (3/4 in. actual) filter (bottom return), depending on where the return air comes in.
Every filter option for this model
| Where return air enters | Filter size (inches) | How many |
|---|---|---|
| side (upflow only) | 16 x 25 x 1 (3/4 in. actual) | 1 |
| bottom | 20 x 25 x 1 (3/4 in. actual) | 1 |
Where the filter goes
Inside furnace blower compartment. PD p5 airflow note: 'Airflow shown is with factory supplied 1-in. washable filter.'
The maker ships a filter with this furnace.
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 | 21 in. |
|---|---|
| Airflow direction | 4-way multipoise (upflow/downflow/horizontal), 2-stage condensing |
| Heat input | 100,000 BTU/hr |
| Model number note | Docs list unit size as 060-12 etc.; nameplate adds series characters (Series 110). |
How to read a Carrier model number
Source
- Carrier 58MTB-2SI Installation, Start-up, Operating and Service and Maintenance Instructions (installation manual, page 25): document. Read 2026-11-03.
- 58MTB Product Data (58MTB-2PD), Physical data table (product data / spec sheet, page 5): 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.