Brands › Rheem › RGRK (90 Plus Dual Comfort two-stage upflow)
Rheem RGRK-12*RAJS furnace filter size
This furnace takes a 22.75 x 25 x 1 filter (single/any (factory permanent filter) return).
Every filter option for this model
| Where return air enters | Filter size (inches) | How many |
|---|---|---|
| single/any (factory permanent filter) | 22.75 x 25 x 1 | 1 |
Where the filter goes
Factory "STANDARD, HIGH VELOCITY PERMANENT FILTER" inside the furnace (spec features: "Molded permanent filters"); optional external racks RXGF-CB/CA "shipped without filters. Filters shipped with furnace may be used or a suitable 1" 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
| Airflow direction | upflow (two-stage) |
|---|---|
| Heat input | 120,000 BTU/hr |
| Efficiency (AFUE) | 92% |
| Model number note | * in model = E (standard) or N (NOx models) per doc note "*N = NOx Models" |
| Also sold as | Ruud |
How to read a Rheem model number
Source
- Rheem RGRK Series spec sheet, Form G11-530 (spec sheet, page 4): document. Read 2026-11-03.
- Ruud Achiever 90 Plus with Dual Comfort Control (RGRK) spec sheet, Form G22-482 Rev. 8 (spec sheet, page 3): 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.