Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| RE37383 | Pressurized air seal for combustion chamber | Joseph Gerstmann | 2001-09-18 |
| 5758820 | Heat recovery system | George M. Celorier, Jr., Joseph Gerstmann | 1998-06-02 |
| 5245952 | Quiet, non-condensing liquid heater using a non-mixing blower combustion system | — | 1993-09-21 |
| 5171144 | Pressurized air seal for combustion chamber | Joseph Gerstmann | 1992-12-15 |
| RE33082 | Combustion product condensing water heater | Joseph Gerstmann | 1989-10-10 |
| 4502626 | Combustion product condensing water heater | Joseph Gerstmann | 1985-03-05 |
| 4445464 | High efficiency water heating system | Joseph Gerstmann | 1984-05-01 |
| 4403572 | Combustion product condensing water heater | Joseph Gerstmann | 1983-09-13 |
| 4338888 | High efficiency water heating system | Joseph Gerstmann | 1982-07-13 |