| All Trade Mechanical And Electric | Jacob Lee Pritchard | office@alltradeservices.com | (530) 918 5547 | HVAC | Mount Shasta · Siskiyou County | — | — |
| Archer Mechanical | Archer Mechanical | — | (530) 925 5748 | HVAC | Mount Shasta · Siskiyou County | — | — |
| Beale Mechanical | Beale Mechanical | — | (415) 246 8989 | HVAC | Dunsmuir · Siskiyou County | — | — |
| Daniel Corson DBA Dressler Heating & Cooling | Dressler Heating & Cooling | — | (530) 598 2179 | HVAC | Yreka · Siskiyou County | — | — |
| Downey Heating & Cooling INC | David Dale Downey | — | (530) 468 4288 | HVAC | Etna · Siskiyou County | — | — |
| Frank's Fuel Oils & Heating | Frank's Fuel Oils & Heating | — | (530) 235 1003 | HVAC | Dunsmuir · Siskiyou County | — | — |
| Mcintyre Heating And Air | Mcintyre Heating And Air | — | (530) 339 2162 | HVAC | Weed · Siskiyou County | — | — |
| Meyer & Sons Heating Plumbing & A/c INC | Louis Adam Meyer | — | (530) 235 2400 | HVAC | Dunsmuir · Siskiyou County | — | — |
| Mountain Air Heating Cooling & Refrigeration INC | Sarah Fay Mead | — | (530) 842 3910 | HVAC | Yreka · Siskiyou County | — | — |
| Nelson's Heating And Air INC | Ernest Felix Nelson | service@nelsons-hvac.com | (530) 598 2651 | HVAC | Yreka · Siskiyou County | — | — |
| Pigoni Corporation DBA Mark's Heating And Cooling | Mark Daniel Pigoni | — | (530) 925 9868 | HVAC | Mt Shasta · Siskiyou County | — | — |
| Pipetrades North LLC | Roger James Gifford | — | (530) 340 1395 | HVAC | Hornbrook · Siskiyou County | — | — |
| Roger Gifford | Roger Gifford | — | (530) 340 1395 | HVAC | Hornbrook · Siskiyou County | — | — |
| S V M Plumbing | Theodore Jay Johnson | — | (530) 842 7862 | HVAC | Yreka · Siskiyou County | — | — |
| S W Maintenance Corp | Mark Allen Keys | — | (530) 938 2969 | HVAC | Weed · Siskiyou County | — | — |
| Siskiyou Hydrokleen | Siskiyou Hydrokleen | kdunnauto@sbcglobal.net | — | HVAC | Yreka · Siskiyou County | — | — |
| Stone Heating & Air | Stone Heating & Air | office@stoneheatair.com | (541) 855-5521 | HVAC | Yreka · Siskiyou County | — | — |
| Wilden Heating And Air | Wilden Heating And Air | — | (530) 926 0310 | HVAC | Mt Shasta · Siskiyou County | — | — |