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Bosch Gas Tankless Water Heaters Greentherm | C 1050 ES

Condensing technology with 96% thermal efficiency and ENERGY STAR rating.

The Bosch Greentherm model C 1050 ES has Energy Factor 0.95, and is equipped with an automated and fully modulating bypass for unsurpassed DHW temperature stability.

Features & Benefits

  • Improved energy factor of 0.95
  • Benchmark temperature stability achieved with an active bypass
  • Inlet water filter featuring easy external access
  • New venting options
  • Concentric up-and-out venting for single boilers and two to four unit single pipe cascades
  • Introducing the water heater mobile app for sizing and technical documentation downloads

Greentherm C 1050 ES Specifications
Condensing/Non-Condensing Condensing
Application Residential or Commercial
Max Input (BTU) 199,000
Min Input (BTU) 19,900
Capacity at 35°F Rise (gpm) 10.7
Capacity at 55°F Rise (gpm) 6.8
Intelligent Cascading Yes
Min Flow Rate 0.50 gpm
Temp Range (°F) 100 – 140
Temp Stability (°F) +/- 2
Default Temp (°F) 122
Energy Factor .95
Thermal Efficiency 96%
Installation Options Indoor or Outdoor
Dimensions (w x h x d) 17.875″ x 30½” x 11¼”
Weight (lbs.) 74
Inlet Connection ¾” NPT
Outlet Connection ¾” NPT
Gas Connection ¾” NPT
Max Water Pressure 150 psi
Min Water Pressure 30 psi
Min NG Presure 3.5″ WC
Condensing Heat Exchanger Aluminum
Venting Options PVC, CPVC, ABS, Cat III, Stainless Steel
Outdoor Kit and Polypropylene
Vent Maximun Run 63′
Energy Star Rated Yes
* 3 Years if used in direct recirculation applications See full details in “Warranty” section


  • 15 year limited warranty on heat exchanger; 3 year warranty if used in uncontrolled recirculation applications
  • 10 year warranty on heat exchanger if used in controlled recirculation applications, such as by an aquastat
  • 10 year limited warranty on heat exchanger if used in combination DHW and hydronic forced air heat
  • 5 year warranty on all other parts
  • 1 year labor warranty

You can also visit Kitchen & Bath Showcase or Central Kitchen & Bath Showroom and make a wish list, create a user profile and send/share your wish list estimate email to: and we will get back to you shortly with supplier pricing and dates we can install.