Specs and Docs

Mascot® ST Tankless Water Heater

High Efficiency Tankless Water Heater

The Mascot ST is a cascadable high-efficiency wall-mounted tankless water heater packed with features that easily satisfy the hot water needs of the modern home. Within the Mascot ST is an advanced stainless steel condensing heat exchanger that delivers a quick response and exceptional efficiency. When there is a need for hot water, the Mascot ST immediately begins to produce hot water, running for as long as you need it to make sure you never run out of hot water. It’s a very efficient and responsive system that will take care of your family’s hot water needs with years of reliable service. The Mascot ST will run for as long as there is demand, producing 5.0 gpm (19 l/m) at a 77F rise!

Mascot ST Tankless Water Heater (Size Range: 199MBH) – Indoor


  • 0.92 Uniform Energy Factor: Ultra-High Efficiency
  • 10:1 Modulation: For small to large hot water demands
  • 199,000 BTU/Hr: Ample hot water for the whole family
  • Environmentally Friendly Low NOx Emissions
  • Reliable Stainless Steel Condensing Heat Exchanger
  • Vent up to 100 ft. in PVC, CPV & Polypropylene
  • Cascadable up to 18 total units (up to 3.6 MBTU/h)

Saves You Money

Greatly reduce water heating bills when compared to older, low–efficiency water heaters! A 0.92 uniform energy factor equals lower fuel use. In older conventional tankless water heater designs, the heat trapped in the flue gas goes up the chimney instead of heating your water.

Our technology releases the heat stored inside the exiting flue gas to reach ultra-high efficiencies. Potentially saving thousands of dollars in water heating bills over the life of this condensing tankless water heater!

  • When the flue gas contacts the Mascot ST stainless steel heat exchanger it begins to condense, releasing stored heat
  • The heat released by condensing is combined with the heat from the burner flame
  • The result is the majority of the available heat is transferred to your home–up to 30% more energy verses older low–efficient designs– saving you money
  • Rebate Eligible–check federal, state, and local rebates for upfront savings!

An Outdoor Installation Kit is available for new installations where the only available place to install the unit, is outside. 


The Mascot ST condensing tankless water heater is equipped with the advanced Laars Integrated Control System

  • Easy to use dial and push button input system with large backlit display
  • Functions are clearly displayed for quick set-up and diagnostics
  • Quick access buttons for temperature control and water heater status and functions


Mascot ST Tankless models are powered by an advanced stainless steel condensing heat exchanger using the latest in combustion technology.




  • Hot flue gas is evenly distributed across an array of oval water tubes. 
  • The oval tube shape causes turbulent flow and releases stored heat trapped inside the hot flue gases to better transfer heat from the water heater to your home.
  • Self-cleaning, condensate flows down along the tube walls and out through condensate collection system.
  • Uniform heat distribution reduces stress points in the heat exchanger. Combined with erosion–and corrosion–resistant materials, the result is a durable design for a long lifetime of use.