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Getting ready for 🛠️ reno season? Save 10% on select products at checkout* with "ready10"
Getting ready for 🛠️ reno season? Save 10% on select products at checkout* with "ready10"

SioGreen Sio-18 Whole House Tankless Water Heater

SKU SIO 18 Pro
Original price $884.25 - Original price $884.25
Original price
$884.25 - $884.25
Current price $884.25
in stock, ready to be shipped
Getting ready for 🛠️ reno season? Save 10% on select products with ready10 at Checkout. Brand and product exclusions apply

Why Is This Product On Rise?

The SioGreen Infrared Tankless Water Heater – Model Sio 18 is the high-range model for Residential and Commercial use, ideal for large family homes or medium to large businesses, with a capacity of 0.5 to 5.0 gallons per minute. This powerful, efficient hot water heater applies Quartz Infrared heating elements and a tankless design for maximum performance and efficiency.

A traditional hot water heater has metal heating elements that are placed in the tank where the water is stored. Eventually, these metal elements corrode and break down inside the tank, leading to a loss of efficiency, system failure, and possibly even water contaminants like bacteria and algae. SuperGreen's Infrared Tankless design does not experience these problems, making it up to sixty percent (60%) more efficient and up to twice as long-lasting as many conventional designs. Use the SuperGreen sizing guide to determine which model is ideal.

The Infrared Tankless Water Heater – Model Sio 18 can even be used to upgrade an existing traditional unit as it's is also designed for HYBRID applications. SioGreen's tankless units can be integrated into an existing conventional electric or gas tank hot water heater, providing all the benefits of tankless water heating – energy savings and continuous hot water on demand. The super-efficient Quartz Infrared heating elements heat the water quickly and then store the hot water in the traditional unit's tank. This means you never run out of hot water.


  • Multiple Redundant High Power Quartz Heating Elements
  • Thermostatic Intelligent Fuzzy Logic PID Temperature Controller
  • Fully Modulating Power Control
  • Solid State Relay (SSR)
  • LED Temperature Outlet/Set Display ( °F/ °C setting)
  • 3 Digit LED Flow Indicator (GPM)
  • Compact Design for Space Saving
  • Superior Energy Efficient (98%)
  • Environmental Friendly and Recyclable
  • Continuous Hot Water On-Demand
  • Self Cleaning Design for Maintenance Free Operation

Order Processing and Shipping

Rise ships manufacturer direct. We work hard so you receive your product(s) as quickly as possible. Shipping times are subject to each carrier's daily cut-off time, and dependent upon warehouse turnaround. Learn more about our order processing & shipping times here.


Voltage supply220 VAC/50-60Hz
Amperage80A (8 redundant Far-Infrared Heating elements)
Maximum output power18 kW
Temperature control range60°F to 140°F (±1°F increment)
Water connection (Inlet/Outlet)3/4” NPT
Pressure range15 psi to 150 psi
Minimum flow rate0.5 US gal/min
Maximum flow rate4.0 US gal/min (30GPH)
Dimensions14” W x 20” H x6” D
Weight27 pounds

Power Requirements

ModelPower (KW)Voltage (V)Breaker Sized (A)Recommended Electrical ServiceWire Size (AWG)
Sio 1818 kW220 VAC2 x 40 Amp200 Amp#8 (2 sets)

Sizing & Installation



See the color chart of North America to find the average incoming water temperature in your region.

Choose Your Inlet Ground Water Temperature:

  • 37 - 51 degrees
  • 52 - 61 degrees
  • 61 - Above



Look at the chart for the applications that call for hot water and much water they use per minute or ( GPM) , base on the applications you plan on running at one time your water heater must heat that much water per minute.


 Average Hot Water Temp is 105°F-115°F. To get your temperature rise take your desired hot water temp minus the incoming water temp = temp rise. Example: 107°F desired hot water – 57°F inlet = 50°F temperature rise.


Choose Your Application:


Standard Deviation:

Power:  -1 kW / +1 kW

TempRise: -3°F / +3°F

Water Flow: -0.1 gpm / +0.1 gpm



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