SioGreen Infrared Tankless Water Heater Model SIO18-CD / Cosmetic Defects


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SioGreen Tankless Water Heater SIO18-CD Infrared Best Electric 5 GPM 220/240 Volt

*********IMPORTANT INFORMATION***********

These are NEW units with COSMETIC DEFECTS in the paint.  

All units have been tested and work as designed.  The units have chipped paint in random locations which does not affect the function or performance of this unit. The image of the unit with the chipped paint is an example.  The unit you receive may possibly have cosmetic defects in a different location. 

These units with cosmetic defects have been tested by the manufacturer and are in new working condition and qualify for the same warranty that the other SioGreen SIO18 units.  


Contact us for purchase options and updates.
Text: 7755250811


The new SIO18 FLEX will be available soon, just not on the internet. Contact us for more details.
The FLEX can be installed to the full power for the SIO18 or reduced power for the SIO14.


SioGreen Model SIO18-CD

Infrared Electric Whole House Tankless Water Heater,


5.0 GPM 220v, 18.0 kW, 80 amps

The SIO18-CD Whole House Tankless Water Heater 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. Energy costs for water heating can add up quickly in a large building, especially when people are using multiple sources for hot water. Conventional hot water heaters lose efficiency and break down over time because they have metal heating elements that are in direct contact with the water in the tank. Corrosion is virtually inevitable, leading to low efficiency and higher energy bills.


This whole house tankless water heater has Quartz Infrared heating elements that do not make contact with the water, which increases efficiency and longevity in the system while also helping to keep the water clean. A SioGreen tankless water heater uses up to 60% less energy than conventional models, and it lasts over 10 years.


The Model SIO18-CD whole house tankless water heater is also designed for HYBRID upgrades, which means integration into your existing traditional electric or gas tank water heaters. If you already have a conventional tank water heater, you can improve its efficiency and lifespan by using SioGreen technology to create a hybrid tank / tankless system.


By using infrared energy to heat the water it also helps to break down hard water deposits.
The self-cleaning and maintenance-free operation is a great selling point.



– Residential/Commercial
– Electric Tankless Heating
– Hot Water Re-circulation Loop
– With Storage Tank
– Radiant Heating
– Hydronic Heating
– Solar Heating Backup

– Flow Rate @ 40°F Temp Rise 3.07 (GPM) @ 107°F Output, Inlet 67°F
– No Metallic. No Corrosion. No Calcium Deposits. Maintenance Free. Superior Heating Efficiency
– Reduce Energy Cost up to 65% compared to any current Electric Tankless Water Heater in the Market
– Uses lower amperage, maintains higher water flow capacity, integrated into various application
– Continuous hot water on-demand
– Temperature Setting Control
– High heating efficiency (98%)


Maximum Flow Rate 5.0 GPM

With a 67° or higher incoming water temp, this unit would work well for multiple water requests at a time

Multiple Points of use Application

– Perfect for a whole house


Downloadable PDF Manual




How Infrared Works



A point-of-use infrared tankless water heater can turn virtually any water source into an endless supply of hot water, without having to install a full, whole-building hot water heater or expand an existing water heating system.

If you are adding a bathroom or kitchen area, upgrading a home or office, improving a camper or motor home, remodeling a cabin or apartment, or planning to add hot water capabilities to any property, the point of use infrared tankless water heater may be the best choice for you.


Why SioGreen?

Easy to install.
Maintenance Free Operation.
Conditions the water.
Superior Heating Efficiency.

Reduces Energy Cost up to 65% compared to any current Electric Tankless Water Heater on the Market.
Uses lower amperage, maintains higher water flow capacity, and integrates into various applications.

Environmentally Friendly footprint

Many of the SioGreen units are EXCELLENT for use in Hybrid hot water delivery systems.
The larger SioGreen units integrate well with Radiant Heated Floor Systems.
It can be installed in series and for recirculation.
Longevity (more than ten years)


Design Features

– Thermostatic Intelligent Fuzzy Logic PID Temperature Controller
– Fully Modulating Power Control
– LED Temperature Outlet/Set Display ( °F/ °C setting)
– Compact Design for Space Saving
– Superior Energy Efficient (98%)– Continuous Hot Water On-Demand
– Self Cleaning Design for Maintenance-Free Operation


Safety Features

– Overheat Thermal Cut Off Fuses
– High Limit Temperature Safety Cut Off
– Outlet Thermocouple Constantly Monitor Temperature and Anti-Scald Protection
– Residual Leakage Current Detection


Hybird Applicatons

Hybrid ApplicationsY




WRAS   CE Marking   MET Labs

SioGreen Infrared Tankless Technology

SioGreen today is the only manufacturer in the world that produces an instant hot water system with an Infrared Quartz heating element that serves distributors in North America, Europe, and Asia.

All water heaters rely on a heating element of some type, generally, this is in the form of hot metal components.

Normally when the metal elements are introduced to direct contact with water, only the water in the immediate area of the heating element is affected. This can actually reduce the flow rates in an attempt to heat the water.

Infrared technology works on the molecular level and because the far-infrared rays affect all of the water it gets hot faster and more thoroughly.

Scientifically the water is clustered with 5-12 water molecules. When the far-infrared rays stimulate the clusters, the water molecule movement is activated. This is due to resonance absorption. The number of water molecules which form the clusters is decreased and the result is activation/agitation of the water.

As a result of this activation, the infrared energy is able to heat the excited molecules on an individual basis ensuring the water is thoroughly heated at an accelerated rate. This allows SioGreen is operating at higher flow rates.


Quartz heating elements

Watch This Quick Video



Part Number SIO18
Item Weight 27 pounds
UPC  00049447000082
Certifications MET(US) – WRAS Certificate – CE Certificate
US Patented Technology Yes
Product Dimensions  14 x 20 x 6 inches
Cabinet Power Coated 20 Gauge Steel
Installation Requirements Must be installed by a licensed contractor according to local building codes.
Warranty Heat Exchanger 10 Years
Warranty  Electrical Components 3 years
Warranty Registration Online at SioGreen or fill out and submit the warranty card.
Registration Time Limit Within 60 days from purchase or will revert to 1 Year Pro-Rated
Item model number SIO18
Power Source  220/240 VAC
Voltage  Single Phase 220 Volts
Phase Single Phase
Wattage  Max Output 18 kW
Amperage Capacity  80A (8 redundant Far-Infrared Heating elements)
Recommended Main Electrical Service Panel 200 Amp
Required Breaker Size 2 X 40 Amp Double Pole
Item Package Quantity 1 Unit
Special Features Easy to Install, Quiet, Quiet Close, Adjustable
Usage Large House / Apartment / Town home / Condo/ Commercial
Suggested Geographic Location 67° and above incoming water temperature
Batteries Required No / not included
Usable for Radiant Heat? Yes, radiant heat is an application design that uses a closed re-circulation loop.
Solar Panels SioGreen SIO and IR-Series heaters can be used as Solar Backup with the Solar Storage tank.
Life expectancy of the Quartz Heating Elements Without direct contact with the coating, the estimated lifecycle is 10-20 years, depending on application and usage.
Insulation around Quartz Heating Elements Boiler Cotton Fiberglass
Water Connections 3/4" NPT
Suggested Wire Size 8 Gauge (X2)
Minimum Flow Rate for Activation (GPM) 0.5
Maximum Flow Rate through Unit (GPM) 5.0
Flow Rate @ 60° Temp Rise (GPM) 2.5
Minimum / Maximum Working Pressure (PSI) 10-150
Protections Thermal / Manual
Temperature Control Range 60°F to 145°F (±1°F increment)
Factory Default Settings (Residential) 120° F
Factory Default Settings (Commercial) 160° F
18 kW
2 X 40 Amp Double Pole
200 Amp
8 Gauge ( X 2 )

Warranty and Registration Information

Manufacturer only warrants to the original purchaser at the original installation address of purchaser (collectively, the “Buyer”) the hot water generator and its components as manufactured by the Manufacturer (the "Product") to be free from defects in materials and workmanship, under normal use and service for the period of time identified below beginning from the date of installation.

Manufacturer Warranty is only offered if the Manufacturer products are installed by a licensed contractor In accordance with National and Local Codes having jurisdiction governing the installing area, and installed to Manufacturer Specifications using all included components supplied by Manufacturer and other parts that may be required to protect equipment.

The warranty is 100% void if the unit has been opened.



  • Product misuse, tampering or misapplication, accidental damage, or improper installation. Product failure caused by chemical corrosion, or freezing. Product failure due to lightning, flood or other natural or man-made calamities. Costs incurred for shipping, delivery, handling, and/or administrative charges.
  • Labor charges of any kind.

Manufacturer will replace the defective unit on a prorated basis, in accordance with the terms of this Limited Warranty, if it fails in normal use and service during the Applicable Warranty Period.

Manufacturer shall not be liable for incidental, consequential, special or contingent damages or expenses arising, directly or indirectly, from any defect in the hot water generator or the use of the hot water generator.

Manufacturer shall not be liable for any water damage arising, directly or indirectly, from any defect in the hot water generator component part(s) or from its use. Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you.

This warranty gives you specific legal rights and you may also have others.


Registration can be done by filling out and mailing in the warranty card or online by visiting the SioGreen website.



  • FREE Shipping to U.S. Mainland addresses only.
  • We do not offer free shipping to Alaska or Hawaii, however we do ship to those locations. Enter your zip code under the Shipping and Payments tab to get your rate.
  • We do offer International Shipping on this item, contact us for a quote.
  • When product has been paid for, we will submit the order to be processed and shipped within 24 hours. Weekends and holidays are excluded. Shipping time may vary due to your requested delivery location.
  • Your shipment will originate from a warehouse nearest to your location if possible. Most items are shipped FedEx, USPS and UPS.
  • You will receive a shipping update email containing a tracking number.
  • If your package arrives damaged, refuse the shipment and contact us. If the shipping company has left before you realize the package is damaged, contact us immediately. Concealed damages must be reported to the carrier within 24 hours of receipt.
  • All shipping and handling cost are non-refundable. If buyer provides incorrect address or refuses delivery, the original actual shipping cost will be deducted from any monies refunded.

As per our contract, we can not sell or ship to the UK or Viet Nam.


30 Day Returns


To help us expedite your return please follow these instructions:

  • Units must be in new unused condition the same as when shipped from the warehouse.
  • Contact us in advance for a RMA number (Return Merchandise Authorization)
  • Follow the detailed return instructions that we provide to you, which include the RMA# and shipping address to the SioGreen.
  • You will then receive your refund after a SioGreen service technician inspects the returned product and has issued a credit memo.
  • Buyer is responsible for all shipping costs associated with the 30 day return, plus all returns are subject to a restocking fee.

*Free Return Shipping only available on units with actually manufacturer defects.

Refunds will not be issued on products that have been broken or damaged! Product defects are covered by SioGreen's Warranty as verified by the manufacturer.

  • Buyer must consult with a SioGreen Service Technician and the unit deemed to have a factory defect.
  • Units not functioning properly due to "customer set up" DO NOT qualify as a manufacturer's defect.
  • Returned units that have been damaged by buyer will be subject to restock fee or possible rejection of return claim.

Sizing Guide and Map

How to Size a Whole House Tankless Water Heater

It is easy to determine what size of tankless water heater will work best for your application.

1.   Start with the map and determine your location.

2.   Check the chart for the number of Points of Use, (POU) you plan on using simultaneously. 

3.   Add up the requirements and check the chart to see which model is designed to meet those needs. ,/strong>


STEP 1: Look at the color chart of North America to find the average incoming water temperature in your region.


Map Sizing Guide

STEP 2: Look at the chart to the right for the applications that call for hot water and much they use per minute or (GPM), base on the applications you plan or running at one time your water must heat that much water per minute

  • Faucet Image    Image represents hand wash sink faucet with flow rate of 0.5 – 1.5 GPM, hot side only.
  • Shower Head Image    Image represents water-saver/low flow shower head with flow rate of 1.5 – 2.5 GPM, hot side only
  • Average Hot Water Temp is 105°F-115°F.
    To determine the desired temperature rise test the incoming water and subtract from the set point temperature.
    Example : 107°F set point – 57°F incoming water = needed 50°F temperature rise

  • Standard deviation:
    Power: (±) * 1kW
    Tem Rise: (±) * 3°F
    Water Flow: (±) * 0.1gpm


  • Standard Shower Head 2.0 GPM
  • Water-Saver Shower Head 1.5 GPM
  • Bathroom Vanity Sink Faucet 0.5 – 1.5 GPM
  • Kitchen Sink 1-2 GPM
  • Bath Tub 2.5 – 4 GPM
  • Dishwasher 1-2 GPM
  • Washing Machine 1-1.5 GPM
  • Body Shower 1.6-2.0 GPM Each
  • Jacuzzi or Roman Soaker Tub 4.0-5.0 GPM


Inlet Temp: 37°F

Model Temp Rise/GPM Approx. Usage
IR-260 POU 65°/ 0.8 temp-2.png
IR-288 POU 65°/ 1.8 temp-2.png
SIO14 65°/ 1.8 Faucet Image
SIO18 65°/ 2.4 Shower Head Image  temp-2.png

Inlet Temp: 47°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 60°/ 0.5 temp-2.png
IR-260 POU 60°/ 0.8 Faucet Image
IR-288 POU 60°/ 2.0 Faucet Image
SIO14 60°/ 2.0 temp-3.png
SIO18 60°/ 2.5 temp-3.png Faucet Image Faucet Image

Inlet Temp: 52°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 55°/ 0.5 Faucet Image
IR-260 POU 55°/ 0.9 Faucet Image
IR-288 POU 55°/ 1.73 Shower Head Image Faucet Image
SIO14 55°/ 2.1 Shower Head Image Faucet Image
SIO18 55°/ 2.7 Shower Head Image Faucet Image Faucet Image

Inlet Temp: 57°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 50°/ 0.6 Faucet Image
IR-260 POU 50°/ 1.0 Faucet Image
IR-288 POU 50°/ 2.3 Shower Head Image Faucet Image
SIO14 50°/ 2.3 Shower Head Image Faucet Image
SIO18 50°/ 3.0 Shower Head Image Faucet Image

Inlet Temp: 62°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 45°/ 0.6 Faucet Image
IR-260 POU 45°/ 1.1 Shower Head Image Faucet Image
IR-288 POU 45°/ 2.5 Shower Head Image Faucet Image Faucet Image
SIO14 45°/ 2.5 Shower Head Image Faucet Image Faucet Image
SIO18 45°/ 3.3 Shower Head Image Faucet Image

Inlet Temp: 67°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 40°/ 0.7 Faucet Image
IR-260 POU 40°/ 1.2 Shower Head Image Faucet Image
IR-288 POU 40°/ 2.8 Shower Head Image Faucet Image Faucet Image
SIO14 40°/ 2.8 Shower Head Image Faucet Image Faucet Image
SIO18 40°/ 3.6 Shower Head Image Faucet Image Faucet Image

Inlet Temp: 72°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 35°/ 0.8 Faucet Image
IR-260 POU 35°/ 1.3 Shower Head Image Faucet Image
IR-288 POU 35°/ 3.1 Shower Head Image Faucet Image
SIO14 35°/ 3.1 Shower Head Image Faucet Image
SIO18 35°/ 4.0 Shower Head Image Faucet Image Faucet Image

Inlet Temp: 77°F

Model Temp Rise/GPM Approx. Usage
IR-30 POU 30°/ 0.9 Faucet Image
IR-260 POU 30°/ 1.5 Shower Head Image Faucet Image
IR-288 POU 30°/ 3.6 Shower Head Image Faucet Image Faucet Image
SIO14 30°/ 3.6 Shower Head Image Faucet Image Faucet Image
SIO18 30°/ 4.6 Shower Head Image Faucet Image Faucet Image


STEP 3: Match your location on the map, shown above, to the corresponding chart below to determine unit capacity.


Model Number kW Volts Minimun Breaker Max Power (AMP) Minimum Wire Dimensions Weight
IR-30 POU 3.4 110 30 Single Pole 28.3 10 13.5″x 8.5″x 2.5″ 5 lbs.
IR-260 POU 6.0 240 30 Double Pole 25 (2)10 13.5″x 8.5″x 2.5″ 5 lbs.
IR-288 POU 14 240 40 Double Pole 58.4 (2)6 18.5″x 12.5″x 3″ 13 lbs.
SIO14 14 240 2 X 30 Double Pole 58.4 (2)6 20″ x 14″ x 6″ 27 lbs.
SIO18 18 240 2 X 40 Double Pole 75 (2)4 20″ x 14″ x 6″ 27 lbs.

  • Model: SIO18-CD
  • Shipping Weight: 32lbs
  • 4 Units in Stock
  • Manufactured by: SioGreen

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This product was added to our catalog on Sunday 16 February, 2020.