SanCO2: The Water Heater to End All Water Heaters

Note: The SANCO2 was formerly a product of SANDEN, and is now distributed in North America by ECO2 Systems


After HVAC systems, water heaters can be among the biggest energy sinks in a building. Although high-performance building strategies can allow you to dramatically downsize your HVAC systems, supplying hot water can remain a challenge for those seeking to reduce building energy loads. Fortunately, the ideal solution to the challenge has arrived: the SANCO2 Heat Pump Water Heater. With a stainless steel storage tank, lowered energy demand, elimination of traditional refrigerants and the best performance around, the SANCO2 may well be the water heater to end all water heaters.

Unlike conventional heat pumps, the SANCO2 uses carbon dioxide as a refrigerant. Because of the properties of CO2, this allows the SANCO2 to function efficiently across a wide temperature range: it is able to extract heat from the air down to ambient temperatures of -20°F, and works without a backup coil or heating element in a wide range of climates. There is no capacity loss or reduction in COP above freezing; below freezing, there is only a small reduction in COP, far lower than traditional circulating coolants. The SANCO2 warms water up to 175°F at a rate of 0.3 gallons/minute. And with a first hour rating of 97.8, the highest in the business, the SANCO2 is almost twice as efficient as traditional heat pump water heaters.

For both energy efficiency and reducing the environmental impact of buildings, the SANCO2 is ideal. Because of the high efficiency of the CO2-based heat pump system, the SANCO2 uses 70% less energy than traditional water heaters. The system runs on electricity, and therefore has the potential to be emissions-free. Operating costs and emissions can be further mitigated by running the system on off-peak power, and storing hot water for later use. And when compared other refrigerants commonly used in heat pump systems, CO2 has relatively low global warming potential, and is not ozone-depleting. Other refrigerants often found in these heat pump systems, such as R410A, have global warming potential as much as 2000-4000 times higher than CO2.


Efficiency and Performance

  • Coefficient of performance (COP) of 5.0, by far the highest of any system on the market
  • Heat pump capacity of 4.5kW, or 15,400Btu/hr
  • Uses 70% less energy than traditional water heating systems
  • Ambient air operating temperature range: -20°F to 110°F
  • Water temperature setting range: 130°F to 175°F
  • Highest first hour rating (97.8) of any heat pump water heater - almost twice the average for traditional HPWH systems
  • 101 gallons at 135°F delivered in the first hour for the 83-gal system
  • Warms water at a rate of 0.3 gallons/minute
  • Energy Factor (EF) of 3.84 for the 83-gal system (NEEA Tier 3+)
  • Backup electric heating element not needed in the storage tank
  • Water can be heated using off-peak power, further reducing operating costs
  • Faster recovery after a hot water draw than traditional HPWH systems

    Design and Installation

    • Two part system (exterior compressor and interior water tank) allows for easy installation and maintenance
    • Tank and compressor can be installed as much as 50 feet apart, with 16 feet of lift
    • Outdoor noise operating level of only 37dB is whisper-quiet
    • The slimline design of exterior compressor significant reduces its footprint relative to traditional compressors
    • Scalability: additional compressors and/or tanks can be added for larger buildings
    • All controls located in tank/indoor thermostat

    Quality and Longevity

    • The stainless steel storage tank is corrosion resistant, and carries a 15-year warranty
    • Compressor, refrigeration system, and all other outdoor components carry a 10-year warranty

    The "split" design of the SANCO2 HPWH is another unique design feature that enhances the performance of the system. Traditional, integrated HPWHs, in which the compressor and the tank are co-located, draw heat from the interior of the building and therefore cool year-round - not ideal in colder climates, as it would increase space heating demand. The SANCO2 uses outside air instead, and the outdoor compressor can be as far as 50 feet from the interior tank, with as much as 16 feet of lift. The hot and cold water pipes connecting the compressor to the tank are only 1/2" in diameter, allowing for integration of the units even at a distance (use Roflex 20 or Roflex 20 Multi to air seal line sets). And because both units are far smaller than traditional HPWH systems, the tank can easily fit anywhere, and the slim profile and relative quiet of the exterior compressor make it easy to place near the home.

    SANCO2's applications are not limited to simply providing domestic hot water - though it does a fantastic job of meeting all DHW needs with much less energy than conventional systems. But because of its efficiency, for buildings with very low heating demands - like passive or near-passive houses - the SANCO2 can provide hot water for both DHW needs and for space conditioning. Because of its ability to meet these simultaneous needs and be integrated into a dual heat pump water heater-space conditioning system, SANCO2 serves as an ideal solution for high-performance, multi-family buildings and low-energy homes. Download the brochure for a handy summary of the system.

    Continue the conversation on social media