Manual
49-50300-2  5
Water Heater Sizing Information
For existing home replacements:
Replacing an existing tank water heater? If your 
current water heater has provided adequate hot water, 
and no other plumbing changes and/or renovations 
that would require additional hot water demand are in 
process or planned, then:
• The GeoSpring™ Hybrid Water Heater can replace 
an equivalent size or smaller standard electric water 
heater. 
• If switching from gas to electric, the GeoSpring™ Hybrid 
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tank type water heater. 
For new construction installation:
Residential Water Heater Sizing Guide
Family 
Size
Demand*
Gallon Capacity Recommended
Electric 
or GeoSpring 
™
Gas
5+
High 100 (378.5L) 75 (283.9L)
Avg or Low 80 (302.8L) 50 (189.3L)
3 to 4
High 80 (302.8L) 50-75 (189.3-
283.9L)
Avg or Low 50 (189.3L) 40 (151.4L)
2 to 3
High 50 (189.3L) 40-50 (151.4-
189.3L)
Avg or Low 40 (151.4L) 40 (151.4L)
1 to 2
High 40-50 (151.4-
189.3L)
40-50 (151.4-
189.3L)
Avg or Low 30 (113.6L) Avg or Low
*Assumptions for Avg or Low Demand household:
- Use of standard or low flow shower heads (2.5 gpm/11.4 
L per minute or less)
- No showers with multiple shower heads and/or body jets.
- Standard bathtub (no oversized/jetted tubs)
Water Heater Capacity and Increasing 
Temperature Setpoint:
The water heater temperature setting strongly impacts 
the amount of usable hot water available for showers 
and baths.
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of water heaters, including the GeoSpring™, is 
performed according to Department of Energy (DOE) 
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• 
Safety regulations require a factory setting no greater than 
125°F (52°C) for all new water heaters. Therefore, if your 
old water heater was set to a hotter temperature than 
your new water heater with a factory set setpoint of 120°F 
(49°C), the new water heater may seem to provide lower 
capacity than your old water heater. This can be corrected 
by increasing the temperature setpoint.
•  If more hot water capacity is desired, increasing the 
temperature from 120°F to 135°F (49°C to 57°C) will 
enable the same tank of hot water to last about 25% 
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or faucet.
•  Increasing the water temperature setpoint may improve 
the cleaning performance of dishwashers and washing 
machines.
• The user can adjust the temperature setting to meet 
their needs. Always read and understand the safety 
instructions contained in the owner’s manual before 
adjusting the temperature setpoint.
Mixing Valves
• 
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commercially available. Contact a licensed plumber or the 
local plumbing authority for further information.
OPERATING INSTRUCTIONS: Sizing Information










