Home Size Southern climate: 3-4 bathrooms
Northern climate: 2 bathrooms
Indoor Unit Dimensions 23.6” (H) x 13.8” (W) x 9.4” (D)
Outdoor Unit Dimensions 23.6” (H) x 13.8” (W) x 9.4” (D)
Weight 54 lbs. (SV and OD), 58 lbs. (DVC)
Gas Consumption
(NG & LP)
Max. 199,900 Btuh - Min. 16,000 Btuh
Capacity Range 0.5-9.8 Gal./min.
Energy Factor 0.82 (NG), 0.88 (LP)
Thermal Efficiency 84%
Temperature Settings 100-140° F (in 5° F Intervals) (9 options)
Accessories Anchoring Screws, Remote Control & Cord
(SV & OD models only), Power Cord Kit
(SV model only).


With more power than any tankless water heater in its class, the NR981 series is ideal for mid-size homes with up to 4 showers. Built-in features include safety lock-out, freeze protection, and high elevation adjustment. PVC CANNOT be used for venting.

Owner's Manual
NR981 Owner's Guide


Click for actual home installation photos:
Installation #1:

Installation #2:

These units offer several innovations:
Safety lock out - Default max. 120 degrees (refer to owner's manual for higher temp)
Dual flame burner - Noritz exclusive! Minimizes temperature fluctuations.
Fully modulating - Automatically adjusts burner level accordingly.
Turbo Flow - Up to 9.8 GPM @ 35 degree temperature rise (7.5 GPM @ 45 degree rise).
Quick Connect - Doubles the output by connecting two identical heaters.
Direct ignition - No standby pilot light.
Thermal fuse - Automatic overheat protection system.
Resin coated PC board - Increases durability and protection from elements.
Automatic air regulator - Monitors internal temperature/maximizes burner efficiency.
Commercial grade heat exchanger - 25% thicker piping than our competition