| Efficiency ratings (UEF (NG & LP)) | 0.81 |
| Flow rate (DHW) (35°F temp rise) | 8.5 GPM |
| Flow rate (DHW) (45°F temp rise) | 6.6 GPM |
| Flow rate (DHW) (67°F temp rise) | 4.5 GPM |
| Minimum flow rate | 0.4 GPM, < 0.01 GPM option* |
| Connection sizes (Cold water inlet) | 3/4" NPT |
| Connection sizes (Hot water outlet size) | 3/4" NPT |
| Connection sizes (Gas inlet) | 3/4" NPT |
| Natural gas supply pressure (from source) | 3.5 " WC to 10.5 " WC |
| Propane gas supply pressure (from source) | 8 " WC to 13 " WC |
| Natural gas manifold pressure (min-max) | 2.3 " WC to 0.7 " WC |
| Propane gas manifold pressure (min-max) | 4.5 " WC to 1.3 " WC |
| Power supply (Main supply) | 120V AC, 60 Hz |
| Power supply (Normal) | 100 W |
| Power supply (Standby) | 4 W |
| Power supply (Anti-frost) | 114 W |
| Power supply (External pump) | < 150 W, 1.5 A W |
| Power supply (Fuse) | 5.0 A |
| Dimensions | 17.3" W x 26.5" H x 10.3" D |
| Boiler weight | 65 lbs |
| Materials (Casing) | Cold rolled carbon steel |
| Materials (Heat exchangers) | Stainless steel |
| Safety Devices | Flame rod, APS, VID (vent installation detector), ignition operation detector, water temperature high limit switch, power surge fuse |
| AHRI number | 212617042 (Natural gas) 212617048 (Propane) |
| CSA | Yes |
| NSF (Standard 5) | Yes |
| Low Lead (<0.25%) | Yes |
| Gas input (Domestic hot water) | 10,700 - 180,000 BTU/h |
| DHW water pressure | 15-150 PSI |
| Ultra low NOx | Yes |
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Description
The Navien NHW700-180AI-NG is a compact tankless water heater from Navien's NHW series with the recirculation pump and buffer tank built in. Indoor installation.
Rated input is 10,700 - 180,000 BTU/h on natural gas. It modulates from 180,000 BTU/h all the way down to 10,700, so it is not running at full fire to fill a sink.
How much hot water you actually get
Navien rates every tankless unit by temperature rise, because the colder the incoming water, the less of it one burner can heat. Here is what the NHW700-180AI-NG delivers:
| Temperature rise | Flow rate | Typical use |
|---|---|---|
| 35°F | 8.5 GPM | Warm-climate groundwater, or a preheated feed |
| 45°F | 6.6 GPM | The usual design point across most of the U.S. |
| 67°F | 4.5 GPM | Northern winter, incoming water near 40°F |
Sized against a 2.5 GPM showerhead, the 67°F column is worth roughly one shower on the coldest day of the year, and more than that the rest of the year. Size to the 67°F row if your winter groundwater runs cold.
Minimum activation flow is 0.4 GPM, so it fires for a hand wash, not just a full shower.
With a Navien recirculation setup this unit also supports the low-flow activation option, down to under 0.01 GPM.
The recirculation pump and buffer tank are built in, so hot water reaches the far fixture without the wait and without a second box on the wall.
Installing it
- Cabinet: 17.3" W x 26.5" H x 10.3" D
- Weight: 65 lbs
- Water connections: 3/4" NPT cold in, 3/4" NPT hot out
- Gas connection: 3/4" NPT
- Water pressure range: 15-150 PSI
- Power: 120V AC, 60 Hz
- Venting: per the Navien installation manual for this model — this is a non-condensing unit and does not vent in PVC
- Heat exchanger: Stainless steel
Ratings and certifications
- UEF: 0.81
- CSA certified
- NSF Standard 5
- lead free (<0.25%)
- ultra low NOx
- AHRI: 212617042 (Natural gas) 212617048 (Propane)
Model details
- Brand: Navien
- Manufacturer part number: NHW700-180AI-NG
Ships in the manufacturer's carton. Shipping is calculated at checkout by weight, dimensions and destination. Gas connection and venting must be done by a licensed installer, to the Navien manual and to your local code.