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Non-Condensing Tankless Water Heaters
A high-efficiency, space-saving technology that can supply endless domestic hot water for residential applications. Unlike bulky tank water heaters that continuously reheat water, wasting energy.
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Non-Condensing Products
How Non-Condensing Tankless Water Heaters Work
High-efficiency non-condensing tankless units only heat water when you want it, unlike wasteful tank water heaters. In simple terms, cold water travels through one heat exchanger supplying endless hot water to the fixtures in your home. When you upgrade to a tankless water heater, you can save energy and money.
When a hot water tap is opened, the tankless water heater detects the flow
The flow sensor activates to determine the amount of hot water needed
The igniter activates
The gas control valve opens to supply the correct amount of gas
The burner ignites providing a flame to heat the water
Cold water passes through the heat exchanger
The unit determines outgoing set temperature and adjusts the flame to heat the water
Desired hot water amount delivered to the faucet
When a hot water tap is opened, the tankless water heater detects the flow
The flow sensor activates to determine the amount of hot water needed
The igniter activates
The gas control valve opens to supply the correct amount of gas
The burner ignites providing a flame to heat the water
Cold water passes through the heat exchanger
The unit determines outgoing set temperature and adjusts the flame to heat the water
Desired hot water amount delivered to the faucet
What is a non-condensing tankless water heater?
Non-condensing tankless water heaters are gas-fueled tankless water heaters with a single heat exchanger.
Unlike condensing tankless water heaters, non-condensing models don’t have a secondary heat exchanger to capture and recycle heat from the exhaust gas.
What type of venting is used for a non-condensing tankless unit?
The exhaust temperature of a non-condensing tankless water heater is typically higher than that of a condensing tankless water heater. Non-condensing tankless water heater typically require metal venting material in order to tolerate the higher temperature and corrosive nature of the exhaust gas.
What’s the difference between non-condensing & condensing tankless water heaters?
Non-condensing tankless water heaters have a heat exchanger (burner) that heats water as it flows through the unit. They vent hot exhaust gas which is why Navien non-condensing models are built with exhaust systems that tolerate high temperatures. Because the exhaust gas doesn't cool or condense inside the unit, non-condensing tankless water heaters don't need a drain.
Condensing tankless water heaters have a secondary heat exchanger that captures heat from the exhaust gas and uses it to preheat cold water before it’s fully heated by the primary heat exchanger. Because the exhaust gas loses heat and condenses inside the unit, condensing tankless water heaters require a drain and allow more types of venting material to be used.
Are non-condensing tankless water heaters better than condensing?
It depends on your preferences:
Non-condensing tankless water heaters offer more flexibility for installation because they don’t require a drain. They’re also smaller than condensing models, and need minimal maintenance. Non-condensing tankless water heaters have an efficiency rating of 0.81 UEF, which is much more efficient than traditional storage tank water heaters.
Condensing tankless water heaters offer an ultra-high efficiency rating of up to 0.96 UEF, as well as higher flow rates. They’re also compatible with more types of venting material like PVC and polypropylene. But condensing tankless water heaters need a drain for the condensate, and annual maintenance is recommended.
Condensing vs Non-Condensing Tankless Water Heaters
| Condensing | Non-Condensing | |
| Initial cost | Usually higher than comparable non-condensing | Usually lower than comparable condensing |
| Long term operating cost | Lower than typical non-condensing tankless and storage tank system | Could be higher than condensing but lower than storage tank systems |
| Efficiency | Ultra-high Efficiency (UEF up to .96) | High Efficiency (UEF > .80) |
| Maintenance requirement | Annual service recommended | Minimal |
| Venting | PVC acceptable | 3" x 5" metal concentric required |
| Installation Location | Indoor or Outdoor | Choice of interior or exterior |
| Durability | Stainless steel heat exchanger extend service life | Stainless steel heat exchanger extend service life |
| Dimensions | Slightly larger than non-condensing, about 70-80% smaller than tank system | Slightly smaller than condensing, 80% smaller than tank system |
Navien Non-Condensing Tankless Water Heaters
The Navien New NHW-A series and NPN series are a line of indoor/outdoor non-condensing tankless water heaters. These tankless water heaters typically have a longer lifespan than condensing models and require less maintenance.
Compare our advantages to other non-condensing tankless water heaters
ComfortFlow®
The NHW-A is designed with the patented ComfortFlow® recirculation system built in. This Navien exclusive innovation eliminates the need for an external pump and buffer tank.
Navitech™ exclusive stainless steel heat exchanger.
NPN series are the first and only non condensing tankless water heaters with a stainless steel heat exchanger to deliver unmatched durability and performance.
Navitech™ stainless steel burner.
Designed and manufactured by Navien to burn gas at higher efficiency than other systems on the market.
Cascading capability.
For increased domestic hot water flow demand, the NPN can be cascaded with another NPN unit.
NaviLink™ Wi-Fi remote control.
This optional accessory enables you to control temperatures remotely, access usage data and receive diagnostic notifications on your smartphone or tablet.
Space saving and lighter weight design.
These sleek wall-hung units use much less space and are substantially lighter than traditional tank water heaters and other non-condensing tankless water heaters.
New Navien NHW-A Non-Condensing Tankless Water Heaters, with built-in recirculation system
NHW-AI Series
Premium non-condensing tankless water heaters for indoor installations.
NHW-AE Series
Premium non-condensing tankless water heaters for outdoor installations.
New Navien NHW-S Premium Non-Condensing
Tankless Water Heaters
NHW-SU Series
Universal premium non-condensing tankless water heaters for indoor/outdoor installations.
NHW-160SU
Max DHW Input: 160,000 BTU/h
Indoor or outdoor wall-hung (vent cap kit required for outdoor)
Residential/Commercial
NHW-160SU
NHW-180SU
Max DHW Input: 180,000 BTU/h
Indoor or outdoor wall-hung (vent cap kit required for outdoor)
Residential/Commercial
NHW-180SU
NHW-199SU
Max DHW Input: 199,900 BTU/h
Indoor or outdoor wall-hung (vent cap kit required for outdoor)
Residential/Commercial
NHW-199SU
NHW-SE Series
Non-condensing tankless water heaters for indoor/outdoor installations.
Navien NPN Premium Non-Condensing
Tankless Water Heaters
NPN-U Series
Universal premium non-condensing tankless water heaters for indoor/outdoor installations.
NPN-160U
Max DHW Input: 160,000 BTU/h
Indoor or outdoor wall-hung
Residential/Commercial
NPN-160U
NPN-180U
Max DHW Input: 180,000 BTU/h
Indoor or outdoor wall-hung
Residential/Commercial
NPN-180U
NPN-199U
Max DHW Input: 199,900 BTU/h
Indoor or outdoor wall-hung
Residential/Commercial
NPN-199U
NPN-E Series
Non-condensing tankless water heaters for outdoor installations.
Lower energy bills, easier on the planet
Unlike systems that waste energy to heat large tanks of water, Navien NPN series tankless units utilize 82¢ of every $1 to heat your water. NPN only fires up when hot water is needed, allowing great utility savings and a lower impact on the environment.
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