Condensing
Non-Condensing
Navien NPE-2 Series, New NHW-A Series, & NPN Series high-efficiency tankless water heaters provide endless domestic hot water, all while keeping your utility bills low.
A tankless water heater is a type of water heater that doesn’t use a storage tank to heat water. Instead, hot water is produced only when you need it. Tankless water heaters are smaller and more efficient than traditional water heaters.
Navien offers models of tankless water heaters that use either condensing or non-condensing technology. Details on the differences between the two are below.
Condensing Tankless
Water Heaters
Navien Premium Efficiency condensing tankless water heaters are the #1 selling high efficiency condensing tankless water heaters in North America. The NPE-2 series offers ultra-high efficiency up to 0.96 UEF to keep your utility bills low, endless hot water, and exclusive ComfortFlow® technology with a built-in recirculation pump and buffer tank.
New NPE-A2 Series
Three NPE-A2 Advanced Premium models offer a Uniform Energy Factor up to .95 and feature Navien’s patented ComfortFlow system.
New NPE-S2 Series
Four NPE-S2 Standard Premium models offer a Uniform Energy
Factor up to .96, providing more output, lower installation costs
and lower operating costs.
Non-CondensingTankless Water Heaters
Navien premium non-condensing tankless water heaters deliver a continuous flow of hot water for as long as you need it. No waiting for a tank to reheat more water, wasting time and energy. NPN & NHW-A series are the only non-condensing tankless water heaters to offer NaviTech™ stainless steel heat exchanger and stainless steel burner for durable and eco-friendly performance.
New NHW-AI Series
NHW-AI (Advanced Interior) models are the only indoor non-condensing tankless water heaters with ComfortFlow® built-in recirculation pump and buffer tank for faster hot water and no cold water sandwiches.
New NHW-AE Series
NHW-AE (Advanced Exterior) models are the only outdoor non-condensing tankless water heaters with ComfortFlow® built-in recirculation pump and buffer tank delivering hot water faster without cold water sandwiches.
NPN-U Series
NPN-U (Universal) premium non-condensing tankless water heaters offer a compact tankless solution, good for retrofits in both indoor and outdoor installations.
NPN-E Series
NPN-E (Exterior) non-condensing tankless water heaters offer a compact tankless solution ideal for retrofits outdoor installations.
Condensing vs Non-Condensing Tankless Water Heaters
What’s the difference between condensing and 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 | Indoors or Outdoors (wall mounted) | Indoors or Outdoors (wall mounted) |
| 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 |
Learn more about the
types of tankless water heaters
All the hot water you need, for as long
as you need it
NAVIEN TANKLESS WATER HEATERS FEATURES
Bulky tanks are history... Navien high efficiency tankless is the future
- Endless hot water when you want it
- Compact, space-saving design: wall-hung units free up floor space
- Lower energy bills
- Longer life than tanks
- 15 year warranty dual stainless steel heat exchangers
What does high efficiency mean for tankless water heaters?
Tankless water heaters heat water only as it’s needed, which makes them more efficient than even the highest-efficiency tank style gas water heater. According to the U.S. Department of Energy, tankless water heaters can be up to 34% more efficient than storge tank water heaters.
High-efficiency tankless water heaters are rated by a UEF: Uniform Energy Factor. This rating is based on how much energy the unit uses, and what percentage of that energy is used to power the unit. Navien’s NPE-2 series condensing tankless water heaters have up to .96 UEF, which is at the top of the high-efficiency range:
| Type | UEF Range |
| Condensing tankless water heaters | .85 - .96 |
| Non-condensing tankless water heaters | .80 - .82 |
| Gas storage tank water heaters | .54 - .72 |
Switching from a conventional gas water heater to a Navien high efficiency tankless water heater (gas or liquid propane) means you’ll use less fuel to heat the same amount of water.
Tankless Water Heaters FAQs
Below are the top questions (and answers) about tankless water heaters from our customer service team.
Is it worth switching to a tankless water heater?
It is worth switching to a tankless water heater if you are looking for a more efficient option. Tankless water heaters can save you money on your energy bill, and they can also have a longer lifespan than traditional water heaters.
How long do Navien tankless water heaters last?
Navien tankless water heaters have a lifespan of up to 20 years. However, proper maintenance is required in order to achieve this lifespan.
What size tankless water heater do I need?
To choose the right size tankless water heater for your home, you will need to consider a few factors, such as: the number of people in your household, the average water usage in your household, and the climate in your area.Use our Navisizer tool to quickly find the right model for your home or business.
Do tankless water heaters need a condensate drain?
Condensing tankless water heaters need a condensate drain. This is because when the water is heated, it produces condensation that needs to be drained away. The condensate drain ensures that this doesn’t build up and cause problems with the tankless water heater.Non-condensing tankless water heaters do not need a condensate drain.
How often do I need to descale my tankless water heater?
Descaling is a process that removes mineral deposits from the inside of the tankless water heater. It’s something that needs to be done yearly, unless you have very soft water.
How do you install a tankless water heater?
Installing a Navien tankless water heater is best done by a licensed plumbing contractor professional because it involves disconnecting and reconnecting gas lines. Venting and wiring also require professional expertise to ensure the installation meets building codes. Use Navien’s installer and service locator to find a specialist in your area.
Where can I buy Navien tankless water heaters?
A Navien tankless water heater must be purchased and installed by a licensed plumber. Find a Navien installer near you.
How much power does a tankless water heater need?
Navien tankless water heaters only require 2-4 Amps to run, and don’t need a dedicated electrical line. All Navien tankless water heaters have a factory-installed 3-pronged (grounded) plug and can be plugged into any grounded electrical outlet nearby.
