Introduction

If you’re looking for a whole-home hot water solution that doesn’t waste energy or take up floor space, a tankless water heater might be the answer. The APUS 190000 BTU tankless water heater promises instant hot water for up to five outlets simultaneously, all while offering smart controls and a compact design. But does it live up to the hype? In this APUS tankless water heater review and rating, we’ll take a balanced look at its features, performance expectations, and who it’s best suited for.

Whether you’re upgrading from a traditional tank water heater or building a new home, this APUS propane water heater review verdict will help you decide if it’s worth buying. We’ll cover the key specs, real-world usability, and how it compares to similar units on the market.

What Is the APUS 190000 BTU Tankless Water Heater?

The APUS 190,000 BTU Outdoor Tankless Water Heater is a propane-powered, wall-mounted unit designed for whole-house hot water delivery. It is a gas tankless water heater that heats water on demand, so you never run out of hot water during back-to-back showers or simultaneous appliance use. With an output of 190,000 BTU and a flow rate of 8.1 gallons per minute (GPM), it is aimed at medium to large households that need reliable hot water at multiple points.

This model falls into the category of high-efficiency condensing tankless water heaters, but note that it uses a non-condensing design (the manufacturer does not specify condensing; the staged combustion technology is likely a non-condensing approach). It is intended for outdoor installation, which means it vents directly to the outdoors and does not require additional venting through the roof or wall. The APUS unit also features WiFi connectivity and a wired remote controller, giving users flexible temperature adjustment from 95°F to 149°F.

Key Features & Specifications

Below is a detailed look at the specifications and standout features of the APUS 190,000 BTU propane water heater.

Feature	Specification
Power Source	Liquid Propane
BTU Output	190,000 BTU
Flow Rate	8.1 GPM
Minimum Flow to Activate	0.79 GPM
Temperature Range	95°F – 149°F (via remote or app)
Temperature Accuracy	±1°F (claimed)
Power Supply	120V AC (standard outlet)
Water & Gas Connections	3/4 inch NPT
Heat Exchanger Material	100% oxygen-free copper
Smart Home Compatibility	Works with Tuya Smart App
Dimensions (W x H x D)	22.48 x 15.51 x 6.54 inches
Weight	Approximately 35 lbs (based on similar models)
Wind Resistance Rating	10-level (claimed)
Anti-Freeze Protection	Electric heating element (keeps internal components warm)
Safety Features	Flame failure, overheat, freeze, and over-pressure protection
Warranty	2 years (full component coverage)

Smart Temperature Control

The APUS water heater can be controlled via the Tuya Smart app (available for iOS and Android) or through the included wired remote. According to the manufacturer, the unit maintains a consistent output temperature within 1°F of the set point. This is a common claim among tankless water heaters, and user feedback suggests that in ideal flow conditions, temperature stability is good. However, sudden changes in flow (e.g., opening another tap) may cause brief temperature fluctuations, which is typical for tankless units without buffer tanks.

Advanced Heat Exchanger

The heart of the system is a 100% oxygen-free copper heat exchanger. The company states it is 30% more efficient than conventional copper heat exchangers due to the material purity and design. Combined with intelligent staged combustion—which adjusts the gas burner output based on demand—the unit is said to achieve 20% energy savings compared to standard gas water heaters. While independent testing is not available, oxygen-free copper is known to resist corrosion better than standard copper, which could improve longevity.

All-Weather Construction

For outdoor installation, the APUS heater includes a wind-resistant design that can withstand wind speeds up to 10 on the Beaufort scale (roughly 55-63 mph). Additionally, an electric anti-freeze protection system kicks in when internal temperatures approach freezing, circulating warm water or activating a heating element to prevent ice damage. These features make it suitable for colder climates, though the unit must still be installed in a location that complies with local building codes for gas appliances.

What’s Included in the Box

When you purchase the APUS 190,000 BTU propane tankless water heater, you should expect the following components (based on the product listing):

Tankless water heater unit (AP-AWH-W26LPG)
Wired remote controller (optional) with 1 cable
Screws and wall anchors (mounting hardware)
Closed circuit terminals (for electrical connections)
Installation and owner’s manual
Expandable screw and additional mounting accessories

The remote controller is listed as “optional” but is included in the box. The unit does not come with the gas supply line, water shut-off valves, a dedicated 120V outlet, or venting (since it is designed for outdoor installation, it vents directly to the atmosphere). You will need to provide these elements for a complete installation, as well as propane supply piping.

How to Use

Setup

Because this unit is intended for outdoor installation, setup involves mounting the heater on a wall that can support its weight (approximately 35 lbs). The water and gas connections are standard 3/4 inch NPT, which are compatible with most household plumbing. The unit requires a 120V AC power outlet—this is used to power the control board, the electric anti-freeze system, and the WiFi module.

Important: You should have a licensed plumber or gas fitter handle the gas line connection and ensure proper gas pressure (propane at 11–13 inches water column is typical). The water inlet should be connected to the main cold water line with a shut-off valve, and the hot water outlet should be piped to the house distribution system. The manufacturer’s manual provides specific clearance requirements for outdoor installation—typically at least 3 feet from windows, doors, and gas meter regulators.

Operation

Once installed and the gas supply is turned on, plug the unit into a grounded 120V outlet. Turn on the hot water tap, and the heater will automatically ignite when it detects water flow above 0.79 GPM. You can adjust the desired temperature using the wired remote (which you can mount indoors) or via the Tuya app once you connect the heater to your home WiFi. The app allows you to set schedules, monitor usage, and adjust temperature remotely.

The unit is designed to handle up to five simultaneous outlets, such as two showers, two faucets, and a dishwasher. For the best performance, avoid running multiple high-flow appliances (like two showers and a washing machine) at the same time if the incoming water temperature is very cold (below 40°F), as the heater may struggle to maintain 8.1 GPM at a 100°F rise. In most regions, the 190,000 BTU output is sufficient for three standard showers simultaneously.

Maintenance

Routine maintenance is minimal for most tankless water heaters. The manufacturer recommends flushing the heat exchanger with vinegar or a descaling solution once a year to remove mineral buildup—especially if you have hard water. An isolation kit (field supplied) can make this process easier. You should also periodically inspect the air intake and exhaust for debris, and check the gas line for leaks. The external casing can be wiped down with a damp cloth.

Troubleshooting

If the heater fails to ignite, check that the gas supply is on, the power cord is plugged in, and the water flow is above 0.79 GPM. If you get error codes, refer to the manual. Common issues include “E1” (flame failure) which could mean the propane tank is low or the gas pressure is incorrect. “E2” indicates overheat; the unit may need to cool down. The WiFi pairing process can sometimes be tricky—ensure your phone is on a 2.4GHz band and the Tuya app is updated. If problems persist, contact APUS customer support through Amazon or their website.

Performance & User Experience

We have not personally tested this unit, so we rely on manufacturer claims and aggregated user feedback. The APUS 190,000 BTU tankless water heater is positioned as a high-output unit for whole-home use. The key performance indicators are flow rate and temperature rise.

At a 100°F rise (e.g., incoming water at 50°F and output at 150°F), the heater should deliver approximately 4.0 GPM based on the formula: GPM = BTU / (500 x ΔT) = 190,000 / (500 x 100) = 3.8 GPM. For a 60°F rise (more common in warmer climates), the flow rate can reach 6.3 GPM. The advertised 8.1 GPM is likely achievable at a lower temperature rise (around 45°F rise). So for homes in cold northern climates, you may not get the full 8.1 GPM at usable shower temperatures—that is typical for tankless heaters of this size.

Users on Amazon and other forums have reported that the unit provides consistent hot water for showers and appliances when the demand does not exceed its capacity. Some have noted that the WiFi app is convenient for preheating and adjusting temperature without going outside. A few complaints mention a slight delay in ignition (a few seconds) when first turning on a tap, which is common for non-recirculating tankless models.

The 0.79 GPM minimum flow rate is relatively low, meaning it can still activate with a slow-flowing faucet, but very low-flow fixtures (like some modern lavatory faucets) may need a minimum flow to be reliable. The wind-resistant design has been appreciated by users in gusty areas.

Overall, the APUS 190k heater appears to deliver on its core promise of unlimited hot water, but as with any tankless unit, performance is highly dependent on incoming water temperature and simultaneous usage. The smart features and durable construction add value, but the unit is not without its limitations, which we’ll cover next.

Pros and Cons

Pros

High BTU output (190,000) suitable for up to 3-4 simultaneous hot water uses in moderate climates.
Compact outdoor design saves indoor space and eliminates the need for venting through the roof.
App and remote control allow easy temperature adjustments and scheduling.
Low activation flow (0.79 GPM) helps with low-pressure situations.
Wind-resistant and electric anti-freeze protection for all-weather outdoor installation.
Oxygen-free copper heat exchanger is corrosion-resistant and claimed to be more efficient.
2-year warranty offers some peace of mind.

Cons

Non-condensing design may not be as energy efficient as condensing models (no Energy Star rating seen).
8.1 GPM rating is optimistic in cold climates; actual flow at high temperature rise will be lower.
Gas hookup and electrical connection require professional installation (additional cost).
Wired remote is included but the cable length may limit mounting options.
Limited brand reputation compared to established names like Rinnai or Noritz.
Customer service responsiveness is mixed according to some online reviews.

Comparison With Alternatives

Let’s see how the APUS 190k compares to two popular tankless water heaters in the same category.

Model	BTU	Max GPM	Energy Source	Control	Warranty	Condensing
APUS 190k (this review)	190,000	8.1 GPM	Propane	WiFi + remote	2 years	No
Rinnai RL94iP	199,000	9.5 GPM	Propane	WiFi optional	12 years (heat exchanger)	Yes (condensing)
Fogatti 180K	180,000	7.2 GPM	Propane	Remote only	3 years	No

The Rinnai RL94iP is a premium alternative with higher efficiency (condensing) and a longer warranty, but it comes at a higher price point. The Fogatti is a closer competitor with similar specs but lacks WiFi. The APUS offers smart features that the Fogatti doesn’t, but its warranty is shorter. For buyers who prioritize connectivity and have a moderate hot water demand, the APUS is a compelling value. However, for maximum efficiency and longevity, the Rinnai may be a better long-term investment.

Who Should Buy This Product?

Ideal Users

Homeowners looking to replace a 40-50 gallon tank water heater with a space-saving outdoor unit.
Those who want remote control of their water temperature via smartphone.
People in moderate climates (incoming water temperature above 50°F) who want reliable hot water for 2-3 showers plus other uses.
DIY-friendly homeowners who can handle basic mounting and have a propane line ready.

Not Ideal For

Large homes with heavy simultaneous hot water use (e.g., 4+ showers) in very cold regions.
Those who need very high efficiency to qualify for energy rebates – consider a condensing model.
Users who want a long manufacturer warranty without extended coverage.
Homes without an available 120V outlet near the installation site.

Expert Tips

Check your incoming water temperature. Before purchasing, measure your ground water temperature in winter. In very cold regions, you may need a higher BTU unit or a recirculation system.
Use a water softener or conditioner if you have hard water. Mineral buildup can reduce flow and damage the heat exchanger over time.
Install an isolation kit with shut-off valves and drain ports. This makes annual descaling much easier and extends the life of the unit.
Place the remote controller in a convenient indoor location (like a utility room or kitchen) so you can adjust temperature without going outside.
Keep the manual and warranty info handy. The APUS documentation includes troubleshooting codes that can save you a service call.

Common Mistakes

Underestimating the impact of cold inlet water. Many buyers assume the 8.1 GPM is always available. In reality, flow drops as water temperature drops. Plan your usage accordingly.
Using undersized gas piping. Propane tankless heaters require adequate gas pressure. A long run of small-diameter pipe can cause pressure drop and erratic operation.
Neglecting to register the warranty. Some outdoor units require registration within 30 days to activate full coverage. Check the APUS website.
Installing too close to windows or vents. Outdoor gas water heaters must have proper clearance to avoid recirculation of exhaust gases.
Forgetting the electrical outlet. Ensure a 120V outlet is installed within reach of the unit’s power cord (approx. 3-4 feet).
Not flushing the system annually. Even with soft water, a simple vinegar flush prevents scale and maintains efficiency.

Where to Buy

The APUS 190,000 BTU tankless water heater is available through major online retailers. The most current listing can be found on Amazon, where you can read additional customer reviews and check for any available promotions. As with any purchase, verify the seller’s return policy before buying.

View Product on Amazon

Final Verdict

After examining the specifications, user feedback, and comparable products, the APUS 190000 BTU tankless water heater appears to be a well-equipped option for households that need a propane-powered whole-home solution with smart controls. Its high BTU output and compact outdoor design make it a practical choice for those upgrading from a tank heater or building a new home.

We appreciate the inclusion of WiFi and a remote controller at this price segment, as well as the oxygen-free copper heat exchanger and wind-resistant construction. However, the non-condensing design and shorter warranty compared to premium brands mean it might not be the best for every situation. If you have a moderate hot water demand and live in a temperate to warm climate, this unit could serve you well. For colder regions or higher efficiency requirements, consider stepping up to a condensing model.

Our APUS 190,000 BTU review honest opinion: If you value connectivity and want to save space without breaking the bank, the APUS is worth buying. Just set realistic expectations regarding flow rates and installation requirements.

FAQ

1. How many bathrooms can the APUS 190K heater support?

According to the manufacturer, it can support up to 5 outlets simultaneously, including 3 showers and 2 faucets. Actual performance depends on groundwater temperature and flow rates of your fixtures.

2. Can this unit be installed indoors?

No, it is designed for outdoor installation only. Do not install it indoors, in a garage, or any enclosed space unless specifically permitted by local codes and with proper venting.

3. Does it work with natural gas?

This specific model (AP-AWH-W26LPG) is for liquid propane only. APUS sells a separate natural gas version; check the model number before purchasing.

4. How do I connect it to the Tuya app?

Download the Tuya Smart app, create an account, and add a device. The heater must be powered on and in pairing mode (usually initiated by pressing a button on the unit). Ensure your phone is connected to a 2.4GHz WiFi network.

5. What size gas line do I need?

For propane, a 1/2-inch or 3/4-inch line is typical depending on the distance from the tank. Always consult a licensed gas fitter to determine the correct pipe size.

6. Is there a cold water sandwich effect?

Like most tankless heaters, there can be a brief blast of cold water when the unit starts, then it stabilizes. Some users report a 2-3 second delay. Installing a small buffer tank can help.

7. How long does the heat exchanger last?

With proper maintenance (annual descaling), the oxygen-free copper heat exchanger should last many years. The manufacturer offers a 2-year warranty on the entire unit, which is shorter than some competitors.

8. Can I use this with a recirculation pump?

Yes, but you may need to install a check valve and ensure the pump flow is high enough to activate the heater. Some users have successfully integrated it with a basic recirculation loop.

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APUS 190000 BTU tankless water heater review – see more details about this product.

Read our best tankless water heaters guide for additional comparisons.

Check out propane tankless water heater buying tips for installation advice.

For more information on tankless water heater efficiency, visit the U.S. Department of Energy’s guide at Energy.gov.