APUS 190000 BTU Tankless Water Heater Review: Pros & Cons

Introduction

Replacing a traditional storage tank water heater with a tankless model is a decision that can affect both your energy costs and daily convenience—especially if you live in a cold climate or have a large household. The APUS 190000 BTU tankless water heater is one of the more powerful propane-driven options on the market, promising up to 8.1 gallons per minute (GPM) and the ability to run multiple showers and faucets at the same time. But does it live up to the promise? In this APUS 190000 BTU tankless water heater review, we’ll examine the manufacturer’s claims, the included features, and what you should consider before buying.

What Is the APUS 190000 BTU Tankless Water Heater?

The APUS 190000 BTU outdoor tankless water heater (model AP-AWH-W26LPG) is a propane-powered, whole-house instant hot water system. It is designed for outdoor wall mounting only (not for indoor installation) and delivers on-demand hot water without the need for a storage tank. Key characteristics include:

• Fuel: Liquid propane (LPG).
• Heat output: 190,000 British Thermal Units (BTU).
• Flow rate: Up to 8.1 GPM.
• Application: Whole-home use—can supply up to 3 showers plus 2 faucets simultaneously, according to the manufacturer.
• Control: Works with the Tuya smart app (WiFi) and includes a wired remote controller.
• Safety features: Freeze protection, overheat protection, flame failure safeguards, and 10-level wind resistance.

The APUS targets homeowners who already have propane service or are willing to install an outdoor propane tank, and who want a compact unit that still offers high flow rates for simultaneous use.

Key Features & Specifications

Below is a detailed look at the main specifications and technologies claimed by APUS. Note: These are based on manufacturer data and publicly available information; real-world performance may vary based on installation, incoming water temperature, and local gas pressure.

Feature	Specification / Detail
Heat Output	190,000 BTU (propane)
Flow Rate	8.1 GPM (max)
Minimum Flow to Activate	0.79 GPM
Temperature Range	95°F – 149°F
Temperature Accuracy	±1°F (claimed)
Dimensions (W×H×D)	22.48 × 15.51 × 6.54 inches
Mount Type	Outdoor wall mount
Power Source	120V AC (required for electronics & fan)
Water & Gas Connections	¾-inch NPT (standard)
Heat Exchanger Material	100% oxygen-free copper (claimed to be 30% more efficient than conventional copper)
Combustion Technology	Intelligent staged combustion (20% energy savings claimed)
Wind Resistance	10-level wind rating
Anti-Freeze Protection	Electric heating element (active freeze protection)
Smart Home Compatibility	Works with Tuya App (WiFi)
Warranty	2-year full coverage on all components
Certifications	UL/ETL (as per typical APUS units; verify model)

The unit also includes a wired remote controller with a 16-foot cable, allowing you to set the temperature from inside the house or near the point of use.

What’s Included in the Box

According to the product listing, the package includes:

• APUS tankless water heater (main unit)
• Installation and owner’s manual
• Wired remote controller (optional use) with cable
• Screws, wall anchors, and mounting bracket hardware
• Closed circuit terminals (for electrical wiring)

It is worth noting that the water and gas connections are standard ¾-inch NPT, so you will need to supply your own shut-off valves, flexible gas line, and water lines. Professional installation is strongly recommended.

How to Use the APUS 190000 BTU Tankless Water Heater

Setup & Installation

The unit is designed for outdoor installation only—it must be mounted on an exterior wall that can support its weight and with adequate clearance around the unit for proper ventilation. Typical installation steps include:

• Mounting the heater on a sturdy wall using the included bracket and screws.
• Connecting the cold water inlet and hot water outlet (¾-inch copper or PEX).
• Connecting the propane gas line with a shut-off valve. The unit requires a gas supply that can deliver sufficient BTU capacity (consult a licensed professional to verify your propane tank and regulator).
• Wiring a dedicated 120V AC outlet near the unit. The heater requires electricity to power the control board, fan, and ignition system. In case of a power outage, the unit will not operate.
• Optionally connecting the wired remote controller or pairing with the Tuya app via WiFi.

Important: Always follow local building codes. Improper installation can lead to gas leaks, fire hazards, or carbon monoxide exposure.

Operation

Once installed and powered, the heater operates on demand. When you open a hot water tap, the unit’s electronic ignition lights the burner, heating the water as it passes through the copper heat exchanger. The temperature can be set via the wired controller or the app anywhere between 95°F and 149°F in 1°F increments.

The manufacturer states a minimum flow of 0.79 GPM is needed to trigger ignition—a lower than average threshold that helps the unit work well even with low-flow fixtures. The smart seasonal technology adjusts the gas flow based on incoming water temperature to improve efficiency.

Maintenance

• Descaling: In areas with hard water, mineral deposits can build up inside the heat exchanger. Periodic descaling (every 6–12 months) with a vinegar or citric acid solution is recommended.
• Cleaning the air intake filter: If the unit is installed in a dusty or coastal environment, check and clean the intake screen to maintain proper combustion.
• Winter precautions: Although the unit has active freeze protection (electric heating), the manufacturer recommends draining the unit if you plan to leave it unused for extended periods in sub-freezing temperatures.

Troubleshooting Common Issues

• No hot water / burner does not ignite: Check that gas supply is on, the electrical outlet is live, and the minimum flow rate is being met. Error codes on the digital display can help diagnose (refer to manual).
• Temperature fluctuations: Ensure that the flow rate does not exceed the unit’s capacity (8.1 GPM) at the desired temperature rise. Also check for undersized gas line or low incoming gas pressure.
• WiFi/app connectivity: If the remote app fails to pair, verify that the heater is within range of your WiFi network (2.4 GHz band only) and that the Tuya app is up to date.

Performance & User Experience

Because we have not personally tested this unit, we rely on manufacturer specifications and aggregated customer feedback (as of this writing, the product has a 4.3-star rating from 42 reviews on Amazon). Common themes from users include satisfaction with the strong flow rate, ease of temperature adjustment, and the compact size. Some have noted that the unit is quiet during operation and that the WiFi control works reliably once set up.

On the flip side, a few reviewers reported difficulty with the initial setup, particularly if they were not experienced with gas plumbing. Others mentioned that in very cold climates (incoming water below 40°F), the flow rate needed to be reduced to achieve the desired temperature—this is normal for any tankless heater. The claimed ±1°F accuracy appears to hold true for steady flow conditions.

It is important to set realistic expectations: the maximum 8.1 GPM flow rate assumes a 35°F temperature rise (e.g., from 70°F to 105°F). For larger temperature rises (common in northern winters when incoming water may be 40°F), the actual GPM will be lower. Calculating your required flow rate using the formula GPM = BTU / (ΔT × 500) can help determine if this unit is suitable for your home.

Pros and Cons

Pros

• High output: 190,000 BTU and 8.1 GPM provide enough capacity for most medium-to-large homes.
• Smart control: WiFi app (Tuya) and wired remote offer convenient temperature adjustments.
• Compact size: At just over 6 inches deep, it fits on smaller exterior walls.
• Low minimum flow: 0.79 GPM activation means it works well with water-saving fixtures.
• Wind resistance: 10-level wind rating helps maintain stable operation in breezy areas.
• Freeze protection: Electric anti-freeze system reduces risk of damage in cold weather.
• Advanced heat exchanger: Oxygen-free copper is more durable and efficient than standard copper.

Cons

• Outdoor only: Cannot be installed indoors, which limits options for some homes.
• Electricity required: Will not work during a power outage (unlike some fully gas-fired units with no electric components).
• Propane fuel only: This model is not convertible to natural gas (different burner assembly). You must use liquid propane.
• Professional installation recommended: Gas and electrical work can be expensive if you are not handy.
• Condensation possible: In humid conditions, the heat exchanger may sweat; proper drainage is needed.
• Limited app support: The Tuya app works well but may require some troubleshooting for first-time pairing.

Comparison With Alternatives

To help you decide, here is how the APUS compares with two other popular tankless water heaters in a similar category (no pricing included):

Product	BTU / kW	GPM (max)	Fuel	Indoor/Outdoor	Smart Features	Notable Difference
APUS 190K BTU	190,000 BTU	8.1 GPM	Propane	Outdoor only	WiFi + wired remote	High wind resistance, low min flow
Rheem RTEX-13	13 kW (44,000 BTU equiv.)	3 GPM (electric)	Electric	Indoor/outdoor	No WiFi	Much lower flow; good for small homes or point-of-use
Rinnai RUC98i	199,000 BTU (NG/LP)	9.8 GPM (NG)	NG or LP (convertible)	Indoor/outdoor	WiFi (Rinnai Control-R)	Higher flow, condensing (96% efficiency), higher price

The APUS sits in the mid-range of propane tankless heaters—its 8.1 GPM is suitable for homes with 2–3 bathrooms, but a condensing unit like the Rinnai offers slightly higher flow and indoor installation flexibility. If you do not have propane service, an electric tankless (like the Rheem) may be an alternative, but its flow rate will be significantly lower.

Who Should Buy This Product?

Ideal for:

• Homeowners with an existing or planned propane tank who want a whole-house tankless solution.
• Those living in areas with moderate to high wind (the 10-level wind resistance adds reliability).
• Households that need to supply multiple hot water fixtures simultaneously (2–3 bathrooms, kitchen, laundry).
• Users who appreciate remote temperature control via app or wired controller.
• DIYers comfortable with gas and electrical installation (or willing to hire a professional).

May not be the best choice for:

• Homes without propane service or where natural gas is preferred (this model is propane-only).
• Indoor applications (the unit is for outdoor use only).
• Very cold climates where incoming water temperature drops below 40°F and a high flow rate is required—the 8.1 GPM will drop significantly at a high temperature rise.
• Those who want a non-electric backup during power outages (the unit needs 120V).
• Small households with low hot water demand—a smaller, less expensive unit may suffice.

Expert Tips

• Calculate your required flow rate correctly: Use the formula: required GPM = (Total simultaneous fixture flow) × (Temperature rise needed). Make sure the 8.1 GPM is enough for your peak demand.
• Check your propane tank size and regulator: A 190,000 BTU burner demands a substantial gas supply. A standard 20-lb BBQ tank is usually insufficient; you may need a 100–500 gallon tank with a high-capacity regulator. Consult a gas professional.
• Install a water softener if you have hard water: Tankless units are more prone to scaling than tank heaters. A water softener will prolong the heat exchanger life and maintain efficiency.
• Use a pressure regulator if supply pressure exceeds 80 psi: High water pressure can cause flow noise and reduce lifespan. A pressure regulator set to 50–60 psi is typical.
• Flush the heat exchanger annually: Even with a softener, calcium can build up. Use a descaling kit (vinegar or citric acid) to prevent performance loss.
• Position the remote controller wisely: Place it near your main shower or kitchen to allow quick temperature adjustments without going outside.

Common Mistakes to Avoid

1. Undersized gas line: Running the heater with a gas line that’s too long or too narrow (e.g., ½”) can starve the burner, causing incomplete combustion, soot, or failure to ignite. Ensure your gas line can deliver at least 190,000 BTU per hour at the required pressure.
2. Ignoring freeze protection: While the unit has anti-freeze, it relies on electric power and proper water flow. If you have a power outage while the unit is idle in freezing weather, drain the unit.
3. Installing in a recessed or enclosed area: Outdoor installation does not mean placing the unit inside a cabinet or tight alcove. Adequate clearance for combustion air and exhaust is necessary.
4. Not using the right pipe material: Connecting with galvanized iron pipes may cause corrosion; copper or stainless steel flexible connectors are recommended.
5. Setting the temperature too high: Temperatures above 125°F increase scalding risk, especially for children or elderly users. Use the remote to set a safe maximum.
6. Skipping the manual: The APUS unit has a specific error code display and settings menu. Familiarize yourself with the manual before calling for service.

Where to Buy

The APUS 190000 BTU tankless water heater is available online through major retailers. The product listing we reviewed offers the unit with standard packaging. If you decide to purchase, consider verifying the seller’s return policy and warranty support.

Final Verdict

After analyzing the specifications, user feedback, and comparing it with alternatives, the APUS 190000 BTU tankless water heater appears to be a capable and well-featured propane unit for homeowners who need whole-house hot water output. Its smart controls, wind resistance, and low activation flow set it apart from many basic tankless models. However, its outdoor-only design and reliance on 120V power are limitations to consider.

• Performance score: Solid for propane applications; expect reduced flow in cold winters.
• Value: Competitive given the generous feature set (WiFi, remote, freeze protection).
• Reliability: Early customer reviews are generally positive, but long-term data is limited.

If you already have propane and need a compact, smart-capable tankless heater, the APUS is worth considering. For those who require indoor installation or want to use natural gas, other models may be a better fit. As with any major appliance, professional installation is strongly advised to ensure safety and optimal performance.

For a deeper look into other tankless water heater options, check out our guide to best tankless water heaters and our propane vs. electric tankless comparison.

Frequently Asked Questions (FAQ)

Can the APUS 190000 BTU be used indoors?

No. This unit is designed for outdoor wall mounting only. Installing it indoors would create a safety hazard (carbon monoxide) and violate building codes. The manufacturer explicitly states outdoor use.

Does the heater need electricity?

Yes, the heater requires a 120V AC electrical connection to power the control board, fan, and electronic ignition. It will not operate during a power outage.

What is the minimum flow rate to activate the burner?

According to the manufacturer, the minimum flow is 0.79 GPM. This is lower than many tankless units (typically 0.5–1.0 GPM) and allows the heater to work well with low-flow faucets and showers.

How long does it take to get hot water?

Since the unit is instantaneous, hot water arrives as soon as the cold water in the pipes between the heater and the tap is pushed out. This “lag time” depends on the distance from the heater. The burner typically lights within seconds of flow.

Is the APUS unit compatible with a recirculation system?

The product does not include a built-in recirculation pump or dedicated return line. However, you can add an external recirculation system, but the manufacturer’s instructions should be consulted to avoid false firing.

What kind of warranty does APUS offer?

The unit comes with a 2-year full warranty on all components, covering parts and labor (as stated in the product details). Registering the product after purchase is recommended.

Can I use this heater with well water?

Yes, but you must install adequate filtration to remove sediment and minerals. Hard well water without softening will lead to rapid scaling and reduce the life of the heat exchanger.

Does the heater have a pilot light?

No, it uses an electronic hot surface or spark ignition (typical for modern tankless units). There is no standing pilot, which improves efficiency.

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