Best APUS Tankless Water Heaters Under $300: 3 Spec-Based Picks
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Finding the best APUS tankless water heaters under $300 requires focusing on published specifications. We compared 3 models to help you match performance to your home. The APUS 3.6 GPM Propane Tankless Water Heater leads because its 80k BTU output ensures steady hot water for indoor use. This unit fits buyers who prioritize temperature accuracy and a compact 19.3-inch width. Each pick relies strictly on data like flow rate, voltage, and dimensions. This guide helps you decide which unit meets your specific hot water demands without guessing.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | APUS 3.6 GPM Propane Tankless Water Heater Best overall | Indoor propane hot water needs | Check price of APUS 3.6 GPM Propane Tankless Water Heater on Amazon |
| 2 | APUS 14kW 3.3 GPM Electric Tankless Water Heater Also great | Single sink or shower point-of-use applications | Check price of APUS 14kW 3.3 GPM Electric Tankless Water Heater on Amazon |
| 3 | APUS 18kW 4.4 GPM Tankless Water Heater Best budget | high flow whole-house electric heating | Check price of APUS 18kW 4.4 GPM Tankless Water Heater on Amazon |
The best fit for you
- You need precise temperature control for indoor propane use APUS 3.6 GPM Propane Tankless Water Heater Its 80k BTU output and digital display ensure steady, accurate hot water indoors.
- You have limited space for a single sink application APUS 14kW 3.3 GPM Electric Tankless Water Heater This 11.4-inch wide 14kW unit fits tight spots while providing precise temperature control.
- You require high flow for whole-house electric heating APUS 18kW 4.4 GPM Tankless Water Heater Its 18kW power and 4.4 GPM flow rate support multiple sinks or showers.
Our 3 picks
APUS 3.6 GPM Propane Tankless Water Heater
Best for: Indoor propane hot water needs
- Fuel Type
- Propane Gas
- Flow Rate
- 3.6 GPM
- BTU
- 80,000 BTU
- Installation Location
- Indoor
- Temperature Control
- 95°F–140°F, ±1°F
- Dimensions
- 20.55 H × 13.27 W × 5.91 D in
View on Amazon: APUS 3.6 GPM Propane Tankless Water Heater Affiliate link
This APUS propane unit delivers 80,000 BTU of heating power with a flow rate of up to 3.6 GPM. It maintains temperature within ±1°F of your setting, adjustable from 95°F to 140°F. The compact design fits indoor spaces, measuring 20.55 inches in height. It features an LED touchscreen and oxygen-free copper heat exchangers for 85% thermal efficiency. This model suits small households needing reliable on-demand hot water without the bulk of a tank.
Pros
- 80,000 BTU heating capacity
- 3.6 GPM flow rate
- Precise ±1°F temperature control
- 85%+ thermal efficiency
- LED digital display
Cons
- Indoor installation only
- 2-year warranty coverage
- Requires propane fuel source
Good fit if
- You need a compact unit for small spaces
- You want precise temperature stability
- You have indoor propane access
Skip if
- You require outdoor installation
- You need higher flow rates
- You prefer natural gas
Verdict: APUS 80k BTU Propane Tankless Heater provides steady hot water with precise control for indoor use. It fits buyers who prioritize temperature accuracy and compact size over outdoor versatility.
APUS 14kW 3.3 GPM Electric Tankless Water Heater
Best for: Single sink or shower point-of-use applications
- Fuel Type
- Electric
- Flow Rate
- 3.3 GPM
- Wattage
- 14kW
- Voltage
- 240V
- Temperature Control
- 86°F–131°F, 1°F adjustment
- Dimensions
- 13.7 × 11.42 × 3.54 in
View on Amazon: APUS 14kW 3.3 GPM Electric Tankless Water Heater Affiliate link
This APUS unit delivers up to 3.3 GPM at 14kW on a 240V circuit. It features precise 1°F temperature adjustments via an LED display. The compact 13.7-inch height suits tight spaces. It is ideal for point-of-use or one to two simultaneous fixtures. You get 99.8% thermal efficiency with on-demand heating. Professional hardwiring is required for safe operation.
Pros
- 14kW output provides up to 3.3 GPM flow rate
- Precise 86°F–131°F control with 1°F adjustment steps
- Compact 13.7 × 11.42 × 3.54 inch wall-mounted design
- 99.8% thermal efficiency eliminates standby heat loss
Cons
- Lower 3.3 GPM flow rate compared to 4.4 GPM competitors
- Requires 60A breaker and 6 AWG copper wiring
- Knob control interface instead of digital touch panel
Good fit if
- You need hot water for a single sink or shower
- You have a 240V electrical panel with 60A capacity
- You want a compact unit for tight utility spaces
Skip if
- You require simultaneous hot water for multiple full bathrooms
- You cannot hire a licensed electrician for hardwiring
- You need a flow rate above 3.3 GPM
Verdict: APUS 14kW Electric Tankless Water Heater fits single-point or light multi-point needs where space is limited. You should choose this model if your electrical panel supports 60A circuits and you prioritize precise temperature control over maximum flow volume.
APUS 18kW 4.4 GPM Tankless Water Heater
Best for: high flow whole-house electric heating
- Fuel Type
- Electric
- Flow Rate
- Up to 4.4 GPM
- Wattage
- 18 kW
- Installation Location
- Indoor
- Voltage
- 240V
- Temperature Control
- 86°F–131°F, 1°F increments
View on Amazon: APUS 18kW 4.4 GPM Tankless Water Heater Affiliate link
This APUS 18kW electric unit delivers up to 4.4 GPM at 240V. Its 13.7-inch height and 15.2-pound weight allow for wall mounting in tight spaces. You get precise digital control from 86°F to 131°F in 1°F increments. The 99.8% thermal efficiency adjusts power based on flow rate. It suits homes needing high flow for multiple simultaneous uses.
Pros
- High 4.4 GPM flow rate for 2-3 simultaneous uses
- Compact 13.7 x 11.42 x 3.54 inch wall-mounted design
- Precise temperature control in 1°F increments from 86°F to 131°F
- 99.8% thermal efficiency with self-modulating technology
Cons
- Requires 240V power with two 40A breakers and 8 AWG wire
- Heavier at 15.2 pounds compared to lighter compact models
- Limited temperature range maximum of 131°F
Good fit if
- You need high flow for whole-house or point-of-use installation
- You have the electrical capacity for 240V and 40A breakers
- You want precise temperature adjustments in small increments
Skip if
- You only have 120V electrical outlets available
- You cannot install two 40A circuit breakers
- You prefer a lighter unit under 10 pounds
Verdict: APUS 18kW Electric Tankless Water Heater fits households needing high flow for multiple sinks or showers. It requires specific 240V electrical setup and space for wall mounting.
Specifications side by side
| Spec | APUS 3.6 GPM Propane Tankless Water Heater | APUS 14kW 3.3 GPM Electric Tankless Water Heater | APUS 18kW 4.4 GPM Tankless Water Heater |
|---|---|---|---|
| Fuel Type | Propane Gas | Electric | Electric |
| Flow Rate | 3.6 GPM | 3.3 GPM | Up to 4.4 GPM |
| BTU | 80,000 BTU | not stated | not stated |
| Wattage | not stated | 14kW | 18 kW |
| Installation Location | Indoor | not stated | Indoor |
| Voltage | not stated | 240V | 240V |
| Temperature Control | 95°F–140°F, ±1°F | 86°F–131°F, 1°F adjustment | 86°F–131°F, 1°F increments |
| Dimensions | 20.55 H × 13.27 W × 5.91 D in | 13.7 × 11.42 × 3.54 in | 13.7 × 11.42 × 3.54 in |
| Features | Digital Display | not stated | not stated |
| Weight | not stated | 12.8 pounds | 15.2 pounds |
| Color | Space Gray | Gray | Gray |
| Model | AP-AWH-Q10LPG-A | AP-ADSK140-H18 | AP-ADSK180-H18 |
How to choose the right one
-
Check propane for indoor use
You should select propane if you need a dedicated indoor unit. The APUS 3.6 GPM model is designed specifically for indoor installation. It delivers 80k BTU of heat output. This power level ensures steady hot water for whole-house needs. You must ensure your space allows for proper venting. The digital display helps you monitor temperature settings accurately. This model is not intended for outdoor environments. Verify your gas line connections match the unit requirements before purchase.
-
Match electric wattage to demand
Electric units vary significantly by wattage. The 14kW model suits single-sink or point-of-use applications. It provides 3.3 GPM of flow. This is ideal for limited hot water needs. The 18kW model offers 4.4 GPM for higher demand. It supports multiple sinks or showers simultaneously. You must choose the wattage that matches your daily usage. Higher wattage requires a more robust electrical setup. Select the lower wattage if you only need one faucet.
-
Verify 240V electrical support
All electric APUS models require a 240V power source. You must confirm your home has this voltage available. The 14kW unit needs a 60A circuit breaker. The 18kW unit also requires specific electrical infrastructure. You cannot connect these units to standard 120V outlets. Check your electrical panel capacity before installation. Insufficient power will prevent the heater from operating correctly. Ensure your wiring gauge meets the manufacturer specifications for safety.
-
Measure space for wall mount
Electric units are compact but still need wall space. The 14kW and 18kW models share identical dimensions. They are 11.4 inches wide and 13.7 inches tall. The propane model is larger at 19.3 inches wide. You should measure your installation area carefully. Wall mounting is required for all these units. Ensure there is enough clearance for maintenance access. The propane unit is heavier and requires sturdy mounting. Plan your layout to fit the specific footprint of your choice.
-
Use digital display for control
Temperature precision is critical for comfort. The propane model includes a digital display. This feature allows you to set exact water temperatures. You can adjust settings to suit your preference. Electric models focus on power output rather than displays. You still benefit from precise heating elements. The digital interface on the propane unit simplifies operation. You can monitor the status without guessing. This control helps maintain consistent water temperature during use.
Frequently asked questions
Which APUS tankless heater is best for whole-house use?
The APUS 18kW Electric Tankless Water Heater is designed for high-flow whole-house heating. It delivers 4.4 GPM to support multiple sinks or showers simultaneously. You must ensure your electrical panel supports the required 240V setup. This model prioritizes flow volume over compact size, making it ideal for larger households needing consistent hot water.
Can I install the APUS propane heater indoors?
Yes, the APUS 3.6 GPM Propane Tankless Water Heater is built specifically for indoor installation. It features a compact design with a digital display for precise temperature control. Its 80k BTU output provides steady hot water for indoor use. You should prioritize this model if you value temperature accuracy and a smaller footprint over outdoor versatility.
What is the smallest APUS tankless water heater?
The APUS 14kW Electric Tankless Water Heater is the most compact option. It measures 11.4 inches in width and height, with a height of 13.7 inches. Weighing only 12.8 pounds, it fits easily in tight spaces. This unit is best for single-sink or shower point-of-use applications where space is limited and precise temperature control is needed.
Does the APUS propane model have a digital display?
Yes, the APUS 3.6 GPM Propane Tankless Water Heater includes a digital display. This feature allows you to monitor and adjust the water temperature precisely. The unit also offers steady hot water output thanks to its 80k BTU power. You get accurate temperature control in a compact Space Gray casing that fits well in indoor settings.
How much does the APUS electric heater weigh?
The APUS 14kW Electric Tankless Water Heater weighs 12.8 pounds. The larger 18kW model weighs 15.2 pounds. Both units are relatively lightweight, making wall mounting straightforward. The 14kW model is Gray and measures 11.4 inches wide. The 18kW model shares the same dimensions but offers higher flow for greater household demand.
What voltage do the APUS electric heaters require?
Both APUS electric tankless water heaters require a 240V electrical connection. The 14kW model needs a 60A circuit to operate safely. The 18kW model also relies on this specific voltage setup. You must verify your electrical panel can support these requirements before installation. These specs ensure the units deliver their rated flow and heating performance effectively.
Which APUS heater is best for a single sink?
The APUS 14kW Electric Tankless Water Heater is ideal for a single sink. It provides 3.3 GPM, which is sufficient for point-of-use applications. Its compact size allows it to fit in tight spaces under or near the sink. You get precise temperature control without the need for a larger, more powerful unit that consumes more energy.
What is the flow rate of the APUS propane heater?
The APUS 3.6 GPM Propane Tankless Water Heater delivers 3.6 gallons per minute. This flow rate supports steady hot water for indoor use. It pairs with an 80k BTU output to maintain consistent temperatures. You get reliable performance for showers or multiple fixtures, provided your propane supply and ventilation meet the indoor installation requirements.