Best APUS Tankless Water Heaters: 6 Models Compared
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Finding the best APUS tankless water heaters means matching your specific hot water needs to the right fuel type and flow rate. This guide compares 6 models based strictly on published specifications. APUS offers compact propane units for RVs and indoor spaces, alongside electric models for residential use. The APUS 68,000 BTU RV Propane Water Heater leads as the best overall choice for standard 15x15 inch replacements. Its compact dimensions and propane efficiency make it ideal for travelers. Each pick reflects real-world spec performance, from BTU output to physical footprint.
Quick picks
Our 6 picks
APUS 68,000 BTU RV Propane Water Heater
Best for: RVs needing standard 15x15 inch replacement
- Fuel Type
- Propane
- Flow Rate
- 3.9 GPM
- BTU
- 68,000 BTU
- Voltage
- 12V DC
- Certification
- CSA
- Dimensions
- 14.96 x 14.96 x 14.18 inches
View on Amazon: APUS 68,000 BTU RV Propane Water Heater Affiliate link
This APUS propane unit delivers 3.9 GPM of hot water for RV use. It fits standard 15x15 inch compartments, replacing smaller tank heaters. The 68,000 BTU burner works at elevations up to 9,800 feet. It includes a remote control and operates on 12V DC power. You get reliable on-demand heating with safety certifications for campers and travel trailers.
Pros
- 68,000 BTU propane burner for on-demand hot water
- Compact 14.96 x 14.96 x 14.18 inch design fits standard RV openings
- Operates at elevations up to 9,800 feet
- Includes remote control for temperature adjustment
- CSA certified with multiple safety protections
Cons
- Lower 3.9 GPM flow rate than indoor home models
- Requires 12V DC power connection
- Propane fuel source limits indoor installation options
Good fit if
- You need a direct replacement for a 6, 10, or 12-gallon tank in an RV
- You camp at high elevations up to 9,800 feet
- You want a compact unit with a remote control
Skip if
- You need a higher flow rate than 3.9 GPM
- You require indoor installation for a home
- You prefer electric heating over propane
Verdict: APUS RV Propane Water Heater, 68,000 BTU fits travelers who need a compact propane heater for standard RV compartments. It suits those camping at high elevations or replacing small tank heaters who value remote control convenience.
APUS 95,000 BTU 4.42 GPM Indoor Propane Heater
Best for: indoor propane hot water needs
- Fuel Type
- Propane
- Flow Rate
- 4.42 GPM
- BTU
- 95,000 BTU
- Installation Location
- Indoor
- Voltage
- 120 V
- Temperature Control
- 95°F–140°F, ±1°F
View on Amazon: APUS 95,000 BTU 4.42 GPM Indoor Propane Heater Affiliate link
This APUS propane tankless water heater delivers 95,000 BTU and up to 4.42 GPM for indoor use. It maintains temperature within ±1°F using smart CPU technology and oxygen-free copper heat exchangers. The unit operates on 120V AC and features a 36dB quiet profile. It includes built-in freeze protection and measures 20.55 inches high. This model suits households needing steady hot water for multiple fixtures without large footprint.
Pros
- 95,000 BTU heating capacity
- 4.42 GPM flow rate
- ±1°F temperature precision
- 98% thermal efficiency
- 120V AC operation
Cons
- Indoor installation only
- Propane fuel type
- 19.2 pounds weight
Good fit if
- You need steady hot water for two showers and a sink
- You prefer propane fuel for indoor heating
- You want precise temperature control within ±1°F
Skip if
- You require outdoor installation
- You need natural gas compatibility
- You want higher flow rates than 4.42 GPM
Verdict: APUS Propane 95k BTU Indoor Heater offers precise temperature control and high efficiency for indoor propane setups. It fits homes needing reliable hot water for multiple simultaneous uses without complex electrical requirements.
APUS 140,000 BTU Indoor Propane Tankless Water Heater
Best for: Whole-home indoor propane heating
- Fuel Type
- Propane
- Flow Rate
- Up to 6.8 GPM
- BTU
- 140,000 BTU
- Installation Location
- Indoor
- Voltage
- 120V AC
- Temperature Control
- 95–140°F, ±1°F
View on Amazon: APUS 140,000 BTU Indoor Propane Tankless Water Heater Affiliate link
This indoor propane unit delivers 140,000 BTU and up to 6.8 GPM for whole-home use. It features a built-in booster pump, smart app control, and precise ±1°F temperature regulation. The oxygen-free copper heat exchanger supports a 0.81 UEF rating. It suits households needing high flow rates and consistent hot water across multiple points.
Pros
- 140,000 BTU output for high demand
- Built-in booster pump increases flow to 6.8 GPM
- Smart Tuya app control and monitoring
- Precise ±1°F temperature adjustment
Cons
- Indoor installation only
- Requires 120V AC power for controls
- Must drain unit if ambient temp drops below 41°F
Good fit if
- You need high flow for multiple bathrooms
- You want smart monitoring via app
- You have indoor space for propane units
Skip if
- You require outdoor installation
- You need natural gas compatibility
- You lack 120V AC power access
Verdict: APUS 140k BTU Propane Tankless Heater provides robust whole-home hot water with smart features. It fits large households prioritizing flow rate and digital control over outdoor versatility.
APUS 18kW 4.4 GPM Tankless Water Heater
Best for: Space-constrained installations needing precise temp control
- 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 electric unit delivers up to 4.4 GPM at 240V, making it suitable for two to three simultaneous uses. Its ultra-slim 13.7 × 11.42 × 3.54-inch design saves space, while 99.8% thermal efficiency reduces standby loss. You get precise digital control from 86°F to 131°F in 1°F increments. It is a practical choice for point-of-use or whole-house installation where space is limited.
Pros
- Delivers up to 4.4 GPM for 2–3 simultaneous uses
- Ultra-slim wall-mounted design measuring 13.7 × 11.42 × 3.54 inches
- 99.8% thermal efficiency with self-modulating technology
- Precise digital control from 86°F to 131°F in 1°F increments
Cons
- Requires 240V power with 2 x 40A breakers
- Lower flow rate than the 140,000 BTU propane model
- Heavier at 15.2 pounds compared to lighter propane units
Good fit if
- You need a space-saving wall-mounted unit
- You want precise temperature control in 1°F increments
- You have 240V electrical capacity available
Skip if
- You require higher flow rates for multiple bathrooms
- You only have 120V electrical outlets
- You prefer propane fuel for off-grid use
Verdict: APUS 18kW Electric Tankless Water Heater fits buyers who need a compact, efficient solution for point-of-use or small whole-house applications. It is best for those prioritizing space savings and precise temperature control over high-volume flow.
APUS 27kW 240V Tankless Water Heater
Best for: high-flow whole-home residential use
- Fuel Type
- Electric
- Flow Rate
- Up to 6.5 GPM
- Wattage
- 27 kW
- Installation Location
- Indoor
- Voltage
- 240V
- Temperature Control
- 86°F–140°F (1°F increments)
View on Amazon: APUS 27kW 240V Tankless Water Heater Affiliate link
This APUS unit delivers up to 6.5 GPM of hot water using 27kW of power on a standard 240V circuit. It features a compact wall-mounted design measuring 17.7 by 11.4 inches. You get precise temperature control from 86°F to 140°F in 1°F increments. The self-modulating heating system adjusts output based on flow. It suits larger households needing continuous hot water for multiple fixtures.
Pros
- 27kW heating element provides up to 6.5 GPM flow
- Digital display allows 1°F temperature adjustments
- Compact wall-mounted design saves floor space
- Self-modulating technology maintains stable outlet temperature
Cons
- Requires three 40A breakers and 6x8 AWG cable
- Limited to indoor installation only
- No remote control included
Good fit if
- You need high flow for whole-home use
- You have the required 240V electrical capacity
- You want precise digital temperature control
Skip if
- You only have a single 40A circuit available
- You need outdoor or RV installation
- You prefer propane fuel sources
Verdict: APUS 27kW Electric Tankless Water Heater fits homes with strong electrical infrastructure that require high flow rates for multiple simultaneous uses.
APUS 80k BTU RV Propane Heater
Best for: RV owners needing compact propane hot water
- Fuel Type
- Propane
- Flow Rate
- 4.8 GPM
- BTU
- 80,000 BTU
- Voltage
- 12V DC
- Temperature Control
- 95–124°F
- Certification
- CSA
View on Amazon: APUS 80k BTU RV Propane Heater Affiliate link
This APUS unit delivers 80,000 BTU of heat for up to 4.8 GPM of hot water. It runs on propane with a 12V DC power draw. The compact 14.96-inch square body replaces standard RV tanks. It operates safely up to 9,800 feet. You get precise temperature control between 95–124°F. This model suits RV owners needing reliable, space-saving hot water.
Pros
- 80,000 BTU output provides strong heating performance
- Compact 14.96 x 14.96 inch footprint fits tight spaces
- Operates efficiently at altitudes up to 9,800 feet
- Includes CSA certification and multiple safety protections
- Smart staged combustion adjusts power for fuel efficiency
Cons
- Lower flow rate of 4.8 GPM compared to indoor models
- Requires 12V DC electrical connection for operation
- Propane fuel type limits use to RV or outdoor settings
Good fit if
- You need a direct replacement for a 6–12 gallon RV tank
- You travel to high-altitude campsites above 5,000 feet
- You want precise temperature control between 95–124°F
Skip if
- You require indoor installation with standard 120V power
- You need a flow rate above 5 GPM for multiple showers
- You prefer electric heating over propane fuel
Verdict: APUS 80k BTU RV Propane Heater offers compact, high-altitude reliable hot water for RV travelers who prioritize space savings and fuel efficiency over maximum flow rate.
Specifications side by side
| Spec | APUS 68,000 BTU RV Propane Water Heater | APUS 95,000 BTU 4.42 GPM Indoor Propane Heater | APUS 140,000 BTU Indoor Propane Tankless Water Heater | APUS 18kW 4.4 GPM Tankless Water Heater | APUS 27kW 240V Tankless Water Heater | APUS 80k BTU RV Propane Heater |
|---|---|---|---|---|---|---|
| Fuel Type | Propane | Propane | Propane | Electric | Electric | Propane |
| Flow Rate | 3.9 GPM | 4.42 GPM | Up to 6.8 GPM | Up to 4.4 GPM | Up to 6.5 GPM | 4.8 GPM |
| BTU | 68,000 BTU | 95,000 BTU | 140,000 BTU | not stated | not stated | 80,000 BTU |
| Wattage | not stated | not stated | not stated | 18 kW | 27 kW | not stated |
| Installation Location | not stated | Indoor | Indoor | Indoor | Indoor | not stated |
| Voltage | 12V DC | 120 V | 120V AC | 240V | 240V | 12V DC |
| Temperature Control | not stated | 95°F–140°F, ±1°F | 95–140°F, ±1°F | 86°F–131°F, 1°F increments | 86°F–140°F (1°F increments) | 95–124°F |
| Certification | CSA | not stated | not stated | not stated | not stated | CSA |
| Dimensions | 14.96 x 14.96 x 14.18 inches | 20.55 x 13.27 x 5.91 in | 21.26 × 13.58 × 7.09" | 13.7 × 11.42 × 3.54 in | 17.7 × 11.4 × 3.5 in | 14.96 x 14.96 x 14.18 inches |
| Use | RV | not stated | Whole House | not stated | Whole House | RV |
| Weight | 24 pounds | 19.2 pounds | 26.9 pounds | 15.2 pounds | 19 pounds | 24.1 pounds |
| Color | White | Propane Gas,4.42GPM,95,000BTU，Space Gray | Space Gray | Gray | AP-27kW,Gray | Black |
| Model | AP-AWH-RV10W-NEW | AP-AWH-Q13LPG | AP-AWH-Q20LPG | AP-ADSK180-H18 | AP- ADSK-270G13 | AP-AWH-RV12B-A |
APUS Tankless Water Heater Models
APUS propane heaters suit RV travelers and indoor setups. The 68,000 BTU RV Propane Water Heater fits standard compartments. The 95,000 BTU Indoor Propane Heater offers precise control for homes. The 140,000 BTU Indoor Propane Tankless Water Heater provides whole-home capacity for large households. These units rely on propane fuel for reliable performance in various environments. Electric models target space-constrained installations. The 18kW Tankless Water Heater delivers point-of-use efficiency with a compact footprint. The 27kW 240V Tankless Water Heater supports high-flow residential needs. Both require 240V power and suit buyers prioritizing temperature precision over volume. Choose propane for RVs or indoor gas lines. Select electric for dedicated circuits and smaller footprints.
Where APUS Fits Your Home
APUS offers six models spanning propane and electric fuel types. Propane units range from compact 68,000 BTU RV heaters to 140,000 BTU indoor whole-home systems. Electric options include an 18 kW unit for point-of-use and a 27 kW model delivering 5.0 GPM. Shapes vary from narrow indoor panels to wider RV-compatible boxes. The lineup lacks outdoor-rated propane heaters and natural gas models. Shoppers needing those specific features should look elsewhere. This brand suits those prioritizing compact propane RV solutions or efficient indoor electric heating.
You can compare flow rates and heating capacity across the best tankless water heaters with tankless.
How to choose the right one
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Match fuel to location
Decide between propane and electric based on your power source. Propane models like the 68,000 BTU RV Propane Water Heater work well where grid power is unavailable. Electric units such as the 18kW Tankless Water Heater require a dedicated 240V circuit. Check your existing infrastructure before buying. Propane offers portability for RVs, while electric units often provide more precise digital temperature control for fixed indoor installations.
-
Check flow rate needs
Flow rate determines how many fixtures you can use at once. The 27kW Electric Tankless Water Heater delivers 5.0 GPM for whole-home use. Smaller units like the 18kW model offer 4.4 GPM, suitable for point-of-use or small households. The 95,000 BTU Indoor Propane Heater also provides 4.42 GPM. Ensure the GPM rating meets your peak demand to avoid temperature drops during simultaneous showers or appliance use.
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Verify physical dimensions
Tankless heaters vary significantly in size. The compact 18kW Electric unit measures 11.4 by 13.7 inches, fitting tight spaces. RV models like the 68,000 BTU heater are designed for standard 15x15 inch compartments. The 140,000 BTU Indoor Propane unit is wider at 7.09 inches. Measure your installation area carefully. Ensure the width, height, and length fit your intended space without obstructing access for maintenance or venting.
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Assess BTU capacity
BTU rating indicates heating power. Higher BTUs handle larger volumes or colder inlet water. The 140,000 BTU Indoor Propane Tankless Water Heater suits large households needing robust whole-home heating. Smaller RV units like the 80k BTU model prioritize efficiency over raw power. Match the BTU output to your household size and water usage patterns. Higher output ensures consistent hot water during peak usage times.
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Confirm installation type
Installation location dictates model selection. Some units, like the 95,000 BTU Indoor Propane Heater, are designed specifically for indoor use. RV models are built for mobile environments and standard compartments. Electric units require proper electrical wiring and ventilation considerations. Verify that the chosen model supports your intended setup. Indoor propane units need specific venting, while RV heaters are self-contained. Choose based on where you plan to mount the unit.
Frequently asked questions
Which APUS tankless water heater is best for RVs?
The APUS 68,000 BTU RV Propane Water Heater is the top choice for most travelers. It measures 14.2 by 15 inches, fitting standard RV compartments. This compact unit runs on propane and weighs 24 pounds. It is designed for those who need reliable hot water in mobile settings without complex electrical requirements.
What is the highest flow rate available from APUS?
The APUS 27kW 240V Tankless Water Heater offers the highest flow rate at 5.0 GPM. This electric model delivers robust performance for whole-home residential use. It requires a 240V power source and weighs 19 pounds. This unit suits homes with strong electrical infrastructure needing high-volume hot water for multiple simultaneous uses.
Can I install an APUS heater in my garage?
Yes, the APUS 95,000 BTU and 140,000 BTU models are rated for indoor installation. These propane units are suitable for spaces like garages or utility rooms. The 95,000 BTU model weighs 19.2 pounds, while the 140,000 BTU version weighs 26.9 pounds. Always follow local codes for indoor propane appliance venting and placement.
Which model is best for small spaces?
The APUS 18kW Electric Tankless Water Heater is ideal for space-constrained installations. It measures just 11.4 by 13.7 inches and weighs only 15.2 pounds. This compact unit provides precise temperature control for point-of-use or small whole-house applications. It is the smallest footprint option among the listed electric models.
How much does the APUS 140,000 BTU heater weigh?
The APUS 140,000 BTU Indoor Propane Tankless Water Heater weighs 26.9 pounds. It measures 7.09 by 21.3 inches and features a Space Gray finish. This model is designed for large households prioritizing flow rate and digital control. Its weight reflects the robust construction needed for whole-home hot water delivery.
Do APUS propane heaters work at high elevations?
Yes, the APUS 68,000 BTU and 80k BTU RV Propane Heaters are noted for high-altitude reliability. These units are designed to perform consistently in mountainous or high-elevation camping locations. They use propane fuel, which is less affected by thin air compared to some other systems. This makes them suitable for travelers who camp at higher elevations.
What voltage do the electric APUS models require?
Both the APUS 18kW and 27kW electric tankless water heaters require 240V power. The 18kW model is suited for point-of-use applications, while the 27kW model delivers higher flow for whole homes. Ensure your electrical panel can support the required amperage for these units before installation. They are not compatible with standard 120V outlets.