Propane or Electric Tankless Water Heaters? Compared by Specs
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You are comparing a propane unit designed for RVs against an electric mini-tank for under-sink use. While both provide hot water on demand or with fast recovery, they serve different needs. This guide breaks down the propane vs electric tankless water heater debate by looking at fuel type, capacity, and voltage. You will see how each spec impacts your daily use, from camping trips to kitchen sinks.
Key differences
| Aspect | APUS 68,000 BTU RV Propane Water Heater | Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank |
|---|---|---|
| Fuel Type | Propane | Electric |
| Use | RV | Under Sink |
| Capacity | Tankless (3.9 GPM) | 6.5 Gallons |
| Voltage | 12V DC | 120 V |
| Wattage | 68,000 BTU | 1.44 kW |
Which one should you choose?
Choose APUS 68,000 BTU RV Propane Water Heater if
- You need endless hot water for showers in an RV.
- You have a 12V DC power system available.
- You want a compact unit that fits standard RV openings.
Choose Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank if
- You need instant hot water for a kitchen or bathroom sink.
- You have a standard 120V household outlet nearby.
- You want a small tank to reduce standby heat loss.
Verdict: Choose the APUS propane heater if you are traveling in an RV and need continuous hot water for showers. Select the ThermoMate electric unit if you are installing a dedicated hot water source under a sink in a home or stationary setup. Your decision depends entirely on your power source and whether you need tankless flow or stored hot water.
Propane RV vs Electric Mini Tank
fuel type and energy source
The APUS unit runs on propane, requiring a gas line and tank connection. This makes it ideal for RVs and off-grid setups where electrical power is limited. The ThermoMate uses 120V electricity, needing a standard outlet. You must have access to grid power or a generator. Propane offers portability for travel, while electric is simpler for fixed under-sink installations. Your choice depends on whether you prioritize mobility or convenience.
hot water delivery method
The APUS is a true tankless system, heating water only when you turn on the tap. It delivers up to 3.9 GPM, supporting longer showers and dishwashing in an RV. The ThermoMate is a mini-tank with 6.5 gallons of stored hot water. It provides instant hot water at the point of use but has a limited reserve. Once the tank empties, you wait for recovery. The APUS is better for continuous flow, while the ThermoMate suits brief tasks like handwashing.
installation location and fit
The APUS is designed for standard RV water heater compartments, with a 12.6 x 12.6 inch cutout requirement. It fits most travel trailers and motorhomes. The ThermoMate is built for under-sink mounting in homes or cabins, measuring 17.7 x 17.7 x 14.6 inches. It plugs into a wall outlet. The APUS replaces traditional RV tanks, while the ThermoMate replaces small residential tanks. Choose the APUS for RVs and the ThermoMate for kitchen or bathroom sinks.
power requirements and voltage
The APUS operates on 12V DC power, compatible with RV electrical systems. It also includes a remote control for temperature adjustment inside the vehicle. The ThermoMate requires a standard 120V outlet with a 12-amp nominal current. It comes with a 2-foot power cord. The APUS is self-contained for mobile use, while the ThermoMate needs a dedicated household circuit. Your existing power infrastructure will dictate which unit you can install without additional wiring.
safety certifications and protections
The APUS holds CSA certification and includes flame failure, gas leak, dry-burn, and over-temperature protections. It also features a 203 PSI pressure relief valve and intelligent freeze protection at 35.6°F. The ThermoMate is UL Listed and includes a temperature and pressure relief valve. It offers a freeze mode to prevent tank damage. Both units prioritize safety, but the APUS has more comprehensive gas-specific safeguards, while the ThermoMate focuses on electrical and tank integrity.
Choose Your Tankless Heater Type
RV travelers needing endless hot water
This propane unit delivers 3.9 GPM continuously. Its 68,000 BTU burner handles high flow rates. It works at elevations up to 9,800 ft. The compact 14.96-inch square design fits standard RV compartments. You get reliable hot water for showers and dishes without waiting for tank recovery during your journeys.
Homeowners wanting point-of-use sink heat
This electric mini-tank holds 6.5 gallons for instant access. It plugs into a standard 120V outlet with a 12-amp draw. The glass-lined tank retains heat efficiently. You can adjust the thermostat from 50°F to 149°F. Its UL listing ensures safe operation for under-sink installation in your kitchen or bathroom.
Off-grid campers without grid power
Propane fuel allows operation away from electrical grids. The unit runs on 12V DC power for controls. Intelligent staged combustion adjusts to incoming water temperature. You save propane by only heating what you use. The CSA certification confirms safety for gas appliances in mobile living spaces where electricity is scarce.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | APUS 68,000 BTU RV Propane Water Heater | RV owners replacing standard 6-12 gallon tanks | Check price of APUS 68,000 BTU RV Propane Water Heater on Amazon |
| 2 | Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank | Single sink or small appliance hot water | Check price of Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank on Amazon |
The products compared
APUS 68,000 BTU RV Propane Water Heater
Best for: RV owners replacing standard 6-12 gallon tanks
- Fuel Type
- Propane (what this guide is about)
- 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 68,000 BTU of heat for on-demand hot water. It flows up to 3.9 GPM and starts with just 0.55 GPM. The compact 14.96-inch square body fits standard RV compartments. It runs on 12V DC power and includes a remote control. You get reliable performance at elevations up to 9,800 feet with built-in freeze protection.
Pros
- 68,000 BTU propane burner for continuous hot water
- 3.9 GPM flow rate with low 0.55 GPM start
- Compact 14.96 x 14.96 x 14.18 inch dimensions
- CSA certified with multiple safety protections
- Includes remote control for temperature adjustment
Cons
- Limited to 12V DC electrical requirement
- Maximum elevation rating of 9,800 feet
- Single color option available in this listing
Good fit if
- You need a direct replacement for a 6 to 12-gallon RV tank
- You travel to high-altitude campsites up to 9,800 feet
- You want on-demand hot water without waiting for recovery
Skip if
- You require a high-flow unit for multiple simultaneous showers
- You need a unit rated for elevations above 9,800 feet
- You are looking for an electric-only installation option
Verdict: APUS RV Propane Tankless Heater fits RV owners who need a compact, CSA-certified replacement for standard tank heaters. It provides reliable hot water for solo travelers or couples who do not require high-volume simultaneous usage.
Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank
Best for: Single sink or small appliance hot water
- Fuel Type
- Electric (what this guide is about)
- Wattage
- 1.44 kW
- Capacity
- 6.5 Gallons
- Voltage
- 120V
- Temperature Control
- 50°F to 149°F
- Certification
- UL Listed
View on Amazon: Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank Affiliate link
This is a 6.5-gallon electric point-of-use water heater designed for under-sink installation. It operates on 120V power with a 1.44 kW heating element, delivering fast recovery for single fixtures. The unit features a glass-lined tank and adjustable thermostat settings ranging from 50°F to 149°F. It is UL Listed and weighs 26.5 pounds. This compact heater suits users needing localized hot water without running long pipe runs.
Pros
- 6.5-gallon capacity provides instant hot water for point-of-use applications
- Adjustable thermostat allows temperature control from 50°F to 149°F
- UL Listed for safety with glass-lined tank for durability
- Compact dimensions of 17.7 x 17.7 x 14.6 inches fit under sinks
Cons
- Low 1.44 kW wattage limits heating speed compared to higher-capacity units
- Small 6.5-gallon tank capacity is insufficient for whole-house needs
- Requires 120V electrical outlet, limiting placement options in some areas
Good fit if
- You need hot water for a single sink or small appliance
- You have a 120V outlet available near the installation site
- You want a compact unit that fits under standard cabinetry
Skip if
- You require hot water for multiple simultaneous fixtures
- You need a high-flow rate for showers or bathtubs
- You only have 240V electrical circuits available
Verdict: ThermoMate 6.5 Gal Electric Mini Tank is a practical solution for single-point hot water needs. It fits well in tight spaces where a full-sized heater cannot go.
Specifications side by side
| Spec | APUS 68,000 BTU RV Propane Water Heater | Thermomate 6.5-Gallon Under-Sink Electric Mini-Tank |
|---|---|---|
| Fuel Type | Propane | Electric |
| Flow Rate | 3.9 GPM | not stated |
| BTU | 68,000 BTU | not stated |
| Wattage | not stated | 1.44 kW |
| Capacity | not stated | 6.5 Gallons |
| Voltage | 12V DC | 120V |
| Temperature Control | not stated | 50°F to 149°F |
| Certification | CSA | UL Listed |
| Dimensions | 14.96 x 14.96 x 14.18 inches | 17.7"H x 17.7"W x 14.6"D |
| Use | RV | Under Sink |
| Weight | 24 pounds | 26.5 pounds |
| Color | White | white,blue |
| Model | AP-AWH-RV10W-NEW | ES700 |
| Size | not stated | 6.5 Gallon |
Frequently asked questions
Can I use a propane tankless water heater indoors?
You must verify local codes before installing any propane unit indoors. The APUS model is CSA-certified, which indicates it meets specific safety standards for combustion and ventilation. Indoor propane heaters require proper air supply and exhaust pathways to prevent carbon monoxide buildup. Always follow manufacturer instructions for safe indoor placement and ensure adequate clearance from combustible materials.
What is the difference between tankless and mini-tank electric heaters?
Tankless heaters provide continuous hot water by heating it as it flows through the unit. Mini-tanks like the ThermoMate store a limited volume of pre-heated water, such as 6.5 gallons. The mini-tank offers a buffer for immediate use, while tankless units deliver endless supply but depend on flow rate. Choose based on whether you need instant refill or sustained flow.
Do electric tankless heaters require special wiring?
Electric units often need dedicated circuits with specific amperage and voltage. The ThermoMate mini-tank operates on standard 120V power, making it easier to install in existing outlets. Higher-capacity electric tankless models usually require 240V circuits and heavier gauge wiring. Check your home’s electrical panel capacity before selecting an electric unit to avoid overloading your system.
How does elevation affect propane water heaters?
High altitudes reduce oxygen availability, which can impact combustion efficiency. The APUS propane heater is rated for elevations up to 9,800 feet without modification. Above this height, you may need a derating kit or adjustments to the gas mixture. Always check the manufacturer’s specifications for your specific altitude to ensure proper performance and safety.
Which heater is better for a small bathroom sink?
A small electric mini-tank is often better for single sinks due to its compact size and ease of installation. The ThermoMate fits under sinks and provides ready hot water for handwashing or brushing teeth. Propane units are generally larger and require gas lines, making them less practical for tight indoor spaces. Consider flow rate needs and available power sources.
Can I install a propane heater in an RV?
Yes, propane heaters are common in RVs because they work independently of shore power. The APUS unit is designed for RV use and fits standard compartments. It connects to your existing propane tank and provides hot water even when boondocking. Ensure your RV’s ventilation system can handle the exhaust and that the unit is securely mounted for travel.