120,000 BTU or 199,000 BTU Tankless Water Heaters? Compared by Specs
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Choosing between a 120000 btu vs 199000 btu tankless water heater depends on your home’s hot water demand. Both units run on propane and are designed for indoor installation. The main difference lies in their heating power and flow capacity. The APUS model offers 120,000 BTU with a 5.43 GPM flow rate, suitable for smaller households. The Westinghouse unit delivers 199,000 BTU and 9.2 GPM, supporting larger homes with multiple bathrooms. You need to match these specs to your usage patterns.
Key differences
| Aspect | APUS 5.43 GPM Propane Tankless Water Heater | Westinghouse 9.2 GPM Propane Indoor Tankless Heater |
|---|---|---|
| BTU Output | 120,000 BTU | 199,000 BTU |
| Flow Rate | 5.43 GPM | 9.2 GPM |
| Temperature Control | ±1°F | ±1.8°F |
| Freeze Protection | Near 41°F | Down to -13°F |
| Dimensions | 20.55 x 13.27 x 5.91 in | 24.8 x 15.9 x 15.9 in |
| Weight | 19.2 pounds | 56.7 pounds |
Which one should you choose?
Choose APUS 5.43 GPM Propane Tankless Water Heater if
- You have a smaller household with 3–4 water points.
- You need a compact unit that preserves floor space.
- You prefer tighter temperature stability at ±1°F.
Choose Westinghouse 9.2 GPM Propane Indoor Tankless Heater if
- You require hot water for 4+ bathrooms simultaneously.
- You live in a colder climate needing -13°F freeze protection.
- You want higher flow capacity for large appliances.
Verdict: The APUS 120,000 BTU model is ideal for smaller homes where space and precise temperature control are priorities. The Westinghouse 199,000 BTU unit is better for large households needing high-volume hot water and robust freeze protection. Choose based on your peak simultaneous water usage and local climate conditions.
120k vs 199k BTU Specs Compared
Heating capacity
The APUS model delivers 120,000 BTU of heating power. This output supports three to four water points, such as two showers and a sink, making it suitable for larger homes with moderate simultaneous use. The Westinghouse unit provides 199,000 BTU. This higher capacity supplies continuous hot water for four or more bathrooms, laundry, and other appliances at the same time. You get significantly more thermal energy with the Westinghouse option if you need to run multiple high-demand fixtures without pressure drops.
Flow rate
Flow rate determines how much hot water you get per minute. The APUS heater offers 5.43 GPM. This volume handles moderate demand well for smaller households or specific zones. The Westinghouse heater provides 9.2 GPM. This higher flow supports whole-home performance for large families. If you plan to use the washing machine while someone showers, the Westinghouse handles that load better. The APUS is sufficient for lower-volume needs, but the Westinghouse offers nearly double the capacity for peak usage times.
Temperature control
Precision matters for comfort. The APUS unit features ±1°F control. It uses high-precision sensors and a smart CPU to regulate temperature when other faucets open. The LED touchscreen shows your setting. The Westinghouse model offers ±1.8°F stability. It uses self-modulating technology to adjust flow and maintain consistent heat. While both keep temperatures steady, the APUS has a tighter tolerance. You will notice slightly less fluctuation with the APUS if you are sensitive to small temperature changes during your shower.
Efficiency
Energy efficiency affects your operating costs. The APUS heater has a UEF of 0.81. It uses oxygen-free copper and segmented combustion to reach up to 98% thermal efficiency. The Westinghouse unit highlights a 1:20 turndown ratio and a 6-stage combustion system. It optimizes usage based on real-time demand. The APUS provides a specific UEF number for easy comparison. The Westinghouse emphasizes adaptive staging. Both are efficient, but the APUS gives you a quantifiable efficiency rating to track performance against conventional tanks.
Freeze protection
Winter performance depends on freeze safeguards. The APUS activates freeze protection near 41°F. It also includes automatic shutoff when abnormal conditions are detected. You must drain the unit below that temperature. The Westinghouse heater offers integrated freeze protection down to -13°F. It also includes CSA-certified safety protection. The Westinghouse handles extreme cold better with its lower threshold. If you live in a region with severe winters, the Westinghouse provides more robust protection against freezing damage without manual intervention.
Physical size
Space is often limited in utility areas. The APUS measures 20.55 inches high, 13.27 inches wide, and 5.91 inches deep. It weighs 19.2 pounds. The Westinghouse measures 24.8 inches high, 15.9 inches wide, and 15.9 inches deep. It weighs 56.7 pounds. The APUS is significantly more compact and lighter. It preserves floor space better in small closets or tight installations. The Westinghouse is larger and heavier, requiring more wall support and clearance. Choose the APUS if you have limited mounting space or need a lighter unit.
Which unit fits your home best?
Small household with moderate usage
The APUS model delivers 5.43 GPM and 120,000 BTU. This capacity supports three to four water points, such as two showers and a sink. Its compact size at 20.55 inches high saves floor space. The 0.66 GPM low-flow start responds to lighter demands efficiently. This unit suits homes with moderate simultaneous hot water needs.
Large home needing high flow
The Westinghouse unit provides 9.2 GPM and 199,000 BTU. This high output supplies four or more bathrooms, laundry, and appliances simultaneously. The 1:20 turndown ratio and six-stage combustion optimize energy use based on real-time demand. This model ensures continuous hot water for large families with heavy usage patterns.
User prioritizing precise temperature control
The APUS heater maintains temperature within ±1°F using high-precision sensors and a smart CPU. This tighter control minimizes fluctuations when another faucet opens. The LED touchscreen displays the selected setting clearly. This precision offers stable comfort for users who prefer exact temperature settings without significant deviation during use.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | APUS 5.43 GPM Propane Tankless Water Heater | Indoor propane use with precise temperature control | Check price of APUS 5.43 GPM Propane Tankless Water Heater on Amazon |
| 2 | Westinghouse 9.2 GPM Propane Indoor Tankless Heater | large homes needing high flow and stability | Check price of Westinghouse 9.2 GPM Propane Indoor Tankless Heater on Amazon |
The products compared
APUS 5.43 GPM Propane Tankless Water Heater
Best for: Indoor propane use with precise temperature control
- BTU
- 120,000 BTU (what this guide is about)
- Fuel Type
- Propane
- Flow Rate
- 5.43 GPM
- Installation Location
- Indoor
- Voltage
- 120V AC
- Temperature Control
- 95–149°F, ±1°F
View on Amazon: APUS 5.43 GPM Propane Tankless Water Heater Affiliate link
This APUS unit delivers 120,000 BTU and 5.43 GPM for indoor propane use. It targets 3–4 water points with ±1°F temperature control via an LED touchscreen. The oxygen-free copper heat exchanger offers a UEF of 0.81. Its compact 20.55 x 13.27 x 5.91-inch design mounts on walls. Standard 120V AC powers the controls and sensors.
Pros
- 120,000 BTU output with 5.43 GPM flow rate
- ±1°F temperature precision using high-precision sensors
- Oxygen-free copper heat exchanger with 0.81 UEF
- LED touchscreen display for easy setting visibility
- Compact indoor wall-mount design at 19.2 lbs
Cons
- Lower 120,000 BTU capacity compared to 199,000 BTU competitors
- Smaller 5.43 GPM flow rate limits simultaneous high-demand use
- Standard 2-year warranty coverage is shorter than typical industry standards
Good fit if
- You need a compact indoor propane unit for 3–4 water points
- You want precise ±1°F temperature control with an LED display
- You prefer a lighter 19.2 lb unit for easy wall mounting
Skip if
- You require higher flow rates for more than 4 simultaneous fixtures
- You need outdoor installation capabilities for this specific model
- You want the maximum 199,000 BTU heating capacity available
Verdict: APUS 120,000 BTU Propane Tankless Water Heater suits households needing precise temperature control and compact indoor installation. It fits smaller families or renovations where wall space is limited and propane is the preferred fuel source.
Westinghouse 9.2 GPM Propane Indoor Tankless Heater
Best for: large homes needing high flow and stability
- BTU
- 199,000 BTU (what this guide is about)
- Fuel Type
- Propane
- Flow Rate
- Up to 10.3 GPM
- Installation Location
- Indoor
- Voltage
- 120V AC
- Temperature Control
- 95-149°F, ±1.8°F
View on Amazon: Westinghouse 9.2 GPM Propane Indoor Tankless Heater Affiliate link
This Westinghouse unit delivers 199,000 BTU and 9.2 GPM for whole-home hot water. It maintains temperature stability within ±1.8°F using self-modulating technology. The 1:20 turndown ratio and 6-stage combustion system optimize gas usage. It is designed for indoor installation and includes freeze protection down to -13°F. You need a 120V power source for operation.
Pros
- 199,000 BTU output for high demand
- 9.2 GPM flow rate for multiple fixtures
- ±1.8°F temperature stability control
- Integrated freeze protection to -13°F
Cons
- Requires 120V AC electrical connection
- Heavier at 56.7 pounds
- Indoor installation only
Good fit if
- You need 9.2 GPM for large homes
- You want precise temperature stability
- You have indoor gas and power access
Skip if
- You need outdoor installation
- You lack 120V power near the unit
- You require natural gas instead of propane
Verdict: Westinghouse 199k BTU Propane Indoor Heater offers high flow and precise control for large households with indoor gas lines. It suits buyers needing 9.2 GPM and stable temperatures without outdoor exposure.
Specifications side by side
| Spec | APUS 5.43 GPM Propane Tankless Water Heater | Westinghouse 9.2 GPM Propane Indoor Tankless Heater |
|---|---|---|
| Fuel Type | Propane | Propane |
| Flow Rate | 5.43 GPM | Up to 10.3 GPM |
| BTU | 120,000 BTU | 199,000 BTU |
| Installation Location | Indoor | Indoor |
| Voltage | 120V AC | 120V AC |
| Temperature Control | 95–149°F, ±1°F | 95-149°F, ±1.8°F |
| Certification | not stated | CSA |
| Dimensions | 20.55 x 13.27 x 5.91 inches | 24.8 x 15.9 x 15.9 inches |
| Use | not stated | Whole House |
| Features | not stated | WiFi |
| Weight | 19.2 pounds | 56.7 pounds |
| Color | Space Gray | Grey 103PI |
| Model | AP-AWH-Q16LPG | HW199A0G-LP |
Frequently asked questions
Can I install a 199,000 BTU tankless heater indoors?
Yes, the Westinghouse 199,000 BTU unit is designed for indoor installation. It requires proper ventilation and gas line connections. This model is suitable for large homes needing high flow rates. Ensure your indoor space meets the manufacturer’s clearance requirements for safe operation.
What is the difference in flow rate between these two models?
The Westinghouse 199,000 BTU model provides 9.2 GPM. The APUS 120,000 BTU model offers 5.43 GPM. Higher flow rates support more simultaneous outlets. Choose the Westinghouse for large households. Select the APUS for smaller families or moderate usage needs.
Which unit is better for small spaces?
The APUS 120,000 BTU model is more compact. It measures 19.3 inches wide and 27.6 inches high. It weighs only 19.2 pounds. The Westinghouse unit is larger and heavier at 56.7 pounds. The APUS fits better in tight indoor areas.
Do both heaters use propane fuel?
Yes, both the APUS and Westinghouse models run on propane. They are designed for indoor use with gas lines. Propane provides consistent heating power. Ensure you have a reliable propane supply for either unit to function correctly in your home.
Is the 120,000 BTU unit heavy to mount?
The APUS 120,000 BTU heater weighs 19.2 pounds. This light weight makes it easier to mount on a wall. It is suitable for renovations where space is limited. The lighter design simplifies installation compared to heavier high-output units.
How many water points can each heater support?
The APUS 120,000 BTU model supports three to four water points. The Westinghouse 199,000 BTU model supports more due to its higher flow. Use the APUS for two showers and a sink. Use the Westinghouse for larger simultaneous demand.