Rheem Tankless Water Heater Size Calculator

Planning to install a Rheem tankless water heater? Our Rheem Tankless Water Heater Size Calculator helps you determine the perfect size unit for your needs. Simply enter your requirements and get instant Rheem model recommendations.

1. Introduction to Rheem Tankless Water Heaters

History and Innovation

Rheem has established itself as a leader in water heating technology since 1925. Throughout nearly a century of innovation, they have consistently pushed the boundaries of energy-efficient water heating solutions. Their commitment to quality and continuous improvement has earned them a reputation as one of the most trusted brands in both residential and commercial applications.

The company’s dedication to innovation is evident in their tankless water heater line, which incorporates advanced technologies such as condensing heat exchangers, smart home integration, and sophisticated self-diagnostic systems. These innovations have not only improved performance but also significantly enhanced energy efficiency and user experience.

Rheem Advantage

What sets Rheem apart in the tankless water heater market is their comprehensive approach to product development. Their units consistently achieve energy efficiency ratings up to 99%, setting industry standards for performance. The integrated EcoNet® Smart Monitoring System provides real-time performance data and maintenance alerts, allowing users to optimize their system’s operation.

Rheem’s professional-grade heat exchangers are designed for longevity and reliable performance. The company backs their products with industry-leading warranty coverage, demonstrating their confidence in product quality. Their commitment to customer support includes extensive training programs for installers and a nationwide network of certified professionals.

Product Lines Overview

Professional Series

The Professional Series represents Rheem’s flagship line, designed for maximum performance in demanding applications. These units deliver up to 199,000 BTU output and can achieve flow rates up to 11 GPM, making them suitable for larger homes and commercial applications. The built-in recirculation pump ensures instant hot water availability while reducing water waste.

The series incorporates ultra-low NOx emissions technology and condensing design, making it environmentally friendly and energy-efficient. The commercial-grade heat exchanger ensures long-term reliability under heavy usage conditions.

Prestige Series

Targeting premium residential applications, the Prestige Series combines advanced features with user-friendly operation. These units provide up to 180,000 BTU output with maximum flow rates of 9.5 GPM. The optional recirculation capability can be integrated with home automation systems for enhanced convenience.

The series features enhanced scale prevention technology and smart home compatibility, making it ideal for modern households. The high-efficiency rating translates to significant energy savings over traditional water heaters.

Performance Series

The Performance Series offers reliable operation for standard residential applications. With outputs up to 150,000 BTU and flow rates reaching 7.0 GPM, these units provide excellent value for typical household needs. The basic digital controls ensure straightforward operation while maintaining essential functionality.

2. Rheem Tankless Water Heater Size Calculator Usage Guide

Understanding the Parameters

Flow Rate Calculation

The calculator utilizes Rheem’s tested flow rates to ensure accurate sizing recommendations. Different fixtures have varying flow requirements: standard shower heads typically range from 1.5 to 2.5 GPM, while bathtubs may require 4.0 to 7.0 GPM. Kitchen and bathroom faucets generally operate between 1.0 and 2.2 GPM.

Modern appliances like dishwashers and washing machines have varying requirements based on their efficiency ratings and cycle types. Understanding these requirements is crucial for proper system sizing.

Temperature Rise

Temperature rise calculations consider both incoming water temperature and desired output temperature. Rheem’s gas units can handle temperature rises up to 120°F, while electric units are optimized for rises up to 80°F. Condensing units offer enhanced capability with rises up to 140°F.

Climate Considerations

Rheem designs their units to perform optimally across various climate zones. In northern regions where groundwater temperatures fall below 45°F, units require greater heating capacity to achieve desired output temperatures. Central regions with groundwater temperatures between 45-55°F represent typical installation conditions, while southern and tropical regions with warmer groundwater temperatures can often utilize lower-capacity units effectively.

Installation Requirements

Proper installation of Rheem tankless water heaters requires careful attention to specifications. Gas units need correctly sized gas lines to ensure adequate fuel supply under peak demand. Venting requirements vary by model, with condensing units requiring specific materials and configurations. Electrical service must meet unit specifications, particularly for electric models that may require substantial amperage.

3. Understanding Rheem Models

Gas Tankless Models

RTGH Series (Prestige)

The RTGH Series represents Rheem’s premium condensing technology. The RTGH-95 delivers maximum performance with 9.5 GPM flow capacity, ideal for larger homes with multiple simultaneous hot water demands. The RTGH-84 and RTGH-75 offer scaled solutions for medium-sized applications while maintaining premium features.

These units incorporate Rheem’s proprietary Guardian overheat film wrap system, providing enhanced safety and reliability. The self-diagnostic system continuously monitors performance parameters, alerting users to potential issues before they become problems. High-altitude certification ensures reliable operation in elevated locations.

RTG Series (Performance)

The RTG Series provides reliable performance for standard residential applications. The RTG-70 offers 7.0 GPM flow capacity, suitable for most household needs. Digital temperature control ensures precise output temperatures, while standard venting options simplify installation requirements.

External recirculation capability allows integration with hot water recirculation systems, improving convenience and reducing water waste. The standard warranty provides peace of mind while maintaining competitive pricing.

Electric Tankless Models

RETEX Series (Professional)

The RETEX Series showcases Rheem’s electric heating technology. The RETEX-36 delivers 5.5 GPM flow capacity through advanced self-modulating technology, adjusting power consumption to match demand precisely. Multiple heating elements ensure reliable performance and provide redundancy.

These units excel in applications where gas service isn’t available or practical. The advanced flow sensor technology ensures accurate temperature control, while the compact design allows flexible installation options.

RTE Series (Performance)

Designed for residential point-of-use applications, the RTE Series offers efficient electric water heating in a compact package. The RTE-13 provides 2.5 GPM flow capacity, perfect for single-point or small multi-point applications. The simplified control system ensures reliable operation while maintaining essential functionality.

Enjoyed this Rheem Tankless Water Heater Size Calculator? Then be sured to check out our other heating guides.

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