Solar Thermal Hot Water Systems and Individual Components



  •  Complete SOLkit packages and individual components
  •  Systems to meet any needs
  •  Ultra-High Performance Components
  •  Custom mounting hardware
  •  Vertical and horizontal configurations
  •  40 years of experience designing and manufacturing solar thermal systems


SOL 27 Premium installed

Solar Water Heating Solutions

Stiebel Eltron has been designing solar thermal systems for 40 years. Because every installation is different, we have a full line of SOLkits, mounting hardware, and the individual components necessary for solar thermal installations. We are committed to making and supplying the best solar thermal components available. We’ve been at the forefront of water heating technology for over 95 years. As a leader in the field we have no intention of standing still.

Why Solar Thermal?

The cost to make hot water is the largest utility expense for a household. The average is about 20% of household energy for just domestic hot water (cooking, cleaning, bathing). This jumps to about 50% if hot water is also used for heating. It makes sense to save as much as possible on hot water, which is exactly what solar thermal can do.

Solar thermal has been used to capture the power of the sun and turn it into hot water for decades before solar photovoltaic (PV) became a possibility. Solar thermal is 3 to 5 times as effective in capturing the sun’s power as PV. Solar thermal can save up to 75% off water heating bills. It reduces carbon footprint and increases the property value of a home.

Federal tax credits are in place for 30% of the installed cost of a solar thermal system. State rebates and incentives, as well as local utility incentives, exist in many parts of the country.

How a Solar Thermal System Works

SOLkit 2 with Built-in Electric Backup

Collectors absorb the sun’s heat energy and transfer it to a heat transfer fluid in the system. A pump moves the hot fluid to a domestic water tank where the heat is transferred to the water through a heat exchanger. The now cool heat transfer fluid circulates back to the collector to gather more heat.

Stiebel Eltron has been designing and manufacturing solar thermal components for 40 years. Like all of Stiebel Eltron’s products, our solar components are carefully engineered. They are designed to work both individually and system-wide to bring you the best in performance and reliability.

Explore a Live Solar Thermal Installation

You can interact with a live Stiebel Eltron solar thermal installation in real-time to learn more about how our system functions.

› Residential DHW Installation Live Dashboard

Systems to Meet Any Needs

Solar thermal systems can be tailored to meet just about any need or existing mechanical situation. The diagrams show three common solar thermal installations. Many components of a solar thermal system are universal to all systems.

SOLkit 2 in Wide Configuration with Auxiliary Ports Utilized

Solar Thermal Collectors
Absorbs energy from the sun, converting it into heat.

Heat Transfer Fluid
A propylene glycol food- and pharmaceutical-grade fluid that holds and transfers heat from the collectors to the tank. The heat transfer fluid is freeze-proof for cold nights.

Pump Station
Moves the heat transfer fluid around the system.

DHW Storage Tank
The internal heat exchanger transfers the heat from the heat transfer fluid to the domestic hot water the tank holds. A backup heating element keeps the tank hot when the sun isn’t shining.

An electronic device that controls the operation of the pump and the safety of the system.

Backup Options
A backup system is used to add additional heat to the household hot water if necessary. This situation can happen, for instance, on a very cloudy day if the solar system can not make enough hot water to satisfy the demand or make it hot enough. The Stiebel Eltron SB E tanks in SOLkits have integral electric backup, but other possible solutions include Stiebel Eltron Tempra® tankless electric water heaters or existing site-specific backup systems.

SOLkit Water Heating Packages

SOLkit Solar Water Heating Packages

Stiebel Eltron SOLkits highlight our 40 years of solar thermal experience by combining the best solar components into complete packages. SOLkits come in 1, 2, or 3 panel sizes in up-roof configuration, and 2 or 3 panel sizes across the roof. Selection of the correct kit depends on family size, domestic hot water needs, and space heating needs if required. Our expert service representatives are available by phone or email for assistance and recommendations. Kits come complete with recommended pump station, controller, and tank. A rack kit, and the line set for a particular installation, completes the package, supplying every component needed. Our components are designed for maximum compatibility, ease of installation, and reliability.


Flat Plate Collectors

SOL 27 Premium S & W

Stiebel Eltron SOL 27 Premium is a highly efficient solar thermal collector, among the top 10 collectors measured for output by the SRCC. The net absorber surface of over 25 square feet results in a maximum output of 31,300 btu/day per panel (SRCC clear day rating). The SOL 27 Premium features a highly selective absorber coating, low-iron, tempered solar glazing, and very effective insulation around the absorber plate. The internal fluid tubes are copper and the absorber plate is aluminum. The low 3˝ profile of the SOL 27 makes it visually less obtrusive and able to accommodate a variety of architectural and engineering needs.

SOL 27 Premium collectors are available in both Standard (Vertical) and Wide (Horizontal) configurations. Manufacturing in the US for our collectors and racking systems also means we can custom-anodize collector frames and racks to meet specific architectural color requirements.

Evacuated Tube Collectors

S-Power Evacuated Tube Collectors

Stiebel Eltron’s S-Power solar collectors are engineered and made in Germany. They are three to five times more effective at capturing solar power than photovoltaic (PV) systems. Their latest-technology copper absorber plates are sealed inside single-walled, proprietary glass tubes with an uncompromising vacuum seal. Ideal for conditions where the outside temperatures are low and the demands for thermal energy are high, they are particularly well suited for combination systems where hot water, space heating, and air conditioning are required.


Solar Tanks

Stiebel Eltron SB 300 & 400 E DHW tanks are made in our factory in Slovakia. They come in both 80 gallon (300 l) and 110 gallon (400 l) sizes and can serve as a dedicated high-capacity solar storage tank in both residential and commercial installations.

Stiebel Eltron tanks and heat exchangers are made of heavy gauge steel. All surfaces in contact with domestic hot water receive a thick ­porcelain enamel coating after shot-peening to clean the steel surface. In addition, vessel exteriors receive a light porcelain coating. Two inches of urethane foam insulation ensures that hot water stays hot, and standby heat loss is minimized. Stiebel Eltron SBB tanks are equipped with large sacrificial anodes with wear indicator and an extra-large clean-out port for ease of maintenance.

SB 300 and 400 E storage tanks are equipped with a 3 kW electric heating element to back up the solar production. This heating element is sheathed in a steel cylinder inside the tank, and can be removed and replaced without needing to depressurize and drain the tank.

Auxiliary ports allow for additional installation applications, including boiler backup, split heat pumps, and hydronic applications.

Stiebel Eltron also sells German-made single and dual coil storage tanks without the electric backups.

Stiebel Eltron Controller

SOM 6 Plus

The SOM 6 Plus controller is used for all Stiebel Eltron standard solar thermal systems. The controller is equipped with an illuminated system-monitoring display. Adjustment and control of the solar system can be easily carried out through the user-friendly pictograph display. The SOM 6 Plus features 4 temperature sensors, a solar operating hours counter, variable pump speed control, vacation mode, and an industry-standard resol vBus®.

Other Stiebel Eltron controllers are available for larger residential and commercial systems, including complex commercial systems.

Pump Station

Flowstar Pump Station

Stiebel Eltron Pump Stations are specially designed for closed loop solar systems. The 3-speed Wilo circulator pump is designed to perfectly integrate with our SOM 6 Plus controller. Pump station piping is high grade brass. Pump stations come preassembled with a steel wall mounting bracket
and feature 2 drain valves, brass check valves to prevent thermo-siphoning, integrated flow meter, and include fittings for tank mount as well as NPT adapters. The pump station can be completely isolated from the system, so no draining is necessary during servicing.

Online Datalogging

DL2 Online Datalogger

Stiebel Eltron’s optional Solarwave DL2 datalogger gives owners remote access via the internet to their solar thermal system. Dashboards are designed for both owners and installers, and include a diagram view for virtual inspection of the system. Installers can manage and control systems remotely and set optional email alarms for notification of performance issues. Remote access reduces on-site cost for service contracts.

Mounting Systems

Fixed Rack Installation on a residential pitched roof

Stiebel Eltron mounting systems are made in the U.S. from extruded aluminum. Racks are available in three different configurations: the 45° Rack Kit; the 30-60° Rack Kit, an adaptable rack capable of installations at both 30° & 60°; and the Flush Mount Kit. All Rack Kits are available in versions for both Standard (Vertical) or Wide (Horizontal) collectors.

The Flush Mount Kit is used for installations where the roof structure itself is at the proper angle to mount the collectors. The 45° and 30-60° Rack Kits are designed for flat roof installations or for other installations where the existing roof angle is not optimal by itself.

Flush Mount Installation on a residential roof
The simple, strong u-channel design of our racks can withstand high wind and heavy snow. Stiebel Eltron mounting systems can be assembled using only two different socket sizes. Additional mounting components, such as hardware, in addition to flush mount and fixed angle racks, are available.

Flush Mount Racks come standard with SOLkits, but the raised rack kits can be specified with any SOLkit order when the need arises.