The Trombe Wall is one of the earliest practical solar thermal energy inventions -the original form of solar panel. It is passive in its functioning principles but adds active control and freedom of positioning, making it one of the first active solar thermal devices. The technology was invented to allow the addition of passive solar properties to buildings without the need for radical change in design or very large expanses of windows -which when this was invented in the 19th century were not capable of insulation and were very limited in individual pane area.

The Trombe Wall uses a glass enclosure (ideally, UV transmitting insulated glass) over a southern-facing wall structure with high thermal mass to create a stack effect driven duct. A dark color surface helps the thermal mass collector wall -usually made of a masonry material or water-filled containers- absorb heat during the day while upper and lower vents with light air flow dampers allow air from inside the building to through the duct from floor to ceiling, heating it. One can control the rate of flow by opening or closing the vents. Optionally, the Trombe Wall may feature an upper external vent which, when opened with the upper indoor vent closed, uses the stack effect created in the external duct to draw air out of the building without heating the indoor air. Some contemporary Trombe Wall designs incorporate electric fans to increase rate of air flow and wavelength selective surface coatings or plates or phase-change material panels on the thermal mass wall to improve gain. Some Trombe Walls may also employ conductive thermal mass collector walls to communicate their collected heat to the interior while others use insulation to isolate the collector wall so that it only heats the air passing through it -which is helpful if the system is used as a stack effect ventilator in warm weather.

The Utilihab Modular Trombe Wall is designed to reduce the classic Trombe Wall system to light and self-contained unit that can be installed like any other standard Utilihab panel. It features an alloy box frame and multi-wall polycarbonate front grazing surface with a composite collector panel featuring a thermally selective absorber surface, a phase-change composite collector panel, a polyester reinforced aerogel insulator sheet, and rigid backing panel. An integral screened upper exterior vent can be opened for stack effect ventilation mode while upper and lower through-vent slots with membrane flow dampeners mate to a standard indoor wall panel modified to combine with the Trombe Wall unit and provide narrow vent slots at top and bottom. Alloy or plastic channels along the top and bottom of the unit, which form the through-vents, also provide routing channels for utilities, as the whole Trombe Wall unit is sized to fill the full interior volume of the standard walls. Similar side channels provide access for mounting bolts during panel installation. A set of interior mini-box fans along the lower portion of the wall duct are driven by small solar cells along the glazing panel. Opening and closing the exterior and interior vents is achieved using sliding tabs concealed behind the vent slots along the the inner wall panel. Automated control versions are also possible.

Utilihab Modular Trombe Wall units are sized to match the Primary framing thickness used and those designed for thicker framing offer increased thermal storage capacity. They can also be sized for high ceiling structures and work well in large span work/industrial buildings.