Modern panel radiators are one of my favorite hydronic heat emitters. They’re easy to install, emit radiant and convective heat, and have high-quality powder coat finishes. They are versatile in new construction and very well suited to retrofitting. With proper sizing, they can also work well in low-temperature distribution system supplied by air-to-water or geothermal water-to-water heat pumps.
The panel in Figure 1 is about 2 feet high and 5 feet wide. You can see the two 1/2-inch PEX-AL-PEX tubes that supply it connecting at the middle of the base of the radiator. You can also see the non-electric thermostatic valve at the upper right corner of the radiator. That valve automatically regulates the flow rate and thus the heat output of the panel, making it an independent zone. There’s also a dual ball valve fixture at the base of the radiator that can isolate the panel from the system if ever necessary.