Separated tube designs are constructed with each individual riser tube being "separate" from all the others. IE: Each tube is free across the length of the panel and not joined to either tube next to it. This design allows air to pass through the body of the panel.
Separated tube designs do not require any tie-down strapping; this feature reduces the overall number of penetrations required for installation. Because they allow wind to pass through the body of the panel, they are far more stable in climates with violent storm winds.
On the performance side, these panels do heat more efficiently in low wind climates. This is because separated tubes allow air in-between the riser tubes, which leads to heat loss as the air moving through the panel will strip some heat.
Separated tube designs do generally have much thicker riser tubes, making them ideal for areas with cold winter conditions (thicker riser tubes are less susceptible to freeze damage). *These systems do still need to be winterized properly, however are more resistant to this type of damage.
The separated tube systems we carry utilize a specialized clamping system to connect the panels together & make attachments to the supply and return PVC plumbing. This clamping system eliminates any gaps between panels, minimizing the space required for installation (also leads to a more appealing appearance). The downside to this clamping style is on the installation side; these systems can take longer to install.
Separated tube designs are generally far more robust and, in our experience, incur fewer pin-hole leaks across the lifespan of the panel. These systems are also protected by longer warranties.
*This panel type is far better suited for installation on a tile roof.