As with any product, HRFs come with a list of requirements and cautions. If you've never installed an HRF before, here are some things to consider. Gypsum underlayments must be applied by authorized installers, who may be hard to find in some areas. If so, or if floor heights are a problem, you can also install the tubing beneath the subfloor between the floor joists. In this case, heat is transferred to the floor by aluminum fins.
Higher temperature means lower system efficiency.
Nearly every manufacturer now offers a tubing with an oxygen diffusion barrier that prevents oxygen from penetrating the tubing and getting into the water. While this might add 30 percent to the tubing cost, it protects metal parts such as boilers and valves from rust. The key to success is getting a qualified heating designer. If you don't have experience with radiant technology, look for a manufacturer who provides generous technical support. Most manufacturers offer design assistance, and some will even plan the circuit layout for you.