Hydronic Radiant-Floor Heating
Concrete slabs, thin slabs, and metal plates offer different ways of routing radiant heat underneath every floor in the home.
Synopsis: Different techniques offer flexibility for installing the ultimate comfort system under a variety of finished flooring materials.
Living in a house with radiant-floor heating can almost make you forget that it’s winter outside. I can’t think of any other heating system that is as comfortable. Like a campfire on a cool night, heated floors deliver warmth to the skin and clothing without overheating and drying out the surrounding air.
Although usually associated with thick concrete slabs, hydronic radiant systems are now versatile enough to install underneath almost any type of finish flooring. New materials and installation techniques make hydronic heating adaptable to a great range of flooring choices. Although a complete hydronic under-floor heating system requires a boiler, manifolds, and controls, this article focuses on tubing installation.
Basically, there are three methods of bringing radiant heat underneath the floor of a room: a slab-on-grade system, a thin-slab system, and a plate-type system. Each type has advantages and disadvantages, but each system relies on tubing circuits laid underneath the floor. Rooms are heated by warm water circulating through these continuous circuits of tubing. The various circuits receive their heated water from a central supply manifold, a distribution point (like an electrical junction box) that receives water directly from a boiler. After circulating through the tubing, cooled water returns via the return manifold to the boiler to be reheated.
Special considerations for radiant-floor systems
There are some general rules that apply to all types of hydronic radiant systems that can make the difference between success and failure. First, always have an accurate heating-load estimate for the spaces to be heated. Reputable dealers of floor-heating equipment are a good source of assistance, and most can provide complete designs, including load estimates, layout drawings, and help with the sizing and the…