Placing Radiant Tubing in the floor over Foil Insulation with a set point sensor, you can maintain a desired temperature within 1 degree at the roots of your plants on the floor, and the temperature at the ceiling can be 10-20 degree less. Your concern will therefore be with the temperature at the plant base, and not the void above.

There are many types of Radiant Floor Tubing available today; with or without oxygen barrier, that range in size from 3/8” 1/2” 5/8” 3/4“ 1”.

Why should you have this oxygen barrier?

The oxygen diffusion barrier prevents oxygen from permeating into the tubing water as it travels to the Boiler and potentially rusts from the inside out. Other system parts like circulators and valves will also last you much longer.

Why use a different size tubing?

Difference sizes are as longer lengths are needed. For example:

3/8” inside diameter tubing 200 ft. loop length max.
1/2” inside diameter tubing 300 ft. loop length max.
5/8” inside diameter tubing 300 ft. loop length max.
3/4” inside diameter tubing 400 ft. loop length max.

1” inside diameter tubing are usually used as supply and return to your bench heating manifolds.

1/2” Tubing is most frequently used because of price ease of handling, and if your greenhouse is 100 ft. long the best way to install is singular runs 200 ft. length.

Standard Pex Tubing is used in concrete slab installations maximum loop lengths are important.