Summer has finally arrived here on the high desert. While temperatures outside were climbing, inside Desert Rain, Pat and Scott with Bobcat and Sun Inc. http://bobcatandsun.com/were installing the ‘Infloor’ tubing that will heat the house during the cool months. Infloor radiant heat, combined with the passive house design, will keep Desert Rain warm and comfortable.
Infloor heating works by pumping heated water through distribution tubing. The PEX or AL PEX tubing is selected by comparing pressure and temperature ratings, as well as, the wall thickness for heat transfer and durability. Copper or brass manifolds provide complete control over each loop and will precisely regulate the flow and allow for individual loop control as well as isolation, air elimination, and purging capabilities. At Desert Rain tubing was stapled to the wood sub-floor on 8” centers. In the living, kitchen, dining area of Desert Rain a 4” thick slab of pre-colored concrete was poured over the tubing. The concrete creates thermal mass – storing and releasing the radiant heat.
Some of the floor area at Desert Rain will eventually be covered with reclaimed myrtle wood flooring. Those areas will first receive a thin slab underlayment of gypcrete over the radiant heat tubing. Gypcrete is a light weight gypsum and sand concrete that will provide thermal mass for the floor areas that are not concrete slab. Radiant heat moves from the tubing or concrete through the air in waves, similar to radio waves. It heats without pressurizing the air within the house, reducing heat loss and saving energy. As heat moves to cooler surfaces like walls, furniture and people, it warms those surfaces. Radiant heat is always trying to reach thermal equilibrium so the whole room or house heats evenly from the floor up.
The water in the radiant heat system at Desert Rain will be heated with three options. The desired 120 degree water temperature will rely first, on the solar thermal system. The solar thermal system heats water from the sun’s light. There will be a set point on the solar thermal system. If the water temperature is depleted to 90 degrees the source will automatically switch to the heat pump. These two systems should be sufficient to keep the water at the desired temperature. There is an electrical heat source in place as back up.
Passive house design, thermal mass heat collection through concrete and gypcrete, tubing throughout the house filled with solar thermal heated water – this winter Desert Rain will be warm and absolutely, radiant!