Hydronic Radiant Floor Heating
Hydronic radiant floor heating is a system of plastic or metal tubes/pipes laid within a floor that carries hot water into specific rooms or "zones," dispersing the heat through the floor surface.
The pipes can be encased in a concrete slab, a concrete or gypsum cement overpour, laid into thin grooved panels that nail on top of a subfloor, or suspended below a wooden subfloor using metal fins fastened under the floor surface. The heat output is determined by pipe spacing, water temperature, flow rate and floor covering.
One type of tubing commonly used is a new leak-resistant, non-toxic, high-temperature, flexible piping called cross-linked polyethylene (PEX). PEX is a durable tubing that doesn't become brittle over time and isn't affected by aggressive concrete additives or water conditions.
Is hydronic radiant floor heating available in both new and existing homes?
Yes. While the system can be easily designed and installed in new construction, homeowners wishing to renovate may incorporate hydronic radiant floor heating throughout the home, given certain conditions exist: the building structure can support the additional weight of the concrete/cement overpour, or the underside of the subfloor is accessible, or if being added to the basement, there is enough height for a concrete overpour above the insulation.
Entire House Versus Selected Rooms
Homeowners can chose to install hydronic radiant floor heating throughout the house, or in selected rooms. The most popular rooms with this type of heating are the bathroom, kitchen and living room–rooms where the most time is spent. If only selected rooms have this type of heating, then a separate heating and ventilation system is required to heat the remainder of the home. The system can also be "zoned" so that there are temperature controls for each area.
Designing a hydronic radiant floor heating system
Prior to the installation of a system, a qualified floor-heating specialist should make a heating-load estimate of your home on a room-by-room basis. The heating-load estimate will assist in an efficient system design.
By placing the tubing in specific patterns and spacings, the system can accommodate the insulation of the room/home and flooring choices.
Once designed and installed, a copy of the design should be given to the homeowner, should pipes/tubing need to be located at a later date. When renovating, extra care must be taken that piping or tubing not be punctured.
Exposed surfaces that conduct heat well are best for radiant floor heating, such as finished concrete or ceramic tile. It should be noted that if any later flooring renovation is undertaken, the hydronic radiant floor heating installer should be notified to make any required adjustments to the heating system. For example, the water temperature of the heating system would need to be adjusted if there was a change from a bare or painted finished floor slab to ceramic tile, or wood flooring or to carpet with underlay. Wood flooring and thick carpets act as an insulation blanket, restricting upward heat flow and reduce the efficiency of the system.
Hydronic radiant floor heating system component
There are three components to this heating system: a heat source, a distribution piping system and controls. The heat source in hydronic radiant floor heating is usually a boiler or a hot water heater, but other heat sources can be used too. The energy used to heat the hot water can be natural gas, oil, electricity, propane, wood or solar hot water collection. A geothermal heat pump works well with this system.
A circulator pump near the water supply manifold moves the water from the mixing valve to the supply manifold into the distribution piping system (tubing) inside the floors. Properly designed, this delivers even heat to rooms. A properly designed radiant floor system will not exceed 29ºC (85ºF). To select how warm or cool a room or home will be, controls are required to set the system to a particular temperature. A manifold system with thermostat or aquastat switches typically located in an accessible wall cavity provides a series of simple valves that are used to regulate the flow of water through each zone. There is a caution not to exceed the recommended maximum temperature as it could warp solid hardwood flooring and cause stress to the system.
Hydronic Radiant Floor Heating copyright 2011 Digtheheat.com