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Radiant Floor Heating Home
What are the Methods of Heating Radiant Floors?
More FAQs: How much does it cost? Can the floor get too hot? Can the tubing leak?
Benefits of In-Floor Radiant Heating
Lower Heating Costs
In-Floor Heating Benefits
Installing Radiant Floor Heating Systems
Installing Radiant Heat
Retrofitting a Concrete Floor with Radiant Heat
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Common Questions about Concrete Floors: Are they cold? Are they loud? Are they expensive?

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Radiant Floor Heating

Radiant Floor Heating

The two most common methods of delivering radiant floor heat are:

  • Electrically, through heated cables, mesh, preformed mats or elements embedded in plastic films
  • Hydronically, through tubing that circulates water heated by a boiler or water heater
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Your choice will often depend on the energy costs in your area and the size of the project. Electric systems tend to be less expensive upfront than hydronic systems, according to the Radiant Panel Association, because they are simpler in construction. If you live in an area where electricity is more affordable than other power options, electric could be the way to go. Most systems operate on 120 or 240 volts and require a separate circuit breaker. However, low-voltage systems are available that can operate on as little as 24 volts, using a transformer to reduce the line voltage, according to RPA (see Radiant Heating with Electricity). Some electric radiant systems are intended only for warming floors in specific rooms; others are designed for use as whole-house primary heating.

With hydronic systems, you have more flexibility in choosing a power source. The boiler that heats the water can be powered by electricity and almost any fuel (including natural gas, propane, oil and wood). You can also use environmentally friendly alternative heat sources that don't consume fossil fuels, such as a geothermal heat pump or solar energy. However, you don't always have to buy a separate boiler. You can save money and use the same water heater you use for hot water and get double duty out of it. New high-efficiency water heaters are available that are powerful enough to provide both space heat and domestic hot water.

PEX Tubing vs. Metal Pipe:Heating concrete floors hydronically isn't a new technology. In the 1930s, architect Frank Lloyd Wright piped hot water through the concrete floors of many of his structures. Thousands of tract homes built at Levittown on Long Island and in the San Francisco Bay area during the 1950s also used a system that circulated heated water through steel or copper pipes embedded in concrete slab-on-grade floors. Unfortunately, many of these older systems failed, because the metal pipes reacted chemically with the concrete and eventually corroded and leaked.

Today, most hydronic systems circulate the water through PEX tubing—a tough, flexible plastic made of cross-linked polyethylene. PEX has properties that make it ideal for radiant floor heating and plumbing applications. Unlike copper pipe, PEX is flexible and can easily be laid in serpentine loops and bent around corners and obstacles. It also resists corrosion and scale buildup, eliminates hammering noise, muffles the sound of rushing water, and ensures tight seals without the need for soldering. (Read what the NAHB Research Center says about the advantages of PEX).

Components of a Radiant Floor Heating System

Here are the components required for a radiant floor heating system:

  • Heating Source - this can be electricity, solar, natural gas, propane, oil, wood, or any other heating source.
  • Boiler - houses the water to be heated
  • Pump - to circulate the water through tubing located under the floor.
  • Tubing - the water will circulate in tubing running beneath the floor in the concrete, under wood floors, or on a sub floor of wood, precast concrete, or slab-on-grade concrete.
  • Qualified System Installer - The company who designs the radiant floor heating system may also install the system. Look for a track record of satisfied customer. See hiring a contractor.
  • Qualified System Designer - like any mechanical system, a qualified, experienced designer should design radiant floor heating systems.

The designer will know which components work well together, capacities of various systems, special considerations for installations in your area, and manufacturers warranties and reliability.

The designer should do a room-by-room heat loss analysis of your home or building, as well as a step-by-step system sizing process.

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