Radiant floor heating zone manifold (C) D Friedman R ArlyckRadiant Heat: Usage Guide, Strategies

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Radiant heat uses, designs, options:

This article discusses the basics of radiant heat for auxiliary heating or basic heating in buildings, including strategies for using radiant heat. The article also compares the costs of types of heating system use and we describe hydronic (hot water) radiant heat and electric radiant heat systems.

We describe typical installations of both hydronic tubing and electric radiant heat, including thin film electric radiant heat panels below several types of finish flooring. Our page top photo illustrates the heating boiler, circulators & mixing controls for a multi-zone radiant floor heating system installed during reconstruction of a home in Tivoli, NY.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Radiant Heat Use in buildings: when, why, how to use radiant heating

Radiant heat floor under construction (C) Daniel FriedmanSketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

The sketch explains that the radiant heat effect of a hot surface depends on the angle that the surface forms with the subject. Large surfaces facing and close to the subject provide the most radiant heat.

[Click to enlarge any image]

Key articles on radiant heated floors & radiant heat installation, troubleshooting, repair

Also see THIN FILM RADIANT HEATING SYSTEMS for Ceilings & Floors for examples of how electric radiant heat may be installed beneath several types of finish flooring.

Fuel cost comparison for space heating (C) Daniel Friedman"Radiant Heating, how it works, when to use it"

The table (left) included in this radiant heat article provides a typical fuel cost comparison for space heating.

The basics of Radiant Heating Systems

This article explains how radiant heating systems work, it describes the comfort of radiant heating systems, and it provides strategies for using radiant heat in buildings effectively.

The author, Steven Bliss, explains how to use radiant heat most comfortably, citing the ability to heat large areas to relatively low temperatures (rather than providing concentrated heat source), the evenness of radiant heat, and the importance of mass inside the structure to help keep temperatures even and comfortable through the thermostat cycling on and off where radiant heating systems are installed.

The author describes relatively low-cost in-floor radiant heating systems using hot water as well as electric heating elements. In-drywall radiant heat products are also explained and described for ceiling use.

Advantages of radiant heating systems

Radiant heat floor under construction (C) Daniel Friedman

Our photo (above) shows a radiant-heated concrete slab under construction in Two Harbors, MN in 2007.

Disadvantages of electric radiant heat systems

Radiant heat boiler (C) Daniel Friedman

Floor Damage, Gaps, & Odor Complaints with Radiant Heat Installed under Wood Floors

Radiant heat caused floor gaps (C) Daniel Friedman

We (DJF) have investigated a number of complaints of gaps opening between the boards of finished wood flooring and complaints of odors emitted from some types of tubing used in radiant floor heating systems.

Diagnosing gaps in finished wood flooring can be tricky, since these may appear with or without under-floor radiant heating systems installed, especially if the flooring is installed too quickly, without having adjusted its moisture level to that of the building. Installing wood flooring that is at too high a moisture level risks shrinkage and floor gaps as the building dries out.

In some cases that we investigated, flooring gaps appeared after an installer or owner pushed the radiant floor heating system to a temperature higher than recommended by the equipment and tubing manufacturers.

The temperature push was made in an attempt to "cook out" odors emitted from the radiant floor tubing when the heating system was first fired up.

Typical Cost of Radiant Heating Systems

Electric radiant heat ceiling panels (C) Daniel Friedman

Heating system costs are divided into installation or "first" costs, regular maintenance costs, and operating costs. Our photograph (left) shows two Therma-Ray electric radiant heat panels being installed in the ceiling of a 1960's home in Poughkeepsie, New York.

These panels were replacing previously damaged ceiling components. Be careful about cutting holes in drywall ceilings where electric radiant heating panels have been installed.

Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Thin Film Radiant Heating Systems for Ceilings & Floors - types, where to buy

An alternative to hydronic, tubing-based radiant heating systems that were discussed above, at TYPICAL COST of Radiant Heating Systems we cited electrical radiant heating systems including panels used in ceilings or floors. [See our photo above for an older version of electric heat in gypsum ceiling panels.]

These electric radiant floor heating systems use comparatively thin flexible heating film panels (IHS-CPF) that are wired to a dedicated electrical circut and of course controlled by a room thermostat. Some radiant heat panel sources include:

Note on Avoiding or Insulating Heat Sources rather than Producing Heat:

Too many of the electric radiant heat flooring searches we made turned up advertising pages where writers collected sources a bit hastily. We include the content below to help readers sort out the products they want (radiant heat flooring materials) from other stuff.

HeatShield panels, (Valley Center, CA 800-750-3978 ) produces heat insulating panels - in case you need to shield from heat rather than to direct heat into a building area. Heatshield Radiant Heat Mats ( are sold in an adhesive-backed form used, for example, in the automotive industry.

Examples of Thin Film Radiant Heat Flooring Installations for Different Flooring Materials

The Calorique company provides radiant floor heating systems in several designs including specifically for use below laminate flooring, carpeting, vinyl tile, linoleum, and ceramic tile floors. Calorique's system uses individual thin film panels connected to a 30-A electrical circuit to provide heat below these types of floor materials. Calorique describes these radiant heat floor installation examples:

Radiant Heat below glued carpet, wood, vinyl, or linoleum floors in dry surroundings

Radiant Floor heat below floating type wood, laminate, or parquet flooring in dry surroundings

Radiant Floor heat below ceramic tiles in dry surroundings

Radiant Floor heat under tiles in wet surroundings

- Thanks to reader Jim O'Dowd for suggesting this resource.

Original article

Links to the original article in PDF form immediately below

CONTACT us to suggest other types or suppliers of radiant heating systems and equipment. InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information for the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website. We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles.


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