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The best radiant systems will use a high quality, high efficiency water heater instead of a boiler. These systems cost about half as much as one using a typical boiler. Yet, they are much more efficient. They are a simple, ingenious way to make warm water for radiant space heat.
- POST a QUESTION or COMMENT about radiant heat system temperatures
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Proper operating temperatures for radiant heating systems.
This article discusses the maximum, minimum, & recommended operating temperatures for radiant heated floor systems, including typical temperatures used in different types of radiant-heated floors: tile, wood, laminate, carpeting, etc.
We describe the normal or correct radiant heat setting temperatures and we explain what happens if the radiant heat temperatures are set too low or too high.
We discuss: Radiant heat temperature settings at the boiler. Radiant heat temperature settings in the tubing. Maximum temperature for radiant-heated floor surfaces. Energy efficiencies of radiant floor heating. Heat loss rates into earth below radiant heated floor slabs. Operating temperature comparisons for types of radiant heating.
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.
What are the Normal Operating Temperatures for Radiant Heat Systems?
Our page top photo shows the output temperature of an electric boiler used to heat tubing in a radiant-heated tile floor set over concrete in a Minnesota home.
Unfortunately that system never worked satisfactorily, as we explain at RADIANT HEAT FLOOR MISTAKES.
Question: what is 'normal' and what is 'too hot' for radiant heat water circulating in the piping?
I just inspected a complex combine forced air (hydronic) heating system combined with a several circulating radiant floor heating components.
My question is what is normal and what is “too hot” for the water circulating through the piping distribution under ceramic tile floors installed over wood framed floor systems.
When I took the Watts® Regulator course they emphasized that temperatures should not exceed 130 degrees.
During my inspection the water leaving the boiler was 167.8 degrees (going into the heating distribution system for hydronic radiant, hydronic forced and also potable (yeah, I know that part is a problem!). - Ron Wells (ASHI#515) Wells Inspection Services, Inc.
Reply: It depends ..
The high temperature effects of too-hot radiant heat under wood flooring, and the effect on finished wood flooring are cited
at WOOD FLOOR DAMAGE,
and more radiant heat design specs are
at RADIANT HEAT FLOOR MISTAKES.
Here we add details about different operating temperatures for radiant heating systems.
Typical Radiant Heat Floor System Operating Temperatures
Typical radiant floor systems operate at 85 - 125 °F water temperature entering the tubing, and put the floor surface temperature about 5 degrees above the room thermostat set temperature.
Similarly other sources such as the Oregon state energy conservation department gives the typical operating temperature range for radiant heating systems at 85-140 °F (30-60C) though we agree that 140 deg.F. is a bit higher than suggested by other sources.
A radiant heat system manufacturer, Radiant Floor Company, opines that 120 to 135 deg F is 'ideal' and most sources we have found discuss typical radiant heat operating temperatures in the 115-135 degree range.
Where PEX tubing is used for radiant-heat under-floor tubing, 125 to 130 °F is typical operating temperature used for water entering the tubing.
Most radiant floor heating systems we've examined run at around 115F water temperature entering the tubing of the radiant section, and you'll see by the temperature gauge at the top of this article that 115 °F was the factory default set temperature on the control of an electric radiant heat boiler we installed.
The control on that boiler's circuit board is shown just above.
But as we explain below, the optimum operating temperature for radiant heat floor systems will vary depending on the insulating or heat-conducting properties of the flooring material itself.
Typical Temperatures at the Upper Surface of Radiant-Heated Floors
Our photo (above) shows our friend Steve and his dog explaining the radiant heat tubing layout in the new garage floor slab of a Minneapolis MN home. Radiant heat tubing was installed under the concrete floor to provide a heated garage.
The open corner garage door design permitted cars to turn into the garage from a narrow alley.
Unless you have a black crayon and an infrared thermometer it may be a bit more difficult to measure the finished-floor surface temperature (what your bare feet would feel when walking on the floor) than it is to just look at a temperature gauge on the hot water heating pipes or heating boiler themselves, but looking at the finished floor surface is one important temperature to note.
The finished floor surface temperature is what the building occupants feel when walking on the floor, affects the rate of heat radiating into the air above the floor, and if too high, can also become a safety concern.
According to CMHC (Canadian Mortgage and Housing Corporation) the finished floor temperature should never exceed 85 F (29 C).
Watch out: Note that for special installations such
as DRIVEWAY & WALK DE-ICING SYSTEMS installation the radiant heat system operating temperatures will be higher than used in an in-building heating system.
Be sure that the tubing you select is rated for use at that operating temperature.
Our photo (left) shows an abandoned driveway de-icing radiant heat system that has been abandoned. Only the mainfold remains in place near the home's heating boler.
Watch out: if you saw 167.8 F at the boiler, that sounds too hot for normal circumstances on a radiant heating system. Running a radiant heat system hotter than necessary can have a range of harmful effects including:
- Shorter heating boiler life
- Shorter radiant heat tubing life
- Oxygen diffusion problems [discussed below]
- Uncomfortably hot or even dangerously hot floor surfaces
- Unnecessarily high heating system operation costs
See PEX PIPING INFORMATION for more details about temperature ratings of plastic tubing. It may be useful to ask why someone has set the temperature of this radiant heating system so high. It could be
- Simply a mistake
- A control not functioning properly
- An improperly installed or designed radiant heat system that is not delivering adequate heat into the occupied space
- A misunderstanding of the controls or a misread of the temperature at the wrong location. See 'Where to Check the Temperature ...' at the end of this article.
Typical Radiant Heat Temperatures Under Ceramic Tile
Under ceramic tile a higher temperature might be allowed without risking floor damage (we don't have wood shrinkage for example) and/or might have been set by a homeowner who likes a really warm bathroom floor.
But since ceramic tile is a *better* heat conductor than wood flooring, if anything, one would expect the temperature setting for that floor to be lower, not higher than otherwise.
Radiant under ceramic tile or vinyl tile, lower end of the temp;
Typical Radiant Heat Temperatures Under Finished Wood Flooring
Under wood floors nailed right to the subfloor and tubing below, radiant heat temperatures are typically at the middle of our 85-135 °F. temperature range, or about 105-115 °F.
![Radiant Heat Systems Radiant Heat Systems](http://www.1stchoiceheating.com/images/2015/05/infloor_heating_diagram.jpg)
The radiant heated wood floor shown in our photo (left) was installed in a New York home.
Attempting to 'drive out' tubing odors the installer pushed the floor temperature up a bit too high, taking the blame for gaps that appeared in the flooring as a result discussed at at WOOD FLOOR DAMAGE.
Radiant Heat Temperatures Under Laminate Flooring
Under laminate type finish flooring, keep the temperature under 82 °F or risk floor damage (per http://www.shawfloors.com/)
Radiant Heat Floor Temperatures Under Carpeting
Under carpet over subfloor, radiant heat will need to operate at the higher end of its temperature range to overcome the insulating effect of the carpeting and carpet padding.
Typical Temperatures for Radiant Heat Ceilings
Question: What should my my hot water temperature be so I don't crack my ceilings?
(Oct 15, 2018) Ronald Tabellione said:
I have radiant heat hot water system in my plaster ceilings. What should my my hot water temp be so I don't crack my ceilings.
I have 2 zone heat and a brand new furnace. House built in 50's
Reply: 150-170 degF in the ceiling or wall panels
Radiant heat ceilings generally run in the 150-170 degF. range - thus delivering more BTUs pe square foot than radiant floor heating.
Radiant heated ceilings and possibly radiant heat wall panels can operate at significantly-higher temperatures than radiant heated floors, probably because we need to be able to walk on the floor without getting a hot-foot.
The wiring in some electrical radiant heat gypsum board (drywall) panels is rated for 250 degF but doubtless operates well below that.
Here are some details and information sources. I'm collecting more and will add that to this page.
Floor heat temperatures, in comparison with radiant heatd ceiling panel temperatures
typical operating temperature range for radiant floor heating systems at 85-140 °F (30-60C) though we agree that 140 deg.F. is a bit higher than suggested by other sources.
The US DOE notes that
Radiant floor heating systems are significantly different from the radiant panels used in walls and ceilings. - www.energy.gov/energysaver/home-heating-systems/radiant-heating#307668-tab-0
Regrettably the DOE doesn't give any different temperature ranges for radiant panel heat in walls or ceilings.
Radiant heat ceiling product manufacturers
Note that some of these radiant heat ceiling or wall panels are entirely electric; other radiant heat panel systems use hot water from a boiler or from a solar heating system.
- Calorique Perfectly Warm Radiant Ceiling Heat, 2380 Cranberry HighwayWest Wareham, MA 02576 USA Tel: 800-922-9276 Email: [email protected] Website: https://www.calorique.com
- Enerjoy Radiant Heating Systems, SSHC, Inc.P.O. Box 769Old Saybrook,CT 06475USA, Tel: 800-544-5182 or 860-399-5434
SSHC, Inc.1244 Old Clinton RoadWestbrook, CT 06498Email: [email protected]
Enerjoy produces radiant heat modules - electrical panels that can be installed on a ceiling or possibly a wall. - Messana Radiant Cooling and Heating ceiling solutions Messana Radiant Cooling4105 Soquel Dr, Suite BSoquel, CA 95073USA
Tel: (855) RAY MAGIC (729-6244) Email: [email protected] Website: https://radiantcooling.com/
radiantcooling.com/messana-radiant-cooling-products/ray-magic-radiant-panel/
Products include an EPS radiant panel built into sections of drywall that can be installed on walls and ceilings. - Thermaray Therma-Ray Inc.670 Wilsey Road, Unit 6Fredericton, New BrunswickCanada E3B 7K4 Tel: 866-457-4600 Website: thermaray.com/radiant-ceiling-electric-radiant-heating-system/
Thermaray produces electric radiant heating systems for floors, ceilings, and other applications such as driveway de-icing systems and snow melting.
I am collecting more operating temperature specifications for those radiant heat panels and will add that information, product specifications, etc. here.
Oxygen Diffusion in Too-Hot Radiant Heated Floors
Radiant Floor Company, a radiant heating system manufacturer, raises another interesting point, indirectly: at temperatures over 140 °F can cause an oxygen diffusion problem and require special 'oxygen barrier' tubing in some cases (depending on the boiler design) - otherwise system life may be reduced or the boiler damaged.
Where to Check the Temperature of A Radiant Heated Floor System
Mixed Radiant & Hydronic Baseboard or Radiator Heating Systems
Watch out: often there are mixing and flow controls on the radiant system that limit the actual temperature in the radiant tubing, typically by only introducing new hot water into the loop when temperature requires it - otherwise recirculating most of the loop water without returning it to the boiler.
You will particularly see this if the boiler is serving a mixed-design system, including some heating baseboards and other radiant floor heated sections.
That's because we want the hotter temperatures in the baseboards (hotter is more efficient heat transfer), and cooler temps in the radiant flooring.
So: was this a mixed design system with some baseboards and some radiant? andwere there mixing controls on the radiant loop section ?
Question: how can I boost the temperature of our radiant-heated floors?
I have radiant heat floor throughout my house and I have some questions about boosting its output. I’d love to enlist the serves of someone from your team who can answer questions about heat exchangers, optimal temperates, max temperatures, etc.
The sooner the better as we are feeling chilly at the moment. - Anonymous by private email 2017/12/11
Reply: (Mod) said: take care not to over-boost radiant heat floor temperatures
I may be able to answer specific questions or I may have a few suggestions but you will be best served by an on-site expert who can look at your equipment, controls, house and its design and points of heat loss.
Watch out: In general, if you boost temperature too high with a radiant heat floor you can find the floors too hot to walk on comfortably; and of course adding rugs to make walking comfortable block the heat output.
- I would take care to keep your radiant heat temperatures in the heating loop under 135°F (57°C).
- The finished floor temperature should never exceed 85°F (29°C).
That is typically managed by adjusting the temperature controls at the mixing valve that maintains the floor temperature by mixing in return loop water with outgoing water from the circulator/boiler.
Too much heat can also damage floors if they're wood, and too much heat may exceed the rating of the radiant tubing that was used, leading to a tubing failure - costly leaks.
My photo shows gaps that developed in a wood floor installed over radiant heat tubing after the radiant heat was driven to temperatures above those recommended by the radiant floor heat system manufacturer.
Start by finding the operating temperature of your system as it is.
Consider also looking over the home to reduce its heat loss, particularly if there are drafts.
I cannot assist on a for-pay consulting basis. We do not sell anything. In order to absolutely assure our readers that we write and report without bias we do not sell any products nor do we have any business or financial relationships that could create such conflicts of interest.
For reducing your home's heat loss these articles might be useful
- HEAT LOSS in BUILDINGS - home
Carpeting Impact on Radiant Heat Floor Systems
Question: does it cost more to operate radiant heat flooring covered by carpeting than by tile?
On carpet - while carpet may impact the performance of radiant heat, does it impact the efficiency? As in, am I spending more money trying to heat the carpeted areas of the house vs the tile? I guess a bad carpet installed could insulate the floors so much that all the heat gets bled off into the unsinsulated parts, but Id think even if I removed all the carpet in favor of LVP for example, Id still be using more gas due to other heat loss issues.
Can carpet cost more to heat? - Anonymous by private email 2019 09 27
Reply: yes
OPINION: Wall to wall carpeting, especially thick or heavy carpeting acts as insulation to slow heat transfer from the tubing and warmed slab up into the occupied space.
The result is that for the radiant heating system to satisfy the thermostat it has to stay on longer. It's a bit over-simplifying but a heat source that has to run longer to satisfy the room thermostat - all other factors being held constant - increases energy consumption and thus heating cost.
One would infer that during that 'stays on longer' only if there were ZERO heat / energy losses through pathways that do not transfer heat into the occupied space would there be close to zero additional heating cost. So yeah we're heating something else besides the occupied space.
Even in a theoretically zero-entropy 'perfect' heating system with zero heat losses through other pathways than into the occupied space, and thus zero additional heating energy cost (electricity or gas or oil or whatever), nevertheless simply running the circulator would add a little energy cost. And of course that ideal case doesn't exist in the real world.
'The capacity of a floor system depends on the heat exchange between the floor surface and the space (convective and radiant heat exchange coefficient), the heat conduction between the floor surface and the tubes (floor surface material, type of concrete, type of floor system, slab thickness, spacing between tubes) and the heat transport by water (water flow rate, temperature difference between supply and return). (Olesen 2002) Olesen is an ASHRAE fellow.
Olesen, Bjarne W. 'Radiant Floor Heating In Theory and Practice' [PDF] ASHRAE Journal July 2002 pp. 19-24. Retrieved 2019/09/27 original source: Universitas Miguel Hernandez, Instalaciones de Climatizacion, offering a masters degree in heating and electrical systems and energy efficiencyt, retrieved 219/09/27 original souirce: http://umh0717.edu.umh.es/wp-content/uploads/sites/482/2015/03/Radiant-floor-heating.pdf
Here is a key remark from that article
For maximum capacity, it is important to avoid floor coverings with a high thermal resistance such as heavy wall-to-wall carpets. This increases the required water temperature and then also the back losses to ground or unheated space. Also, higher water temperature reduces the efficiency of the heat generator (condensing boiler, heat pump).
Really? Well other energy losses can dominate heating cost. Very basic things the air leakage rates will dominate the heating load even in a well-insulated home. We've published some studies on this, for example see
and
Driveway & Walkway De-Icing Systems Installation
What are the basic design parameters, tubing sizes, operating temperatures and controls used in snow and ice melt systems (SIMs) for driveways, walks, and parking lots? Here we discuss these parameters and include links to detailed SIM design guides from experts in the field.
![Radiant Heat Systems Radiant Heat Systems](http://www.radiantcompany.com/wp-content/uploads/3-ZONE-CLOSED.jpg)
Question: can I mix 1/2' and 3/4' tubing on the same PEX radiant heat circuit
2019/09/19 Bill said:
I have a radiant floor heating system for two rooms with 1/2' PEX that works fine. When I put it in, I used a manifold with an extra space in case I wanted to add a circuit.
We are going to repour front steps and sidewalk to the driveway and I thought that that would be a good use of my additional circuit. But I have read that any outdoor application should use 3/4' PEX instead of 1/2'.
Can I mix have two circuits with 1/2' PEX and one with 3/4'? Can I just use 1/2' for the outdoor steps and sidewalk and expect it to keep the snow off? (I live in SE Michigan.)
This Q&A were posted originally at PEX PIPING INFORMATION
Reply: yes but watch out for some snafus: Design Paramaters for Snow or Ice Melt Systems (SIMs) under Driveways & Walks
Bill
Depending on the heating load for your snow and ice melt system for your walk and driveway, you can use 1/2' PEX tubing. Here is a quote from the Radiant Floor Company who have provided an installation and design manual that we cite in detail below:
The 1/2” ID PEX is also a polyethylene tubing with avery high temperature and pressure rating (180 degreesat 100 psi). It emits about half the heat of the 7/8” PEX,but its bending diameter is tighter. Using 1/2” PEX forsmall zones, tight crawl spaces, or snowmelt applicationsmakes sense. It has a bending diameter of 15” and shouldbe spaced 8” to 12” on center. - Radiant Floor Company 2007
In a similar but not identical opinion, the Plastics Pipe Institute (cited below), in discussing outdoor de-icing systems notes that Pex Tube size for driveway and walk de-icing and snow-melt systems is typically 3/4 NTS but adds that 1/2 inch and 5/8 inch tubing is sometimes used.
What PEX tubing size you can use on a de-icing system or snowmelt system will be adequate depends on several factors
- the size of the area to be de-iced
- the drive or slab temperature when snow-fall begins and of courses the rate, density and depth of snow or ice on the surface;
- the outdoor temperature range anticipated. Wind velocity and sky temperature and een outdoor humidity levels are also factors considered when computing the Snow and Ice Melt (SIM) system design loads.
- the design of the outdoor de-icing system (watch out: insulation and tubing placement are absolutely critical)
- the BTUH capacity of the heating boiler that's producing the hot water, and of course the circulator(s) and water flow rates possible
- other simultaneous loads on the system
- the type, placement, and qualty of insulation under the drive or walkway
- the proper placment of the PEX or other heating tubing within the concrete or other paved drive or walkway surface - its proximity to surface versus bottom of the slab - detailed at RADIANT HEAT MISTAKES
I'd start by making sure that the boiler providing hot water to the current and future systems has the needed capacity.
Then, yeah, you MIGHT be fine with 1/2' tubing.
Starting with our article RADIANT HEAT TEMPERATURES you'll see that outdoor or driveway or walkway de-icing systems need higher temperatures than indoor radiant heat flooring. Some details worth noting when choosing tubing for a de-icing or snowmelt system:
- You may need to re-size the hydronic boiler expansion tank when adding radiant heat loops for any purpose as the water volume is also going to increase
- Typically a Snow and Ice Melt System (SIM system) operates at two different temperatures:
an 'idle' temperature of 28°F (-2°C) when melt operation isn't needed but the system is in 'stand-by' mode,
a melting temperature of 38°F (4°C) when the system is at work; both of these temperatures must be adjustable for variation in local conditions. - PE-RT is a type of polyethylene tubing that has Raised Temperature-Resistance (CSSA B137.18)
- Your ice or snowmelt system will need to warm the melt-area by applying 051 BTU/lb (Op. Cit.). MacNevin, writing for the PPI, notes also that
That does NOT mean the same boiler can't serve both, but you'll need temperature regulation devices that provide the proper temperature for indoor versus outdoor PEX radiant heat tubing loops.
See the Radiant Heat Guides suggested just below. You will read that experts (MacNevin 2016) discuss an array of additional controls such as drive or walk surface moisture monitors and other instrumentation that can improve both the efficiency and effectiveness of SIM (snow and ice melt) systems.
Radiant Heat Installation & Operation & Temperature Guides
- Olesen, B.W., et al. 1980. “Thermal comfort in a room heated by different methods.” ASHRAE Transactions 86(1):34–48.
- Olesen, B.W. 1977. “Thermal comfort requirements for floors occupied by people with bare feet.” ASHRAE Transactions 83(2):41–57.
- Olesen, B.W. 1994. “Comparative experimental study of performance of radiant floor heating system under dynamic conditions.” ASHRAE Transactions 100(1):1011–1023.
- Olesen, Bjarne W. RADIANT FLOOR HEATING IN THEORY AND PRACTICE [PDF] ASHRAE Journal July 2002 pp. 19-24. Original source: Universitas Miguel Hernandez, Instalaciones de Climatizacion, offering a masters degree in heating and electrical systems and energy efficiency at http://umh0717.edu.umh.es/wp-content/uploads/sites/482/2015/03/Radiant-floor-heating.pdf
- Radiant Floor Co. Radiant Floor DESIGN & INSTALLATION MANUAL 11th Ed. (2007) Radiant Floor Company Barton, Vermont Fax: 1-802-525-3940 1- 866-WARM-TOES 1-866-927-6863 1-802-525-1132 www.radiantcompany.com retrieved 2019/09/20 original source: https://www.radiantcompany.com/wp-content/uploads/radiantcompanymanual.pdf
- RADIANT HEAT MISTAKES - Additional radiant heat and tubing installation design criteria
- HUD, PPFA, DESIGN GUIDE for RESIDENTIAL PEX WATER SUPPLY PLUMBING SYSTEMS [PDF] (2006) HUD, U.S. Department of Housing & Urban Development, Plastics Pipe Institute, Inc (PPI) 105 Decker Court Suite 825 Irving, TX 75062 www.plasticpipe.org and Plastic Pipe and Fittings Association (PPFA) 800 Roosevelt Road, Bldg. C, Ste. 312 Glen Ellyn, IL 60137 www.ppfahome.org and Partnership for Advancing Technology in Housing 451 7th Street, SW Washington, DC 20410 www.pathnet.org and NAHB Research Center, Inc. 400 Prince George’s Boulevard Upper Marlboro, MD 20774 www.nahbrc.org retrieved 2019/09/20 original source: https://www.huduser.gov/portal/publications/pex_design_guide.pdf
Excerpts: Continuous-use temperature ratingsas high as 200ºF (93ºC) are required as well as standardized chlorine resistance testing toensure that the piping will withstand the most aggressive drinking water conditions.
Temperature and Pressure
PEX piping meets all requirements for pressure and temperature performance in residentialapplications. Consensus standards published by the American Society for Testing and Materials(ASTM) International specify temperature and pressure-resistant capabilities of PEX pipe andall tubing used in residential applications bears the appropriate test marking.
In the event of a water heating system malfunction, PEX piping is designed to accommodateshort-term conditions of 48 hours at 210ºF (99ºC) and 150 psi (1034 kPa) until repairs canbe made. The most commonly used safety relief valve (T&P) activates (opens) at either ofthese temperature or pressure conditions. All PEX piping has been tested to withstand T&Pactivation for 30 days to ensure that safety requirements are met. As such, PEX systems DONOT require the use of a special T&P valve.
ASTM F 876: Standard Specification for Cross-Linked Polyethylene (PEX) Tubing coversPEX piping that is outside diameter controlled, and pressure rated for water at threetemperatures—160 psi @ 73.4ºF, 100 psi @ 180ºF, and 80 psi @ 200ºF. Included arerequirements and test methods for material, workmanship, dimensions, hydrostatic sustainedpressure strength, burst pressure, oxidative (chlorine) resistance, and environmental stresscracking.
ASTM F 877: Standard Specification for Cross-Linked Polyethylene (PEX) Plastic Hot- and ColdWater Distribution Systems covers requirements and test methods for PEX hot- and cold-waterdistribution system components made in one standard dimension ratio, and intended for 100psi water service, up to and including a maximum working temperature of 180ºF.
Componentsare comprised of piping and fittings. Requirements and test methods are included forhydrostatic sustained pressure strength, thermocycling resistance, fittings, and bend strength.
Also in this document see Figure 11.2 – Snow and Ice Melt Piping for a Driveway p. 92 - MacNevin, Lance, P.Eng., DESIGN AND INSTALLATION OF HYDRONICSNOW AND ICE MELTING (SIM) SYSTEMS TOOPTIMIZE PERFORMANCE AND EFFICIENCY [PDF] (2016) Plastics Pipe Institute, Inc (PPI)105 Decker CourtSuite 825Irving, TX 75062www.plasticpipe.org retrieved 2019/09/20, original source: https://www.modernhydronicssummit.com/wp-content/uploads/sites/3/2017/09/MacNevin-Summit-2017.pdf
- RADIANT HEAT MISTAKES includes a table showing the necessary increase in heating system operating temperature as a function of the depth of radiant heat tubing in a concrtre slab.
- SOIL R-VALUES discusses heat transfer or flow through soil or dirt
- John Siegenthaler, is a professional engineer specializing in radiant heat designs and heat transfer theory in buildings. Mr. Siegenthaler principal of Appropriate Design, a consulting engineering firm specializing in hydronic heating design. He is the author of Modern Hydronic Heating and Radiant Precision (available from the Radiant Panel Association (www.radiantpanelassociation.org, 800-660-7187). His work is discussed here
at
RADIANT HEAT MISTAKES (not John's mistakes, rather those of other radiant heat system installers) - THERMAL IMAGING, THERMOGRAPHY an introduction to thermography and what to expect when using thermal scans to study radiant heat floor problems
- WattsRadiant, RADIANT PEX® INSTALLATION MANUAL [PDF] (2017) Watts Radiant, USA: Tel: (800) 276-2419 • Fax: (417) 864-8161 • WattsRadiant.comCanada: Tel: (905) 332-4090 • Fax: (905) 332-7068 • Watts.caLatin America: Tel: (52) 81-1001-8600 • Fax: (52) 81-8000-7091 • WattsRadiant.com retrieved 2019/09/20 original source: http://media.wattswater.com/IOM-WR-PAP-PEX-PEXAL-PERT.pdf
...
Continue reading at RADIANT HEAT CONTROLS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.
Or see RADIANT HEAT TEMPERATURE FAQs - questions & answers about radiant heat temperatures in walls, floors, ceilings, posted originally at this page.
Or see these
Radiant Heating System Articles
- RADIANT HEAT - home
Suggested citation for this web page
RADIANT HEAT TEMPERATURES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
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Technical Reviewers & References
- Ralph Arlyck, Timed Exposures, Tivoli, NY. Mr. Arlyck is a documentary film maker and producer/director of Timed Exposures, an independent film production company, Timed Exposures has produced more than a dozen critically-acclaimed documentaries which span a broad spectrum of subjects. These films have been broadcast widely in the United States and Europe, and have won top prizes at American and international festivals. Email: [email protected]
- Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: [email protected]
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com - Azel Technologies controls, temperature gauges & thermostats for radiant heating systems
- i-Link SERIES ZONE CONTROLS (CIRCULATOR PUMP SWITCHING RELAYS ) FOR HYDRONIC / RADIANT FLOOR HEATING SYSTEMS - Quoting: The i-Link series multi-zone circulator pump switching relays simplify wiring for hydronic heating ( radiant floor heating ) systems. With leading edge features and superior product design, i-Link makes installation quick and easy.
- UNIVERSAL DIGITAL TEMPERATURE GAUGE: DS-60P - Quoting: The i-Link series Zone Valve Controls simplify the field wiring and yet control up to six zone valves in a multi-zone hydronic radiant heating system. The contractor friendly Printed Circuit Board eliminates the problem caused by incorrect wiring and saves hours of installation time. There would be no more “messy” look of conventional zone valve installations.
- DIGITAL NON-PROGRAMMABLE THERMOSTAT FOR HYDRONIC RADIANT FLOOR HEATING - Quyoting: D-508F digital non-programmable heat only thermostat is designed to control either ambient(air) temperature (A Mode) or floor temperature (F Mode) or a combination of ambient temperature with floor temperature limits(AF Mode). An auxiliary remote sensor is provided to measure slab temperature in order to control the floor temperature(within maximum and minimum limits in AF Mode) in hydronic radiant floor heating system. It can also be used for sensing the outdoor temperature in A Mode.
- DIGITAL PROGRAMMABLE THERMOSTAT FOR HEATING/COOLING & HYDRONIC RADIANT FLOOR HEATING - Quoting: Azel Technologies introduces 500 series electronic programmable thermostat that utilizes the lastest digital technologies for residential and light commercial systems. D-500 is designed for 24 Vac single-stage heating and cooling systems. D-502F is designed to control the floor temperature in Hydronic Radiant Floor Heating Systems. The 500 series can accurately control the temperature within one degree. Reliable permanent memory retains the programmed settings in the event of a power failure. In addition, the large, easy to read LCD display with backlit makes the thermostat easy to operate and simple to program.
- SOLAR DIFFERENTIAL CONTROL: DST-932 - Quoting: The DST-932 differential temperature controller is designed for the Solar Heating Systems. The DST-932 switches on a pump in order to transfer heat from solar collector to a storage tank. The controller reads the temperatures of the storage tank (T1) and of the collector (T2), when this differential temperature (T2-T1) is higher than a set value (dt), it will switch on the pump. It is possible to limit the maximum temperature of the storage tank and also activate a freeze protection function. By switching to manual mode it allows the test of the heating system by turning the pump ON or OFF. A universal sensor P-01 or P-02(higher temperature range) is supplied with the control. This solid state temperature sensor probe can be extended up to 500 feet.
- Calorique Radiant Heating Floor & Ceiling Systems, Calorique LLC, 2380 Cranberry Highway, West Wareham, MA 02576 USA, Tel: 800 922-9276, produces thin film radiant heating panel systems used for interior building heating (ceilings or floors), snow melting, de-icing, drum and tank heaitng, agricultural uses, pet heating systems, and consumer end products. The company provides radiant floor heating systems in several designs including specifically for use below laminate flooring, carpeting, and tile floors. - Thanks to reader Jim O'Dowd for suggesting this resource.
- FloorHeat 3130 Sovereign Drive, Lansing, MI 48911, 888-265-5455, Email: [email protected]) radiant floor heating panels,
- Heatshield Panels, 27354 Valley Center Road, Valley Center, California 92082 USA, 800-750-3978
- Nuheat Industries 3105 - 6900 Graybar Road, Richmond, BC Canada V6W 0A5, electric radiant heat systems for use under tile, stone, and laminate flooring, 800-778-WARM (9276) Email: [email protected]
- ASHRAE 25 Heating, Refrigeration, and Air Conditioning engineering standards
- ASHRAE 90.1-2004 User's Manual, instructions for the design of commercial and high-end residential buildings 'to ensure their compliance with ANSI/ASHRAE/HESNA Standard 90.1-2004 including the application of principles of effective energy conserving design...'
- CarbonicHeat radiant heat flooring products, 866.786.1806 [email protected], [no mailing address]
- Entran radiant heat:
- Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v1.pdf
- Passive Solar Design Handbook Volume II, the Passive Solar Handbook Comprehensive Planning Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v2.pdf [This is a large PDF file that can take a while to load]
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
- Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
- Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates'Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page 'Promo/Redemption' space. - ...
- Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: [email protected]. The firm provides professional HOME INSPECTION SERVICES and also extensive HOME INSPECTION EDUCATION and home inspection-related PUBLICATIONS. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The ILLUSTRATED HOME illustrates construction details and building components, a reference for owners & inspectors.
Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page 'Promo/Redemption' space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop Weldon & Associates
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page 'Promo/Redemption' space. - The HOME REFERENCE BOOK - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page 'Promo/Redemption' space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The HOME REFERENCE eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones.
Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page 'Promo/Redemption' space. - Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd
COMMERCIAL BUILDING INSPECTION COURSES - protocol ASTM Standard E 2018-08 for Property Condition Assessments
HOME INSPECTION EDUCATION COURESES (Canada)
HOME INSPECTION EDUCATION COURSES (USA) including home study & live classes at eleven colleges & universities.
HOME INSPECTION EDUCATION: HOME STUDY COURSES - ASHI@Home Training 10-course program.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page 'Promo/Redemption' space. InspectAPedia.com editor Daniel Friedman is a contributing author. - The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones
Table of Contents.What is Hydronic Radiant Floor Heating?There are three major types of radiant floor heating systems. The original (and largely abandoned in the West) method was used most notably in Turkish baths and consisted of a raised floor to allow hot air underneath, keeping the floor nice and warm.While the true origin of radiant floor heating is unknown, Primitive Technology proves it was possible with even stone age methods. While this form of heating may still be found in some historic buildings, it is rarely (if ever) used in modern construction.The second is a more modern solution and uses a series of electric cables installed between the floor and subfloor. Electric radiant floor heating works well in a small space, but (as you can imagine) becomes prohibitively expensive when used throughout an entire house unless you’re generating most of your power off-the-grid.The final method, hydronic floor heating, uses the same basic principles of traditional radiator heating. This provides a cost-effective heating solution that gives a more consistent result than modern forced-air HVAC systems, although it isn’t perfect.Related: How Does Hydronic Radiant Floor Heating Work?Hydronic floor heating takes advantage of the flexibility found in. Uncut lengths snake through the room, with the beginning and end attached to a manifold.Because the floor will be sealed, there can be no joints in the tubing.
Each loop of the tube is set approximately nine inches apart, then held in place with specially shaped staples.The sub-floor and tubing is covered by concrete, gypcrete, or dry-tamped mortar, providing a solid seal.These materials hold heat, allowing it to radiate evenly whether the system is running or not. In most cases, the floor is finished using ceramic floor tiles, as these also hold heat well.Heading from the room to the system itself, the manifold helps keep the water evenly distributing between lengths of PEX tubing and helps vent the system.
At the other end of the system is a dedicated boiler or, with a circulating pump pulling water into the system and returning it to the bottom of the boiler to reheat.As the water generally only loses about ten degrees, a running system maintains heat quite efficiently. Advantages of a Hydronic SystemThere are quite a few things to love about radiant floor heating systems. Because the heat radiates from the floor itself, there are no vents to place furniture around and the furniture itself can pick up a bit of the warmth.Unlike forced air systems, they won’t spread allergens around the room and heat evenly, eliminating cold spots.Best of all, these silent systems tend to be between 10 and 30 percent more energy efficient than standard HVAC systems and will continue to keep the house warm for hours after a power outage. Disadvantages of a Hydronic SystemThese systems are not without their flaws.
The biggest problem is that you’re more restricted on floor coverings. Carpets can actually block the heat, for example.
You will also have a longer wait time when the system is first turned on and can increase the humidity of your rooms near the floor.The biggest headaches, however, happen during installation. You will need a contractor who’s trained to install the system due to its special requirements.They can also get very complicated if you’re installing into an existing floor. Any repairs will likewise be rather complicated and potentially expensive, although any necessary repairs to the submerged portions are very rare.
Hydronic vs ElectricHydronic systems tend to be cheaper to install and run than electric. They used a closed system, making the cost of running the boiler and pump your only real fees.Compare this to an electric system, which needs to pump electricity throughout the system. Hydronic vs Forced AirForced air systems require a furnace and duct work to be run throughout your home. Even with modern systems, this can lead to cold spots and the ducts need regular cleaning to reduce the spread of allergens.The modular nature of duct work can also lead to heat loss and less overall efficiency. Because a hydronic system has its parts embedded and uses a smaller heating unit, most of these problems are eliminated. How Much does Hydronic Radiant Floor Heating Cost?Installing and running a hydronic radiant floor heating system is a very different experience than adding forced air systems.
As such, planning out your expenses isn’t quite as predictable.We’ve broken down many of the details so you can get a better idea of the cost. Please note that some materials, local rates, and other factors may result in higher or lower fees, especially for installation. Cost to InstallAdding one of these systems is best done during a major renovation or new construction to avoid having to rip up an existing floor. Removal of an existing floor will vary greatly in cost depending upon the material and room size.In some cases, you will also need to add extra support for the sub-floor to withstand the heavier weight of your filler material.Hydronic systems tend to be cheaper to install than their electric counterparts, beginning at $6 per square foot (as opposed to $8 for electric).
Larger areas will generally be cheaper to install than smaller, as space restrictions can compound the task.As such, a smaller room may cost $9 or more per square foot, while extremely large areas could cost as little as $5 per square foot. The exact cost per square foot will thus be a combination of system type and project size.One other factor that will affect the cost of installation comes in the form of temperature zones. Some rooms are more lived-in than others, and these will often need a higher average temperature than less frequented areas of the house. Such zones can require more complex systems, adding to the general cost.In all, you can expect to pay anywhere from $6,000 to $14,000 to install a hydronic radiant floor heating system.
This includes the system itself and the cost for a dedicated water heater or boiler (generally $360 to $1,000 for a 50 gallon water heater or approximately $6,000 for a boiler). Cost to OperateThanks to the invention of the programmable thermostat, running a hydronic system can be much cheaper to operate than a traditional HVAC system. You can set the system to run during off-peak hours to reduce your electric bill and the floor will continue to radiate heat long after the system shuts off.Radiant systems can also usually be run at six to eight degrees cooler than forced air, as hot air rises and the latter usually pushes the hot air in at the top of the room, reducing its effectiveness.As water is more efficient at retaining heat, the system needs far less energy to reheat the recirculated water than a furnace does to reheat returning air. This results in energy savings of up to 30 percent.These savings will only get better as solar heating systems continue to improve, promising to eventually replace the need for using grid power entirely in these systems. Important ConsiderationsRadiant floor heating, especially hydronic systems, can offer a lot of options, but also have some restrictions. Planning ahead will save a lot of time and effort when adding one of these systems to your home. Best Places to InstallYou will ideally want to install the system during construction or renovation, but it can also be important to consider whether you wish to do your entire house or just one or two rooms.
Larger rooms where your family spends most of its time are the most ideal.The most common areas to warrant coverage are bathrooms, uncarpeted bedrooms and living rooms, hallways, or kitchens (in a busy household). Some say that bathrooms should only be done when installing a full-house system, but there’s nothing better than stepping on a warm tile floor after waking up on a chilly winter morning.You will also need to think carefully if you plan to add a cooling system. Radiant cooling should be installed in the ceiling, so you may want to further restrict partial installations to account for this fact.Remember, a radiant floor heating system can be used to augment or replace an existing HVAC system, but it’s far more complicated than swapping out a furnace, so plan any partial coverage carefully. Best Flooring for Radiant HeatThe type of flooring you use will have a major effect on the efficiency of your new radiant floor heating system. Thankfully, you have a few options. Porcelain or Ceramic TileTile is perhaps the most popular solution, boasting a high heat conduction rate and the ability to continue radiating stored heat in addition to what’s held in the underlying surface. Natural StoneRight alongside tile are natural stone.
Stone tiles work very similar to ceramic and work well in conjunction with the material beneath. LaminateLaminate floors are also an excellent match, although you will want to pay attention to any heating restrictions by the manufacturer, since water damage from below can ruin laminate easily. As most manufacturers have a limit as high as 85 degrees Fahrenheit, it’s pretty hard to hit those restrictions. WoodWood flooring suffers from reduced efficiency, but can still be used. It’s best to go with engineered wood flooring, as the underlying plywood is less likely to warp. Solid hardwood should be quarter-sawn for improved flexibility and to accommodate any thermal expansion.
Need to hire a plumber? From top local home service pros in your area.In both cases, the floor will take longer to warm up and won’t hold the heat nearly as well as with other materials. Worst Flooring for Radiant HeatingConversely, we have several types of flooring that can negate the effectiveness of your new heating system. CarpetThe biggest culprit is carpeting, which is designed to absorb heat but has terrible conductivity. ConcreteSimilarly, concrete actually defeats itself when used as the main floor covering. Radiant systems rely upon layered flooring to help distribute and store heat.
Without a higher layer of different material, the concrete loses most of its efficiency. RubberWhile not commonly used, rubber flooring is another terrible choice, as it will give off an unpleasant odor due to the heat.
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