FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Electric Radiant Floor heat

| Posted in Energy, Heating & Insulation on June 6, 2006 08:10am

I  am considering replacing an old baseboard water heating system with an electric radiant system in two rooms, one 10 x 14 and one 10 x 20.  Substrate is plywood,, and I plan to put ceramic tile over the electric radiant. I have no experience with Radiant heat — anything I should watch out for? 

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. Lansdown | Jun 06, 2006 08:48pm | #1

    Sharp screw heads not countersunk enough.

    Seriously, do check the grid before you thinset over it. 'Warmly yours' brand includes a continuity tester/alarm that you wire up temporarily while installing. If there is a break the alarm will sound. It is much easier to repair it before the tile goes down.

  2. Varoom | Jun 06, 2006 09:22pm | #2

    http://www.suntouch.net/

    Consider 240V matts instead of 120V.

    1. MJAremodeler | Jun 06, 2006 09:58pm | #3

      would the higher wattage be needed for larger area coverage -- or is that a factor?

      1. Varoom | Jun 06, 2006 10:52pm | #5

        Allows you to run fewer circuits and it will heat up faster.

        1. Tim | Jul 05, 2006 04:12pm | #14

          What you say is incorrect. A watt is a watt, whether supplied by120 volts or 240 volts. For the same wattage (and for a given size they WILL be the same wattage) the 240v floor matt will NEVER heat up faster.

          OTH, electric floor mats have, on average, 10 w/sf. In a 10x20, (the heated area should be no more than 9x18) that is 1620 watts, in a 120v circuit that 13.5 amps, easily handled with a single 20 amp circuit.

  3. Abe | Jun 06, 2006 10:37pm | #4

    I just installed just shy of 200sqft of the Warm Tile system and it worked great.

    http://www.warmtiles.com/     I had looked at some of the mat systems at the big orange box and they did not very practical for my installation because of the shape of the room and vents and other considerations. 

    I installed cement backerboard in a bed of thinset first, screwing the heck out of it because the plywood was on soft side.  I then installed the heating cable with a 3" spacing.  between every third row I tacked down a narrow strip that of 1/4" backerboard to act as a gauge block.  More thinset followed and was allowed to cure and then the marble went down like usual. 

     

    I used thinset instead of leveling compound to bed the cables because of cost,  about 80% less than leveling compound.

    Don't skimp on the thermostat get the programmable one,  it has the ground fault already built into it and just makes sense to only heat the floor when you need it instead of 24-7.

    I also went to 220 volt and ordered everything electrical over the net because Menards could not even come close on cost.

    Grab your volt ohm meter and take readings from time to time just so that you know that the cable has remained undamaged.  It is actually pretty durable but then again why take chances.

    Now the only problem I have is the home owner will want 3 more bathrooms done the same way.

  4. GaryGary | Jun 07, 2006 07:37am | #6

    Hi,
    I guess one thing to think about is that the electric radiant is likely to be more expensive to run, and generate more green house gases.

    Gary

    1. N30X1D3 | Jun 07, 2006 08:25am | #7

      With expected shortages in supply of Natural Gas and Propane and the prices which should jump when in short supply. I would expect that Electric Radiant Floor heat should soon be the least expensive heating method available. Also US powerplants have the most highly regulated emissions of any other type of machine in the world. Per Joule of energy produced they are cleaner than any propane furnace or water heater on the market. I'm far more worried about the green house gasses produced by cars and trucks.

      1. Sbds | Jun 07, 2006 09:26am | #8

        This article is from JLC about installation

      2. GaryGary | Jun 07, 2006 04:47pm | #10

        Hi,"Also US powerplants have the most highly regulated emissions of any other type of machine in the world. Per Joule of energy produced they are cleaner than any propane furnace or water heater on the market. I'm far more worried about the green house gasses produced by cars and trucks."I'd respectfully submit that this is not true.To produce 100K BTU of heat from a coal fired power plant using electric resistance heating generates 62 lbs of Carbon Dioxide. Coal plants generate most of the electricity in the US.To produce the same 100K BTU of heat from a 90% efficient gas furnace or boiler produces 12 lbs of Carbon Dioxide.So, the electic/coal heater makes 5 times more greenhouse gas for the same amount of heat. This is because coal is a high carbon fuel, and coal fired electric plants are only about 30% efficient. Space heating is a major source of GHG -- its right up there with your car.At 10 cents per KWH, the 100K BTU costs $2.92, so gas would have to go up to ($2.93)(0.9) = $2.63 per therm to cost the same as electricity. As controls on carbon emissions come in over the next 10 years or so, electricity produced from coal is going to go up substantially (I think).Carbon calculator here:
        http://www.infinitepower.org/calculators.htmGary
        http://www.BuildItSolar.com

  5. Ribs | Jun 07, 2006 03:05pm | #9

    I'd make sure you check the spec on this. It sounds like you're using this to actually heat the room. Not sure if the 220 puts out significantly more heat than the 120 but I don't think there is any way these mats will heat your room. I installed one in our new mudroom and downstairs bathroom when we did our addition. It is great for making the tile floors comfortable to walk on but doesn't come close to providing enough heat in the room to keep it comfortable.

    Installation was relatively easy and straight forward. A bit of panic about wondering if the wires ever got damaged but the system ended up working great. It definitely increases the electricity bill in the winter however.

    1. MJAremodeler | Jun 28, 2006 05:21am | #13

      Thanks. I've had some trouble checking the requirement, but this is what I think I know at this point: The system I am looking at has 12 watts per square foot, and each watt is the equivalent of 3.4 btuh, for a total of about 41 btuh/square foot. I've tried to equate this to the yield on the steam heating system we currently have, and find that the steam system seems to be scaled for 50 btuh. But that is for a poorly insulated room, 11 ft ceiling, and I plan to insulate the rooms with electric radiant floors very well. I think I will be okay with the 41 btuh/sf. I appreciate the concern and the tips.

  6. BryanSayer | Jun 07, 2006 05:26pm | #11

    I put in Nu-Heat and we are very happy with it. They will custom make the mat for you if their standard sizes do not fit. It takes about 7 to 10 days to get it.

    Our tiler hates the single wire type that are installed by layout out the wire in loops.

    For testing, you will probably need a digital multi-meter. My analog one did not measure resistance sufficiently accurate to meet the manufacturers demands.

  7. User avater
    tfarwell | Jun 07, 2006 06:58pm | #12

    I installed the SunTouch system under my tile floor - we love it.

    Here is what I would have done different to make it go easier.

    • Get the mat down and morter the thing in before you put tile on. Once the morter is dry with just the mat, then thinset the tile onto that. Trying to get the tile level in the places where the mat stops is more work. You can also give it a pretest before putting any tile down.
    • Cut slots in the underlayment before you put the mat down - one less hazard to the mat
    • I ended up stapling the mat down with 1/2" long 1/4" crown staples. The tape they give you stinks, especially if there is the slightest amont of dust.
    • If you ahve more than one mat, run the mat power wires to a junction box, connect to a single 12 gage romex wire that runs to your thermostat. There is not a lot of room in the box with the size of the thermostat unit.

    Good luck,

    TTF



    Edited 6/7/2006 2:54 pm ET by ttfweb

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Two Ways to Test Windows

New devices showcased at the Builders' Show make it easy to measure glass performance, u-factor, SHGC, window thickness, and more.

Featured Video

SawStop's Portable Tablesaw is Bigger and Better Than Before

The 10-in. Jobsite Saw PRO has a wider table, a new dust-control port, and a more versatile fence, along with the same reliable safety mechanism included in all SawStop tablesaws.

Related Stories

  • Podcast Episode 695: Saving Bricks, Cut-and-Cobble Insulation, and Waterproofing Foundations
  • FHB Podcast Segment: Waterproofing Below-Grade Foundation Walls
  • Midcentury Home for a Modern Family
  • The New Old Colonial

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 333 - August/September 2025
    • A Practical Perfect Wall
    • Landscape Lighting Essentials
    • Repairing a Modern Window Sash
  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data