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Radiant Floor Heating: Electric vs. Hydronic

 

 pipe installation Radiant Floor Heating: Electric vs. Hydronic

 

Are you thinking about incorporating radiant floor heating into your home remodel? In temperate climates like the Bay Area, many homeowners decide to install an in-floor heating system because it provides a comfortable, even heat source without relying on forced air.

Benefits of radiant floor heating include:

  • Better air quality
  • Quiet heating system
  • No visible radiators, ducts, or holes
  • Increased comfort
  • Increased energy efficiency in some cases

Hydronic vs. Electric Radiant Floor Heating

When considering radiant floor heating for your home, there are two popular types to consider: electric and hydronic. In this post we will break down the pros and cons of each with particular consideration of cost and energy efficiency.

 

Electric Radiant Floor Heating

If you want to heat a small zoned space like a single bedroom or bathroom, electric in-floor heating is usually the best choice. These radiant floors are powered by electric cables or mats of electrically conductive plastic built in to the floor. Because it does not rely on hot water, this system integrates well with homes that use forced air heating.

 

radiant floor heat wiring Radiant Floor Heating: Electric vs. HydronicElectric wiring for heat system

 

Benefits of electric radiant floor heating include:

  • The installation process is simple and ideal for remodel projects
  • Labor costs are minimal
  • On-demand heating is zoned for specific rooms
  • Heating can run on a timer

Electric radiant floor heating also has a few drawbacks:

  • Uses a large amount of electricity
  • More expensive energy bill
  • Difficult to install in big spaces or whole house
  • Primarily designed for comfort, not as primary heating source

radiant floor heat mat1 Radiant Floor Heating: Electric vs. HydronicElectric underfloor heating mat 

 

Overall, radiant in-floor heating is great for bathrooms and small spaces, especially in homes that do not have a hot water heater. It is affordable and simple to install, making it a popular choice for home remodelers.

Hydronic Radiant Floor Heating

 

water pipes 2 Radiant Floor Heating: Electric vs. HydronicPipes for hydronic radiant floor heating 

 

Another method for in-floor heating relies on hot water instead of electricity. This mode of heating has been used since ancient Roman times. Hydronic radiant heating is ideal for homeowners that like consistent heat year round, as it operates very efficiently and keeps the home at a consistent, comfortable temperature.

Hydronic systems are ideal for homes that already use a water heater as that energy can be efficiently diverted into the floor. In hydronic radiant floor systems, heated water is pumped from a boiler through a network of tubing underneath the floor.

 

concrete pour Radiant Floor Heating: Electric vs. Hydronic  concrete finish Radiant Floor Heating: Electric vs. Hydronic

Concrete floor being poured & finished

 

Benefits of hydronic radiant floor heat include:

  • Floor slab becomes one big heated mass for gentle, pleasant warmth
  • Structure of the house holds in heat
  • Heat remains constant for long periods of time
  • Once mass of home has reached desired temperature, minimal energy is required to maintain it
  • No visible heating ducts
  • Energy savings

Disadvantages of hydronic in-floor heating:

  • Labor costs for installation are higher than electric systems
  • System is more complex and not ideal for small scale remodels
  • Not ideal for homeowners that like to turn heat on and off at different times of day

 

COST

To get some ballpark numbers for homeowners to consider, we called our go-to expert for radiant floor heating systems: Nicholas Donzelli at Green Air.

Electric Radiant Floor Heating

According to Green Air, electric can be cheaper by up to 60% depending on the system’s size and available circuits. To incorporate electric radiant floor heating into one small room (ie. 10x10ft bathroom) during a remodel project, labor and material will add between $1,800-2,500 to the total project cost. However, in the long run, the fuel source (electricity) will be far more expensive than that of hydronic systems. A great way to balance that cost is through solar energy.

Hydronic Radiant Floor Heating

In homes that already use a boiler, hydronic systems from Green Air are 50-60% cheaper than electric. In that case the most expensive heat source is already in place (boilers can cost around $4,000), so it makes sense to use the mass of the home to help distribute that energy. However, if the home has no existing hot water boiler, a whole house hydronic system can start at $12,000 for material and installation. Fortunately the high efficiency boiler uses very little gas to keep the house warm over time, thus the home’s energy bill will not be dramatically increased.

 

 Radiant Floor Heating: Electric vs. HydronicFinished concrete floors with hydronic underfloor heat

 

Final Thoughts

Whether you decide to go with electric or hydronic radiant underfloor heating, you won’t regret the extra comfort. In the chilly temperate climate of San Francisco, the improved air quality and nice consistent warmth of radiant in-floor heating makes the home an enjoyable place to spend time.

What features are you looking for in a heating system? If you have radiant floor heating, which type did you choose and how is it working out for you? Share your experiences in the comments below!

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38 Responses to “Radiant Floor Heating: Electric vs. Hydronic”

  1. Annette said:

    I just installed a hydronic radiant floor. Just received my electric bill and was shocked. Went up $400-500 per month. What the hell is wrong?? Just wondering if u cud give me insight.

  2. Jeff King & Co said:

    Annette, thanks for visiting our blog! We are checking with the team leaders on your question and will get back to you as soon as possible.

  3. Ron Long said:

    thinking of putting electric radiant heat under tile.
    Is it necessary to run a separate circuit for just a 6′ 30″ length? The circuit I want to tap into has only one thing on it. thanks.

  4. Jeff King & Co said:

    Thanks for asking, Ron! Code requires that electric floor heat be on a dedicated circuit.

  5. Sally Mayhew said:

    We just bought a house in Central Pa. with radiant floor heating (hydronic system). We moved into the house the end of Jan. 2014, and have had to spend over $800/month for oil for the boiler to heat the house. I was amazed how quickly we went through a tank of oil with the thermostat set at 69 degrees. We don’t move the thermostat up and down. We like the house a little on the cool side, but the heating bill has been outrageous. The house is carpeted throughout. I’m thinking I need to change the flooring but don’t want a whole house of tile or concrete floors. What do you recommend? I like wood floors, but not sure what kind would work with this type of heating system and how they would be installed without damaging the system. Do you have any advice for me? Thanks

  6. Kirsten said:

    I’m looking at buying a house and would want to install radiant heating on the basement level where we’d finish a bathroom and put in a bedroom and office. I’m thinking hydronic would be best, but am wondering if it is a good option given that this home has a well for water supply and a ceptic system. Do you have any experience with running radiant heating with this type of set-up? How much water does it actually use and is that water then able to be recirculated into other purposes, such as into the faucets? Thank you!

  7. Jeff King & Co said:

    Thanks for your question Sally! The wood floor may be installed over the existing substrate. Carpet would be okay also. We recommend that you have a local general contractor analyze the system for quality and efficiency as it sounds like it’s not working correctly.

  8. Jeff King & Co said:

    Kirsten, the water source isn’t relevant on a closed loop system, and the radiant heating will not effect water usage overall. Good luck with your project!

  9. Lucy said:

    We have to remodel our small condo in the mountains, a place whith sometimes extreme weather, after an accidental fire in the building. We are on a 1st. level and the floor is literally in the air, meaning that we do not have a hard surface (ground) under it (sorry if I cannot be more clear). We are thinking about using bamboo flooring, is it convenient to have floor heating system in a place like this? If so, which would be best? Thank you!

  10. Jeff King & Co said:

    Lucy, thanks for your question. It’s hard to advise on your building without having more details, we recommend that you consult with a local professional to find the best solution. Good luck on your remodel!

  11. Ranny Reynolds said:

    I have a family room 16×30 built over an unheated crawl space, which is 4-8 high. Could I remove the insulation, add a hydronic system and then install new insulation? If so, would a new dedicated water heater be best? Also, would it be best to install hardwood flooring before or after the new system? Located in Charlottesville, VA. Thanks in Advance!

  12. Jeff King & Co said:

    Ranny, thank you for your inquiry. It would be possible to install radiant tubing under the floor and then install new insulation. Though it’s necessary to be very careful when installing new wood flooring over radiant tubing it would be best to install the flooring after the new heating system is working so that the floor can acclimatize to the new heating conditions. As for the type of heat source, your contractor should do a full assessment of your needs before determining a final design for the system.

  13. Marie gibson said:

    Just yesterday I toured a house with hydronic heating throughout, first and second floors. The owner heats with propane so this may be the explanation for enormously high heat bills, $4000 over the past winter. This is more than enough to scare me away from hydronic heat. Any recommendations?

  14. Dennis said:

    I am considering building one of those “tiny houses” – about 200 sq. ft, and was looking to see if radiant heating might be a good way to heat the place. (The walls/ceiling may be high R-value SIPS.) Any suggestions? Thanks for any guidance …

  15. Jeff King & Co said:

    Marie, thanks for your question. Hydronic heating is an efficient method of providing heat and comfort. Most studies show that a hydronic heating system is less costly to operate than conventional forced air systems. So the question becomes what can be done to reduce heating load or cost. Good insulation, efficient windows and glazing, solar gain opportunity are all factors in operating cost and can decrease operating cost. The size of the home, volume of space and desired interior temperature also become factors.

  16. Jeff King & Co said:

    Dennis, thanks for asking! The tiny house concept is commendable and requires very careful thought. It sounds like you are trying to address energy efficiency by considering SIPs as well as radiant. The small size is a challenge from a heating perspective. Many systems are meant for larger square footage. With heating systems more is not better. What ever you choose, be sure that it balances out your heating needs with an energy analysis that includes insulation and window glazing. I would consider lifetime cost of the different systems. Lifetime cost being installation cost plus yearly operating cost for a chosen number of years. I would consider hydronic as well as a mini split unit (includes AC), and electric radiant especially if you are going to do photovoltaic.

  17. Mark said:

    We are remodeling a small 10×13 kitchen and are thinking of adding hydronic heating. There is a finished basement directly under the kitchen. How much hight is needed to install hydronic heating or would we be better off installing electric radiant heat. We already have hot water heat through radiators.

  18. Jeff King & Co said:

    Mark, thanks for asking. There are three places the hydronic tubes can be placed:

    1. On the subfloor and covered with a “gyp-crete” / cementicious cover. This is about two inches in height on top of subfloor, plus you need to consider what the finish floor is and how it is connected
    2. In a specific wood panel made for the tubes. There are in effect grooves in the wood panels that the tube goes into. This goes directly onto the subfloor and adds about 3/4″ in height.
    3. Under the sub floor. in other words, the tubing is added under the floor from the basement space. This does not change your flooring height in the finished kitchen. Hope that helps!

  19. Sarah said:

    We are building a small back yard cottage (<300 sq/f) in the Bay Area and are required to install a non-electric heating system. The structure will be on concrete slab without a crawl space. Would it be possible to install a hydronic system under a new polished concrete floor using our existing water heater or is regular access required?

  20. Jeff King & Co said:

    Sarah: A hydronic system can be integral with a structural slab and that slab can be polished or ground.
    First – The hydronic tube should be secured to the rebar and the tubing should not be allowed to “float up” towards the surface. This is important for even heating.
    Second – If there are score joints in the top of the slab, it is essential that the tubing is below the projected depth of the score joints. This is where tubing floating up can be a problem.
    Third – If there are any electrical boxes or lights that will be embedded into the slab, be sure they are secured so that they don’t move during the pouring of the slab. This usually means packing the base of the electrical item with mortar so that the flowing concrete does not move it or change the layout.
    Using the existing water heater will specifically depend on the system you have, and the energy loads. Your installer should be able to advise you on this.

  21. Melissa said:

    Thanks for all the info on radiant heating. We are looking to buy & want new construction/Green Build. The hydronic radiant heating is very appealing especially since we are not used to cold weather. But seeing some of the comments above I am concerned about heating costs. If the construction is energy-efficient is this an economic system? Thanks!

  22. Jeff King & Co said:

    Melissa: Yes, hydronic heating is considered economically efficient. It has a higher first cost, and lower long term cost. Often when we build efficiently, users then tend to lose their “turn off the lights” urges and this can happen with heating also. I suggest that you talk with some people that have radiant hydronic heating already. It is not an instant heat as you would have with forced air, but rather a slow gradual warmth. Hope this helps!

  23. June said:

    I am building a new home & considering using electric radiant heating in the basement on the concrete slab under tile. The basement has two sides not underground. The manufacturer is recommending a cork underlayment on concrete in particular their synthetic underlayment which is “heat & cold resistant, will not rot, support mold & mildew, or absorb moisture.” This is the more expensive. The house is lake view on the VA – NC border. It is a very humid area in the summer months. Not sure I can do the hydronic due to a second layer of concrete that needed to be poured to correct mistake. Also can hydroponic be used with tankless hot water heaters?

  24. Jeff King & Co said:

    June, thanks for your question. Hydronic (water) radiant heating systems can be used with water heaters, but need to be matched properly to service both effectively. You should consult with your design person or mechanical engineer.

    Electric radiant heat is often installed under tile in smaller locations or where Hydronic Radiant is not possible. Regarding condensation, it will depend on dew points, humidity and your specific location. Your local designers should be able to help specifically.

    On a side note – be sure to have your flooring person account for expansion and contraction of your cork flooring.

  25. Jim said:

    we are replacing tile floor in the kitchen and thinking of maybe running tile into the family room that is currently carpet, if we used a readiant heating system. Is an electric radiant heating system feasible? Kitchen dimensions 8×18 feet… family room is 12×20. Is this too large of an area for electric? We currently have forced air heating/cooling and would be using primarily to keep feet warm in the winter.
    I have enjoyed your answers to privious questions.Thanks!

  26. Jeff King & Co said:

    I certainly enjoy radiant heat and have experienced both hydronic radiant (water tubes) and electric radiant. We usually see electric radiant used in home remodels that do not have hydronic radiant. These electric radiant systems are usually confined to a bathroom, mudroom or installation under large stone slabs for tubs.

    Larger rooms are also appropriate as you describe with tile, not with carpet. My suggestion is consider the power usage. You can get this information from manufacturers literature. If you venture towards radiant electric, you should determine if you need additional electric circuits and if you have space in your electrical panel for more circuits.

  27. Barbara said:

    Hi,
    We are just finishing up a dig out of our basement and are about to pour our last footings and a slab. The space is 400 sq ft and will be a bedroom, bathroom, office and laundry room. We would like heated concrete floors, but are not sure if electric or hydronic is best for us.

    We currently have a ductless heat pump (no gas, no oil, no basebaords) to heat the house, and a 67 gallon hot water tank. Our electrical box is maxed out and we hope to not have to purchase a new one. What would you do?

    I assume electrical requires more space in the box which would mean an upgrade, plus it sounds like hydronic is better for larger spaces. So would the hydronic be best for this large space? And would we be able to hook it up to our existing hot water heater or do we need to buy some kind of boiler?

    Thanks for your time! It is very appreciated!

  28. Jeff King & Co said:

    Barbara, thanks for asking! Generally we would always go for hydronic especially if electrical panel is maxed out.
    If you have to add electrical, instead of replacing the entire panel, you might be able to add a sub panel which is less than a main panel. Hopefully that helps!

  29. Barbara said:

    Thank you! And for heating that, would we get a second hot water tank so we can control it separately from the rest of the water in the house? What is the difference between a boiler and a hot water tank for this purpose?

  30. Jeff King & Co said:

    Barbara,

    To answer your question: Sometimes household and radiant hydronic are separate and sometimes the same. It depends on design and specific needs. A boiler generally does not store water, and often there is a storage tank that works in conjunction (but not always).
    Again it depends on the design and specific needs for the system.

  31. Leslie said:

    I had electric radiant floor heating in my last house under marble flooring in the master. We loved it, it was on a timer, and I don’t think it added significantly to our electric bill. We did, however, have 3 cracks that ran all the way across the floor. I don’t know if that was due to the radiant flooring, or just house settling in general. There were no cracks in the walls/ceiling at that end of the house, so I always attributed it to the radiant heat. I am now in a new (to us) house, and getting ready to start renovations on 2 very small guest baths. The house has electric baseboard heat as a back up, and we are considering taking that out in the bathrooms and putting radiant flooring in instead. What should we know about doing this? (i.e.. How to avoid tile cracking, mats vs wiring, etc). Thanks.

  32. Jeff King & Co said:

    Leslie, thanks for visiting our blog. Regarding electric radiant under a stone floor tile: The warmth from the radiant electric floor is very nice and enjoyable, especially when it’s cold everywhere else. The cracking you experienced in your previous home was most likely from the tile substrate and installation.
    Your tile installer should be able to advise you on crack suppression membranes and anti-fracture sheets.

  33. James said:

    I purchased a new construction home in 2011 in coastal NJ. Originally, my crawl space was insulted with batt insulation. After hurricane sandy, my crawl space was a loss and I chose to use closed cell spray foam instead of batt insulation. My problem is that since the spray foam was installed my floor is considerably cooler than with batt insulation. Additionally, I installed 3 inches of closed cell spray foam which provides a much higher r-value than batt insulation. Please note that I have hardwood floors throughout my entire 1st floor. Upon further investigation, I realized that the reason that the floors appear cooler is that the spray form provides a thermal break whereas previously my batt insulation allowed heat to escape to my floor from my duct lines that run in my crawl space. I assume that I would be best served adding hydronic heating in my crawl space in my “cold pockets”. Please advise.

  34. Jeremy said:

    We are considering a green build split level bungalow (2000 sq ft)+ basement. Winters are cold and snowy and summers very humid. We want something that will last with little maintenance and energy efficient. Is hydronic is best even if we plan on getting a large portion of the roof fitted with solar panels?

  35. Mike said:

    Great blog, Jeff & company.

    We are replacing our carpet with tile and are considering radiant heating. But are trying to decide on electric vs hydronic. We weren’t planning on using it for our only heat source. But our heater just quit on us, so now we are considering it.

    Is electric radiant heat completely out of the question for whole-house heat for a 2 story house?

  36. Jeff King & Co said:

    Mike,

    Radiant hydronic in the floors is a good system. For your two-story home, there are accessory considerations:
    -to install new radiant hydronic, you would need to use a board that holds the tubes in place which would change the finish floor height. The increase of finish floor height changes the stairway riser height at the very top and bottom steps, which would be a code issue in most areas.
    -additionally, it will cause the doors to be cut on the bottom and may also affect your baseboard.

    You could also consider radiant hydronic baseboard units or similar. This would solve the floor height issues mention above. It would require getting piping from the mechanical area to the heating units which would likely mean some wall repairs.

    Correct, electric radiant is not appropriate for a whole house heat source. It is a nice extra comfort under tile in a bathroom and in addition to your existing house heat system.

  37. Jeff King & Co said:

    James, It sounds like the ducting in the crawl space was leaking up through the batt insulation until Sandy.
    That made your floors more comfortable. Hydronic radiant heating would need to go against the bottom of the sub floor.The insulation you have may be in the way. Best of luck with your project!

  38. Jeff King & Co said:

    Jeremy, thanks for your inquiry. Yes, hydronic would be low maintenance and energy efficient. Solar thermal panels are beneficial.

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