Radiant floor heat has existed for millennia. It was originally constructed by ancient Chinese engineers, built upon by ancient Roman inventors, and popularized in recent decades as a fixture in many homes and commercial spaces as an energy efficient, gentle heat source.

And just like every other fixture or amenity, repairs eventually become necessary. While radiant heat can be more efficient than a heat pump, heats spaces more evenly than central air, and leaves your toes toasty and warm out of the shower, allowing it to go unchecked when you suspect there could be a problem will eventually snowball into a bigger issue that requires extensive home or commercial repairs.

So if your radiant heat system, whether electrical or hydronic, is exhibiting signs of uneven heating, inconsistent temperature control, or altogether malfunctioning, keep reading to learn the best first steps to take and what to do next.

Troubleshooting Your Radiant Floor Heat System

  • Identify your radiant heat source: If you aren’t the one who installed the system (i.e. if you purchased it already installed from the previous homeowner) identify what kind of radiant heat your space uses. Each type of radiant heating system has a different potential host of issues.
  • Check your valves: The simplest problems to solve are always the first you should check for. If you have a hydronic radiant floor system, check the radiant heat valves’ temperature settings first, because turning valves to the right temperature is simple and free.
  • Check the thermostat sensors: Another DIY step is to check your temperature sensors for accuracy in case they’re sending the wrong signals to the heater. If your radiant heating system thermostat is gauging the wrong temperature of the room it will send misguided signals to the radiant heat system.
  • Call the professionals: Once you’ve checked for these easy fixes, call a professional. Many HVAC or radiant heat companies offer rental DIY kits for simple fixes, and they’re equipped to handle more difficult problems for you if needed.

Electric Radiant Heating Systems Common Issues:

A thermostat is a valuable component of electrical radiant heat. Because electrical is the least efficient radiant heat source, a thermostat is essential in reducing costs by making sure it’s only utilized when needed. However, it’s also the most common malfunction in the electric radiant system. It isn’t dangerous, but a broken thermostat will either cause your radiant heat to stop working or to work overtime when you don’t need it, increasing your utility cost.

How to fix: Most thermostats can’t be repaired, but if yours isn’t working properly a new one is a cheap and easy solution. Simply identify your model, order a new one, and wire it in place of the broken model. If you have minimal electrical experience this will be easy. If not, any local handyman can take care of this for you.

In-floor heating cables are quite delicate. While they’re protected by the floor itself during daily use, there are a number of occurrences that can cause damage to them. Damaged or broken electrical cables are a serious fire hazard, so if you’ve recently drilled a hole into the floor followed by a malfunctioning radiant heating system, look into repairs immediately. You can avoid this altogether by purchasing or renting a thermal camera to detect wires under the floor before drilling into the floor or altering it in any way, but once the damage is done seek help immediately.

How to fix: If it’s too late for prevention and you’re on the repair side of things, it’s a simple fix if you’re pretty handy with electrical equipment. Using a cable fault finder and thermal camera will help you identify where the damage has taken place. Once you’ve identified the location of the issue, you’ll only need to pull up the flooring in that location to patch the issue. If this sounds intimidating at all to you, contact your local HVAC technician for help rather than attempting to DIY anything electrical. 

Once you’ve troubleshooted the other two most common problems with your electrical radiant heating system, if your problem hasn’t been solved it’s time to move on to the most daunting possibility: your heating mat has become defective. This is the least desirable solution, as it’s also the most expensive to fix. While radiant heating mats are designed to be durable and last a very long time, they can still be subject to problems- and fixing it is a whole ordeal. Cut power to the mat until a repair person can check it out in case of electrical hazard, since faulty wires can lead to smoke or fire.

How to fix: Unless the issue with the mat lies in a single (or a few) faulty area(s), the entire mat will need to be replaced, which is why this solution is the last resort. A repair person will remove the flooring in the entire room and replace the mat with a new one. If you’re a great handyperson you can try to do this yourself. Otherwise, your local HVAC technician can complete the repair for you.

Hydronic Radiant Heating Systems Common Issues:

Zone valves work to move water from your boiler to your under-floor heating system. When they malfunction (whether due to time-related wear or faulty installation), water flow can be inconsistent or even halt altogether, causing unpredictable radiant heat function. While usually not a hazard, whatever’s preventing your valves from functioning properly can still cause headache and financial burden since a faulty valve can cause your system to work overtime to make up for the deficiency. Luckily the solution is often as simple as a minor adjustment. If you’re getting inconsistent heat that seems to come and go, consider the following solutions.

How to fix: The first thing to check is your transformer. Make sure no fuses have blown, and if they have it’s a simple fuse-switch solution. Otherwise, it’s best to call a professional for help because the root of the issue might get complicated. A professional can identify the problem with valves quickly and efficiently, and the solution will require minimal cost to you. They’ll check for a blown transformer, incorrectly installed valves, and worn out gears, all of which are simple for them to fix.

While most installers use piping shown to last a lifetime, defects can happen. When used every day, piping can eventually corrode. Also, remodeling (i.e. replacing flooring or updating plumbing) can trigger problems with piping if an unknown accident goes unchecked. If you’re having similar symptoms to faulty zone valves, the issue could be that your piping has been damaged or has become corroded. If all the valves are working properly but you’re still having inconsistent heat, this is the next thing to check. Another symptom of corroded or damaged hydronic radiant floor heat piping is water damage on the floor, around baseboards and at the bottom of door trim, and water spots on ceilings beneath the suspected piping.

How to fix: Damaged floor heating piping isn’t usually something to attempt at a DIY. Flooring will need to be ripped up and replaced, piping removed, more piping installed, and the whole process is delicate and requires a trained professional. Know that it’s one of the most expensive and extensive solutions to radiant heating problems, and it doesn’t happen very often. So if you suspect this issue, ask your local HVAC technician or radiant heat installer for help identifying the source of this issue.

Sometimes, despite proper planning and installation, flukes can happen. If your hydronic water radiant floor heat system was installed with an open-loop process, interruptions in water from your well, municipality, or other water source can lead to disturbances in your floor heat, just like it does your faucet. The development of an air lock, or an oxygen bubble that builds up and plugs the piping, prevents water from flowing through the piping. While typically harmless (other than the annoyance of malfunctioning heating system), air locks can occasionally cause overheating and flooding. If only part of the floor heat system is working or if it stops working altogether, this is a potential culprit.

How to fix: If you’re familiar with technical instructions, you can do this yourself using the manual from your hydronic water system. Just repeat the same flushing process outlined for installation, since your installer had to go through the same process. If you aren’t confident, however, it’s best to call a professional HVAC technician or hydronic water radiant heat professional for help as you can cause more damage if you aren’t well-versed at what you’re doing.

Editorial Contributors
avatar for Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

Learn More