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Bathroom Heated Flooring Systems Explained: Your Complete Guide to Success

Heated flooring systems are fantastic, especially in cold climates.

Today you’ll see several tips for installing an electric heated flooring system in a bathroom.

I’ll discuss materials, electrical, and some mistakes to avoid.

Let’s dive in!

Electric Floor Heating Systems: The Basics

My favorite electric floor heating system is Schluter’s DITRA-HEAT.

DITRA-HEAT consists of a mat, heat cable, sensors, and thermostat.


I install the mat using thin-set mortar (although that might be optional with some new products), then run the cable, the sensors, and finally the thermostat when the tile is installed.

All electric floor heating systems have a similar setup. Although, some systems are just loose wires embedded in self leveler, which can be tricky and more time-consuming.

I also install conduit to the electrical box. Specifically, I install 3/4-inch conduit for the heat cable wires and 1/2-inch conduit for the floor sensors.

Furthermore, I recommend using a 2-gang electrical work box because more wire can fit into it than a standard box. I’ll explain this a bit more down below.

With the basics covered, I’ll show you some details that will come in handy.

The Schluter Heated Floor System

Schluter has four types of mats:

  • Regular DITRA-HEAT mat
  • Regular DITRA-HEAT with Peal and Stick Technology
  • DITRA-HEAT-DUO with Peal and Stick Technology

DITRA-HEAT mats prevent tiles and grout from cracking over time, they’re an uncoupling membrane. Furthermore, the mat has little pucks in it that help hold the electrical heat cables.

I like these mats because they help waterproof the floor – which is always important in bathrooms or kitchens.

I install the regular mats using Schluter ALL-SET mortar and a 1/4″ x 1/4″ square notched trowel.

It’s essential to clean the substrate and dampen plywood or OSB prior to applying the thin-set.

I do this because dampening the wood subfloor also retains the thin-set stickiness.

Schluter’s DITRA-HEAT-DUO mat is meant to be used over concrete.

The underside has a thermal break which prevents the heat from the electric floor heating system from being absorbed into the concrete.

In addition, the -DUO mats are great for townhomes and apartments because the thermal break reduces noise transfer.

Recently, Schluter introduced DITRA-HEAT mats with Peal and Stick technology. These mats don’t require the use of thin-set mortar, which can save installers and homeowners money.

The other advantage of Peal and Stick technology is that there’s no thin-set that can ooze between mats. Believe it or not, this can be a problem because dried thin-set can prevent heat cables from being installed properly.

Here’s the bottom line,

Choose the mat that’s best for your project. And if you’re not sure, you can always send me an email ([email protected]).

Once the mats are installed, I tackle the electrical.

Typically, I figure out the cable length and voltage using the Schluter DITRA-HEAT Estimator.

This application is terrific because it helps you determine the supplies necessary for your project.

Once you figure out the DITRA-HEAT mats, it’s time to tackle the electrical component.

Heated Floor System Electrical Tips

The size of the room normally determines the voltage. For example, 120V is good for a standard 5-foot x 8-foot bathroom floor plan.

You’ll want to run a dedicated 20A wire to the service panel if possible.

Electrical Wire for Heated Flooring

I recommend hiring a licensed electrician if you’re not familiar with how to do this.

Once the electrical wire is run to the bathroom the next step is to add the correct box and conduit.

All heated floor systems need electrical run to them.

As I mentioned, I use PVC conduit and a deep wall electrical box to make this process easier.

A 30.3 cubic inch double gang electrical box is perfect for the Schluter DITRA-HEAT system.

Electrical Box for Heated Flooring

I like this box because it has knockouts for both the 1/2-inch and 3/4-inch PVC conduit. And there’s a third knockout on the bottom for my 20A wire.

Each knockout should have a push-in connector for bare wires or a male adapter for PVC conduit.

I like 3/8-inch push-in connectors because they’re easy to install and the wires easily slide through them.

Once the wires are fished into the box, I place a mud ring on the electrical box. This single-gang has a 1/2-inch raised perimeter so that 1/2-inch drywall will sit flush to it.

Drywall Mud Ring

The mud ring is perfect for any thermostat that runs the heated floor system.

But if you’re using Schluter DITRA-HEAT, I recommend using their thermostat.

Schluter has several thermostat options, including a new option that uses home assistants and voice commands.

What’s Next

Heated floors are just one aspect of bathroom renovation.

If you’re remodeling a bathroom and need help, join our Platinum Membership.

I promise the step-by-step tutorials and Personal Coaching will make your project easier.

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