Radiant Floor Heating Buying Guide

A radiant floor system is a cold weather heating system that circulates heat, usually a fluid, beneath a floor to heat the floor itself and the air above it. They are an unobtrusive means to heat, and can actually be very effective at reducing energy consumption. In fact, many homeowners with a radiant floor set their heating system lower than normal. They do so, because warm floors can make a room feel comfortable at a lower temp than conventional forced-air installations.

But how do you know if a radiant floor system is right for your home? Don't worry, this buying guide can help.

Radiant Floor Heating Overview

The general public typically does not know much about heated radiant floor systems. So, let's start with the basics:

  1. Radiant energy heating can be used to warm both indoor and outdoor areas.
  2. Most radiant floor systems use heated water, but simple electric sub-floor heating is available.
  3. While most install heated flooring during construction, it can fit into existing buildings.
  4. Fun Fact: The ancient Romans used radiant flooring when they invented the hypocaust.

Types of Radiant Floor Systems

Electric Sub-Floor Heating

Electric radiant floor heating systems use a network of electric cables to heat a floor. Contractors typically install electric on a smaller scale than fluid heating technology. Because brute-force electric heating is more expensive than geothermal heating, most builders do not rely on electric for large-scale installations. However, retrofitting an electric radiant floor system into an existing home is easier than using geothermal. Which makes electric the go-to solution for an upgrade.

Fluid Sub-Floor Heating

Heating a floor with a fluid is the most common radiant floor heating system, and preferred by most professionals. Likewise, a water-to-water geothermal heat pump is the most energy efficient way to power a fluid sub-floor system. However, tankless water heaters are always an option. When the homeowner does choose to use a fluid system, the best time to install is during construction. A full geothermal retrofit is too expensive for many homeowners.

Water-to-Water Geothermal Heat pump

A geothermal heat pump is a very eco-friendly, energy efficient HVAC solution. They're also the best way to power a radiant floor heating system. You can learn more about geothermal with our Geothermal Heat Pump Buying Guide.

Buffer Tank

Unless you're using an electric tankless water heater, a buffer tank is a very useful tool. A buffer tank can store heated water for use in your radiant floor system. This means the geothermal unit doesn't have to operate every time you want warm floors. That can save energy (and money).

Zone Control Board

A zone control board allows the homeowner to manipulate which floors are heated and which are not. They're a useful tool to tailor your home heating experience.

Circulation Pump

The circulating pump provides a flow of fluid through the ground loop, and, in this case, through the sub-floor channels. In a multi-zone radiant floor installation, each zone would feature its own circulation pump.

Zone Thermostat

A zone thermostat is the tool used to control the temperature in a specific interior zone.

Hydronic Air Handler

A hydronic air handler is necessary to deliver air conditioning with a water-to-water geothermal heat pump and radiant floor heating. While they still use a fluid as a heat transfer medium, they rely on conventional ductwork instead of sub-floor channels.

Common Radiant Floor Components & Features

PEX Tubing

Sub-floor heating that use a fluid often circulate that fluid through a material known as PEX tubing. This is a simple, polyethylene pipe that is flexible, durable, and easy to install. It's also not particularly expensive.

Electric Heating Technology

Electric sub-floor heaters commonly use a roll-out mat material that is insulated. Many types can be glued down or otherwise permanently connected to the floor. Some manufacturers might refer to their products as  "heating film" or "heating cable". While the names are different, the products work in fundamentally similar ways.

Answers to Common Radiant Floor Questions

How much tubing am I going to need?

A main level indoor radiant floor installation will need approximately 1 linear foot of tubing per square foot. That equals about 12 inches of spacing between the tubing loops. Outdoor installations, basements, and garages tend to be less compact. 18 inches of tubing between loops is often sufficient.

How do I know what size radiant floor system I need?

Like any other HVAC system, you should have a Manual J Heat Load Calculation performed on your home to determine the size of the radiant floor system you need. Most qualified contractors can provide this service for you.

Can I get air conditioning with radiant floor heating?

Electric floor heating cannot also provide cooling, and neither can fluid heating for that matter. However, a geothermal water-to-water installation can use a hydronic air handler to provide cooling on hot summer days. If you don't use water-to-water, a separate air conditioner would be needed for cooling.

Do I need air filters?

Heated flooring typically does not need an air filter, since the heating comes from a fluid or electrical contact and not air. However, if you used a hydronic air handler for cooling, you will need regular air filters.

How long is a good radiant floor warranty?

A typical radiant floor installation warranty should last at least 10 years.


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