Hydronic Radiant Floor Heating Systems: Things to Consider

Hydronic radiant floor heating

Explore the advantages and benefits of hydronic radiant floor heating systems, including types and installation tips. See is radiant heat worth the investment, and can it save you money.

Hydronic radiant floor heating: What you should know

1. What is radiant heating?
2. How radiant heat is used for heating homes?
3. Types
4. Things to look for
5. Advantages
6. Disadvantages
7. Installation tips
8. Do I need insulation under radiant floor heating?
9. Which flooring type is best for hydronic floor heating?
10. Common problems
11. Popular brands
12. Costs

What is radiant heat?

Radiant heat refers to the transfer of heat from a warm surface to a cooler surface through radiation without the need for a physical medium or direct contact between the two surfaces. This is different from convection heating, which relies on the transfer of heat through the air or other gases.

In a radiant heating system, heat is generated by a heat source, such as a boiler or electric heating element, and is transferred to the surrounding surfaces, such as walls, floors, and ceilings. The heated surfaces then radiate heat to the surrounding air, creating a comfortable and even heat distribution in the room.

Radiant heat can be used in various applications, including home, industrial, and outdoor heating. Radiant heating systems can use different types of heat sources, such as hot water, electricity, or even solar energy.

An example of radiant heat is the warmth you feel from the sun or when the wood-burning stove radiates heat into the room through its hot metal surfaces.

How radiant heat is used for heating homes?

(CC BY-SA 3.0), Photo by Chixoy

Radiant floor heating is the most common method of using radiant heat for home heating. This is an effective and efficient way to heat homes, particularly in cold climates, as it provides a comfortable and even heat distribution throughout the room.

In a radiant floor heating system, a network of pipes or electric heating elements is installed beneath the floor surface, typically in concrete or over a subfloor. Hot water is circulated through the pipes, or electricity is used to heat the elements, which radiate heat through the flooring and into the room above.

PEX tubing is probably the most popular choice for transferring hot water in hydronic radiant heating systems due to its durability, resistance to corrosion and scaling, ease of installation, and cost-effectiveness.

Radiant heating systems can be powered by different types of heat sources, such as boilers, heat pumps, or solar thermal collectors. And the choice of energy source depends on factors such as climate, availability of energy sources, and the homeowner's preference for energy efficiency and sustainability.

The temperature of the water in a hydronic floor heating system is typically controlled by a thermostat, which regulates the temperature of the water as it flows through the system. This allows homeowners to adjust the temperature of their homes to their desired comfort level.

Types of radiant floor heating systems

There are two types of cost-effective radiant heating systems for floors: electric and hydronic radiant floor heating, which use various heat sources.

Both systems heat the floor with coils installed in-floor or underneath the floor. For those who prefer do-it-yourself projects, electric is easier, solar and geothermal are more complicated.

Electric floor heating

Electric radiant floor heating systems are more efficient than traditional electric heaters but less than hydronic systems, and they are also easier to install and service.

They can be installed under a variety of flooring types, including tile, hardwood, and carpet. This gives homeowners more flexibility when choosing flooring.

Hydronic floor heating

Hydronic radiant floor heating systems use liquid as the heating fluid heated by using any known fuels. The most common medium is domestic water, heated by the water heater or boiler.

Hot water is moved through the pipes or tubing and then returns to the water heater or boiler for reheating. The water is retained in the system, which has to be replenished periodically, done automatically by the HVAC system.

In some hydronic systems, the temperature in each room is controlled by regulating the hot water flow through each tubing loop. The flow of hot water is controlled by the system of zoning valves, pumps, and thermostats.

The brain of the hydronic heating system is the control system, consisting of thermostats, aquastats, and switches.

The heat source used for hydronic radiant floor heating can be a gas and oil-fired boiler, as the most common types, while solar and geothermal radiant heating are getting in popularity. These systems are the most popular in colder regions.

A good radiant floor system should last at least 20 years, but it depends on the quality of used materials, heat generator, quality of work, etc.

Things to look for

When considering hydronic floor heating, here are some things to look for:

• Boiler capacity: The boiler is the main part of a hydronic floor heating system. Make sure the boiler has the appropriate capacity to heat your home and provide enough hot water for other uses, such as showers and laundry.
• Piping material: Hydronic floor heating systems typically use PEX piping or copper piping. PEX is less expensive and easier to install, while copper is more durable and has a longer lifespan. Consider which material will work best for your space and budget.
• Heat source: Hydronic floor heating systems can be heated by a variety of sources, including natural gas, propane, oil, or electricity. Consider which heat source is most efficient and cost-effective for your location and energy needs.
• Thermostat: Look for a system that comes with a thermostat that allows you to control the temperature and timing of the system. Some systems may also offer advanced features such as smartphone control or programming for multiple temperature zones.
• Installation method: Hydronic floor heating systems require a professional installation, and the installation method will depend on the type of flooring in your home. Make sure the installer is experienced and knowledgeable in hydronic floor heating and can provide a system that is appropriate for your space.
• Warranty: Look for a system with a warranty that covers the piping, boiler, and other components of the system. A longer warranty can provide peace of mind and protect your investment.

Advantages of hydronic radiant floor heating systems

Hydronic radiant floor heating systems offer many advantages and benefits, making them a popular choice for homeowners who want an efficient, comfortable, and healthy heating system.

Energy efficiency: Hydronic radiant floor heating systems are highly energy-efficient, as they use low-temperature water to distribute heat throughout a space. Water is an efficient heat conductor, allowing heat to be evenly distributed throughout the room without creating hot or cold spots. 

This can result in lower energy bills over time, especially in colder climates where heating costs can be high.

Increased comfort: Hydronic radiant floor heating systems provide a high level of comfort as they distribute heat evenly throughout the room. The heat rises from the flooring, through the furniture, walls, and people inside the room, to the surrounding air. This creates a warm and cozy environment without the need for noisy fans or vents that can create drafts.

The system also provides a better comfort level when heating the room with a higher ceiling than the systems that heat the air first. In radiator heating, as the heat rises above the elements, the area between the radiators and the floor surface is colder, making the room air temperature uneven.

Also, in the case of the baseboard heating systems, the room perimeter gets higher temperatures while the center of the room is less comfortable.

Improved indoor air quality: Unlike forced-air heating systems, which can circulate dust, allergens, and other pollutants throughout a space, hydronic radiant floor heating systems do not use air to distribute heat. This can improve indoor air quality and reduce the risk of respiratory problems.

Quiet operation: These systems operate quietly, as they do not use noisy fans or blowers to distribute heat.

Versatility: They can be used with a variety of energy sources, including gas, oil, electricity, solar, and geothermal energy. This makes them a versatile option for homeowners who want to reduce their carbon footprint and lower their energy bills.

Longevity: They are highly durable and can last for decades with proper maintenance. Unlike forced-air heating systems, which require regular filter changes and duct cleaning, hydronic systems require minimal maintenance.

Increased home value: Hydronic radiant floor heating systems are a desirable feature for homebuyers, as they offer energy efficiency, comfort, and improved indoor air quality. Installing a hydronic system can increase the resale value of a home and make it more attractive to potential buyers.

Zoning: Zoning allows homeowners to divide a hydronic heating system into different zones or areas of the home, each with its own thermostat and control valves. This allows homeowners to adjust the temperature in each zone independently based on their specific heating needs. This results in greater control, comfort, and energy efficiency.

Aesthetics: Hydronic floor heating systems are installed under the floor and are not visible once the floor covering is in place. This can make them a good choice for homeowners who value aesthetics and want a heating system that does not detract from the overall appearance of the room.

Disadvantages

Like any other heating system, hydronic floor systems also have disadvantages.

• Installation cost: The initial installation cost can be higher than other heating systems, especially if retrofitting an existing home.
  
• Installation complexity: The installation process can be complex and time-consuming, requiring specialized knowledge and tools.
• Response time: The system may take longer to heat up than other heating systems, especially if the water temperature is low.
• Floor height: The system may add to the floor height, which can be problematic for some homeowners.
• Maintenance: The system requires periodic maintenance, including flushing the pipes to remove sediment buildup and replacing some components when necessary.

Hydronic radiant floor heating system installation options

Basement floors are the perfect place for radiant floor heating systems, as the concrete, either thick or thin slab, is an excellent thermal mass, making the floor a huge radiator. If the thermal mass in the floor is larger, the HVAC system works better.

Besides the thin slab and thick concrete installation option, you will also find two other popular terms when installing hydronic radiant floor heating systems. They are known as dry systems:

• Above-floor systems
• Below-floor systems

The above-floor systems are installed below the finished flooring (hardwood flooring, for example) but above the subflooring. Proper planning is essential for this type of system as this system uses grooved wood panels installed under the finished floor. The floor height is raised, which can cause a problem with doors or plumbing fixtures.

For the below-floor heating system, the above wood panel and second subfloor are not needed, so this system automatically requires less time, labor, and material for an installation.

When the PEX tubing is installed under the plywood floor, it makes the cost of installation lower. You won't find any issues with the weight which is seen with the slab system, but it requires higher temperatures to provide the feeling as the above radiant home heating systems. This system is popular for retrofits.

Do I need insulation under radiant floor heating?

To enhance the energy efficiency and effectiveness of your hydronic radiant floor heating system and to avoid moisture buildup in the flooring, it is recommended to install insulation of good quality.

Insulation helps prevent heat loss from the heated floor surface into the ground or subfloor, which could lead to a harder-working system and higher energy bills if not installed.

The type of insulation required for a hydronic floor heating system depends on various factors like the type of flooring, the room size and layout, and the heating capacity of the system.

Rigid foam board insulation is commonly used to insulate the underside of the subfloor. It comes in rigid panels that can be cut to fit the space and attached using adhesive or mechanical fasteners.

Reflective insulation is suitable for retrofit projects or in spaces where there is limited room for insulation. It can be installed under or on top of the subfloor.

Fiberglass batts are a cost-effective insulation option, but may not be as effective as other types of insulation in reducing heat loss.

Loose-fill insulation such as cellulose or fiberglass can be installed under the subfloor or between floor joists, but it may be challenging to install compared to other insulation types.

Which flooring type is best for hydronic floor heating?

Hydronic floor heating can be installed under a variety of flooring types, but some are better suited for this type of heating than others.

The best flooring types for hydronic floor heating are those that are good conductors of heat, such as tile, stone, and concrete. These materials allow the heat to radiate evenly and efficiently, resulting in a comfortable and effective heating system.

Laminate is strong and stable flooring that is a good conductor of heat; it can withstand heat and is also water-resistant.

Other types of flooring, such as hardwood and carpet, can also be used with hydronic floor heating, but they may not be as efficient at conducting heat. If you choose to install hardwood or carpet, it's important to ensure that the flooring material and underlayment are appropriate for use with hydronic floor heating and that they do not insulate the heat.

Ultimately, the best flooring type for hydronic floor heating will depend on your specific needs and preferences. Consider factors such as cost, durability, aesthetics, and heat conductivity when selecting a flooring material for your hydronic floor heating system.

Common problems with the floor heating systems

Here are some common problems that can occur with your hydronic floor heating system:

• Air in the system: Air can become trapped in the system and cause a reduction in heat output. This can be resolved by bleeding the system.
• Blockages: Blockages can occur in the piping or tubing of the system, which can restrict the flow of water and reduce heat output. This can be resolved by flushing the system to remove any blockages.
• Temperature fluctuations: Temperature fluctuations can occur if the system is not properly balanced or if there are air pockets in the system. This can be resolved by adjusting the flow rate of water in the system and ensuring that the system is properly balanced.
• Leaks: Leaks can occur in the piping or tubing of the system, which can cause a loss of water and reduce heat output. This can be resolved by repairing or replacing the damaged section of piping or tubing.
• Incorrect installation: Incorrect installation can lead to a variety of issues with the floor heating system, such as improper spacing of the piping or tubing, incorrect pipe size, or incorrect boiler sizing. It's important to have a professional installer with experience in floor heating systems perform the installation.
• Damage to the flooring: Damage to the flooring can occur if the system is not properly installed or if there is a leak in the system. It's important to choose the right type of flooring and to ensure that the system is properly installed to prevent damage to the flooring.

If you would like to know more about common problems, causes, and troubleshooting, use this article to get information on how to repair a hydronic floor heating system.

Popular brands and manufacturers

• Nuheat
• Suntouch
• Wirsbo - Uponor
• Warmboard

Costs

The cost of hydronic radiant floor heating systems is much higher than the conventional types of heating, but as it requires low-temperature fluid, it will cost you less to operate (some manufacturers claim that the cost savings are from 20% to 40%).

The cost can vary widely depending on a variety of factors, such as the size of the space, the type of flooring, labor cost, and the complexity of the installation.

Generally, the cost to install a hydronic floor heating system ranges from $6 to $15-20 per square foot.

Here are some additional factors that can impact the cost:

• Boiler: The cost of the boiler can range from $3,000 to $7,500, depending on the size and efficiency of the unit.
• Piping: The cost of piping will depend on the length of the system and the number of loops required. On average, the cost of piping ranges from $1 to $2 per linear foot.
• Labor: Installation labor costs can vary, depending on the complexity of the installation and the experience of the installer.
• Thermostat and controls: The cost of a thermostat and controls can range from $100 to $500, depending on the type and features of the unit.
• Additional costs: There may be additional costs for materials such as insulation, fasteners, and tubing, as well as any necessary modifications to the subfloor.

So are hydronic radiant floor heating systems worth the investment?

Ultimately, the decision to invest in a hydronic radiant floor heating system will depend on a homeowner's individual circumstances and priorities. It's important to consider the upfront costs, ongoing maintenance requirements, and potential long-term energy savings when making this decision.

Hydronic radiant floor heating systems can provide a number of benefits, such as increased energy efficiency, improved comfort, cleaner air, and reduced noise levels compared to traditional heating systems. They can also increase the resale value of a home, as they are seen as a desirable feature by many homebuyers.