Radiant floor heating is becoming an increasingly popular trend in the US, both for retrofit and new projects. Unfortunately, many homeowners are yet to understand what floor heating entails. How do these HVAC systems work? What is the right radiant heating system for your home? 

If those are some of the questions crossing your mind, we’ve got you covered. In this blog, we’ll help you know the answer to these questions and other issues associated with radiant floor heating. 

That said, let’s get started! 

What’s radiant floor heating? 

Radiant heating dates back to the primeval era and it was very common in ancient Rome. Romans would dig tunnels under the floor and fill them with hot stones to heat up the room. In return, thermal radiation waves would rise from the tunnels, warming up the items above them. These objects would then emit the captured heat, hence increasing the room’s indoor temperature.  

Over the years, the form of heating has developed into more efficient systems, thanks to technological advancements. Today, it’s popularly known as floor radiant heating. More importantly, it involves the transfer of heat from the heat source to a specific object through electromagnetic waves instead of convection/ conduction. Simply put, radiant HVAC systems supply heat directly, either to the ceiling/ wall panels or to the floor. 

Different types of Radiant floor heating systems 

In general, radiant floor heating systems can be categorized into 3 types. That is’ electric, hot water (hydroponic) and radiant air floors. Also, these types can be categorized further by installation. For instance, those systems that use a large thermal mass of concrete slab floor are known as ‘wet installation’. While those radiant heating design systems installed between 2 layers of plywood or attached beneath the subfloor/ finished floors are known as ‘dry installations’. 

  • Electric radiant floor heating design 

Electric radiant floors have electric coils that produce heat when an electric current passes through them. These coils are made of high resistance metals and are usually covered in polymer sheets. Since the polymer is a good heat conductor, the heat generated by the coils is passed on to warm the floor. 

One major benefit of this type of radiant heating design system is that it has high longevity and low maintenance. As a drawback, they’ve huge running expenses, especially in areas with high electricity costs. 

Nonetheless, electric radiant heaters are quite cost-effective for small homes, The same case applies to buildings whose floors’ thermal mass is large enough to store sufficient heat. That way, the system can be used to warm the house for up to 8 – 10 hours without requiring additional heating. 

  • Air-heated radiant floor heating design  

As the name implies, these radiant HVAC systems use heated air to warm the floor. However, this type of radiant heating is less efficient since air cannot hold and retain large amounts of heat. So, although this heating method warms the occupied spaces equally, the heat is lost equally fast. This creates an uncomfortable cold-warm heating pattern in the house. For that reason, these types of radiant HVAC units are rarely used in residential houses. 

  • Hot water (hydroponic) radiant floor heating design 

Hydroponic HVAC units are the most common types of radiant heaters in areas that experience winter. With these systems, water is heated in a central boiler and pumped under the floor through a series of pipes. 

The major benefit of hydroponic systems is that they’re cheaper to run than electric radiant heaters. This is because homeowners have various options of fuels that they can use to warm up the water. 

On the downside, these systems are very costly and complicated to repair if something malfunctions. 

Types of radiant floor installations 

  • ‘Wet’ installations 

Wet installations involve embedding radiant heat tubing or heating cables on a solid floor. They’re the oldest form of modern radiant heating floor systems. A good example of wet installation is embedding the radiant heat cables/ tubing in a thick concrete slab. Also, you can embed them in a thin concrete layer, gypsum, or any other substrates installed over the subfloor. The only downside of thick concrete slabs is that they’ve got a slow thermal response time. This makes strategies like day/ night time setbacks a bit difficult. Other than that, they’re suitable for storing heat from systems that tend to have a fluctuating heat output. 

  • Dry installations 

In ‘dry’ radiant floor installations, the tubing or cables pass through the air space beneath the floor. This technique is becoming increasingly popular since it is less costly and faster to build. However, the radiant system has to operate at higher temperatures since dry floors involve warming an air space. 

In some instances, dry installation involves suspending the electric cables/ tubing under the subfloor between joists. However, you have to drill through the joints when installing the tubing. Also, reflective insulation has to be installed under the tubing to direct the generated heat upward. 

Are our radiant floor heating systems worth it? 

Floor heating is a simple and energy-efficient way to heat your home and keep the living spaces comfortable. The only challenge with this form of heating is that its installation cost is a bit higher than the cost of installation radiators. However, it’s available in various options that can suit your budget. Besides, floor heating will provide significant cost savings on your utility bills in the long run. So, if you’re remodeling your home or building a new one, radiant floor HVAC systems are definitely worth considering. 

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