UNDERFL OOR HEATING
Many people do not know this system and others believe that it is a system only for bathrooms or that it is very expensive to install, but underfloor heating , in fact, is more accessible and affordable than many people believe. It is easier to include underfloor heating when building a house, but it can also be installed in old houses.
With a large part of the domestic budgets dedicated to heating, almost all seek to make the most of our money.
The good news is that underfloor heating could be the answer to your concerns about the cost of energy. It is energy efficient and provides a more comfortable and consistent source of heat.
Many people do not know this system and others believe that it is a system only for bathrooms or that it is very expensive to install, but underfloor heating, in fact, is more accessible and affordable than many people believe. It is easier to include underfloor heating when building a house, but it can also be installed in old houses.
What is underfloor heating?
Unlike warming by forced hot air in which heat enters a room through sockets or vents, underfloor heating radiates from the floor itself.
(Sometimes, radiant heating is placed on wall panels or even on ceilings, but it is most commonly used on floors). The soil heats up and then the heat increases. In other words, the heat goes exactly where you are, starting with the part of the floor and raising the heat to the ceiling.
How does radiant floor heat work?
On numerous occasions, we have heard the following: “in winter hot feet and cold head”. Well, simply with this phrase, it can be understood that underfloor heating is a sign of comfort, since the temperature of the air at the height of the feet is slightly higher than the air temperature at the height of the head .
The explanation of how it works is very simple. It consists of a network of cross-linked polyethylene or polybutylene pipes, which are installed under the pavement and a layer of self-leveling mortar, through which hot water circulates at a temperature of between 30ºC and 45ºC .
The heating systems underfloor depend radiant heat instead of convection heat. The heat is supplied directly from the hot surface through infrared radiation.
In radiant heat floor systems, heat is found in coils that are under the floor.
The heat passes through the coils (either through electricity or hot water) and then heats the ground directly over it.
In contrast, forced hot air heating works in a more random manner, and, therefore, less efficient in terms of energy. The cons of forced hot air heating are the following:
- The forced hot air works basically in what is known as the yo-yo effect . This happens when warm air enters randomly into a room, creating a brief warm-up that then cools quickly.
That in turn creates a yo-yo heating cycle that affects the setting of your thermostat where it is turned on and off often to regulate the temperature. In addition to providing a less constant heat, it is a behavior, less energy efficient.
- The forced heating hot air also has what is known as loss of parasitic heat . The heat travels through a pile of ducts to reach the baseboard heater or vent in the room you are heating.
All these ducts and pipes can develop small openings or leaks where the heat can be lost and not reach the desired room correctly. This means that your system is pumping more energy than it needs to try to reach the desired heat level in your thermostat.
- The stratification is another problem of forced air heating. As the air is pumped randomly through the louvers in the ceiling (where most of it remains) or through the vents on the floor, it quickly rises to the ceiling.
As a result, the upper part of the room (where nobody spends time) is warmer, sometimes up to 10 degrees warmer, than the actual living space that you intend to heat. Due to this, the thermostat continues to rise in the part of the room where time passes.
What are the types of radiant heat floor systems?
The radiant heat floor is, as its name suggests, on the floor. However, there are differences in the types of radiant heat floor systems. This is what you need to know about the two most common types.
- Hydronic floor heating: It is the most popular and economical type of radiant heat floors. In hydronic underfloor heating systems, heated water is pumped from a boiler through a tube that is placed in a pattern under the floor.
Some systems control the flow of hot water through the pipeline through the use of valves or zoning pumps. The thermostats regulate the ambient temperature.
- Electric underfloor heating: Underfloor heating systems such as this have electrical cables that are integrated into the counter-floor. Usually, these are placed in a pattern on some type of plastic carpet under the floor that conducts the electricity.
This type of radiant heat floor is often used for additions, since its dependence on electricity can make large-scale use prohibitively expensive unless your electricity service (that’s the company that manages the procurement of your electricity) offers the option to use flat rates or rates.
Under this scenario, you could heat the house during low activity hours (often from 9 pm to 6 am). The floor will store the heat during most of the day, and in this way it will not be necessary to use electricity during the day.
This potential cost is one of the reasons why electric underfloor heating is often found in smaller spaces, such as bathrooms.
Pros and cons of underfloor heating systems
Advantages of underfloor heating:
- The system is hidden in the ground. There are no radiators or visible vents.
- The underfloor heating systems are mostly silent. The system is activated without the noise associated with forced hot air systems.
- Radiant heating reduces allergens. There is no forced hot air, which means that dust mites or other particles in the air that can be hidden in the heating ducts must not blow.
- The heat is more continuous and uniform. Since the heat is not being carried away by the explosions, the source of heat is constant, which creates a more comfortable environment in general.
- Energy efficiency of radiant heat. Thanks to the way heat is transferred to a room, studies suggest that this type of floor is potentially 30 percent more energy efficient than forced hot air heating systems.
Cons of underfloor heating:
- Cost of underfloor heating: The most profitable option is to install it from the beginning, that is, if you are building a house or adding an area that will require heating.
To make modifications to a structure already built, you could install underfloor heating in places where the pipes can be attached to the bottom of a subfloor on the first floor. If the floor can be accessed from a basement or crawl space, the pipes could be installed that way.
- Hydronic underfloor heating costs more than forced hot air heating or baseboard radiators, but the real savings come in the lowest setting of the thermostat and the highest efficiency as the system operates.
The remodeling of a hydronic underfloor heating system is more complicated due to the requirements of the pipes, but it could be possible depending on the access to the subsoil.
- Radiant heat floor systems can take a while to completely heat the area. This could be a problem at times when the cold wave is very exaggerated. However, this can be compensated by keeping the thermostat at a constant level day and night so that the system remains stable.
This would be the basics on the efficiency of radiant heat energy and how the installation of radiant heat floors can help you in the energy saving of your home.
How is a radiant floor system installed?
The installation of a floor heating system is very simple because
- Prefabricated elements are used
- On the prefabricated elements the pipes are arranged
- The pipes are installed in the form of a coil, double coil or spiral
- Through the pipes we circulate hot water from a heat generation system.
Below, we list the main elements to install in this efficient heating system:
Radiant floor collector boxes:
They are the collectors from where the radiant floor circuits start, and they are usually embedded in the wall.
Socle / radiant floor perimeter band:
It is a band of polyethylene foam whose main mission is
- Absorb the dilatations produced by the cement mortar placed on the emitter tubes, due to its heating / cooling. Likewise, it generates a lateral isolation of the system.
It is fixed to the walls of all the areas to be heated, from the base floor to the upper level of the pavement
Radiant floor polyethylene film:
Radiant floor insulation panel:
Radiant floor pipes:
Cement mortar underfloor heating:
Why is the radiant floor an efficient system?
Let’s see in a schematic way, what are the reasons why a floor heating system is the most efficient system, both from an economic and comfort point of view:
- It employs a very low water discharge temperature (30-45ºC ) with respect to traditional radiator systems (70-75ºC).
- As it is a low temperature system, great savings are achieved by combining it with efficient heat generation systems such as aerothermy, geothermal , low temperature or condensation boilers , and solar thermal energy.
- With a heat pump system , it can be used as a refreshing floor in summer.
- Lower losses in the pipes when working with temperatures closer to the ambient temperature.
- Respect for the environment, due to its low consumption.
- System that provides great comfort to users, by eliminating completely the inconvenience caused by other air conditioning systems (air currents, stratification, dryness, etc)
What is the price of a radiant floor installation?
The price of a floor heating installation is 63 Euros / m2 (approximate). In it, it would include:
- Polyethylene (PE) foam band of 200 × 10 mm.
- Panel of stiffened polystyrene lugs (XPS) and thermoformed polyethylene (PE) coating, impact noise insulator, 1350 × 750 mm and 43 mm thick, tube passage multiple of 7.5 cm, valid for 16 tube with a diameter of 20 mm, with an overlap between plates to avoid thermal bridges and mortar leaks.
- Cross-linked polyethylene pipe (PE-Xa) with oxygen barrier and modified polyethylene (PE) protection layer, 20 mm outside diameter and 2 mm thick.
- Self-leveling mortar CT – C15 – F3 according to UNE-EN 13813, cement based, for thicknesses of 4 to 10 cm, used in leveling pavements.
- Labor and machinery.
What should we consider in a radiant floor installation?
As we have seen before, the underfloor heating system is one of the best heating systems on the market, but it is convenient to take into account some considerations:
- In combination with efficient heat systems, it requires a medium-high initial investment, with respect to other heating systems (such as radiators), but with short-term investment returns.
- It is an adequate system to work continuously, and therefore, in buildings with a high hourly occupancy, since they are systems with a high thermal inertia , that is, it is not convenient in places where it is expected to switch off and on the boiler every day.
- It needs heightening height of 10-12 cm, so it is not possible to install it in all cases. For this, it is necessary to carry out a preliminary study for its adaptation, both in new construction and in rehabilitation.