Underfloor heating with heat pump and photovoltaic systems: are they compatible?

When combined with a heat pump and photovoltaic system, radiant floors can maximise savings. But are they compatible?

When it comes to domestic heating, radiant floor heating systems are one of the most radical changes ever introduced in Italy. Over the last few decades, they have slowly replaced conventional radiators. It is hard to find any critical issues in these systems, except perhaps the fact that installation costs are higher and maintenance is slightly more complex. In contrast, they offer numerous benefits, such as significantly lower fuel costs and increased living comfort.

The advantages of underfloor heating

  • Radiant technology is able to ensure energy savings of approximately 25% a year compared to using radiators.
  • Uniform distribution of heat inside the house: this is the most distinctive element of radiant technology, which ensures a feeling of well-being and comfort.
  • Just like wall and ceiling heating systems, radiant floor systems can make use of renewable energies, thereby further increasing their efficiency.
How do radiant systems work?

The way underfloor heating systems work is completely different to the way conventional radiators work. And here is why.

How radiators work

Conventional heating systems operate on the principle of convection. Once the water that circulates inside radiators has been heated, normally reaching a temperature of 60 to 80 °C, radiators transfer the heat to the air around them, which will then radiate throughout the room.

Unfortunately, however, this method has various disadvantages: heated air is drier, dust is spread more easily and, what is more, a lot of fuel is consumed to heat the water, which makes conventional systems not that economical or environmentally friendly.

How underfloor heating systems work

Radiant systems, instead, work in a completely different way, since they operate on the principle of radiation. When they are being installed, pipes are placed under the floor that run through each room in its entirety, and water circulates inside at a temperature of between 30 and 35 °C. The temperature is lower (compared to conventional systems), which naturally means that less energy is required to achieve the same heating effect. <>This is because the heat produced by the pipes is transferred to the floor, ensuring that it is evenly distributed from the ground up and throughout the room.

Radiant systems and heat pump: is it feasible?
It is not only feasible, but even recommended!

In fact, heat pumps are one of the most cutting-edge technologies available on the market, since they use external renewable energy (air, groundwater or subsoil water) to heat the house and, if necessary, to produce domestic hot water.

They are eco-friendly, since they do not use any fossil fuels – unlike a condensing boiler – and ensure substantial savings, partly due to a number of available government subsidies. The features of radiant floor heating systems are exactly the reason why combining the two is the perfect solution.

In fact, heat pumps need to operate within specific temperature ranges in order to ensure utmost efficiency, which basically rules out combining them with classic radiators. Besides using radiant systems, which are still considered the best solution, heat pumps can also be combined with fan coils. Fan coils, however, require temperatures of about 45-50 °C, which decreases the overall efficiency of the system by about 25%.

Which heat pumps are suitable for radiant heating?

Except for the air-to-air model, which heats and cools rooms by transferring thermal energy between outdoor air and the air inside the home, all other types of heat pumps are well suited to be combined with a radiant floor heating system.

Air-to-water heat pumps

The most widely used product is the air-to-water heat pump, which makes use of air heat, transferring energy to the water in the system. In this case, the advantage is that, besides being able to heat and cool rooms, it is also possible to produce domestic hot water. Its greatest strength is its versatility, of course, since it can be integrated with other kinds of systems such as a condensing boiler, thereby creating a hybrid system, and with solar thermal energy.

Water-to-water heat pumps

In the case of water-to-water heat pumps, instead, heat is drawn from reservoirs and aquifers, while in the case of geothermal systems, the energy source is the subsoil. When compared to their air-to-water counterparts, these two models ensure consistently high performance all year round. When choosing the most suitable heat pump for your home or business, you should, however, take a number of factors into consideration. First of all, you should consider the energy demand required to operate the radiant system and ensure optimal heating in the winter months, and possibly cooling in summer.

Heat pump and radiant system even for cooling?

As well as providing optimal thermal comfort in winter, floor heating systems can also be an interesting solution for cooling in summer. They basically work in a similar way: ‘chilled’ water at a temperature of 15-18 °C circulates through the system’s hydraulic circuits, which cools the floor. In this case, reversible heat pumps are required, which are able to draw heat from inside the home and then release it outside. The end result is perfect indoor comfort even in summer, meaning that you can do without a split air conditioner and significantly reduce consumption. The only thing to bear in mind is that a dehumidifier should also be used to make sure that the air humidity stays within a range of 50 to 60%.

Heating with heat pump and photovoltaic systems: is it convenient?

Heat pumps use renewable sources to generate the thermal energy required for the radiant floor heating system to heat rooms, but are nevertheless electronic devices that use electricity. Consequently, to increase system efficiency and save energy, combining it with a photovoltaic system can prove to be a very good idea. People who install photovoltaic panels on the roof of their home usually do this so that they can produce the electricity they need to use lights and household appliances free of charge, cutting their electricity bills and even getting them down to zero by installing a storage battery. But not everybody knows that combining photovoltaic panels with a heat pump also ensures additional substantial savings on heating and domestic hot water production.

Clivet’s solutions

Is the energy demand of your home not excessively high? The solution offered by Clivet is the Sphera EVO 2.0 split heat pump, which has a wide range of capacities (from 4 to 16 kW), a domestic hot water storage tank with a capacity of 190 to 250 litres and anti-Legionella function, and even a 4-year warranty. This model also stands out for its cutting-edge, which allows it to blend in seamlessly with all kinds of furnishings, and is ideally suited for use in combination with radiant floor, ceiling and wall heating systems.

On the other hand, if the weather is particularly cold in winter, it is best to choose the Edge EVO 2.0 EXC outdoor packaged heat pump, which ensures excellent performance even at low temperatures and is able to produce domestic hot water at 60 °C. Developed by Clivet, this air-to-water pump has a power range from 4 to 30 kW, with the option to connect up to 6 units in cascade in order to reach 180 kW. In case of extreme weather conditions, it can also be equipped with an additional electric heater.

Discover Edge EVO 2.0 EXC