How does water underfloor heating work?

Economics of Water Underfloor Heating System

With water underfloor heating system, you are likely to save on heating costs. Water underfloor heating utilizes the entire floor surface to transfer heat to the room, making it very easy and quick to achieve ideal temperature conditions. Additionally, the heat in the room spreads really evenly, no matter where you are located.

If you have doubts - consider why modern heat sources, which are - let's not kid ourselves - energy-intensive (e.g., heat pumps, gas boilers) - work well in homes with water underfloor heating system, while they are very uneconomical in homes with radiators. Of course this is a simplification of the issue, involving thermal inertia, new/old construction, but the low-temperature water underfloor heating plays a huge role here. This is the economics of the UFH system against classic radiators.

Dry and Wet Variants

Using concrete or anhydrite is definitely better. Above all, the advantage is the higher load capacity, which is about 60-75 kilograms per square meter. However, every solution, besides its advantages, has its drawbacks - if you ask practitioners, the drying time is certainly a disadvantage - it takes time. The floor is definitely not immediately load-bearing; initially, you have to wait before walking on it (which delays other finishing works). The material must harden to achieve its optimal properties. The floor can be laid no sooner than after 5 weeks.

In the case of the dry option - that is, gypsum-fiber boards - the floor can be laid immediately. However, the load capacity in this case is only up to 20 kilograms per square meter. In both cases, the floor should be laid on adhesive. This makes it adhere much better to the substrate. This will ensure that the heat from the water underfloor heating system is better transferred.

Temperature in Water Underfloor Heating

In water underfloor heating, heat is distributed via water, which is the primary heat carrier; other heat carriers are generally discouraged for underfloor heating. Additionally the water in underfloor heating is heated to a relatively low level — lower than in traditional radiators, as mentioned above.

✅ While in a traditional heating system, the water temperature can reach up to 60-70 degrees Celsius, in water underfloor heating, the water temperature should never exceed 40-45 degrees Celsius (in extreme cases, because a maximum of 32-35 degrees is usually recommended - in many cases 28 degrees is enough). The temperature of the floor itself is a maximum of 24-28 degrees Celsius. Therefore water underfloor heating system can save energy. This is due to the fact that there is less water in the pipes and it is heated to a lower temperature.

Best Heat Source for Water Underfloor Heating - Furnace? Heat Pump? Fireplace? Woodburner?

What is the best heat source for warming the water in underfloor heating? The answer is simple:
✅ Any heat source is suitable for water underfloor heating.

For underfloor heating, you can use:

• A gas boiler
  
• A pellet boiler
• An electric boiler
• A heat pump
• In some cases, even a solar collector (though as a supplement to another heat source)
• A fireplace with a water jacket

Don't worry that some heat sources produce higher temperatures than recommended for water underfloor heating. Today, you can use mixing valves, including thermostatic mixing valves—there will be no problem. In other words, water underfloor heating has no special requirements regarding the heat source.

➡️ On our blog, you can also find an article about combining underfloor heating with a fireplace
and about
➡️ combining underfloor heating with a condensing boiler.