Floors with underfloor heating

Why insulation is especially important with these floors


Underfloor heating is becoming more and more common, and for good reason. After all, a warm floor is important for comfortable living. And underfloor heating saves energy. Or does it? Sometimes it doesn't! If there is insufficient insulation, the energy costs can be disadvantageous. See this article, among others. Which is why floor insulation is especially important with underfloor heating. If thermal resistance (R-value) is doubled, downwards heat loss is halved.


The disadvantage of underfloor heating

Underfloor heating is a good way to heat your home, and does have many advantages. But there's a catch. Underfloor heating not only heats the floor, but also the crawl space, the soil and the foundation. In some cases, more heating is used in warming the crawl space than in heating your living room. This can be seen on the thermal image opposite. The bottom surface of the crawl space, below the underfloor heating, is at 23ºC, which is warmer than the room temperature. You can sometimes also detect from the outside of a house whether it has underfloor heating. The foundation walls and even the pavement are then relatively warm, as shown in the thermal image below. And if it snows, you can see that the snow melts more quickly in these locations. Unfortunately, all of this is lost heat and energy. But these losses are easy to reduce with good insulation.

The effect of floor insulation

Heat always flows from a high temperature area to a low temperature area. Since the bottom of the crawl space is colder in winter, much of the heat from the underfloor heating will therefore migrate downwards, rather than up to the underside of the floor surface. Applying insulation material under the floor partially blocks the heat lost downwards. As so much heat is radiated by underfloor heating, extra insulation is needed to prevent that heat being lost.

Milieu Centraal recommends applying U-value =5.0 m²K/W to floors with underfloor heating, as this is technically feasible with various systems. Much higher values can be achieved with TONZON. Every time thermal resistance is doubled, it halves the heat flow (loss). So if there's enough space, don't skimp on increasing the insulation value.

TONZON improves the performance of underfloor heating


TONZON works completely differently from most conventional insulation materials. This is because it is the only brand that stops heat radiation. This unique effect makes it the most efficient way to prevent heat loss from underfloor heating. Even floors that are already insulated with EPS or Pur foam can be significantly further improved with TONZON insulation.
Energy saving is not the only benefit of insulating with TONZON. Due to the insulation, the floor cools down slower and heats up faster. So you can turn the underfloor heating down, or even switch it off, and still retain a warm floor. Customers with underfloor heating without insulation claim that after fitting TONZON, the floor surface becomes warmer than before. For more thermal images and the latest information on underfloor heating, see the following blog article.


How much can I save?


It is always difficult to predict exact savings. With existing, moderately-insulated to non-insulated floors, installing TONZON insulation can save up to 40% on heating costs. Read this interesting article on increasing energy savings on existing underfloor heating systems. And see this blog about underfloor heating.


  • Saves up to 40 per cent on heating costs
  • Stops heat loss to the crawl space
  • Floor stays warm longer and cools down slower
  • The most climate-efficient, sustainable choice
  • 10-year guarantee certificate

Experience the comfort of a well insulated floor



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