Floor heating without mixer - is that recommended?

Many modern underfloor heating systems completely dispense with a mixer. Whether this is recommended, and what effects a waiver of a mixer in the heating system on the energy consumption and other values, you will find in detail in this article.

flow temperatures

Especially modern heating systems work with particularly low flow temperatures. As a rule, work is carried out at below 35° C., whereby the flow temperature is not always controlled in a smooth manner.

Especially in this low temperature range, the use of a mixer in the heating system is worth even more, if no sliding control is available. The heat generation with so-called modulating burners (Gasbrennwertheizung) makes the use of a mixer often superfluous - but not always.

Older floor heating

Older systems that work with flow temperatures of 55° C. In many cases are no longer up to date and in many cases consume significantly more energy than would actually be required.

A renewal often makes sense with these old heaters. All the more so, if after a comprehensive energetic renovation and insulation of the building, the heating demand drops dramatically, and these heaters are then anyway completely oversized.

Operation of the mixer

The functioning of a mixer can be thought of as the mixer tap in the shower: we regulate so long at the hot and cold faucet until we have found the right and optimal temperature for us.

A mixer in heating works in exactly the same way: it regulates the flow temperature by adding a variable amount of return water until a certain flow temperature is reached. The operation can be done automatically or manually.

Arguments for installing a mixer

Apart from the cases where mixers are not mandatory (lubricated VL temperature, modulating burners), the use of a mixer has many advantages.

Oversupply of heat is compensated

High-performance heat generators, such as oil or gas heaters, often work at too high an output and thus provide water at too high a temperature. The heating of water to the required temperatures often below 30° C (with very good insulation or reduced heating operation) is often not possible with powerful heat generators.

Optimized burner run

The main advantage of the mixer, however, is the optimized burner run. The ratio between burner runtime and burner standstill will be significantly cheaper with the use of a mixer.

The burner starts much less frequently. This has many advantages:

  • lower pollutant emissions in heating mode
  • fewer defects - and therefore less repair costs
  • lower energy consumption (thus reducing heating costs)

Mixer with simultaneous DHW heating

If a heat generator, as in many cases, is used simultaneously for DHW heating, there is often a "hot water surge" in the pipes of the heating system. With the mixer, the controllability of heating and hot water production is significantly improved.

Tips & Tricks

The extended life of a heating system due to lower burner work and burner start times should not be underestimated. In this way you can save a lot of money.

Video Board: UNDERFLOOR HEATING GUIDE AND INSTALL PART 1 - Plumbing Tips