Gas boiler for underfloor heating - a useful combination?

In the case of underfloor heating, not only the heating system, but above all the heat generator, plays a major role in energy costs. Whether a gas boiler is a good option for underfloor heating, what this and what speaks against it, read here.

Heat requirement with underfloor heating

Modern underfloor heating work with particularly low system temperatures. Especially in modern, well-insulated buildings (as the EnEV also demands), the heating demand is usually so low that it can be operated with very low flow temperatures.

On average for many modern buildings (or well-insulated old buildings), the VL temperatures are below 30° C.

Prerequisite for the heat generator

The heat generator for underfloor heating must therefore provide only a very low power. Very efficient systems, such as oil and gas heaters, are therefore usually slightly oversized for underfloor heating.

However, this depends on the local conditions and of course on the surfaces to be heated.

Gas boiler versus gas condensing boiler

Gas condensing boilers always display their advantages even more where low power is required.

With condensing technology, a theoretical efficiency of more than 100 percent can be achieved, which compared to conventional gas heaters can reduce consumption by up to 20 percent.

Especially for modern underfloor heating should therefore rather rely on gas condensing thermal baths, as the classic gas boiler. The heating energy requirement is not particularly high, but the savings are well worth it in the long run.

stratified storage

If you want to operate a floor heating with powerful systems such as gas or oil heating, you have to expect that even a corresponding layer or buffer storage must be installed, which cools down the hot water to the VL temperature for the heating.

In some cases, this causes additional costs, but in individual cases you always have to compare them with other costs.

One can hardly make a lump-sum cost comparison in relation to the production costs - for it the used systems, the constructional Gegegbenheiten in individual houses and also the offered gas heaters and Gasthermen are simply too different.

heating costs

In terms of heating costs, however, one can already consider. If a heat generator is needed, the price of the heating means is not insignificant.

  • What costs are incurred for the heating medium for the required amount of heat in kW?
  • how will the costs develop in the future (forecasts)?
  • how available is the heating medium (bottlenecks or shortages can quickly lead to massive price increases)
  • Storage areas for the heating means and similar conditions

For example, if you compare the kW prices, you can see a significant cost advantage in biomass heating systems. Compared to gas, the kW price was much cheaper:

  • Gas costs around 6.7 cents per kWh,
  • Pellets, on the other hand, only 4.8 cents per kWh,
  • Wood chips even only around 3 cents per kWh

Tips & Tricks

In any case, heat pumps are particularly interesting for underfloor heating. Again, the heating costs are around 2.5 - 4 cents per kWh. Solar thermal energy can also be an interesting option, but there are no costs whatsoever (except for the construction costs). In any case, a solar system can pay for underfloor heating as a significant cost-reducing factor.

Video Board: Worcester Greenfloor Underfloor Heating Installation Guide