Difference between Grundofen and Fireplace

Hello everyone,

can someone maybe give me a tip on how to distinguish a masonry heater from a fireplace? I am currently doing several house viewings and often the owners themselves have no idea when I ask what kind of stove it is. I am particularly interested in one (without having to ask the chimney sweep or an expert every time), it is located in the middle of an open room, built from floor to ceiling. Attached is a snippet from the exposé. Do you already see anything? Heating is done on the hearth/floor, there is no grate on which the wood is placed.



My question usually aims at whether I will be allowed to operate the stove from next year without extensive retrofitting. Masonry heaters have fewer restrictions in this regard..

Best regards and thanks to you!

A masonry stove is characterized by the fact that it is only fired with wood and has no ventilation from below. The wood lies on the stove base, ideally in a bed of ashes. Modern masonry stoves with burn control have an extremely clean combustion. Usually, masonry stoves are built with a lot of storage mass, e.g. from fireclay. Flue gas channels run through the storage mass. In this way, the energy is released to the room over hours in the form of radiant heat. The heating curve is long and flat.

Wood stoves usually have a grate and a much faster burn rate. The heating curve is rather short and high. Wood stoves can also be equipped with storage mass to extend the heating curve somewhat.

In our living space (over 300 cubic meters in volume), we have a masonry stove with Ortner technology as the only heat source. In winter, an 11-13 kg filling of good firewood was enough for 24 hours of comfortable warmth. Our boys each have a Hase wood stove in their apartments as an alternative to infrared heating. It gets warm very quickly in the room, but the stove starts to cool down after 2-3 hours.

Fun fact: The heating output of wood stoves is specified in kW. The maximum waste heat is measured here. On paper, a masonry stove appears less efficient than a wood stove because the time over which the output is measured is relatively short.

Cool, thanks for the clarifying answer. What do you think about the fireplace in the picture? I couldn't see any ventilation slot from below. However, the ventilation slots at the top are more an indication of a classic convection stove, that is a normal fireplace and not a Grundofen, right?

Grundofen (in the sense of the energy saving ordinance, that I am allowed to operate the stove from 2020 onwards) then have nothing to do with storage stoves, but only that the combustion takes place on the floor and therefore at a higher temperature and cleaner, right?

Simply call the chimney sweep and ask how long the stove can still be operated. That is the safest option.