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  • 40627 Düsseldorf-Unterbach
    Kirche St. Mariä Himmelfahrt

    temperature:
    21,3
    °C
    humidity:
    65,2
    %rF
    measured:
    09:17
    h
  • 31134 Hildesheim
    Michaeliskirche

    temperature:
    21,2
    °C
    humidity:
    65,7
    %rF
    measured:
    09:17
    h
  • 40668 Meerbusch-Lank
    Kirche St. Stephanus

    temperature:
    21,8
    °C
    humidity:
    52,3
    %rF
    measured:
    09:16
    h
  • 52062 Aachen
    DOM

    temperature:
    22,1
    °C
    humidity:
    64,3
    %rF
    measured:
    09:17
    h
  • 50676 Köln
    Krypta Maria im Kapitol

    temperature:
    18,0
    °C
    humidity:
    78,9
    %rF
    measured:
    09:19
    h
  • 66346 Püttlingen-Köllerbach
    ev. Martinskirche

    temperature:
    21,6
    °C
    humidity:
    65,1
    %rF
    measured:
    09:17
    h
  • Church of St.-Hubertus in Grosselfingen
    MAHRCALOR® church heating built in 2010
  • MAHR archives
    Data and ground plans of thousands of churches kept in our archives
  • Petri church in Lübeck
    MAHR-Actherm® control system for 22.000 m³ of church space
  • Sankt Johann in Denkingen
    MAHR church heating 1978 – long life through quality and regular servicing
  • Cathedral and Church of Our Lady in Trier
    MAHR heating systems in UNESCO world heritage sites
  • Church in winter
    A basic minimum temperature saves the substance of the building

Warm air heating systems

Structure:

Air is sucked by one or several ventilators out of the church room, cleaned in a filter, led along heating surfaces and guided back into the interior of the church. Of course these systems can be fitted with sound absorbers, fire flaps etc.

We basically distinguish centralised and de-centralised warm air heating systems. Centralised means that the warming of the air happens in one place only, whereas with a decentralized system the air is warmed in various places.

Advantages of these systems are:

  • When there is a functioning duct system in place (including insulation) this is a very inexpensive solution that ensures a permanent heating of the building´s structure, thus giving protection against condensation.
  • In any case it can be controlled easily and fast
  • The system being adapted to the energy requirement, you are sure to obtain a pre-defined temperature at a fixed hour.
  • Filtering systems contribute to keeping your church clean.
  • Depending on the version, warm air heaters offer the benefit to ventilate after a lot of people have visited the church service, e.g. in summer.

 

Disadvantages of the system:

  • Depending on the type of system, the investment may be a little higher than with other systems.
  • The filtering of air is an important contribution to keeping the church clean, but the filters need cleaning every 4 to 6 weeks, leading to a higher maintenance work level for the operator.


You often come across prejudices against warm air heaters cited by other producers. To be complete, we will mention a few and give some objective indications.

Prejudice:
„This kind of ventilation only blows the dust and dirt all over the church interior“

Answer:
This is wrong! The natural movement of air occurring in a church over the year (whether it is heated or not) is a multiple of the air movement caused by an air heating system. With a professionally-designed and installed warm air heating the only place where you will perceive a distinct movement of air is right above the gratings. If you then consider how much dirt and dust are filtered out by a good filtering device you can certainly claim that, with a good warm air heating, the amount of dust and dirt circulated in a church is significantly lower than without a heating.

Prejudice:
A warm air heating leads to an extremely high layering of temperatures inside the church.

Answer:
This is wrong. This prejudice bases on ancient types of warm air heating systems (after the second world war), working with unregulated supply air and with only one air outlet. Today´s systems with their branched duct system, or a de-centralised warm air heating with modern control technology, help reducing the difference in temperature between floor and vault considerably.
In 2004, within the framework of a European research project, measurements were carried out on a Mahrcalor® heating system, showing that former statements of a temperature layering of 15 to 20°C with warm air heating belong to the realm of fairy tales, being completely wrong. What they found were temperature differences of only 1 to 2°C in a room 15m high! A temperature difference as little as this was also measured in the Michaelis church in Hildesheim, fitted with a MAHR heating. An impartial expertise conducted in 2009 confirmed that there was a temperature difference of less than 1,5 K in a room over 16m high – an excellent result.

Prejudice:
The organ and other pieces of equipment are damaged by a warm air heating

Answer:
This is wrong. The danger of this happening can be excluded by designing the system sensitively. The prejudice was produced long ago by some heating systems that led the warm air directly along hygroscopic materials (wood, canvas, leather etc), leading to damage in the form of swelling or shrinking.
Heating the church up beyond any reasonable limits, causing a reduction in the relative humidity, has also led to damage to pieces of equipment. Such mistakes can be excluded by our current regulation systems.