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  • 40627 Düsseldorf-Unterbach
    Kirche St. Mariä Himmelfahrt

    temperature:
    18,8
    °C
    humidity:
    71,7
    %rF
    measured:
    20:28
    h
  • 31134 Hildesheim
    Michaeliskirche

    temperature:
    17,9
    °C
    humidity:
    69,8
    %rF
    measured:
    20:25
    h
  • 40668 Meerbusch-Lank
    Kirche St. Stephanus

    temperature:
    17,8
    °C
    humidity:
    68,4
    %rF
    measured:
    20:24
    h
  • 52062 Aachen
    DOM

    temperature:
    20,2
    °C
    humidity:
    72,1
    %rF
    measured:
    20:27
    h
  • 50676 Köln
    Krypta Maria im Kapitol

    temperature:
    18,3
    °C
    humidity:
    79,0
    %rF
    measured:
    20:26
    h
  • 66346 Püttlingen-Köllerbach
    ev. Martinskirche

    temperature:
    17,0
    °C
    humidity:
    73,3
    %rF
    measured:
    20:25
    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

Temperature Control System

Structure of this system:

The original idea behind this system was to lay a copper pipe behind the plastering along the outside walls as well as an operation all year long in order to avoid a drying out of the outside walls (and thereby a reduction in the heat transition coefficient). At the same time, the warming of the plastering above the copper pipe is to produce a film of warm air on the inside of the wall, hoped to increase the surface temperature of a larger area. This increased temperature on the wall´s surface is then hoped to be sufficient to warm up objects and other walls in the church, making for a pleasant atmosphere.

Advantages of this system:

  • As the emission of heat of the pipes is rather low in relation to the volume of the church, a small boiler is often chosen – independent of the actual heat requirement of the church.
  • There is – locally and only to a limited extent – an increase in the surface temperature and thus an active protection against condensation damage. So this system may help to defuse constructional weak points of the building (thin-walled conches, reveals etc). Such an arrangement of pipes to defuse weak spots of a building is no novelty. However, fitting such a temperature control system in an entire church goes counter to our understanding of heating construction, having to guarantee pre-defined temperatures for our customers.

 

Disadvantages of the system:

  • The plastering has to be broken off for the pipes to be installed and afterwards plastering has to be put on again. So you can predict that the walls will get dirty less quickly above the pipes, and more quickly in more distant areas.
  • The heat emission of the pipe is much too low to bring about a pre-defined temperature in the room. Even the installation of a tube loop or even more pipes in different levels, often advertised today, doesn´t improve things much. All cases with such a system confirm, as far as we know, that you cannot reach a pre-defined temperature, not even the 12°C, expected as a minimum.
    In our understanding the user should have the right to know which temperature will be reached after pressing a button. In most cases the temperature control system can only maintain a temperature of between 6 and 8°C. When you consider that temperatures in unheated churches hardly go down to 0°C (the holy water in the unheated Cologne cathedral freezing is a rare happening covered by the media), you may question the efficiency of such a system, given its considerable amount of work.
  • When there is no demand for a pre-defined temperature, one could install any heating system producing the heating power of the temperature control system. The investment would be comparable and the disadvantages of the temperature system could be avoided.
  • The heat transition through a wall depends on physical parametres, i.e. what is the wall made of, how thick is it, what temperature difference is there between inside and outside? Experience has shown that temperature inside a heated church will be between 8 and 15°C. Suppose the outside temperature was minus 12°C, we would have a temperature difference of between 20 and 27 K. With the temperature system mentioned above the temperature on the surface of the wall near the pipes would be close to 25°C, around the pipe itself even much higher, so that you would have a temperature difference of some 40 K between inside and outside.


Result

Increased loss of heat towards the outside where the pipes are laid.

Since the system is to be operated all year round, „24/7“, there will be, despite the limited power, considerable run durations of the heat producers, leading in some cases to operating costs higher than in the case of a “full-room” heating with pre-defined temperatures.