Heating limit

from Wikipedia, the free encyclopedia

The heating limit ( HG ) is a temperature limit value of the mean outside temperature measured on a day , below which the heating system must be switched on in order to keep the inside temperature at the desired value. Days on which the heating limit is undershot are called heating days .

Standard values

Various data are used as a basis for the heating limit, so that the heating limit and related values ​​are indicated:

  • according to the German DIN 4108 T6 heat insulation in buildings and VDI 2067 space heating: calculating the cost of heating systems , the heating limit at 15 ° C and the internal temperature is assumed at 20 ° C, is added HG 20/15 to
  • in Austria, Switzerland and Liechtenstein are used in a heating limit of 12 ° C and internal temperature 20 ° C, you are HG 20/12 to
  • there are also calculations based on HG 25/17

In the past, the limit value of the mean outside temperature for determining the heating period was 12 ° C in Germany as well, but was raised to 15 ° C with increased comfort requirements. Due to improved thermal insulation of the buildings, considerations are being made to lower the limit value again.

The heating limit is also necessary to determine the number of degree days / heating degree days , the accumulated temperature differences between the average daytime outside temperature and the heating limit or inside temperature, a measured value specific to a location that is used for calculating heating requirements and heating costs .

Building-specific values

Deviating from the general information, a building-specific value can also be used; in well- insulated buildings and energy-saving houses , the heating limit can be significantly lower, which means that fewer heating days are required than is customary in the area, and the heating period can be shorter.

Construction type Heating limit
° C		 Heating capacity
W / m 2 1
before 1977 015-17 80-150
1977-1995 014-16 60-120
EnEV and WSchwV after 1995 2 012-15 25-80
Low energy house 11.5-14 20-60
3 liter house 10.5-12 15-30
Passive house 09.5-11 05-20
Source: Energiedepesche 1/2007 Determination of the heating limit ...
1Square meters of living space , according to custom, values ​​rough area

Even if a higher room temperature is desired, there are individual values. When planning a passive house, for example, one calculates at the client's discretion with HG 23/10 - the values ​​required for heating days and heating periods must be taken from local weather data or calculated from climate models.

See also

Web links

  • Dietrich Beitzke: The heating limit. In: heating operation. June 11, 2002, accessed April 3, 2009 .

Individual evidence

  1. ↑ heating days (HT) . energiesparhaus.at
  2. ↑ heating degree days . Homeowners Association Switzerland
  3. ↑ a b Dietrich Beitzke: Heating limit . In: What do the technical terms mean?
  4. ^ Recknagel, Sprenger, Schramek: Pocket book for heating and air conditioning. 68th edition. R. Oldenbourg Verlag, Munich / Vienna 1997, ISBN 3-486-26214-9