Client:
Gundlach GmbH & Co. Wohnungsunternehmen, Hanover
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Auf dem Hollen, Hanover
Description
The apartment house in the characteristic design of the 1950s was situated in a well-tended condition. However, as things are today, the building lacks heat insulation. Loss of heat also occurred at the windows, which had a HTC of 2,8W/(m2K). Decentral combined gas boilers heated the flats. Consequently, annual energy consumption with around 160 kWh per m2 living space was remarkably high.
Visually refreshed and optimized under energetic aspects the building appeared after the modernization. Now, it matches to the standard of a awfully good low-energy-consumption house: the exterior walls and the roof were equipped with a 20 cm thick heat insulation, the basement ceiling was isolated with 6 cm thick insulating material. Valuable passive-house windows as a wood-aluminum-interconnected system, central district heating and a comfort ventilation system with heat recovery for each flat add value to the 50-year-old building into a sustainable house with high living comfort and low energy consumption.
Involved parties
Design:
Architectual office pk nord, Hanover, GMW Engineering office GmbH, Hanover (domestic services)
Building data
Building type:
Apartment house
Location:
Hanover-Vahrenwald
Year of construction:
1957
Modernization:
June to December 2004
Residential units:
20
Heat usable space:
1.391 m2
Subsidies:
KfW, proKlima
Initial condition
EXTERIOR WALLS:
wall plastered on both sides of vertically perforated bricks, HTC = 1.53 W / (m2K)
WINDOWS:
old wooden windows with double-glazing, HTC = 2,8 W/(m2K)
ROOF:
top ceiling made of reinforced concrete, plastered on one side, HTC = 2,46 W/(m2K)
BASEMENT CEILING:
reinforced concrete ceiling with screed and linoleum flooring, HTC = 2,06 W/(m2K)
VENTILATION:
Window ventilation, as well as typical old building joints and cracks
HEATING:
each apartment is equipped with gas combi-boilers for heating and hot water
Modernization in detail
EXTERIOR WALLS:
insulating the massive exteriori wall with 20 cm heat insulation composite system, quality of 0,035 W/(mK), HTC = 0,16 W/(m2K)
WINDOWS:
Passive house windows with 3-pane heat insulation glazing and frame as wood and aluminum composite system, HTC = 0.8 W / (m2K)
ROOF:
insulating the ceiling to the attic with 20 cm from underneath, quality of 0,035 W/(mK), HTC = 0,16 W/(m2K)
BASEMENT CEILING:
insulating the reinforced concrete ceiling with 6 cm from underneath, quality of 0,035 W/(mK), HTC = 0,45 W/(m2K)
VENTILATION:
central comfort ventilation system with heat recovery function
HEATING:
central district heating transfer station in house 25, in each apartment transfer station with heat exchangers for heating and hot water
AIR CONDITIONING:
no active air conditioning installed
Measured values
AIRTIGHTNESS:
House 21
n50 = 1,7 h-1
(improvement took place)
House 23
n50 = 0,6 h-1
House 25
n50 = 1,0 h-1
Calculated values
Calculation method: Passivhaus planning package; Initial values: Hannover building typology
HEATING ENERGY NEEDS:
BEFORE
120 kWh/(m²a)
AFTER
35 kWh/(m²a)
SAVINGS
71 %
TOTAL ENERGY NEEDS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
BEFORE
Gas
180 kWh/(m²a)
Electricity
17 kWh/(m²a)
AFTER
Districht heating
70 kWh/(m²a)
Electricity
23 kWh/(m²a)
PRIMARY ENERGY NEEDS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
BEFORE
246 kWh/(m²a)
AFTER
88 kWh/(m²a)
SAVINGS
64 %
CO2-EMISSIONS FOR HEATING,AIR CONDITIONING,DHW,ELECTRICITY:
BEFORE
55 kg/(m²a)
AFTER
20 kg/(m²a)
SAVINGS
64 %
