Social housing company Zonnige Kempen has a general objective of building houses for low-income people at reasonable costs. On a tight family budget reduced energy costs are even more important than in general, so therefore is providing energy efficiency an essential part of the social housing policy of Zonnige Kempen. The 23 new energy efficient social housing units located in Houtvenne near Antwerp is a demonstration project for introducing energy efficient design and construction in Belgium - and for promoting technology for energy efficiency in housing. Until now the costs for energy efficient products have been considerable due to low general interest.

The project aim was a general performance standard of 50 kWh/m² annually for heating. This is 70% less than a standard house in Belgium, using on average 190 kWh/m² annually for heating. For domestic hot water a target of 50% less energy consumption was set.

The main energy reduction potentials recognised in the Houtvenne project were transmission losses, ventilation losses and hot water. Transmission losses or gains represented a prime subject of attention. Through comprehensive insulation of the entire building envelope with insulating materials such as mineral wool and special double glazing, combined with energy economic design, the project managed to lessen the heating significantly. The 50 kWh/m² heating target was achieved by supplementing the insulation measures with low energy elements like a communal boiler in one block, mechanical heat recovery ventilation, EMS, and passive solar design (solar access in dwellings, south orientated). Solar panels, individually as well as collectively, take care of 50% of the domestic hot water production. The major innovative element in the construction, however, was the individual heating system installed in 2 of the residential blocks, which combines heating, ventilation, and hot water.

Block 1: 3 units with the individual multifunctional heating plant with integrated ventilation and individual solar system with return reservoir.

Block 2: 12 units with collective heating system and collective solar system with chemical product.

Block 3: 8 units without solar system – due to building orientation.

Furthermore, water saving measures were implemented, and only sustainable building materials were specified. 

• Improved insulation to reduce heat demand
• Individual multifunctional heating plant with condensing gas boiler and integrated ventilation
• Solar panels for domestic hot water

Monitoring Scheme:

Building period:	Work started: March 1998
	Work finished: October 1999
Monitoring period:	October 1999 - May 2001
Monitoring results:	23 dwellings with a total floor area of 2202 m2
	Parameter	Norms	Predicted	Monitored
	Heat: (kWh/m2)	190	50	51,6
	Electricity: (kWh/m2)	33	30	Not monitored
	Water: (m3/m2)	1,01	1,04	Not monitored
Other Results/ archievements	The region of Antwerp has shown interest in this project right from the beginning, and due to many good process actively involving tenants, city administrations, financial partners, utilities, consultants and local citizens Zonnige Kempen housing association has succeeded in establishing a local process of awareness rising for sustainable urban housing. The process has gradually spread to regional level comprising also with attention from financial support sources within the region of Antwerp. This has resulted in financial support to establish a training centre for tenants, consultants, technicians, and citizens etc, to promote more sustainable housing projects in the future. See Kamp C Training Centre: http://www.provant.be/kampC/

Further information:

Contact Person /Builder	C.V. Zonnige Kempen Sociale Bouwmaatschappij Grote Markt 39 B-2260 Westerlo Phone: +32 14541941 Fax: +32 14541951 e-mail: zonnige.kempen@cipal.be
Local authority	Mr. Ludo Helsen Province of Antwerp, Belgium Phone: +32 32405274 Fax: +32 32405274 e-mail: lhelsen@provant.be
Architects	MTemaS, Westerlo
Services Engineer	J. Daenen
Technical consultants	Prof. H. Hens, University Leuven VITO (Flemish Institution for Technological Research) Boeretang 200 B-2400 MOL Belgium Phone: +32 14 33 55 11 Fax: +32 14 33 55 99 e-mail: vito@vito.be www.vito.be