1. TITLE : LOW ENERGY AND SUSTAINABLE HOUSING IN THE UK AND GERMANY
By: Christoph Morbitzer
Abstract:
This article reviews the different approaches which have been applied in the development of low energy and sustainable housing in
the UK and Germany.
It describes and compares two different concepts in the German (passivhaus) and the UK (Code for Sustainable) Homes.
Case studies :
1: Energieautarkeshaus (energy independent house) in Germany.
2: BEDZED project near London.
SUSTANABLE HOUSING
GERMANY
ENGLAND
PASSIVE HOUSE CONCEPT
UK CODE FOR SUSTAINIBLITY
Energieautarkeshaus
BEDZED project
main conclusion is the need for better collaboration between different countries.

2. CONCEPT 1 : The Passivhaus:
The Passivhaus concept has been developed at the passivhaus Institut in Darmstadt over nearly 20 years and it has developed a number of easy understanding rules.
A passive house achieves energy efficiency through a high quality building envelope which controls energy flow in and out of the building.
PASSIVHAUS RULES:
1: Compact form and good insulation
2: Southern orientation and shade consideration
3: Energy-efficient window glazing and frames
4: Building envelope air- tightness
5: Highly efficient heat recovery
NOTE: By now more than 6000 successful project examples have been built.
They are mainly found in Germany, Austria and Switzerland.

3. CONCEPT 2 : The Code for sustainable homes:
The code for sustainable homes(CSH) has been developed by the UK Building Research Establishment and has been introduced as an industry standard in the UK from 2006.
the code dose not only address energy consumption, but forms part of a wider environmental assessment method. It rates buildings from one to six stars, under consideration of the following categories:
Co2 emissions
Pollution
Water
Health and Well- Being
Materials 1:
10% 2:
18% 3:
25% 4:
44% 5:
100% 6:
A zero carbon home
NOTE: The table shows the significant differences between the different code levels 4. It can be argued that is perhaps ready to construct on a large scale homes in line with the requirement of level 1 to 3. It becomes more challenging with level 4, difficult with level 5 and next to impossible with level 6.

4. CASE STUDY NO.1 : The Energy Independent House
Project: Energieautarkeshaus
LOCATION: Freiburg, Germany
Date: 90s
Size: 4 Bedroom, a living room, Kitchen and tow bathrooms.
Orientation: Southerly
It has neither gas nor electricity grid connection and it receives all its energy from the sun and the ground. Southerly orientation transparent insulation panels capture energy for space heating purposes, and solar hot water and electricity.
This project achieved the first combined heat and power system in a domestic situation.

5. CASE STUDY NO.2 : THE BEDZED HOUSING IN UK.
PROJECT: Multi Family Housing
ARCHITECT: Bill Dunster Architect
LOCATION: Beddington, UK.
Date: 2002
Size: 82 residential houses.
Orientation: Southerly
This project receives power from a small scale combined heat and power plant(CHP) which also provides hot water. In addition to the domestic energy requirements the designers did also pay close attention to other environmental considerations.
All the buildings have been built from local, natural, recycled or reclaimed materials.
BedZED or the Beddington Zero Energy Development, is an environmentally-friendly housing development near Wallington, England in the London Borough of Sutton. BedZED was designed by the architect Bill Dunster who was looking for a more sustainable way of building housing in urban areas. The 82 houses, 17 apartments and 1,405m² of work space were built between The project was shortlisted for the Sterling Prize in 2003. 

6. CASE STUDY NO.2 : THE BEDZED HOUSING IN UK.
The southern or sunward side of the apartment buildings are designed for passive heating of each unit with high use of insulated windows. Combined with excellent insulation of walls and roofs each unit hardly needs any additional heating during the winter. That combined with energy efficient lighting and appliances reduces the total energy usage of BedZED considerably. Note the bridge to each apartments first floor patio garden. 

7. CASE STUDY NO.2 : THE BEDZED HOUSING IN UK.
BedZED is the UK's largest eco-village. The aim was to help residents and office workers reduce their ecological and carbon footprints to a sustainable, "one planet" level. The plans cover reducing energy use, providing renewable energy, minimizing the embodied energy of the buildings, reducing fossil fuel miles and also tackling food, waste, water usage and flooding.

8. THE BEDZED HOUSING IN UK.
CASE STUDY NO.2 :

9. CASE STUDY NO.2 : THE BEDZED HOUSING IN UK.
External system for Wind control, Ventilation and Heat recovery

10. THE BEDZED HOUSING IN UK.
CASE STUDY NO.2 :

11. THE BEDZED HOUSING IN UK.
CASE STUDY NO.2 :

12. Discussion Of Differences:
THE CODE FOR SUSTAINBLE HOMES & PASSIVHAUS CONCEPT
A Passivhaus is not a Solar House:
The concept of the solar house originates from the 70s. The buildings are oriented towards the south, having large south facing glazed areas and thermal mass captures energy and released it at times when heating is required but not provided via the sun.
First interesting observation is the fact that Germany has for several years applied the passivhaus principle and accepted it as a standard in domestic low energy housing, whilst the most recognized project example in the UK is based on the solar house. The difference may be appear small, but is significant- a passivhaus is not a solar
house.
A Passivhaus has in comparison some distinct differences:
1: A passivhaus lacks the excessive south facing glazing areas.
2: A passivhaus dose not require thermal mass, but the benefits of the solar house is also count for it.
3: Omitting thermal mass can reduce the construction cost of building.
4: site planning in passivhaus concept is easier by the fact that orientation of the building is not important.
5: Passivhaus concept is based on the fact that Germany focused on .technical details

13. CONCLUSION & … THE CODE FOR SUSTAINBLE HOMES & PASSIVHAUS CONCEPT & …
1: We can see that the solar house , on which the BEDZED project is based, has certain disadvantages like summer over heating, winter problems inefficiency of extensive glazing as solar collector… and these have been addressed by the Passivhaus concept.
2: How ever the strength of BEDZED is certainly the variety of environmental issues and it dose not only focused on energy demands of a building, but also by considering aspect such as transport energy, embodied energy water consumption, ecology, or social housing.
3: In the context of the code for sustainable homes that it provides performance requirements not only for carbon emissions, but also pollution, water, health and well being, materials, management, and waste.
& …
1: projects Scales
As we read at the beginig of the article case study 1 (passivhaus)is an individual home which has a few bedrooms and … but the second case study is multi family housing by more than 80 houses. beside accepting the advantages of this comparing we should know that these two projects are not in the same scale so there are lots of problems in the housing scale that made the architects to obey technological, social and also political orders.
1: projects Dates
we know that the first case study was built in 90s but the BEDZED project is built in 2006!.
so, we should also accept that many things have been change in these two decades and it is really hard to compare two projects from two different time, technology, and also two different cultures!