The environmental impact of an ecological house

Here are translated excerpts from an Algerian study that compared the environmental efficiency of the same house before and after it was rebuilt with ecological materials in place of conventional ones.

 

From the Revue des Energies Renouvelables [Renewable Energy Journal] Vol. 13 N°4 (2010) 545 – 559

Abu Bakr Barnes University, B.P. 119, Tlemcen, Algeria (received on September 3, 2010 – accepted December 26, 2010)

 

Summary: An ecological house is more of a concept than a specifically defined kind of house. The idea is to combine various types of heating, ventilation and power supply for appliances to massively reduce energy consumption and cause an exponential decrease in CO2 emissions. This paper covers a study of the effects of an ecological house on the environment. To achieve this review, we first did a comprehensive study of the energy balance, from which we were able to determine, on the one hand, the usage times of each utility in the house, and thus a record of the CO2 emissions, and on the other hand, the carbon assessment in primary energy, as well as the lifecycle of the insulating materials. The results obtained were compared with the results from the same house built with non-insulating materials such as brick, concrete, etc. The comparison shows a significant difference in terms of energy, economics and the environment, which makes us very optimistic about the effectiveness of ecological houses.

 

The ever surfacing reports evaluating and measuring greenhouse gases in the atmosphere are becoming increasingly alarming. In fact, according to a study published in the “Proceedings of the National Academy of Science” and carried out by M. Raupach for the Commonwealth Scientific and Industrial Research Organisation’s Marine and Atmospheric Research and Global Carbon Project, the emission of greenhouse gases, which is responsible for global warming, is always rising. If measures are not taken to limit its rise, global warming will have drastic effects.

As we see it, our obligation to respect our environment is greater than ever, and every individual must find a balanced solution that involves both comfort and a unique contribution to sustainable development.

We’ll speak of ecological houses as being those in which two criteria are met:

  1. At least 80% of the house’s energy is more economical than the average, although this can be taken much further, to the point of no consumption, or even negative consumption (net production of energy).
  2. The usage of ecological, healthy and durable materials.

The main requirements for an ecological house are:

  • Alliance between the land and local climate
  • Orientation: ability to make use of the sun
  • Carbon footprint: hunt down hidden emissions
  • Thermal insulation: absolutely necessary
  • Walls: healthy, natural materials
  • Ventilation: air sufficiently refreshed
  • Favor renewable energies for heating and air conditioning
  • Create a healthy and comfortable environment for the inhabitants

The aim of our work is to make an environmental comparison between an existing house in Tlemcen, Algeria, built with conventional materials (concrete, bricks, etc.), and the same house built with ecological materials (cork, hemp, wood, etc.), to get a clear idea of the impact of such a house on the environment.

The setting is in western Algeria in the Tlemcen region, Latitude 34°52’01” North, Longitude 1°28’01” West, at an altitude of 850 m, in a temperate climate.

Energy efficiency will the major challenge of the years to come, because this issue inherently contains the issues of greenhouse gas emissions and embodied energy, that is to say the energy needed to manufacture materials and systems (heating and ventilation). The question of energy efficiency represents the essence of environmental performance.

View of the House (East side)

The area of the house is 100 m2, and it has three floors. The first floor features a hall, a garage, a living room and a bathroom; on the second floor, there is a living room, a kitchen, a small lounge and bathrooms; on the third floor, three bedrooms, a hall and a bathroom. The area of each room is shown in the below table.

The architecture, orientation, compactness, and surrounding plants help the house capture solar rays and maximally benefit from solar gain. The living space is oriented from the southeast to the southwest, which is precisely the principle of bioclimatic architecture required for an ecological design. The conventional house was originally built with brick and concrete, with windows of wood and doors of wrought iron.”

Types of materials used in the ecological house

For the insulation of the house, we opted for:

  • Thick mineral-wool board (140 mm thickness) for the floor and foundations.
  • Flexible wood-wool board (220 mm thickness) under the roof.
  • Three hundred (300) mm of cellulose wadding for the ceiling and 200 mm for the floors of the rooms.
  • For the walls, a wood framework (U = 0.16 W/m2) with a sound-insulation level greater than 46 db. A double glazing of 20 mm with an interior volume filled with gas (U = 1.1) and a sound-insulation level greater than 31 db.

In our study of the environmental performance, the difference between CO2 emissions from House1 and House2 is clear. This is difference is mainly due to the design materials (material types, primary energy, transportation of materials, life cycle, reduction of heating and air conditioning through better insulation).

(The Pink is CO2 emissions due to natural gas. The Grey is CO2 emissions due to electricity. The ecological house is on the right.)

CONCLUSION

We can draw a number of conclusions from this first environmental comparison, which can guide our actions for the protection and promotion of the environment.

An ecological house cannot be entirely perfect for those who are seeking maximum comfort. Nevertheless, we were able to find materials that are largely compatible and at the same time help to reduce energy costs.

These houses require a higher cost to build. Over time, these buildings will need less energy for heating, lighting, etc. This means less costs overall compared to other buildings.

Ecological construction can meet the needs of current generations without compromising the ability of future generation to meet theirs, thus contributing to sustainable development.

Translated by Zebulon Goertzel