Times are changing, and so are the property and construction sectors: eco-friendly houses, tiny houses, energy-autonomous houses and bioclimatic houses are revolutionising our approach to housing. What advantages and what impact on the environment do they have? Here are a few pointers to clarify what’s what.
Housing – a sector ripe to reinvention
The building and construction sector is one of the main emitters of greenhouse gases and thus contributes considerably to global warming. The construction and public works sector has a big carbon footprint. It emits not only CO2 but also methane and hydrofluorocarbons which produce greenhouse gases throughout their life cycle. This applies from the extraction and processing of raw materials to the production of construction materials such as cement and concrete to the construction of buildings (transit, building site machinery, etc.) to the end-of-life phase and often poorly-executed recycling. All of this is called “grey energy”, i.e. energy used indirectly and not very noticeably, especially upstream of what the end user sees.
Finally, excessive urbanisation is obviously very harmful to the environment. Farmland and rural areas are sacrificed in favour of buildings that destroys local ecosystems. Land gets tarred over to make way for roads or giant car parks on Industrial estates and next to shopping centres.
The principle of eco-friendly houses
Eco-construction is now attracting both private individuals and construction professionals. The objective is twofold: to save energy and construct buildings with the least possible impact on the environment. An eco-friendly house involves paying attention to all stages of the life cycle. This applies from design, which must be in keeping with the surrounding natural environment, to the construction site, which must reduce waste, to the choice of natural, recyclable and eco-friendly (non-toxic) materials, to fittings, which must all be energy-saving, whether in the choice of equipment or alternative installations such as solar panels, etc. This process favours local suppliers and materials. The project must be designed in synergy with external factors: creation of shade in relation to the sun, shoring-up and planting in relation to wind, appropriate windows, etc.
Heating, energy, lighting, water – eco-friendly on all levels
The first thing that comes to mind is of course the choice of natural materials such as wood, clay bricks or even straw, not least for heat insulation. There is an array of natural insulation solutions available, such as flax or hemp wool, wood fibres, etc.
The architect and builder will also think about ventilation to regulate the temperature using as little energy as possible, to keep the house cool in summer and avoid losing heat in winter. They must choose the heating systems carefully to partially heat the house using the likes of energy-autonomous heat pumps driven by air and water, wood burners (especially if they run on wood pellets or waste such as sawdust) and solar panels. The latter can reduce energy usage by careful examination of the building’s orientation and inclination. However, all of these solutions will still not meet the need for heating completely, due to the intermittent nature of sunlight, for example. Similarly, a standalone wind turbine is unlikely to meet energy needs in full, since the devices are very expensive to purchase and not very profitable. Also, favour low-energy lightbulbs, which soon pay for themselves due to their unbeatable lifespan. LEDs in particular use very little energy. Finally, a house cannot be eco-friendly without water-saving systems, or without a system to collect rainwater The latter can be used for watering plants, for cleaning or for flushing toilets. You can also dispense with these completely by using compost toilets.
Differents types of eco-friendly houses
As the sector is developing rapidly, there are many variations on eco-friendly houses.
- “Bioclimatic houses” must have High Environmental Quality (HEQ) certification. In addition to eco-construction principles, they focus on strategies to optimise the orientation and exposure of the house to reduce lighting and heating needs.
- Low-energy buildings focus on reducing energy usage, and must not exceed 50 kWh per square metre per year to be awarded certification as such.
- To be awarded Passivhaus or Passive Energy Building (BEPAS) certification, “passive houses” must produce their own energy and be able to do without heating. They require a feasibility study because the specifications are very exacting, particularly in terms of insulation and waterproofing, hence the steep price.
- Lastly, positive houses are the most successful among eco-friendly houses, because they combine all the characteristics of the Passivhaus, plus installations to produce enough energy to be totally energy-autonomous… Or even go beyond that!
Nomadic wooden houses and tiny houses
Be aware that most eco-friendly houses use a lot of wood, but a wooden house is not necessarily an eco-friendly one! However, new-generation eco-friendly wooden houses are emerging. They are made from biosourced materials and local (or even very local) wood. Some are even built from trees grown on their own land, thanks to mobile sawmills. This sustainable approach is carried through into the choice of untreated wood. The aim of this stance is to create the healthiest possible habitat, free of toxic volatile substances These principles are particularly well suited to new nomadic dwellings such as tiny houses and mobile, scalable, eco-friendly mini-houses. These energy-autonomous nomadic houses go hand in hand with an alternative lifestyle choice guided by the principle of frugality, which implies a certain minimalism. Tiny houses, which are inexpensive and energy efficient, are a perfect match for this concept.
Amid the climate emergency, the construction sector really must change radically, and fast. Eco-friendly houses, which are still not very widespread, are becoming the new standard. These houses are constantly being developed in order to combine energy savings and comfort in synergy with nature rather than by damaging it. Next, this performance needs to be rolled out to older houses. In this respect, owners of houses whose energy consumption exceeds 330 kWh per m² per year are required by law to have an energy overhaul carried out by 2025. Moreover, sellers must have an energy performance assessment carried out on their property to reduce the number of poorly-insulated houses that let heat escape unchecked.