Building a sustainable habitat is not just a matter of choice, it is also a matter of legacy. Here’s the crossroads we are facing: today’s edifices may become our children’s burden or their foundation for a healthy and fulfilling life. A green, responsible approach on how and what we build can reshape our cities’ skylines and create a better perspective for many generations to come.
Sustainable architecture principles can be applied successfully to new constructions as well as older structures, so whether you are building a new home or planning a house remodeling project, here’s what you need to know to get you started on the green path:
Why Sustainable Architecture?
“Sustainability may be defined as meeting the needs of present generations without compromising the ability of future generations to meet their needs.” (Wikipedia/ Fundamentals of building construction: materials and methods. Allen & Iano, 2008). Its goal is, therefore, to reduce the environmental impact of a building by increasing its efficiency in terms of energy, materials used, development space and waste.
The Benefits Of Sustainable Architecture
Although the initial costs of environmentally friendly buildings are higher than those of traditional structures, as some of the materials used and the modern technologies incorporated tend to cost more, over the course of its lifetime the operating expenses are much lower and its financial payback exceeds the original investment by a factor of 4-6 times (source).
Health & Productivity
As most of us spend a huge portion of our time indoors, there’s a direct correlation between our health, mindset, vitality and the spaces we live and work in. The indoor air quality, the lighting and the building materials used impact our well-being from subtle to obvious ways. Addressing these factors can greatly improve our health, productivity and the overall quality of life.
Reduction of greenhouse gases, pollution and waste.
What Makes A Building Sustainable?
A sustainable building is a structure that is planned, built, improved and used in an efficient and eco-friendly manner, respecting and incorporating the core principles of sustainable architecture:
Siting and Orientation
Every home has a home of its own – the building site. When choosing the location of your future sustainable home, you should take into consideration three important aspects: the proximity of main access routes, public transportation and neighboring communities to reduce traffic pollution and other sprawl related environmental effects, the responsibility to protect and retain the landscape’s natural features by causing minimal damage during the building process, and the size of your property.
A building’s orientation in relation to the sun plays a vital role in achieving an optimal level of energy efficiency, which is the primary goal of sustainable architecture. Designing a new house so it will receive as much sunlight as possible for extended periods of time, regardless of season, will increase its efficiency in terms of energy use while reducing costs and utility bills. This is primarily due to solar gain – the increase of indoor temperature caused by solar radiation – which should be maximized in the winter and kept to a minimum during summer through orientation, windows placement, insulation, roof pitch etc. Orientation is also crucial in preventing property damage caused by seasonal particularities and changes (winter winds, snow and ice build-up, etc.).
- In northern hemisphere, surfaces facing south get the most sunlight all year round and surfaces facing north are in the shade all year round so place the most frequently used areas like the kitchen, living room, master bedroom, decks and patios on the southern side and the least frequently used (guest bedroom, storage room, garage) on the northern side.
- Because the summer sun is high and the winter sun is low, vertical south facing windows are the best at maximizing solar gain. Avoid placing large (or too many) windows on the northern side to prevent heat loss.
- Horizontal surfaces benefit from sun mostly in the summer;
- Surfaces with a 45° angle make the most of sunlight all year round;
- Plant deciduous shrubs and trees on the south side as they will filter the direct heat in the summer and allow the light in during winter; plant evergreen trees on the north side to shield it from winter winds and snow build-up.
Energy efficiency primarily means reducing the energy used to build and maintain a house throughout its life cycle. This is achieved through a number of strategies and factors, both passive and active, like orientation and solar gain, efficient sealing, thermal mass, on-site energy generation etc.
- Sealing construction joints, windows and door frames, skylights and downlights, chimneys, vents, exhaust fans, service entry points etc. is extremely important as it will prevent air and water leaks while balancing indoor temperature and moisture levels. A properly sealed building envelope together with a well-designed HVAC system will increase a house’s thermal quality.
- Pay attention to thermal mass or the ability of a building to absorb, retain and regulate internal heat. Overall, this is given by the building materials used during the construction process, each with its own levels of heat absorption and retention. The denser the material, the higher its thermal mass. A high thermal mass means that the material heats up slowly and then, as the temperature changes, gradually releases the heat back into the surrounding environment. In a low thermal mass material, both processes happen at a much faster rate.
- Thermal mass is most effective when adapted to local climate conditions. It can easily work against its purpose if used incorrectly – placed in areas where it can’t absorb heat (from natural or artificial sources) or in areas where it would absorb too much heat. This is the reason why green building specialists recommend using the thermal mass principle in conjunction with building orientation and insulation.
- High thermal mass building materials: concrete, bricks, natural stone. Low thermal mass examples: timber.
- Insulation is extremely important in preventing heat transfer (gain or loss) through the walls. It should have a high R- value (resistance to heat flow) and, of course, be environmentally friendly (wool, cotton, denim etc.).
- Beware of thermal bridges or, in simpler terms, those vulnerable spots in the insulation that enable heat loss, like concrete or steel slabs, metal ties, studwork, etc.
- Install large, double or triple glazed windows with gas filled spaces and low heat emissivity, ideally on the southern side of the house (in northern hemisphere) to increase solar gain in the winter and get as much natural light as possible.
- Choose appliances and fixtures with a low level of energy consumption;
- Install alternative energy sources like photovoltaic cells, solar hot water panels, heat pumps etc.
- Design and implement a natural ventilation system based on wind generated pressure (cross ventilation) and stack effect (movement of air into and out of buildings due to temperature and density differences, or, in simpler terms, the suction created by warmer air rising and escaping an enclosed structure). This type of airing is cheaper, healthier and low maintenance.
A new build is truly sustainable only when the resources being used to create it are renewable, reusable, recyclable, durable, non-toxic, and with little impact on the environment. This leads us to the concept of embodied energy – the energy required to extract, process, transport and install the construction materials. Steel, MDF, hardboard and concrete blocks have a high level of embodied energy. Some of the greenest building materials are lumber from certified forests, bamboo, stone, and recyclable industrial goods. A key tip is to use recycled, renewable and locally sourced materials.
Water is a very important resource and it should always be treated with consideration. Waste can be minimized by installing systems that can collect, recover and purify used water, such as grey water systems or dual plumbing, and bathroom fixtures like ultra-low flush toilets and low-flow shower heads.
Health and Safety
Eco-friendly houses are not just good for the environment but also for their occupants. Integrated part of sustainable architecture, an optimal flow of natural light and fresh air is highly beneficial in terms of health, reducing conditions like allergies, asthma, lethargy and depression and increasing happiness and productivity.
- Avoid building materials, products and finishes which emit toxic gasses like formaldehyde and volatile organic compounds (VOC);
- Choose wood flooring instead of carpet to minimize the buildup of allergy causing particles. Besides being hypo-allergenic, wood can also improve indoor air quality by absorbing or releasing moisture;
- Ventilation is necessary not only to bring fresh, clean air in but also to eliminate moisture from indoor sources, which can promote mold and microbial growth.