Sustainable architecture is often associated with solar panels on the roof or a certification logo. Yet how little energy and water a home will use, and how comfortable it will be to live in, is largely decided much earlier, in the very first sketches. In this article we look at what sustainable architecture means at the scale of a house. We suggest an order of priorities that starts with passive design, moves on to decisions about water and materials, and only then turns to renewable energy. We also briefly cover what green building certifications and Turkey’s Energy Performance Certificate actually tell you.
What is sustainable architecture?
Sustainable architecture is an approach that aims for a building to place less of a burden on nature and people, from its design and construction through its years of use to the end of its life. Alongside energy and water consumption, it is concerned with where materials come from, how long they last and what becomes of them in the end. The health and comfort of the people living inside are also part of the equation; a house that uses little energy but is stifling in summer and damp in winter cannot be called sustainable.
For us, the essence of this approach is an order of priorities. First, reduce the need for energy through design; next, meet the remaining need with efficient systems; and only then supply it from renewable sources. Reverse that order and you end up with an expensive, inefficient result, such as adding panels to the roof to make up for the energy lost by a poorly oriented, weakly insulated house. That is why we begin by reading the local climate and the movement of the sun.
For an energy-efficient home, start with passive design
Passive design aims to deliver indoor comfort through the form, orientation and envelope of the building rather than relying on mechanical systems. The first decision is orientation: in the northern hemisphere, living spaces facing south benefit from the winter sun and can be protected in summer with the right shading. The west facade needs more careful handling because of the low, hot afternoon sun. The second decision is form. A compact mass with few projections and recesses has less external surface for the same internal volume, so it loses less heat.
The quality of the envelope then completes these decisions. Insulation that runs without interruption through walls, floors and roof matters as much as its thickness. Where insulation is broken at points such as balcony slabs, column and beam junctions or window reveals, thermal bridges form. These can cause both energy loss and condensation and mould on internal surfaces. The insulating performance and placement of windows, and the airtightness of the envelope, are also among the main factors that shape how a house behaves in terms of energy.
- Orientation: placing living spaces in relation to the sun and prevailing winds.
- Compact form: limiting the external surface by avoiding unnecessary projections and recesses.
- Continuous insulation: treating wall, floor and roof insulation as a single, unbroken layer.
- Thermal bridges: resolving balcony, column, beam and window junctions at detail level.
- Airtightness: preventing uncontrolled air leakage and designing ventilation deliberately.
How do shading, natural ventilation and daylight work together?
Shading is one of the most effective ways of reducing the need for cooling, particularly in hot climates. A correctly sized overhang on the south facade blocks the high summer sun while letting the low winter sun in. On the east and west, shutters, louvres or vertical fins work better against the low-angled sun. Deciduous trees and pergolas covered in climbers also form a seasonal screen, giving shade in summer and letting the light back in during winter.
For natural ventilation, placing openings on opposite sides of the house allows air to flow through the rooms. A stairwell or a high window helps warm air escape from the top of the building. Windows opened on cool nights can draw off the heat stored in the building’s mass during the day. Daylight, for its part, reduces the need for artificial lighting while also shaping the character of a space. Room depth and the height and position of windows should be balanced so that light reaches deep inside without causing glare or overheating.
Water and materials: using resources with care
Using water carefully is one of the most tangible steps towards a sustainable home. Rainwater collected from the roof can be stored in a tank and used to water the garden and, with suitable treatment, for some indoor uses. Choosing plants suited to the local climate that need little water, and letting rain soak into the ground through permeable paving, matter just as much. In some places there may be a requirement to collect rainwater for certain types of building, so this should be confirmed with the local municipality.
When choosing materials, the first questions are simple: is it produced nearby, will it last, is it easy to maintain? Local materials reduce the burden of transport, are often better suited to the regional climate and help keep local craftsmanship alive. Durable materials that are easy to repair consume fewer resources over the life of the building, as they do not need frequent replacement. Materials that improve with use and do not hide their surface behind a cladding also fit with the idea of honesty in materials.
This is where the concept of embodied carbon becomes important. Embodied carbon refers to the greenhouse gas emissions released across the processes a material goes through, from extracting its raw materials and manufacturing it to transporting it, installing it in the building and removing it at the end of its life. As a building’s energy use in operation falls, the significance of this share grows. Repairing and reusing an existing building instead of demolishing it, avoiding using more material than needed and designing joints that can be taken apart and reused are among the ways of reducing this burden.
Why is renewable energy the last layer?
Once the need for energy has been reduced through passive design and a good envelope, renewable systems come in to cover what remains. Solar photovoltaic panels on the roof or another suitable surface generate electricity, while solar thermal collectors can be used to heat domestic hot water. The output of these systems depends on orientation, tilt, shading and local solar conditions. That is why we treat the placement of panels not as equipment added afterwards but as part of the design of the roof and the overall mass.
Heat pumps provide heating and cooling by drawing heat from the air, the ground or water. They work more efficiently in a well-insulated house that can be heated at low temperatures, for instance with underfloor heating. In a house with high energy demand, both the size of the system and its running costs grow. In other words, renewable energy does not replace good design; it completes it. Systems should be chosen together with mechanical and electrical engineers according to the real needs of the house.
Green building certifications and the Energy Performance Certificate
Green building certifications are voluntary systems that assess a building’s sustainability performance against defined criteria. The best known are LEED, BREEAM and WELL. Each has a slightly different focus, and they tend to be used more on large-scale or commercial projects. In Turkey there is also an official document for buildings, the Energy Performance Certificate (Enerji Kimlik Belgesi). It shows a building’s energy demand and the related greenhouse gas emissions on a graded scale, and it is required for new buildings as part of the occupancy permit (yapı kullanma izin belgesi) process.
Aiming for certification is not necessary for every home; what matters is asking the questions these systems ask from the very beginning of the design. As regulations and certificate requirements can change over time, the current position should be confirmed with the relevant authorities. If you are planning a new home, a good next step is to observe and note the sun’s path across your plot and the prevailing wind on a few different occasions. If you want to improve an existing house, gather your energy bills and any Energy Performance Certificate; a first assessment with an architect will be far more productive with this information to hand.
- LEED: assesses a building’s environmental performance under headings such as energy and water use, materials and resources, indoor environmental quality, and site and transport.
- BREEAM: looks at a building’s environmental impact across a broad range including energy, water, materials, health and wellbeing, ecology and management, at different stages from design to use.
- WELL: shifts the focus from the building to people, measuring how air, water, light, thermal comfort and sound affect occupants’ health.
- Energy Performance Certificate: rates a building’s energy performance on a lettered scale; besides the occupancy permit, it may also be requested in transactions such as a sale or rental.
Frequently Asked Questions
Does a sustainable house cost more to build?
There is no single answer; cost depends on the scale of the project, the systems chosen and the level of performance targeted. Passive design decisions such as orientation, compact form and careful window placement often add no separate line to the budget when made early. Better insulation or renewable systems, on the other hand, can raise the initial cost, which is why decisions should be weighed together over the whole life of the building.
Can an existing house be made more energy efficient?
Yes. In most homes, the right place to start is understanding where heat is escaping. Insulating the roof and external walls, replacing windows, sealing air leaks and adding shading to the west and south facades are common steps. Renewing the heating system or switching to a heat pump becomes more worthwhile once the envelope has been improved.
Does a heat pump work efficiently in every home?
A heat pump’s efficiency depends on the insulation of the house, the climate, the operating temperature of the heating system and whether the unit is correctly sized. It generally works more efficiently in well-insulated homes that can be heated at low temperatures. In a house with high energy demand and a weak envelope, it may not deliver the expected results. The decision should therefore be made with an engineer once the real needs of the house have been calculated.
Is green building certification compulsory?
Certifications such as LEED, BREEAM and WELL are voluntary and are not required for a home. The Energy Performance Certificate is different: it is an official document required for new buildings during the occupancy permit process, and it may also be needed in other transactions. As the requirements around it can change over time, we recommend checking the current position with the relevant authorities.
