Architecture and climate change: how to build today

Buildings are both part of the problem and part of the solution. Heating, cooling and lighting our homes and offices consumes a vast amount of energy, and producing cement, steel and other materials leaves a footprint of its own. At the same time, buildings are what must protect us from heatwaves, storms and floods.

In Bulgaria the change is tangible: ever longer hot spells, nights when flats simply fail to cool down, sudden torrential downpours. Architecture can no longer design out of habit – it has to think about the climate the building will live in over the coming decades.

What does climate-responsible architecture mean?

Climate-responsible architecture creates buildings that use little energy, rely on materials with a lower footprint and stay comfortable in more extreme weather. It has two sides that go hand in hand:

• Mitigation – less energy and fewer emissions: insulation, efficient systems, renewable energy and a sensible choice of materials.
• Adaptation – resilience to change: protection from overheating, torrential rain and power cuts, plus more shade and greenery.

What are the core principles of sustainable design?

The most effective measures are passive: they are settled in the design, need no equipment and work for decades at no running cost.

Orientation and form

A compact building with its main rooms and windows facing south loses less heat and gains winter sun. Long west-facing façades with a lot of glass are the hardest to keep cool.

Insulation and airtightness

Continuous insulation without thermal bridges, together with good windows, keeps the warmth in during winter and the coolness in during summer. It is the foundation on which everything else depends.

Shading

Eaves, canopies, external blinds, pergolas and trees stop the sun before it gets inside. External shading is one of the cheapest and most effective defences against overheating.

Natural ventilation and thermal mass

Windows on opposite façades and openings at different heights allow night-time cooling. Solid walls and floors store the cool night air and release it during the day.

Green and blue

Green roofs and gardens reduce heating of the surroundings, while holding back rainwater – in tanks, rain gardens or permeable paving – eases the load on the sewers during downpours.

Which buildings around the world set an example in sustainable architecture?

Several well-known buildings show different sides of climate-responsible design:

• Bullitt Center, Seattle – an office building designed to generate its own energy from the sun and to use rainwater, including composting toilets.
• The Edge, Amsterdam – an office building famous for its intelligent, sensor-driven control of lighting, heating and use of space.
• Bosco Verticale, Milan – Stefano Boeri's residential towers with trees and shrubs on the terraces, bringing shade and greenery to the city centre.
• One Central Park, Sydney – Jean Nouvel's complex with vertical gardens by Patrick Blanc and a cantilever fitted with mirrors that directs sunlight onto the garden below.
• Masdar City, Abu Dhabi – an ambitious experiment in a sustainable city in a desert climate, drawing on traditional principles such as narrow, shaded streets.

What are the pros and cons of sustainable construction?

A sustainable building sometimes costs more at the outset, but it is cheaper to live in and better prepared for future change.

• Pros: lower energy bills, better comfort in summer and winter, healthier indoor air, higher property value in the long run and less dependence on energy prices.
• Cons: a higher initial investment for some solutions, the need for careful design and quality workmanship, and fewer tradespeople experienced in certain technologies.

The good news is that the most important decisions – orientation, form, shading – cost almost nothing if they are made early enough.

It is also worth thinking about the whole life of the building. Materials that last longer, are easy to repair and can be reused cut the footprint far more than any single “green” technology. Often the most sustainable building is the one that already exists and is simply renovated wisely.

How to make your home sustainable, step by step

First reduce the losses, then improve the systems, and only at the end add energy generation.

1. Assess the building. An energy audit, thermal imaging, and a check of where heat escapes and where the building overheats.
2. Insulation and windows. Façade, roof, floors above unheated spaces, and properly installed windows.
3. Shading. External blinds or canopies on the south and west façades.
4. Ventilation. Natural night-time ventilation and, in very airtight buildings, mechanical ventilation with heat recovery.
5. Efficient heating and cooling. For example, a heat pump sized for the already reduced losses.
6. Renewable energy. Solar panels on the roof once consumption has been brought down.
7. Garden and water. Trees for shade, permeable paving and rainwater harvesting for irrigation.

What does this mean for buildings in Bulgaria?

In the Bulgarian context the biggest challenge is the existing building stock – the blocks of flats and houses built without modern insulation. Retrofitting them for energy efficiency delivers the fastest results. In new construction, protection from summer overheating is becoming ever more important: many new buildings are designed with huge areas of glazing and no external shading, and become difficult to cool. Summer deserves as much thought as winter.

Rain matters just as much. Torrential downpours strain roofs, gutters and sewers, and fully concreted yards cannot absorb the water. Correct falls, adequately sized gutters and downpipes, permeable paving and planted areas around the house are simple measures that protect both the building and the neighbours.

What to ask your architect

• How is the building oriented towards the sun, and why?
• How will the south- and west-facing windows be shaded in summer?
• Can the house be ventilated naturally at night?
• What insulation and windows are specified, and how are thermal bridges avoided?
• Where will the rainwater from the roof and the yard go?
• Is there room for solar panels and a heat pump now or in the future?

The answers to these questions reveal more about the quality of a design than a beautiful rendering of the façade.

Our approach at DARCH Projects

In our architecture studio, orientation, shading, insulation and natural ventilation are resolved in the very first sketch rather than added at the end. We prepare designs for the energy retrofit of existing buildings and architectural designs for new ones, tailored to the climate of each specific site.

Frequently asked questions

How does climate change affect architecture?

Climate change requires buildings to use less energy while also being ready for hotter summers, heavier rainfall and more frequent extreme weather. Architects are therefore paying ever more attention to insulation, shading, natural ventilation, greenery and the drainage of rainwater. Protection from summer overheating is becoming as important as heating in winter.

What is the most effective measure for an energy-efficient house?

The most effective measure is good, continuous insulation combined with quality windows that are properly installed, because it reduces losses in both winter and summer. Close behind come the orientation and form of the house and external shading, which are settled in the design and cost almost nothing extra. Equipment such as heat pumps and solar panels works best only after these measures.

How can I protect a house from overheating in summer?

External shading matters most – eaves and canopies on the south side, external blinds on the west, trees and planted pergolas. Good roof insulation helps, as do light-coloured roof surfaces or a green roof, and night-time ventilation through windows on opposite façades. Solid walls and floors store the cool night air and release it during the day.

Is an energy retrofit of an old block of flats worth it?

In most cases, yes. Insulating the façade and roof and replacing the windows reduce heating costs and improve comfort in both winter and summer. A retrofit extends the life of the building and usually raises the value of the flats in it. It needs a proper design that takes account of the condition of the structure, damp and the details around windows and balconies.