Architect Sönke Hoof’s tips on building summer-friendly homes

BH: What methods and techniques do you use that help keep a home naturally cooler than the outside temperature?

SH: The two most crucial things are providing ample shade and ventilation. A simple shading element can give immediate relief from the sun while shade combined with a breeze (ventilation) increases the comfort even further. Compare this to sitting in direct sunlight or sitting under a tree or an umbrella. It is quite obvious where you will be more comfortable. So, the building should provide protection from the glare of the sun while allowing enough natural ventilation to prevent build-up of heat. We like to play with skylights and use them to let indirect light bounce deep into the spaces without heating them up.

Another important factor is the walls. What is their thickness, what is their material? Do they easily transfer heat from outside? Thin walls heat up fast and might easily transfer this inside. Thick walls, on the other hand, allow for deep, recessed windows which are therefore shaded. In several of our projects, we have used subterranean spaces as summer refuge living spaces.

We also like to use flexible external shading elements such as shutters or louvres which the user can place as required. In several of our buildings, the entire outer facade is made of these elements. In a home called Sinha Slats, we have large sliding shutters with wooden slats. The owners can choose to have it entirely open or closed, just as they like or require. Here, it is not defined whether the building is inside or outside. It can be both. Another project is Black Perch where the entire facade is covered with charred black wooden louvres. Again, the owners can choose how much to open up or close off.

BH: What are some of the materials that help bring the intense summer heat down?

SH: Wood doesn’t store heat and is a poor radiator. Shaded stone can also be useful. But badly placed, dark stone, on the other hand, can heat up during the day and then keep radiating throughout the evening even after ambient temperatures have already dropped. The same is true for exposed concrete which is a terrible radiator.

BH: For homes that are already built, what passive cooling methods would you suggest that are easy to implement?

SH: If the external facade can’t be altered, the last resort is using internal blinds and curtains. There are options available that have a reflective back which at least reflect a part of the heat back outside. Using specific types of internal paint can also help improve the climate inside during hot summer months. Some of these are:

Reflective Paint: Choosing paints with reflective properties can help bounce sunlight away from the interiors of the house, reducing heat absorption and keeping the indoor temperature cooler.

Insulating Paint: Some paints contain insulating properties that help regulate indoor temperature by reducing heat transfer through walls. This can keep the interiors cooler during the hot weather.

By using these types of internal paint, you can contribute to a more comfortable indoor environment during hot summer months while potentially reducing the need for excessive air conditioning, thus saving energy and reducing utility costs.

BH: Are there any lessons from BV Doshi that you keep in mind when designing your projects?

SH: From Doshi, I learnt that there is no clear distinction between the inside and outside as everything is fluid. He also taught me the flexibility of layering elements and spaces.

All images by Karan Gajjar