How garden plants can cool your home in summer: practical and scientific guide

As heatwaves intensify in Europe, an international team has discovered that strategically placing certain plants around a residence can reduce indoor temperatures by several degrees, providing immediate relief without air conditioning. This low-cost approach could become a key resilience tool for urban areas facing heatwaves.

What the study reveals: precise results and key figures

Researchers found that dense hedges placed on the southwest side of a house, combined with evergreen shrubs on the west side, create protective shade that reduces direct solar gain by 15 to 30%, depending on orientation. This translates to a decrease in indoor temperature of 1 to 3°C during heat peaks, according to measurements taken on test houses in France and Spain. The effect is more pronounced in areas where the heat index exceeds 40°C, where each degree counts for public health.

Furthermore, the study indicates that the impact is maintained throughout the duration of the heatwave, with a prediction uncertainty limited to ±0.5°C thanks to the use of predictive models based on neural networks. The authors emphasize that the energy savings are comparable to a 10% reduction in air conditioning consumption, representing significant savings for households.

How: research method and data used

To quantify these effects, scientists coupled Copernicus satellite data with local weather station records, then trained a predictive model of the GraphCast and Pangu-Weather type. This neural network absorbed atmospheric variables - temperature, humidity, solar radiation - as well as plant characteristics (height, density, leaf type). Simulations were validated by the ECMWF model, ensuring consistency with official forecasts.

Field experiments involved over 200 homes, with sensors placed inside and outside. Atmospheric data was collected in real-time and integrated into the machine learning process to reduce prediction uncertainty. This hybrid approach, combining AI and field observations, allowed for isolating the effect of vegetation from other climatic factors.

What it changes: implications for science or the public

For city dwellers, the result opens the door to simple and economical attenuation strategies: choosing species with high evapotranspiration capacity, such as laurel or boxwood, and placing them according to solar orientation principles. Municipalities can also integrate these recommendations into urban plans, favoring green corridors that mitigate the heat island effect.