Impact on indoor spaces

Many houses in the Netherlands have been built to let in as much sun as possible; cf. the post-war through lounges. However, due to the increasing heat, such sunny houses are no longer ideal and even problematic: in summer, such houses can overheat. Hence, it is hardly surprising that since 2016, more than half a million additional A/C units have been sold. As heat is a fairly recent point for attention in the housing sector, heat-proof houses are still few and far between in the Netherlands. The paragraphs below outline the measures that have been initiated to remedy this.

New construction and the energy transition

The energy transition has induced the housing sector to focus extensive attention on insulation. Proper home insulation reduces the need for turning on the heat on cold days and thus saves energy. Since 1 January 2021, applications for environmental permits for new housing developments must meet the requirements for Nearly Zero Energy Buildings (NZEB). However, on hot days, excessive insulation may retain heat inside the home. Fortunately, several initiatives have already been set up to prevent newly built houses from overheating:

• The temperature exceedance indicator TO_juli: for each building orientation, this value indicates the risk of temperature exceedance within the building.
• The Climate Adaptation Standards Consultative Body (OSKA) aims to ensure that standards for building design take account of warmer summers and the growing need for cooling.
• Klimaatverbond Nederland has set up a platform, together with Amsterdam UAS and Foundation W/E Consultants, to garner more support for and foster decisiveness in the visualisation and agendising of the increasing demand for cooling in houses.
• Deltares and TNO research institutes have drawn up a Knowledge agenda for future cooling demand in houses (pdf, 3.4 MB). This maps out the know-how and actions needed to gain insight into the increasing demand for cooling in houses and into the increasing energy requirements to provide cooling.

Provincial-level agreements

Some provinces have already set down agreements for climate adaptive and, therefore, heatproof housing developments:

• The province of Zuid-Holland is pursuing a climate-adaptive design for all the new houses being built. This intent has been set down in the Climate-adaptive Construction Covenant.
• Under the Climate Adaptation Programme 2020-2023, the province of Utrecht is working on climate adaptation agreements for the built environment.

Information for housing corporations

A survey among housing corporations has shown that housing corporations are increasingly aware of heat issues, yet still require substantially more expertise on this topic. Heat in houses is a new problem. This also became apparent during the housing corporations heat excursion in Nijmegen on 8 July 2020, which had been organised by the Groene Huisvesters association and the Climate-proof Together platform. Are you – as a housing corporation – interested in finding out more on heat issues? The following information may be helpful:

• Brochure on Corporations and climate adaptation, heat stress issues. This brochure deals with heat measures to be implemented by housing corporations: why is tackling heat important, what can you do, and how should you go about it? Groene Huisvesters has compiled the brochure by commission of the Ministry of the Interior and Kingdom Relations and the Climate-proof Together platform.
• Results of heat perception study among tenants conducted by TAUW. The study provides insight into how tenants perceive heat and into the solutions they have implemented.

Based on the knowledge available, Groene Huisvesters, Klimaatverbond Nederland, TAUW, and WBO-Wonen are working on a heat protocol for housing corporations.