CCN examines the ambitious global targets set out by the International Energy Agency (IEA) to reach net zero by 2050.
Renovating the existing building stock to a zero-carbon-ready level is a key priority to achieve decarbonisation targets.
However, the retrofitting of buildings is a significant challenge since at least 40 per cent of buildings floor area in developed economies was built before 1980, when the first thermal regulations came into force.
Retrofitting 20 per cent of the existing building stock to a zero-carbon-ready level by 2030 is a necessary milestone to achieve a 2050 roadmap. To achieve this goal, an annual deep renovation rate of over two per cent is needed from now to 2030 and beyond.
For this to happen swiftly and effectively, a strong political will is required, and policy, legal, regulatory, and administrative support frameworks need to be developed.
Older, existing buildings are on average inefficient compared to newer buildings.
While appliances can be replaced with ones that have greater energy efficiency due to their shorter lifespans, the building envelope (walls, roof, and windows), as well as technical and mechanical equipment systems, are rarely upgraded since they are high-cost and done on an as-needed basis.
These components also have a longer shelf life at 40-plus years for building envelopes and 15-plus years for technical systems.
Nonetheless, these are the building elements whose performance improvement can bring the most significant benefits in reducing CO2 emissions, especially in regions with very cold or hot climates.
Improving the performance of older buildings that have not integrated energy efficiency requirements since their construction is a critical priority.
As a first step, it is necessary to implement passive measures to the building envelope to enhance its thermal performance to at least the minimum levels defined by the building energy codes to reduce the energy service demand for heating and cooling.
High-efficiency HVAC and Domestic Hot Water (DHW) equipment would complement the building renovation, further reducing the energy use that renewable or other clean energy sources would ultimately supply.
Retrofitting rates for existing buildings are currently around one per cent, with most of these shallow renovations. However, awareness of the importance of deep building renovation is rising quickly.
Efforts to support these changes are starting to emerge, from policy programmes and building regulations to fiscal incentives and training. Retrofitting residential buildings by decarbonising heating and cooling systems should be a priority.
One of the most significant factors influencing the decision-making process is the initial investment required, which can be very high and often with long payback periods.
The availability of easy-to-use and reliable tools for building designers to increase energy efficiency is still limited.
Another challenge is the scarce availability of transparent and easy-to-access building performance data, which is indispensable for cultivating the market for renovations and providing a higher level of energy efficiency planning.
The fact that buildings are unique to one another is a common issue for renovation challenges, including the acceleration of retrofitting rates for existing buildings.
Shifting the scale of renovation from individual buildings to a building cluster or district level can enable energy retrofitting at a quicker pace and reduce overall cost.
Top five 2030 targets
Renovation of near 20 per cent of existing building stock to be zero carbon-ready by 2030.
Installation of about 600 million heat pumps covering 20 per cent of buildings heating needs
Solar PV and wind supply to account for 40 per cent of building electricity use by 2030.
Solar thermal technologies deployed in around 400 million dwellings.
100 per cent LED lighting by 2025.
NB: This report provided by the International Energy Agency (IEA) was created as part of the Technology Collaboration Programme. (TCP). These collaborations involve over 6 000 experts worldwide who represent nearly 300 public and private organisations located in 55 countries.