What is Retrofitting and Why is it Key to Climate Action?
It is no secret: regulating the temperatures of buildings contributes more to global energy consumption than any other human activity.
According to the IEA, heating buildings now accounts for an eye-watering 40% of energy use worldwide.
On the other side of the spectrum, the UNEP has found that cooling buildings now draws 20% of the planet’s energy resources.
Put simply, our built environment is far too inefficient when it comes to both conserving and staving off heat.
This is an issue that will only grow as the effects of climate change worsen and temperatures fluctuate more extremely.
So, what can be done to address this crisis? Renewable energy seems like the obvious solution. It isn’t, however, the cheapest, easiest or most sustainable solution.
‘Retrofitting’ offers a way forward that doesn’t require huge demolition or construction projects, or an overhaul in global energy systems.
But what is it? In the simplest terms, retrofitting means upgrading existing buildings to improve their energy performance.
It is a process that typically involves enhancing insulation, replacing outdated heating systems, installing double or triple glazing and sealing any gaps that allow warmth to escape.
Retrofitting can also help to keep buildings cool in the warmer months by improving air flow, shading (using shutters or high quality blinds) or adding reflective exteriors.
These interventions reduce the amount of energy needed to maintain comfortable indoor temperatures, cutting both carbon emissions and operational costs.
Why retrofitting matters
The case for retrofitting rests on a stark reality: most of the buildings that will exist in 2050 have already been built.
Architecture from the 20th century prioritised aesthetics and space over thermal performance, resulting in structures that leak heat through single-pane windows, uninsulated walls and poorly sealed doorways.
Modern sustainability standards, on the other hand, demand far better from the built environment. Nevertheless, replacing every inefficient building would be economically and environmentally disastrous.
Retrofitting is the clear solution for bridging this gap.
Rather than expending more energy (or capital on expanding renewable energy capacity), retrofitting actually decreases the demand for energy by passively maintaining temperatures.
Cost, comfort and carbon
The main benefits of retrofitting are threefold: cost, comfort and carbon reduction.
Obviously each building is different, but it is thought that retrofitting can help reduce the energy bills of property owners by 30-50%.
The Empire State Building, for instance, managed to reduce its energy consumption by 38% after a retrofit.
Though these procedures can be expensive, retrofitting does deliver value over time.
The Quantum Group also suggests that ‘shallow’ retrofits deliver ROI in between two to six years. For more comprehensive, ‘deep’ retrofits, ROI could take 10 to 20 years.
The human impact is impressive too. Employees report improved comfort and productivity in buildings with stable temperatures and better air quality, according to research from scientific journal Energy and Buildings.
For nations committed to net zero targets, retrofitting represents the fastest route to significant carbon reductions without disrupting housing stock or commercial infrastructure.
What retrofitting actually costs
The construction work involved varies dramatically by building type and ambition.
A basic residential retrofit might cost between US$5,000 and US$15,000 and include loft insulation, draught-proofing and a new boiler.
Commercial buildings require deeper intervention, with costs running from US$50 to US$150 per square metre for comprehensive upgrades including façade improvements, HVAC system replacements and smart building controls.
At a city-wide level, retrofitting programmes can require billions in initial investment, though the long-term savings typically dwarf the upfront expense.
- HVAC stands for Heating, Ventilation and Air Conditioning. These all-in-one systems are composed of several vents placed around a building, regulating the temperature of buildings by circulating air. Modern HVACs can function automatically to improve efficiency.
Which companies are leading in energy efficiency?
Lots of organisations are demonstrating what ambitious retrofitting can achieve.
Siemens, a company known for its sustainable buildings, retrofitted its German headquarters in Munich recently, reducing energy consumption by 40% while still managing to preserve the building's historic character.
Across the pond, Microsoft's campus in Puget Sound underwent some extensive upgrades that managed to cut energy use by 30% across 125 buildings.
At a national level, the Netherlands has started to implement one of Europe's most comprehensive retrofitting schemes, targeting one million homes by 2030 with subsidised insulation and heat pump installations.
Elsewhere, Sweden's ‘Million Programme’, which is retrofitting large-scale housing estates built in the 1960s and 1970s, has seen energy reductions of up to 50% while simultaneously improving living conditions for residents.
At the end of the day, the transition to a low-carbon economy cannot succeed without addressing the buildings we already have.
Retrofitting transforms these energy-hungry structures into efficient, comfortable spaces that serve both present needs and future climate goals.
The technology exists, the business case is proven, and the environmental imperative grows stronger each year. All that remains is turning words into action.