The Complete Guide to Sustainable Office Space in the UK

The way we think about offices is changing. Rising energy costs, tightening regulations, and growing pressure from employees and investors mean sustainability is not optional anymore. It is a core business decision.

But what actually makes an office "sustainable"? And how do you find one, or turn your existing space into one?

This guide covers everything UK businesses need to know about sustainable office space: what it means, why it matters, what to look for, and where the market is heading.

What Is a Sustainable Office Space?

A sustainable office is a workspace designed and operated to minimise its environmental impact while supporting the health and productivity of the people inside it.

That sounds broad, because it is. Sustainability in offices touches everything from how a building uses energy to the materials in the furniture, the air quality in meeting rooms, and even how employees get to work.

The UK Green Building Council (UKGBC) breaks it down through its Net Zero Carbon Buildings Framework, which sets a clear principle: reduce first. Buildings should be highly energy efficient, with all energy sourced from renewables. Offsets are only acceptable during the transition period.

In practical terms, a sustainable office in the UK typically addresses five areas:

• Energy: efficient lighting, heating, cooling, and ventilation systems, ideally powered by renewables. The UKGBC target for offices is 70 kWh/m2 per year for base build and 45 kWh/m2 for tenant fit-out.
• Materials: low-carbon construction and fit-out materials, responsible sourcing, and circular economy principles. UK offices currently send around 300 tonnes of furniture to landfill every working day.
• Waste: recycling infrastructure, reduced single-use items, and strategies to keep materials in use longer.
• Wellbeing: good indoor air quality, natural light, thermal comfort, and biophilic design elements like plants and natural materials.
• Transport: cycling facilities, EV charging, proximity to public transport, and support for active commuting.

The British Council for Offices (BCO) raised the bar in its 2023 Guide to Specification update. New offices should now target a minimum BREEAM rating of Excellent (up from Very Good), a 5-star NABERS UK energy rating, and net zero operational energy. The guide also introduced embodied carbon targets of 350 to 600 kgCO2/m2.

And here is something worth noting: the BCO makes the point that the most sustainable office is often the one already standing. From an embodied carbon perspective, refurbishing an existing building almost always beats knocking it down and starting again.

How the BCO defines "sustainability gentrification"

There is also a geographic divide. According to the BCO, the Big Six UK cities (London, Manchester, Birmingham, Bristol, Edinburgh, and Glasgow) average 19 highly sustainable office buildings each. Smaller cities? Just three. The BCO calls this "sustainability gentrification", and it means businesses outside major cities face a tougher time finding green workspace.

Why Sustainability Matters for UK Businesses

The regulatory picture

The UK was the first major economy to pass a net zero emissions law, committing to a 100% reduction from 1990 levels by 2050. Buildings account for roughly 23% of all UK emissions, so the commercial property sector is squarely in the government's sights.

The Climate Change Committee has set the pace: commercial building emissions must fall by 87% by 2040 compared to 2023 levels. That is an aggressive target, and regulations are moving to match it.

The most immediate regulation affecting offices is MEES (Minimum Energy Efficiency Standards). Since April 2023, all commercial properties in England and Wales need a minimum EPC rating of E to be legally let. The government has consulted on tightening this to EPC B by 2030, though the formal response has not been published yet. CBRE's analysis suggests the deadline will land somewhere between 2030 and 2035.

The scale of the challenge is significant. Around 85% of existing non-domestic buildings would need improvements to meet EPC B. In Central London alone, 58% of office stock falls below that threshold. The national retrofitting bill is estimated at around 30 billion pounds.

Penalties for non-compliance are not trivial either, up to 150,000 pounds per property, plus public listing on the enforcement register. And you simply cannot legally lease a non-compliant building.

Other regulations adding pressure include:

• SECR (Streamlined Energy and Carbon Reporting): mandatory for around 11,900 UK companies, requiring disclosure of energy use and greenhouse gas emissions in annual accounts.
• Biodiversity Net Gain: since February 2024, major developments must deliver a minimum 10% increase in biodiversity value under the Environment Act 2021.
• The Energy Act 2023: the largest energy legislation in UK history (Royal Assent October 2023), giving government powers to reform EPC regulations and introduce new building performance standards.
• UK Sustainability Reporting Standards: based on IFRS S1/S2, expected to become mandatory from the 2026 financial year.

What investors and lenders expect

ESG is not just a nice-to-have in commercial property anymore. According to Knight Frank's 2025 ESG Property Investor Survey (covering around 300 billion pounds in assets under management), 69% of investors cite internal net-zero goals as a key driver, and 62% are actively seeking poor-ESG assets to improve.

Even more telling: 71% of lenders surveyed by CBRE said they would not finance assets that do not meet sustainability criteria. As CBRE put it in their 2025 outlook, "Sustainability objectives will become increasingly important to securing debt."

JLL's research paints a similarly stark picture. Their "Green Tipping Point" report warns that inaction over decarbonising real estate will lead to economic obsolescence sooner than most investors realise. Green-certified buildings already command sales premiums of up to 18% in London.

What employees expect

Younger workers care about this. A lot. Deloitte's 2025 Global Survey (23,400+ respondents) found that 70% of Gen Z and millennials consider a company's environmental credentials important when choosing an employer. About 15% of Gen Z workers have already changed jobs due to environmental concerns.

In the UK specifically, a Compass Group survey found 66% of workers believe their employer has a responsibility to promote workplace sustainability, peaking at 73% among millennials. And a Co-operatives UK study showed 60% of UK respondents actively seek sustainable buildings (versus 44% globally).

With Gen Z and millennials set to make up 74% of the global workforce by 2030, these preferences will only become more influential.

Key Features of Sustainable Offices

So what does a sustainable office actually look like in practice? Here are the features that matter most.

Energy-efficient systems

This is where the biggest gains are. HVAC (heating, ventilation, and air conditioning) alone accounts for 40 to 60% of total commercial building energy, so upgrades here have an outsized impact.

Key systems include:

• LED lighting: uses up to 75% less energy than traditional fluorescent lighting. A medium-sized office can save 3,000 to 4,500 pounds annually. Payback is typically under two years.
• Smart HVAC: AI-driven controls, CO2-responsive ventilation, and heat pump systems. Optimisation can cut heating and cooling costs by 30 to 50%.
• Building Management Systems (BMS): centralised platforms that monitor and control energy use in real time. Smart buildings typically save 15 to 30% on energy. London's 22 Bishopsgate collects over 1 million data points daily through its BMS.
• On-site renewables: solar panels can reduce electricity costs by 30 to 40%, with a typical payback period of 4 to 6 years for commercial systems.

Overall, UK businesses can cut energy costs by 20 to 40% through efficiency measures, with a typical payback of 2 to 3 years.

For a deeper look at these technologies, see our energy-efficient office buildings guide.

Sustainable materials and circular design

The materials used in construction and fit-out carry significant embodied carbon. BREEAM V7 (launched July 2025) now requires mandatory life cycle assessments for buildings targeting Excellent or Outstanding ratings.

Circular design strategies, like reusing materials, choosing recycled content, and planning for disassembly, can cut material waste by up to 70%.

If you are planning a renovation, our sustainable office fit-out guide covers the practical steps.

Indoor air quality and wellbeing

This is where sustainability and wellbeing overlap directly. Harvard's landmark COGfx studies found that cognitive function scores were 61% higher in green building environments compared to conventional offices, and 101% higher in enhanced green buildings with better ventilation. Workers in green-certified buildings also reported 30% fewer sick building symptoms and 6% higher sleep quality scores.

Features that make the difference:

• Ventilation rates above minimum code requirements
• Low-VOC paints and materials that do not off-gas harmful chemicals
• Living walls and indoor planting, associated with 14% improvement in short-term memory
• Natural light, with employees near sunlit windows showing 15% higher productivity rates (World Green Building Council)

Water conservation

UK commercial buildings can meet up to 75% of their water demand through rainwater harvesting and greywater recycling. Bloomberg's London HQ, for example, achieves a 73% reduction in water use through rainwater harvesting, greywater recycling, and water-efficient fixtures.

Waste management

The average office worker generates about 2kg of waste daily, and roughly 70% of it is recyclable. From 31 March 2025, UK businesses with 10 or more employees must separate core waste streams (paper, plastic, glass, metal, and food waste) under the new Simpler Recycling regulations. Good waste infrastructure is not just good practice; it is a legal requirement.

Green transport infrastructure

• EV charging: new commercial buildings with 10 or more parking spaces must provide one charging point per five spaces. The Workplace Charging Scheme covers up to 75% of installation costs, capped at 350 pounds per socket, for up to 40 sockets.
• Cycling facilities: despite BCO recommendations, 45% of UK offices still lack showers, even though 24% of workers say having them would encourage cycling.

Our cycle to work and green commuting guide covers the full picture on sustainable transport.

Smart building technology

The UK smart building market is projected to grow at 26.6% CAGR from 2024 to 2030. Already, 76% of top landlords are integrating building technology, and 70% of UK commercial buildings are expected to be data-driven by the end of 2025.

Benefits of Sustainable Office Space

Lower operating costs

The financial case is strong. Here is what the numbers look like:

These are not theoretical figures. 103 Colmore Row in Birmingham, connected to a district energy system with no fossil-fuelled boilers, runs service charges 12% below the city average. Nova in Oxford generates 44,000 pounds in annual savings from solar panels alone. And building a BREEAM Excellent office costs only 0.4 to 1.8% more than a standard building, while commanding 4.7 to 15% higher rents.

Higher productivity and better wellbeing

This is perhaps the most undervalued benefit. Staff costs (salaries, benefits, etc.) account for roughly 90% of a building's total operating costs. Even a small improvement in productivity dwarfs energy savings.

The research backs this up:

• Harvard COGfx studies: workers in green-certified buildings scored 26.4% higher on cognitive function tests, with 30% fewer sick building symptoms.
• World Green Building Council: better ventilation alone produces productivity benefits that exceed the additional energy costs by over 150 times.
• Medibank (Australian case study): after moving to a sustainable office, 80% of staff reported working more collaboratively, absenteeism dropped 5%, and two-thirds reported feeling healthier.
• Saint-Gobain: saw a 97% increase in sales-generated leads and 101% increase in leads per call after moving to a sustainable HQ.

Given that a 1% productivity improvement has a major bottom-line impact when 90% of building costs are people, the wellbeing case is arguably stronger than the energy case.

For a detailed look at this connection, see our guide on workplace wellbeing and sustainable offices.

Easier talent attraction and retention

70% of workers are drawn to environmentally sustainable employers, and nearly half would accept a lower salary to work for one. In the UK, average employee turnover runs at about 35% (CIPD). Organisations prioritising wellbeing have seen turnover drop by up to 27%.

Over half (52%) of HR professionals rank talent attraction as the top benefit of ESG reporting. That makes sense when you consider the cost of replacing an employee is typically 50 to 200% of their annual salary.

Higher property values and rental premiums

Green-certified buildings consistently command premium pricing in the UK market:

The gap is widening too. JLL estimates 65% of UK office stock is at risk of stranding by 2030 if it does not meet modern ESG standards. In Central London, top sustainable stock has roughly 1% vacancy, while the lowest-quality stock sits at around 12.6%.

Only about 27% of Central London stock even has a BREEAM rating. That means most of the market still has work to do.

Stronger brand and ESG credentials

The UK was the first G20 country to mandate TCFD-aligned climate reporting in 2022. Over 7,600 companies globally have signed the Science Based Targets initiative, with 80% joining in just the past two years. And 89% of institutional investors now incorporate ESG data into their decision-making.

With UK Sustainability Reporting Standards expected to become mandatory, having a genuinely sustainable office provides concrete data for your ESG disclosures.

Green Building Certifications: A Quick Overview

Certifications give you a credible, third-party-verified way to measure and communicate your office's sustainability performance. Here are the main ones used in the UK.

BREEAM is the world's leading sustainability assessment method, developed in the UK by BRE in 1990. Over 300,000 UK buildings are certified. It assesses nine categories including energy, materials, health and wellbeing, and waste. Ratings run from Pass to Outstanding (fewer than 1% of buildings achieve Outstanding). Bloomberg's European HQ scored 98.5%. Nova in Oxford became the first building to achieve a perfect 100% in August 2024. BREEAM holds around 80% of the European market for sustainability assessments. The latest version, BREEAM V7 (July 2025), includes mandatory whole life carbon assessments.

LEED is the global standard developed by the US Green Building Council in 1998. It has a growing presence in London's premium market, with 71% of UK projects valued at 50 million pounds or more referencing LEED. LEED v5 launched in April 2025 with decarbonisation now accounting for 50% of all points.

WELL Building Standard is the first certification focused entirely on occupant health and wellbeing. Developed by IWBI in 2014, it covers 10 concepts: Air, Water, Nourishment, Light, Movement, Thermal Comfort, Sound, Materials, Mind, and Community. UK adoption has grown rapidly. Cundall at One Carter Lane became the first UK WELL Gold building in 2016, and reported a 19% drop in absenteeism. WELL formally complements BREEAM, with a crosswalk document published in 2017.

SKA Rating is the only environmental assessment designed specifically for non-domestic fit-outs. It covers 104 Good Practice Measures across 8 areas and is the lowest-cost certification option (around 900 pounds total). This is particularly useful for tenants who do not control the whole building.

NABERS UK measures actual operational energy performance, not design-stage predictions. This matters enormously, because Innovate UK found that non-domestic buildings use on average 3.8 times more energy than predicted at design stage, with "almost no correlation" between EPC rating and actual performance. The City of London plans to require minimum 5-star NABERS for all major office developments.

EPC Ratings are legally required for all UK commercial properties when built, sold, or let. The A to G scale is currently subject to MEES minimum of EPC E, with proposed tightening to EPC B by 2030. Around 73% of offices in England and Wales fall below EPC C. Government EPC reform, including changes to the methodology, is expected in the second half of 2026.

Fitwel is a health-focused certification created by the US CDC. The UK is one of the top three countries globally for Fitwel certifications, with over 205 UK Ambassadors. A 2025 Cambridge University study found Fitwel-certified offices achieve a 4.6 to 4.8% rental premium.

For a detailed comparison of all these certifications, including costs, timelines, and which is right for your situation, see our green building certifications UK guide.

How to Find Sustainable Office Space

What to look for

Start with the basics: EPC rating of B or above (to future-proof against MEES changes), a BREEAM certification of at least Very Good, and ideally a NABERS UK rating showing actual energy performance.

Beyond certifications, look for:

• Actual operational energy data (kWh/m2/year), not just design predictions
• On-site renewable energy generation
• LED lighting and smart building management systems
• Green lease provisions: the Better Buildings Partnership defines these in three tiers: light green (non-binding MoU), medium green (creates obligations), and dark green (legally binding, where breach could result in forfeiture). Properties with green leases typically achieve 12 to 15% higher rental values, and tenants typically reduce energy costs by 20 to 30%.
• Cycling storage, showers, and EV charging
• Waste and recycling infrastructure
• Biodiversity measures such as green roofs, bird nesting sites, or habitat creation

Red flags

Watch out for:

• EPC rating of D or below
• No actual energy performance data available
• Landlord unable to provide utility or service charge history
• No sustainability certifications of any kind
• No clear net zero strategy or pathway

Questions to ask the landlord

1. What is the current EPC rating and when was it last assessed?
2. Can you share two years of actual utility and service charge data?
3. Does the building hold BREEAM, WELL, NABERS, or other certification?
4. What renewable energy sources are on-site?
5. Is a green lease available, and what does it include?
6. What is the building's net zero strategy or pathway?
7. How is energy data shared between landlord and tenants?
8. What waste management and recycling infrastructure is in place?
9. What EV charging and cycle storage provision exists?
10. What HVAC system is installed and when was it last upgraded?

Where to look: UK cities with strong sustainable office stock

London leads with nearly 3,000 green-rated buildings, first place worldwide for ESG adoption. In 2024, 73.6% of office take-up was Grade A space. Standout developments include Bloomberg's European HQ (BREEAM Outstanding 98.5%), The Forge at Bankside (the UK's first UKGBC net zero aligned commercial development), White Collar Factory (mass-timber construction), and Roots In The Sky with its 1.1-acre rooftop forest. London's "Retrofit-First" planning directive requires developers to explore all upgrade options before seeking demolition permission. But demand for low-carbon offices is projected to exceed supply by 35% by 2030.

Manchester is the UK's most competitive regional hub. The Eden at New Bailey, completed in January 2024, may be Britain's most sustainable office, with operational energy of just 41 kWh/m2 (beating UKGBC targets set for 2030 to 2035), a NABERS 5.5 Design Reviewed rating, Passivhaus principles, Europe's largest living wall at 36,000 sq ft, and a 174% increase in biodiversity. Manchester was also the first UK city to mandate BREEAM through its Core Strategy.

Birmingham is shaped by major infrastructure investment. One Centenary Way achieved BREEAM Excellent and EPC A with an all-electric, fully demountable superstructure that saved 6,000 tonnes of embodied CO2 using recycled British steel. 103 Colmore Row is connected to a district energy system with no fossil-fuelled boilers. And 10 Brindleyplace won the BCO National ESG Award in 2024 after a back-to-frame refurbishment achieving 65% reduction in energy demand.

Bristol punches above its weight. Aurora achieved BREEAM Outstanding and commands the top city rent of 37.50 pounds per sq ft. The Osborne Clarke HQ (Halo) is targeting WELL Platinum, with photovoltaic panels, greywater recycling, and a connection to Bristol's Heat Energy Network. Bristol also holds the highest Fitwel score globally.

Edinburgh and Glasgow offer growing sustainable stock, particularly in finance, energy, and legal sectors. Glasgow's 177 Bothwell Street features a recyclable glass and aluminium facade.

Flexible and coworking options

If you are not ready for a traditional lease, several sustainable coworking spaces offer genuine green credentials. x+y operates six UK locations as a certified B Corp with 100% renewable electricity. Sustainable Workspaces at County Hall London, run by Sustainable Ventures, serves climate startups using modular FSC-certified timber and sheep wool insulation. The UK flex workspace market now includes over 4,400 locations, with average occupancy at 80%.

Making Your Current Office More Sustainable

You do not need to move to become more sustainable. Most offices can make significant improvements through a phased approach.

Quick wins: 0 to 6 months

Get an energy audit. The average SME achieves 18 to 25% reduction in energy bills after an audit. A typical commercial audit leads to about 20% cost savings with a 1.8-year payback and 15% carbon reduction. Cost is roughly 1% of your annual energy spend. Providers include the Carbon Trust, Energy Saving Trust, and TEAM Energy.

Switch to LED lighting. For a 1,000m2 office, expect installation costs around 6,000 pounds, annual savings of roughly 4,200 pounds, and payback in about 17 months. LED bulbs last around 50,000 hours, five times longer than fluorescents, cutting maintenance costs by up to 70%. Enhanced Capital Allowances are available.

Set up proper recycling. From 31 March 2025, businesses with 10 or more employees must segregate paper, plastic, glass, metal, and food waste under the Simpler Recycling regulations.

Implement power-down policies. Smart plugs, automated shut-offs, and basic behaviour change programmes cost very little but reduce standby energy waste significantly.

Medium-term improvements: 6 to 18 months

Install smart building controls. Occupancy sensors, CO2-responsive ventilation, and real-time energy dashboards. UKGBC research shows building optimisation alone achieves an average 26% reduction in operational energy.

Upgrade HVAC. Consider air source heat pumps to replace gas boilers. The Boiler Upgrade Scheme offers grants of up to 7,500 pounds for eligible non-domestic properties. EC direct-drive motors can also significantly reduce energy demand.

Improve building fabric. Better insulation, improved glazing, and draught-proofing follow the "retrofit hierarchy":

1. Minimise demand through fabric improvements
2. Install efficient lighting and controls
3. Replace heating systems
4. Generate renewable energy on-site

Retrofitting is typically 40 to 60% cheaper in capital expenditure compared to rebuilding, and it preserves the embodied carbon already locked in the existing structure.

For a step-by-step approach, see our guide on how to reduce your office carbon footprint.

Long-term strategies: 1 to 5 years

Install solar panels. A 50kW system costs 40,000 to 60,000 pounds, saves roughly 12,750 pounds per year, and pays back in 3 to 6 years. A 100kW system saves around 25,500 pounds annually. Solar panel costs fell 4.5% between March 2024 and 2025, and panels last 25 to 40 years. The Smart Export Guarantee lets you earn 5 to 15p per kWh for surplus exported to the grid.

Consider a deep retrofit. The UKGBC identifies three levels: optimisation (26% energy reduction), light retrofit (targeted upgrades), and deep retrofit (comprehensive fabric plus heating plus renewables). Case studies show what is possible. The Entopia Building in Cambridge achieved an 84% whole-life carbon saving versus a standard retrofit, with world-first triple certification: EnerPHit, BREEAM Outstanding, and WELL Gold. A Grade II listed building in Manchester is targeting a 74% reduction in Energy Use Intensity.

Government incentives available

Several financial support mechanisms exist for UK businesses:

Note: 0% VAT on energy-saving materials (solar, heat pumps, insulation) applies to residential and charitable buildings only. It does not apply to commercial premises.

Future Trends in Sustainable Office Space

Net zero carbon offices

The direction is clear. UKGBC energy performance targets tighten every five years through to 2035, by which point all offices claiming net zero should meet 2050 standards. The UK Net Zero Carbon Buildings Standard (pilot launched September 2024) will provide verified measurement against science-based targets for around 30 building types, based on actual measured data rather than theoretical models.

The Forge at Bankside is the benchmark: the UK's first commercial development designed and operated in line with the UKGBC net zero framework.

AI-powered building management

AI is moving from novelty to necessity in building management. A meta-analysis of 126 studies found reinforcement learning achieves 22.3% average energy savings, with hybrid methods reaching 28.1%. In practice, offices using AI-optimised HVAC are seeing energy bill reductions of up to 37%, and AI systems reduce equipment downtime by up to 40% through predictive maintenance.

UK examples include Grid Edge's "Flex2X" AI system, 22 Bishopsgate's AI-driven BMS, Bloomberg's 500+ energy sub-meters connected to intelligent management, and Schneider Electric's EcoStruxure platform at The Forge.

The circular economy in fit-outs

The typical office fit-out lasts just 2.5 years, and 91% of the carbon emissions from fit-outs come from sourcing and disposing of materials. In the UK, 1.2 million desks and 1.8 million chairs are landfilled annually, despite 51% being suitable for reuse with light repair. That is 165,000 to 200,000 tonnes of office furniture discarded by UK businesses every year.

WRAP reports that refurbishing furniture reduces embodied carbon by up to 80%. White Arkitekter's London office achieved 80% material reuse in their fit-out, saving 40% on costs (around 80,000 pounds) and roughly 7 tonnes of CO2 on furniture alone.

Hybrid working and sustainability

Hybrid working can reduce commuting emissions significantly. An IWG/Arup study suggests reductions of up to 70%, with London emissions cut by 49% specifically. The typical hybrid worker's carbon footprint is about 40% lower than a traditional office-only worker, and the Carbon Trust estimates full-time home workers save up to 4.1 tonnes of CO2 per year.

But the picture is more nuanced than it first appears. WSP research suggests the optimal approach is working from home in summer and in the office in winter, because domestic heating can offset transport savings in colder months. And many organisations have not right-sized their office footprint to match lower occupancy, creating a "rebound effect" where energy savings are lost.

Most UK employees currently attend physical workplaces 3 to 4 days weekly, with a third attending only 0 to 2 days.

Tightening regulations ahead

Several regulatory changes are coming:

• MEES tightening to EPC B: deadline likely between 2030 and 2035
• EPC reform: changes to the metrics and methodology expected in the second half of 2026
• UK Sustainability Reporting Standards: mandatory reporting expected from the 2026 financial year
• Growing lender pressure: 71% of lenders will not finance assets failing sustainability criteria (CBRE, 2025)
• Part Z campaign: industry push for mandatory embodied carbon limits in Building Regulations

Embodied carbon moves centre stage

Embodied carbon accounts for about 12% of global CO2 emissions and 20% of UK built environment emissions. Annual embodied carbon from UK buildings totals 40 to 50 million tonnes, more than aviation and shipping combined.

The RICS Whole Life Carbon Assessment (2nd Edition, effective July 2024) now requires demolition emissions assessment, strongly encouraging a "retrofit first" approach. The London Plan already requires whole life carbon assessments for major developments. And one-third of contractors are now asked by clients to provide these assessments, up from 14% just a year earlier.

The Bottom Line

Sustainable office space in the UK has moved well past the nice-to-have stage. Between tightening MEES regulations, growing investor scrutiny, shifting employee expectations, and the proven financial benefits (from lower energy bills to higher rental premiums), the business case is hard to ignore.

The good news is that whether you are searching for a new sustainable workspace, upgrading your existing space, or simply starting with basic sustainable office practices, every step counts. The buildings that adapt will thrive. Those that do not face a very real risk of stranding: financially, legally, and reputationally.

Start with an energy audit. Check your EPC rating. Talk to your landlord about green lease provisions. And if you are in the market for new space, look beyond the brochure and ask for actual performance data. The gap between what buildings promise and what they deliver is still enormous. Closing that gap is what sustainable office space is really about.