Energy-intensive buildings now account for 44% of the energy consumed in France, compared with 31.3% for transport. Office buildings account for an estimated 15% of this total, with an average lifecycle carbon footprint of 9 tonnes CO2 equivalent/m². Through renovation, redevelopment and ad hoc equipment, it is possible to achieve a successful energy transition.
In 30 years, office consumption has risen by 30%. The majority of them have a poor Energy Performance Diagnostic (DPE): 58% belong to classes E, F or G, the worst. Retrofitting or renovating these buildings offers the prospect of substantial savings. It also contributes to the fight against global warming.
Workspaces: heating more efficiently
Heating is still the biggest energy cost, accounting for 50%. The solutions to be implemented focus first and foremost on the building: internal or external insulation of walls, installation of double windows and double-flow CMV.
In the case of a gas or oil-fired system, replacing a conventional boiler with a condensing model alone can result in savings of up to 30%. Opt for thermostats, too, to adjust heating requirements according to location: 19 to 21°C for workspaces, 10 to 12°C for storerooms or warehouses.
As part of a "smart building" approach, connected thermostats can be used to digitally manage heating systems, turning them off at night. Or to lower room temperatures by 1°C during the day, and save up to 7% on your heating bill.
Smarter lighting for offices
Lighting accounts for 10-20% of an office's total energy consumption. To optimize lighting, choose low-energy LED, metal halide or class A lamps.
Timers or presence detectors can be used to automatically switch off lights in unoccupied offices. As an added bonus, light-sensitive cells can be used to dim the lighting according to the strength of natural light.
The right layout of premises encourages natural light. Increasing the number of glazed walls, choosing light-colored paints, reorganizing workstations into open spaces or co-working rooms - these are all economical alternatives. But they're also good for employee comfort!
Target energy-efficient equipment for workspaces
The expansion of computer fleets also explains the rise in office energy costs. Purchasinglaptops with the "Energy Star" label is a good idea, both in economic terms - with consumption reduced by 50 to 80% - and in productive terms - with their suitability for telecommuting.
When it comes to printers, opt for shared, collective machines rather than individual ones. For auxiliary equipment, such as microwaves, coffee machines and kettles, it's logical to choose appliances with low power consumption.
Take simple steps to reduce your electricity bill
Usage is a significant factor in reducing costs. When you're not at work, switch off your appliances! Compared to "normal" use, a computer still consumes 20 to 40% on standby; the same mode accounts for 80% of a printer's total consumption.
The multiplication of tabs, the accumulation of files in the cloud or the use of the Internet are also more greedy than they appear. Sending an e-mail generates between 4 and 50g of CO2. It's up to users to empty their mailboxes regularly, update their systems and send lighter attachments.
Committed to sustainable building?
Ideally, an office's energy-saving policy will take the form of a CSR approach, or even HQE certification.
The most ambitious can commit to a positive-energy building approach, i.e. one that produces more than it consumes. The solutions are well known: installation of photovoltaic panels, heat pumps, solar water heaters, rainwater harvesters, etc. In some cases, government financial assistance is available.
Sources: www.ecologie.gouv.fr, ADEME, Observatoire de l'immobilier durable, GRDF, Carbon Literacy Project.
1 - Or: from inputs
2 - Or: from daylight