What is a Net Zero building?
Net zero, in general, means that we produce less carbon than we remove from the atmosphere.
The UK Green Building Council divides a ‘net zero’ building
into two distinct definitions: construction energy
- carbon linked to the construction materials (“embodied carbon”
), equipment and processes involved in development - and operational energy
, the daily emissions generated by lighting, heating, and, broadly, simply using the building stock.
What's the goal of Net Zero? That carbon emissions associated with (a) construction stages up to practical completion and (b) functional energy use on an annual basis are zero or negative. This is achieved by using offsets, on-site or off-site renewable energy and designing highly energy efficient buildings from the building fabric to the heating systems, glazing and airtightness.
So you want a thermally efficient, low carbon home. What's involved?
In new builds, the most effective way to achieve this is though energy efficient design. Existing dwellings should be upgraded in thermal performance through retrofitting, insulation and design alterations. Here are some suggestions to lower your home's carbon emissions for the long term.
Build to a low-energy standard and specification.
The Future Homes Standard
is expected to alter the current UK building regulations to reduce carbon by 70-80% in new homes by 2030. Passive House
(for new builds), EnerPHit
(for retrofits) offer clear, road-mapped ways to design, build and refurbish homes to low-carbon standards and significantly reduce the operational energy of homes. You can work with consultants from the Passive Institute to ensure the building meets its stringent performance requirements.
Monitor and limit energy usage in your home. The Government plans to expand the use of Smart metres (SMETERS) that allow you to modify the temperature settings of your home. Improving insulation in floors, roofs and other easy-to-access areas are available to many homeowners.
You can expect greater emphasis on measuring the in-use performance of all homes in the coming years.
Upgrade your heating system. Replacing the heating system of existing houses is key to reducing operational energy of the UK’s housing stock. Gas boilers, which currently heat 85% of UK homes, will be outmoded by 2025 in favour of heat pumps, considered the most energy efficient low carbon heat source.
Consider retrofitting to avoid embodied carbon from new builds.
Retrofitting existing homes to be more energy efficient extends their lifespan and avoids the significant uplift in embodied carbon created in replacing old buildings with new. Embodied carbon
refers to the CO2 created in producing materials. It includes transportation, extraction and production of materials and is responsible for roughly one third of carbon from the built environment. Embodied carbon can be mitigated by wider emphasis on reusing building materials and structures rather than rebuilding from scratch.
Work with landlords towards mutually beneficial green leases. Make public commitments to only taking ‘green leases’ or occupying low carbon spaces (considerations might include being fossil fuel-free, provision of 100% additional renewable energy, waste reduction or management, water efficiency etc.). Both owners and occupiers can take responsibility for the sustainable operation and occupation of a property. UKGBC envisions that by 2025 only green leases will be accepted.
“To keep the temperature of the planet under control – limiting its increase to 1.5 degrees - the science dictates that by the second half of the century, we should be producing less carbon than we take out of the atmosphere. This is what reaching ‘net zero’ means.”
- Alok Sharma, COP President-Designate