It starts with a plan.
NET ZERO HOMES
We tend to equate carbon emissions with things that move under their own power, such as cars, trains and aircraft. But some of the biggest prospective wins for net zero are actually to be found among those least mobile of objects: the buildings we live and work in.
The built environment is responsible for almost 40 per cent of the UK’s total carbon footprint, according to the Green Building Council. And with government targets to build an additional 300,000 homes by the mid 2020s, the race to decarbonise the sector is on.
Why are our buildings – and our homes in particular – so carbon intensive? Partly because of the materials traditionally used to build them: bricks, concrete, steel and cement all require large amounts
of energy to produce. And partly because older homes in particular are nothing like as energy efficient to heat, cool or power as they could be.
Modern methods of construction using factory-built panels made of low-carbon materials can slash the embodied carbon in a new home while also reducing the building times from several months to a few weeks. They can also help improve the ways in which people interact with their homes, enhancing the living experience as well as reducing running costs. Thorough insulation, draught proofing and passive heating and cooling via careful solar design can help maximise comfort and minimise ongoing energy requirements, cutting bills for owner/occupiers as well as moving closer to the ultimate goal of net zero. Smart home technology will provide householders with a much greater level of transparency around energy use as well as new ways of managing it via apps and “intelligent” appliances.
Key Elements What A Net Zero Home Looks Like:
- Construction and insulation materials
With cement production accounting for 8 per cent of the world’s carbon emissions, we need more planet-friendly ways to build. Future homes may feature frames of timber or reclaimed steel and be insulated with sheep’s wool, cork, hemp or straw. More than a fifth of newbuild houses in the UK are already timber framed, with the proportion in Scotland reaching 76 per cent.
- Airtight building and energy recovery ventilation system
- Energy production
Many of us may soon have an air source heat pump warming our home instead of a boiler. This absorbs heat from outside (even from air as cold as minus 15C) to warm internal rooms and produce hot water, a little like a fridge operating in reverse. Solar panels, meanwhile, can provide electricity needed to run the pump and support electric vehicle charging too – with any excess fed back to the grid.
- Energy efficient lighting and appliances
Replacing traditional bulbs with LEDs can save as much as 65kg of CO2 a year – equal to driving a car 220 miles. And, as 20 per cent of the average UK electricity bill goes on lighting, UK homeowners save an average of £240 per year by swapping incandescent lights for LED alternatives. Replacing old appliances with energy-efficient models can be healthy for our wallets too; switching from a C- to an AA-rated fridge-freezer could save £113 per year, for example.
- Energy efficient water use
Over half of the public water supply is used in homes, with the average person getting through 150 litres a day. Installing low-flow taps and showers that aerate water is an easy way to cut hot water use, and therefore the energy used to heat it. A five-minute shower from a water-efficient single spray showerhead will use 40–50 litres, half of what’s needed for a bath.
- Smart meters
In future, a smart home energy app is likely to monitor how much energy we’re using and make real-time suggestions for reducing it. It could inform us when our electric vehicle battery is full, point out when the house has reached optimal temperature and offer to turn down the heating, remind us when our air source heat pump is due for a service, and sell surplus energy back to the grid at a profit.