Net-Zero Carbon Housing: A Guide for Property Investors and Buy-to-Let Landlords
More and more houses will be net zero carbon housing in the future. Here’s a guide to net zero carbon housing including what it is, why it’s important and how to build a net zero carbon house.
What is Net-Zero Carbon Housing?
Net-zero carbon housing is housing that contributes no additional carbon to the environment. Net-zero carbon housing contributes no additional CO2 or greenhouse gases to the atmosphere.
Net-zero carbon housing is often connected with a number of other terms such as eco-housing, sustainable housing, low energy housing or Passivhaus. These are not necessarily the same as net zero carbon housing, however.
Net-zero carbon housing may also be known as carbon-neutral housing.
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A Quick Guide to Net-Zero Carbon
The concept of net-zero carbon recognises that a house will actually produce some carbon, but that the carbon may be offset somewhere else resulting in net-zero. Strictly there is no such thing as a carbon zero house since building and using any building invariably involves producing carbon.
When considering net-zero carbon housing it is necessary to consider both embodied carbon and operational carbon. Embodied carbon is carbon connected with the building of the housing. Operational carbon is connected with using or living in the housing.
Potentially a net-zero carbon house can be a carbon-negative house instead. That is, it is responsible for removing more carbon from the environment than it actually produces.
Why Net-Zero Carbon Housing is Important
It has long been recognised that carbon emissions are directly connected to the risk of global warming and climate change. The carbon emitted from housing is believed to be a major contributor to climate change alongside carbon from other sources such as commercial buildings, motor vehicles, aircraft, shipping and industry.
Housing is in fact believed to be one of the biggest emitters of carbon today. It is estimated that on a global basis buildings emit up to around 40% of all CO2 emissions. This comprises both the construction of buildings in the first place and the day to day operation of them. For example, conventional heating systems and particularly gas boilers all produce a significant level of carbon.
The concept of net-zero carbon housing is relevant to the UK’s commitment to meet climate change targets and become net carbon zero by 2050 at the latest.
A number of laws and policies have been introduced in recent years to work towards this objective. The Climate Change Act 2008 was originally introduced with the aim of reducing carbon emissions by 80%, and subsequently by 100%, compared to 1990 levels by 2050.
The UK Climate Change Committee has said that it is not possible to meet climate change targets without an almost complete decarbonisation of our housing stock.
Recent changes to the buildings regulations are quickening the move toward net-zero carbon housing. The recent Future Homes Standard which specifies new buildings regulations standards should ensure that all new homes built from 2025 will produce 75-80% fewer carbon emissions than homes delivered under current regulations. Emissions from other new buildings, including offices and shops, should be reduced by 27%.
The Heat and Buildings Strategy also sets out a plan for how the UK will decarbonise homes and commercial, industrial and public buildings. It is also part of setting a path to net carbon zero by 2050.
The advantages of net carbon zero housing include:
- Net-zero carbon housing is good for the environment. Net-zero carbon housing will directly help towards wider decarbonisation of the economy. It will directly help achieve wider net carbon zero targets and help to mitigate the risks of climate change.
- Net-zero carbon housing is potentially cheaper to run. Net carbon zero houses should use minimum amounts of energy in their operation and so should lower bills for both homeowners and tenants.
- Net-zero carbon housing can be both private housing and social housing allowing all of society to benefit in this way.
- Net-zero carbon housing should also be healthy to live in. A net-zero carbon property should be warm in winter, cool in summer and have good air quality.
- For home buyers, net-zero carbon houses may also qualify for a green mortgage. Green mortgages may offer preferential terms for energy-efficient buildings.
- For landlords and investors, net-zero carbon housing may help them comply with planned and future letting legislation. For example, it is likely that only houses meeting a certain energy efficiency standard will be able to be rented out as buy-to-lets in the near future.
There are some possible disadvantages of net-zero carbon housing. One issue is that net carbon zero houses are currently normally more expensive to build than a house that is not built to net-zero carbon standards. As more net-zero carbon housing is built it is anticipated that the costs of building them will fall in real terms, however.
Net-zero carbon houses may not necessarily be cheaper to run than a conventional house. A house that uses renewable electricity for heating may be net carbon zero compared to a house heated using a gas boiler which is not. The cost of that electricity may be higher, however.
What Makes a House Net-Zero?
Housing can become net-zero carbon housing in two main ways: A house can be originally built as a net-zero carbon house or it can be retrofitted to become a net-zero carbon house. It is not always easy or even possible to retrofit an existing house to become a net-zero carbon house, however.
Net-zero carbon houses generally use a multi-pronged approach to becoming net carbon zero.
First, there is fabric energy efficiency. A house can achieve net-zero carbon by being designed and built for maximum energy efficiency. It should have a high level of heat retention, airtightness, natural ventilation and efficient heating or a heat recovery system. Ways of achieving this include highly efficient wall, roof and floor insulation, double or triple glazing and energy-efficient lighting amongst other methods.
Very importantly these measures need to be manufactured and installed to a consistently high standard to ensure that they fully contribute to fabric energy efficiency.
Houses may make use of energy-efficient building materials, such as timber construction or low carbon concrete. It is estimated that conventional concrete is responsible for around 8% of the world’s CO2 emissions.
It is also important to consider operational energy efficiency. A net-zero carbon house will need to be able to make use of renewable energy rather than fossil fuels. This might be energy that is generated away from the property such as from wind power, water power or nuclear energy. Or it may be from some kind of microgeneration at the property itself, such as solar PV panels. Local or district heating networks are another possible element in helping to make housing net carbon zero.
Some properties may achieve net-zero carbon status using offsite solutions, such as carbon offsetting. Carbon offsetting may involve tree planting, a form of carbon sequestration.
Net-Zero Carbon Housing – The Same as Eco Housing?
There is no exact definition of what makes a net-zero carbon house, an eco-house, a sustainable house or even a low energy house.
An eco-house is any house that is built using materials that reduce its carbon footprint and has reduced energy needs. It may also be a net-zero carbon house but not necessarily. Eco houses may have other environmentally friendly features such as the ability to recycle or treat their own water.
A sustainable house makes efficient use of energy and resources in its construction and use. It may also be a net-zero carbon house but not necessarily.
What is a Passivhaus?
When considering net-zero carbon housing you may come across Passivhaus houses.
The Passive House Institute (PHI) based in Germany is an independent research institute that has played a leading role in the development of the passive house concept globally. The Passivhaus Trust is an independent non-profit organisation that provides leadership in the UK for the adoption of the Passivhaus standard.
Unlike net-zero carbon housing or eco-housing where there is no specific definition for how it should be built Passivhaus is a design and construction standard. There is a specific standard for how a Passivhaus should be designed and built.
For example, the Passivhaus standard requires a house to be comfortable to live in whilst also consuming an absolute minimum of energy for heating or cooling. A Passivhaus is designed to have a high standard of airtightness and make use of natural heat and ventilation where possible. They draw on passive energy sources such as sunlight and human and appliance-generated heat. A Passivhaus should also achieve this in an affordable way.
Passivhaus is applicable to new builds while EnerPHit is a standard to guide the retrofitting of existing buildings to a slightly more relaxed Passivhaus standard.
To be a genuine Passivhaus a property needs to be professionally certified as complying with the appropriate standards.