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Zero carbon housing
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Zero carbon housing
Zero-carbon housing is housing that does not emit greenhouse gasses (GHGs) into the atmosphere, either directly (Scope 1), or indirectly due to consumption electricity produced using fossil fuels (Scope 2). Most commonly zero-carbon housing is taken to mean zero emissions of carbon dioxide, which is the main climate pollutant from homes, although fugitive methane may also be emitted from natural gas pipes and appliances.
There are nevertheless a number of definitions of zero carbon housing, particularly concerning the scope of emissions in the housing lifecycle (eg construction vs operation or refurb), and whether it is acceptable to count off-site emissions reduction (eg due to renewable energy export) or other external reductions against any residual emissions from the house to make it a Net Zero Home. The Chancery Lane legal climate project gives 6 definitions of zero carbon housing or buildings, of which 2 explicitly allow for the inclusion of off-site emissions reductions, via off-site renewables or other carbon offsets, and one is a net zero definition, allowing for net renewable energy export to be included. Some definitions are at odds with the apparent meaning of zero carbon, with the UK government at one point proposing to define a zero carbon home as one with "70 per cent reduction in carbon emissions against 2006 standards" - ie by definition not literally zero, as it allows up to 30% of conventional emissions.
Construction vs operation: Some scopes cover operation only, some give the option of including construction too. For the purposes of present day policy to reduce emissions, it is most useful to include construction and operation in the scope of new buildings, and refurbishment and operational emissions in the scope for existing buildings (as their construction impacts cannot be changed in retrospect). For a refurbishment to be genuinely zero-carbon, the embedded carbon needs to be "paid back" by the emissions saved by the house within a timescale relevant for action on climate change (normally within a few years), and well within the lifetime of the equipment concerned. Where a new zero carbon house is constructed, the embedded carbon of the whole building must be considered and paid back. As there is substantial embedded carbon in conventional building materials such as brick and concrete, a new zero carbon home is a bigger challenge than a retrofit and is likely to need more novel materials.
Another way in which a home can become zero carbon in operation is simply that it is powered, heated and cooled purely by a zero carbon electricity grid. While these are currently (2024) few (eg Iceland, Nepal), a significant number of countries are targeting zero carbon electricity grids by 2035, including Austria, Belgium, Canada, France, Germany, Luxembourg, the Netherlands, Switzerland and the UK.
The following main changes are required:
Most conventional houses in countries where space heating is required use fossil fuels or wood for space heating, hot water and cooking. In order to become zero carbon, these heating systems need to be replaced with zero emission heating methods. The main options are:
The cost of these measures to householders is naturally a critical factor. Because conventional systems benefit from economies of scale and installation skills are widely available, new zero carbon technologies may have a higher capital cost, although this may be offset by lower operating costs or efficiency savings, depending on the relative costs of electricity and fossil fuels. For this reason some governments provide householders with grants or subsidies towards the cost of the shift, for example the Boiler Upgrade Scheme in the UK, which helps to fund heat pump installations.
In almost every case the renewable source of choice for dwellings is solar photovoltaic (PV) power. Use of solar PV power is now becoming routine worldwide, as solar power costs have fallen to become the cheapest source of electricity. Solar panels are typically placed on roofs, outhouses, or on the ground near the home, and it is practical for almost all scales of dwelling and most parts of the world. The only exception may be flats / apartments in dense urban areas, which may lack a roof or even any exposure to the sun.
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Zero carbon housing AI simulator
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Zero carbon housing
Zero-carbon housing is housing that does not emit greenhouse gasses (GHGs) into the atmosphere, either directly (Scope 1), or indirectly due to consumption electricity produced using fossil fuels (Scope 2). Most commonly zero-carbon housing is taken to mean zero emissions of carbon dioxide, which is the main climate pollutant from homes, although fugitive methane may also be emitted from natural gas pipes and appliances.
There are nevertheless a number of definitions of zero carbon housing, particularly concerning the scope of emissions in the housing lifecycle (eg construction vs operation or refurb), and whether it is acceptable to count off-site emissions reduction (eg due to renewable energy export) or other external reductions against any residual emissions from the house to make it a Net Zero Home. The Chancery Lane legal climate project gives 6 definitions of zero carbon housing or buildings, of which 2 explicitly allow for the inclusion of off-site emissions reductions, via off-site renewables or other carbon offsets, and one is a net zero definition, allowing for net renewable energy export to be included. Some definitions are at odds with the apparent meaning of zero carbon, with the UK government at one point proposing to define a zero carbon home as one with "70 per cent reduction in carbon emissions against 2006 standards" - ie by definition not literally zero, as it allows up to 30% of conventional emissions.
Construction vs operation: Some scopes cover operation only, some give the option of including construction too. For the purposes of present day policy to reduce emissions, it is most useful to include construction and operation in the scope of new buildings, and refurbishment and operational emissions in the scope for existing buildings (as their construction impacts cannot be changed in retrospect). For a refurbishment to be genuinely zero-carbon, the embedded carbon needs to be "paid back" by the emissions saved by the house within a timescale relevant for action on climate change (normally within a few years), and well within the lifetime of the equipment concerned. Where a new zero carbon house is constructed, the embedded carbon of the whole building must be considered and paid back. As there is substantial embedded carbon in conventional building materials such as brick and concrete, a new zero carbon home is a bigger challenge than a retrofit and is likely to need more novel materials.
Another way in which a home can become zero carbon in operation is simply that it is powered, heated and cooled purely by a zero carbon electricity grid. While these are currently (2024) few (eg Iceland, Nepal), a significant number of countries are targeting zero carbon electricity grids by 2035, including Austria, Belgium, Canada, France, Germany, Luxembourg, the Netherlands, Switzerland and the UK.
The following main changes are required:
Most conventional houses in countries where space heating is required use fossil fuels or wood for space heating, hot water and cooking. In order to become zero carbon, these heating systems need to be replaced with zero emission heating methods. The main options are:
The cost of these measures to householders is naturally a critical factor. Because conventional systems benefit from economies of scale and installation skills are widely available, new zero carbon technologies may have a higher capital cost, although this may be offset by lower operating costs or efficiency savings, depending on the relative costs of electricity and fossil fuels. For this reason some governments provide householders with grants or subsidies towards the cost of the shift, for example the Boiler Upgrade Scheme in the UK, which helps to fund heat pump installations.
In almost every case the renewable source of choice for dwellings is solar photovoltaic (PV) power. Use of solar PV power is now becoming routine worldwide, as solar power costs have fallen to become the cheapest source of electricity. Solar panels are typically placed on roofs, outhouses, or on the ground near the home, and it is practical for almost all scales of dwelling and most parts of the world. The only exception may be flats / apartments in dense urban areas, which may lack a roof or even any exposure to the sun.