What Does A Net Carbon Zero Home Actually Mean?
The goal is for UK housing to be net carbon zero by 2050. But, what does this mean in practice – particularly for the homes we are building today?
The first question is how to define net zero carbon. In a general sense, a net carbon zero home is responsible for zero carbon emissions. This means that it is sufficiently thermally efficient for all of its energy needs to be met from renewable sources – ideally generated onsite. It also means that the carbon emissions produced to build the home are also offset by renewable energy generation.
In practice, there are a few complications. Defining and calculating the expected energy needs is the first of these. True net zero would include both regulated energy use for heating, lighting and cooking, as well as unregulated use from appliances used in and around the home. More ‘real world’ energy use data is needed to give a reliable picture of likely consumption.
There also needs to be more clarity on how embodied carbon levels are calculated and minimised through material choices. Finally, there has to be confidence that the theoretical energy performance will be matched in reality – there is currently a significant performance gap between the two.
Despite these complications there is a clear direction of travel and a clear goal. Net zero carbon housing across the UK by 2050 means that:
- New homes should be highly energy efficient and capable of generating as much energy from renewable sources as they use.
- They should be built using a material-first approach to minimise levels of embodied carbon.
- They should be built using modern methods that minimise the gap between theoretical and real world energy use.
These priorities make an unanswerable case for using offsite manufacturing as fully as possible – and for ensuring there’s significant structural timber content.
Further innovations in house building are bound to come along, but we already have proven methods that meet zero carbon objectives. We know how to deliver them at scale and with no significant cost penalty.
Given that social housing providers already face a mountainous task in retrofitting their existing stock, there is every reason to make sure that new homes built from today onwards are as energy efficient as possible. And this means making offsite methods the preferred option during procurement.