If you want a low carbon home - or one with a low carbon footprint - you’ll need to know how it’s built and the way it’s heated. Find out how you can reduce the carbon footprint of your new build home from the construction stage to everyday operation.

How Much CO2 Does the Average Home Produce?

An average new build home emits 65 tonnes of CO2 at the construction stage. A study from the ASC (American Chemical Society) revealed that the average carbon footprint of an American household stands at 48 tonnes of CO2 equivalent (or CO2e) per annum. 

Whether your home has a high or low carbon footprint depends primarily on the materials used in its construction and the amount of energy needed to heat it.

Low Carbon-Embodied Homes

A low carbon-embodied home is one that stores carbon safely in its structure instead of emitting it into the atmosphere - according to Citu, a leading property developer which specialises in sustainable construction. Citu claims that building homes from timber, a carbon-negative material, is the answer to a low carbon dwelling. That’s because other commonly used building materials -  namely brick, concrete and steel - embody a lot more carbon dioxide. 

Embodied carbon refers to all the greenhouse gas emissions produced by the processes used to create and deliver the materials needed to construct a home. A Citu Home typically uses a timber frame design that removes over 23 tonnes of CO2 from the atmosphere and stores it safely in the home’s structure. If we remember that building an average new home emits 65 tonnes of CO2, that’s a huge carbon saving.

According to the registered charity WRAP (Waste & Resources Action Programme), significant applications for timber in the home’s construction, resulting in embodied carbon savings for a low carbon home, include:  

• External timber cladding -  as a finishing material instead of steel, aluminium or glass cladding.

• Internal partitions -  as a framing material, instead of steel.

Research from WRAP reveals that using reclaimed timber instead of new timber will reduce the level of embodied carbon even further. Reclaimed timber is timber wood that has already served a purpose in a previous life, such as beams from barns that have fallen into disrepair. 

To ensure your new build home has a low carbon footprint, WRAP warns against using cement, which requires relatively high amounts of energy and associated carbon emissions in its production. The charity’s research shows that low carbon substitutes for cement, in addition to timber, include:

1. Pulverised Fuel Ash (PFA)  - a derivative of coal burned in power stations.

2. Ground Granulated Blast furnace Slag (GGBS) - a derivative of steel production. 

If your newbuild is constructed with a timber panel system, you’ll have reduced its embodied carbon, paving the way for a low carbon footprint home. The next step involves reducing its operational carbon emissions. These include emissions from the heating system.

Lower Your Home’s Operational Carbon Emissions

To get your home’s carbon footprint as close to zero as possible, you need to reduce the amount of heating needed. The key to achieving this is to have a highly insulated and airtight thermal envelope that retains as much heat as possible. This involves installing a Mechanical Ventilation with Heat Recovery system (or MVHR). 

MVHR involves heat exchange to bring fresh air from the outdoors into the home while extracting moist stale air from its wet rooms, such as the bathroom or utility room. The fresh air passes through a filter. In the heat exchanger, the heat from the extracted air is used to warm the filtered fresh air. 

As more than 90% of heat is used to warm the filtered fresh air, the home’s heating needs are reduced by up to ten times, compared to a traditionally built home. According to Citu’s research, having an MVHR system, in conjunction with a timber panel system, is key to building a home with zero-operational emissions. 

Summing Up

As we strive towards climate preservation, you can play your part by ensuring that your newbuild property has a low carbon footprint. This starts with construction materials that have low embodied carbon, such as timber. Check the building specifications to ensure that timber will be used in external cladding and internal partitions. Also, ensure your new home will have an MVHR system to reduce its operational carbon emissions. With these in place, your home may well boast one of the lowest carbon footprints in your neighbourhood.  

Author: Selectra UK

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