UK building regulations have recently been updated to ensure new build homes have to be built with even greater energy efficiency in mind. The regulations require homes to be built to use less energy and therefore produce less Co2 emissions. HexxHomes are designed and built with sustainability in mind and have taken the regulations seriously but then gone a step further. The HexxHome standard build system provides a fabric energy efficiency (building regulation requirement) that is between 30 - 50% more efficient then current building regulations require. Once combined with modern green technologies (Air Source Heat Pumps, Solar Panels, Battery Storage) a HexxHome can generate you money and effectively absorb Co2 emissions (feeding the national grid Co2 free energy). Should you choose a HexxHome you will experience energy cost-free living and help make the environment a cleaner for future generations. The build system ensures the high levels of energy efficiency also remain the same not just 10 years into the future, but for the life of the building (up to 100 years).
The Technical Detail
Our standard system build produces the following parameters: U-values U-values are a measure of insulation effectiveness of materials; our standard build system provides the following U-values:
• Floor U-value: 0.12 W/m2K (notional dwelling spec: 0.13W/m2K)
• Wall U-value: 0.15 W/m2K (notional dwelling spec: 0.18W/m2K)
• Roof U-value: 0.13 W/m2K (notional dwelling spec: 0.13W/m2K)
The HexxHome Build System is such that insulation is provided for inside the whole of the structure and because of this standard Accredited Construction details do not apply. The thermal bridges have had to be independently assessed by BRE. Our thermal junctions have proven to be very efficient; in the majority of cases they are 50% more efficient than ‘SAP approved’ junctions thus aiding the home to be very energy efficient.
The HexxHome build system is extremely airtight, this is due to the watertight and airtight seals between slabs and panels as well as all window, door and service entrances into and out of the building. The Hexpod Show Home will have an air leakage rate of below 1 m3/hr/m2 @50Pa.
Windows and Doors
An integral part of any home, we only choose doors and windows with a high energy efficiency (U value: 1.2W/m2K or less). These products are either economic UPVC windows or longer lasting aluminium/timber doors and windows, we can offer you a range of specifications to suit your needs and budget.
It is true that cement (making up approx 10% of concrete) requires a lot of energy to produce and an associated amount of Co2 is generated. It is also true that reinforced concrete is heavy, requiring a lot of energy to move it to site and build with it.
However, by nature, the UK’s concrete generation is local and therefore the transportation footprint is relatively limited. Studies from the Mineral Products Association have outlined that the average distance concrete raw materials travel around the country is just 54km with a further onward travel (once products are manufactured) of just 43km. It is also true that concrete by nature is extremely durable, outlasting many other building products. It also carbonates over its lifetime, in effect recapturing Co2 from the atmosphere. And when, finally, it has reached the end of its natural life it can be reconstituted for other uses, crushed for groundworks/ foundations or roadways.
On average HexxHome concrete contains 115 kgCo2/tonne (once a home is built). A Standard 90m2 2 bed HexxHome will therefore have used 18,000 kg of Co2 worth of energy in its manufacture and construction.
Design life of HexxHome concrete (the time at which is considered that the concrete might start to degrade): 60 years. Realistic in useable life of a HexxHome: 100 years.
Co2 Generated by living in a HexxHome (through life CO2 cost):
a. Baseline model (gas boiler): 1,370kg Co2/ year
b. Standard HexxHome Model (Air Source Heat Pump/ Solar/ Battery): 0kg Co2/ year
The average UK 3 bed (94sqm) house in the UK consumes 4,000kwh electricity and 12,400 kw of gas = 4,630 kg Co2/ Year (Co2 embodied Co2 for superstructure build = 10,000kg).
Embodied Co2 payback through life:
a. Baseline HexxHome: 5.5 years
b. Standard HexxHome: 3.9 years
Through life Co2 cost (assumed over 60 years):
a. Traditional home: 10,000kg (build), 277,800 kg (through life) = 287,800kg Co2/ 60 years
b. Baseline HexxHome: 18,000kg (build), 82,200 kg (through life) = 100,200kg Co2/ 60 years c. Standard HexxHome: 18,000 kg (build), 0kg (through life) = 18,000kg Co2/ 60 years
Taking into account maintenance of systems over the 60 year design life and down-cycling of the concrete at the end of its design life, a Baseline HexxHome is estimated to produce between 30-35% Co2 when compared to a traditional UK home and a Standard HexxHome is estimated to produce between just 5-10% of a standard UK house.
House building of any nature will require Co2 to be generated; the key is ensuring a home is efficient throughout its whole design life. HexxHomes achieve this as standard and with very relative ease compared to other house building systems, which is why we see our product as very attractive to those interested in looking after the environment.