Decarbonising built environment and reducing carbon emissions in new buildings with low-carbon heating and hot water

As the world comes together and doubles down on its efforts to build a Net-Zero Emissions future, every sector is developing transitioning strategies, none more so than construction companies operating in the built environment.

The entire built environment ecosystem, from design and manufacturing to building materials, construction and demolition, directly or indirectly contributes to around 40% of global CO2 emissions from fuel combustion and 25% of greenhouse gas emissions, according to a report by McKinsey.

The report also tells us that emissions in the Construction Industry are greater than those of shipping, aviation, and electricity production as well. According to Arup, the global decarbonisation trajectories indicate that the building industry needs to half its total emissions by 2030 to be able to reach net zero by 2050 and achieve the Paris Agreement climate goals.

The carbon impact is equally alarming in the UK. A total of 40% of UK carbon emissions is linked to the built environment, which includes emissions related to heating buildings.

The role of renewables in decarbonising the built environment

Emissions in the construction sector result from inefficient technology and building designs to carbon-intensive production.

These emissions can be classified into two types:

  • Operational – emissions from the operational or the ‘in-use’ phase of the building over its life span.
  • Embodied – which involves emissions related to transporting raw materials and construction of new builds.

According to McKinsey’s analysis, 76% of emissions are operations-related which are continuously released post-construction, while only 24% are embodied emissions which can only be offset but never reduced.

Operational energy is essentially required for the daily maintenance of the building and is related to providing comfortable living conditions such as heating and cooling — it can be abated to a great extent.

For instance, McKinsey’s Real Estate Climate Action Platform’s findings show us that about 75% of operational emissions in a building come from space and water heating, i.e. out of the total 2178 kg CO2 annual emissions per household, about 1670 kgCO2 comes from space and water heating alone.

source: McKinsey’s Real Estate Climate Action Platform

The report also adds that about 60% of the emissions can be abated by including a key decarbonising lever: heat pumps. But for the decarbonisation potential to reach its level, solutions need to be produced and brought into effect at scale.

The UK government has acknowledged the role of heating efficiency in built assets, and has brought into effect changes to Part L (conservation of fuel and power) of UK Building Regulations in order to improve the energy efficiency of new & existing buildings. The changes include higher performance targets on all residential property buildings and their extensions.

This is just an interim step, and more stringent regulations will follow in 2025 as a part of the government’s Future Homes Standard (FHS) and Future Buildings Standard.

Two of the three key metrics measured under these initiatives involve changes to fuel consumption and carbon emissions, namely target primary energy rate (TPER) measured in kWhPE/m2 per year) and target emissions rate (TER) (measured in kgCO2/m2 per year).

TPER was a new addition to the Part L 2021 regulations, even as the term ‘primary energy’ was previously used in its introduction in Building Regulations.
TPER considers how much energy is required to provide heating, hot water, cooling and ventilation to a newly built dwelling.

A unit of ‘primary energy’ represents how much raw fuel is required to produce a unit of final energy. This means considering the energy source for home systems is crucial.

Emphasising renewable technologies can provide regulatory benefits when aiming for TPER due to their high efficiency. For instance, electricity has a primary energy factor (PEF) of 1.501, meaning 1.501 units of raw energy are needed to produce 1 unit of electricity in your home. A monobloc or a split system heat pump having coefficient of performance (COP) of 3 can help achieve TPER effectively. In this case, the heat pump uses 1.501 units of primary energy to produce 3 units of heat from 1 unit.

TER, on the other hand, aims to limit carbon emissions associated with a dwelling, taking into account energy used for space heating, hot water and lighting within the home. Based on the new changes in Part L 2021 over Part L 2013, a higher performance target of reducing CO­2 emissions by 31% for dwellings and 27% for other buildings has been set.
Because of continuous decarbonisation of the grid over the years, electricity now has the lowest carbon emissions impact compared with gas and oil.

The Net Zero Whole Life Carbon Roadmap project outlined the pathway to net zero for UK’s built environment. In examining the operational carbon emissions for new builds, it brought forth a crucial point: today’s new buildings will be less than halfway through their lifespan in 2050 (the net zero deadline), and currently need to meet the necessary energy performance targets to avoid retrofitting cost and disruption in future.

This means meeting the fabric standards and minimising heat demands through low-carbon heating systems. More importantly, there is need to look at other metrics; according to the project’s analysis, energy storage will be essential to minimise peak demand and enable load shifting.

As UK government brings FHS into effect to complement the existing ‘Building Regulations’, the new homes to be built from 2025 will be required to produce 75-80% less carbon emissions than those built under the older regulations. Improving heating and hot water systems by replacing current heating systems with low-carbon technologies will be key to bringing down the target emissions by such a substantial degree.


The benefits of pairing renewable technologies with low-carbon thermal storage in new buildings

As housing developers are compelled to move away from installing gas boilers in new buildings to pass the SAP ratings, meet the FHS regulations and futureproof their stock while lowering energy bills for residents, low carbon alternatives such as heat pumps and solar PV come to the fore as the go-to technologies when thinking energy efficiency.

And while these low-carbon alternatives increasingly become the go-to efficient solutions, they will also need to be accompanied with a thermal store for providing low-carbon hot water in newly built dwellings. Given that around 17% of an average UK household’s total energy consumption is used to heat water, it’s just as important to find an energy-efficient alternative to traditional hot water cylinders.

While considering energy efficiency in a thermal store, the key issue is heat losses. Spray foam cylinders stand to lose 2-3kWh per day while a copper cylinder with red puffer jackets can lose up to 4kWh per day, which could all add up to a loss of over 1000kWh/year, translating to over £300 based on the current tariff prices.

Sunamp’s Thermino range of heat batteries is exceptionally energy efficient and compact, as they are made of the highly energy dense patented phase change material, which store 4x more energy than an equivalent hot water cylinder. Thermino’s heat loss rate, thanks to the high-powered vacuum insulation, is at 0.67-0.84 kWh/day, which is less than a quarter of that of a typical hot water cylinder.

And because the heat battery can be charged from a variety of energy sources, such as heat pumps and solar PV, residents can be assured of reliable, on-demand, mains pressure hot water from renewable energy.

Take the case of the award-winning Whetstone apartments, where MKM developments chose Sunamp heat batteries for their residents to harness solar energy from the photovoltaic panels installed in the building. The housing developers didn’t just benefit from a reliable and efficient hot water solution for their green-thinking residents, but they also ended up saving an estimated 7.651 tCO2e of operational carbon in the first year and 269.763 tCO2e over 25 years compared to a gas boiler.

To know how Sunamp can be a part of your new build project, get in touch with us by clicking here.