Improving Efficiency in New Build Residential Dwellings

As the heating industry moves towards a more sustainable future, there is pressure for housebuilders to meet increasing energy efficiency standards. Tom Murray, Specification Director Commercial and Residential at Baxi Heating, discusses the heating technologies designed to improve SAP ratings

In January, Government published its response to the Building Regulations Approved Document L&F consultation from 2019, which will see that new homes are required to achieve a carbon emissions reduction target of 31% over the current rate from 2022. While the update places an emphasis on building fabric considerations, heating technologies will still play an important role. In fact, the Part L changes are a stepping stone towards the far more stringent energy efficiency requirements for new homes under the Future Homes Standard. The Future Homes Standard should be in place from 2025, and seeks to reduce the carbon footprint of new build homes by mandating low carbon heating in all new build houses.

The Standard Assessment Procedure (SAP), which is the method for calculating the energy performance of dwellings, in support of Part L, is also changing. Currently, SAP 2012 is used to demonstrate compliance with regulated emissions targets and for producing Energy Performance Certificates. However, SAP 10 will come into effect when the revised version of Part L is enacted next year, this entails a number of changes to the calculation methodology including revised fuel factors which will alter the compliance benefit of heat pumps.

What this all points to is that new build developers will need to be readying themselves for more stringent fabric and energy efficient heating measures now and even more so over the next four years. This includes a move away from gas powered heating and hot water systems to electricity-powered heating technologies like cylinders and heat pumps. However, while gas boilers are still being specified for new-builds, until the Future Homes Standard is enacted in 2025, extra measures and design considerations will still need to be made to ensure compliance to make up the 31% emissions reduction needed from next year.

SAP Boosting Measures

There are a number of energy efficiency boosting additions that can be specified to improve the SAP rating of a dwelling including a gas boiler, such as weather compensation, load compensation, smart controls, and heat recovery systems. These systems are often combined to deliver the best results and some even deliver 2-in-1 benefits, like smart controls which often include features such as load compensation functionality along with time and temperature control. These devices measure the gap between what the internal temperature is and what the user wants it to be and modulates the boiler so that it only uses as much fuel as necessary to close the gap.

Weather compensation devices, monitor outdoor conditions and tell the boiler when to adjust its flow temperature. This leads to fuel savings and a more consistent environment. When paired with smart controls, weather compensation is a cost-effective way to raise energy efficiency and lower emissions.

Flue Gas Heat Recovery (FGHR) recycles the heat from the flue gases which would normally be expelled into the atmosphere. The recovered heat is then used to pre-heat water coming into the boiler from the cold mains supply, significantly reducing the amount of gas required by the boiler to heat the water. Likewise, Shower Heat Recovery Units (SHRU) save energy by recycling residual heat from waste shower and bath water via a heat exchanger. When working to peak efficiency, it can recover up to 63% of heat that would otherwise be lost. SHRUs can boost SAP ratings by 5-6%.

Getting It Right

Getting the building design right and knowing how to best use these efficient heating and hot water technologies in the wider context of the building is a science. It involves careful selection of components to meet customer needs as well as emissions considerations. This among other factors such as how the fabric, area and volume of the building will impact heat loss and the overall performance. For this reason, developers should consider partnering with trusted advisors who can consult on the most cost-effective and efficient hot water and heating solution for new build properties.

While the future of the heating industry is set to change vastly in the coming years, it remains important to consider the challenges facing professionals now. Demand for new housing will continue to rise, and with it the requirement for efficient, low-carbon heating.