January 2022

In December the Department for Levelling Up, Housing and Communities (DHLUC) announced a major update to England’s Building Regulations which will come into effect on 15 June this year.

The updates are focused on helping the UK to meet its net-zero carbon emissions by 2050 target through measures such as increased insulation, improved materials, and low carbon technologies.

They are an important step ahead of the Future Homes Standard in 2025, which will ensure an average new home produces at least 75% less CO2 emissions than one built to current energy efficiency requirements and will mean all future homes are net-zero ready and will not need retrofitting.

“The changes will significantly improve the energy efficiency of the buildings where we live, work and spend our free time and are an important step on our country’s journey towards a cleaner, greener built environment.”

Eddie Hughes, Housing Minister

The new regulations come alongside £6.6 billion of direct government investment into improving the energy efficiency of buildings.

Although not outlined as a specific requirement, these changes support the adoption of more sustainable heating systems, and the government expects heat pumps to become the primary heating technology for new homes.

To allow for planning applications currently in progress, England is now in a transition period until June.

WHAT DOCUMENTS HAVE CHANGED?

Alongside amendments to the Building Regulations, five new approved documents have been published:

1. Uplifts to Approved Document L, volume 1: dwellings;
2. Uplifts to Approved Document L, volume 2: buildings other than dwellings;
3. Uplifts to Approved Document F, volume 1: dwellings;
4. Uplifts to Approved Document F, volume 2: buildings other than dwellings;
5. New: Approved Document O covering overheating.

The scope of the new regulations affects both existing and new build properties and will change how heating and ventilation is specified. Significantly, amendments to Part L are focused on measures that enable a building to produce fewer carbon emissions.

So what are the top-level key changes within these documents?…

NEW BUILD HOMES: 30% CUT IN CARBON EMISSIONS

The new regulations require carbon emissions from new build homes to be cut by around 30% compared to current standards. This will be achieved through a variety of methods outlined in the regulations.

NEW COMMERCIAL BUILDINGS: 27% CUT IN CARBON EMISSIONS

Emissions from other new commercial buildings including offices and shops must be reduced by 27%, also through a variety of methods, some of which we’ll explore in this blog.

55°C MAXIMUM FLOW TEMPERATURE

As part of the Approved Document L uplift, all new and replacement wet space heating systems in domestic and non-domestic buildings will have to be designed with a maximum flow temperature requirement of 55°C. This is considered important for system efficiency.

To conform with this regulation, radiators that can provide high heat outputs with low flow temperatures must be considered.

When a heat pump is installed, the regulations state a flow temperature of 45°C should be used to achieve maximum Coefficient of Performance (COP).

Due to the much lower flow temperatures, steel panel radiators would need to significantly increase in size, presenting location and aesthetic issues. For example, to provide 900 watts of heat output with a flow and return of 45°C/35°C, a double panel radiator would need to be 1800mm L x 600mm H compared to 1000mm L x 600mm H when using 75°C/65°C so nearly double the size,  however, thanks to the efficiency of Jaga’s Low-H2O Hybrid radiators, they can be sized at almost half that of a steel panel radiator providing comparable heat output.

When a heat pump is used as the water heating source, the weather compensation must be set and commissioned to alter the flow temperature. This should be considered if opting for oversized steel panel radiators, as output would be further reduced if the actual flow temperature is lower than the design temperature. Using a Jaga Hybrid radiator, although not totally immune to the effects of a decreasing flow temperature, can make up for a lower flow temperature by utilising its intelligent control system.

These Hybrid radiators use Dynamic Boost Hybrid (DBH) technology, where small, quiet electric thermal activators are fitted inside the radiator to increase airflow and significantly boost radiator output without increasing radiator size. This is extremely useful where wall space is limited and aesthetics are paramount. Further information on fan convectors and emitter types suitable for heat pumps, can be found in MCS’s Domestic Heat Pumps – A Best Practice Guide.

In addition to the 55°C maximum flow temperature, the building regulations outline a requirement for self-regulating, zoned control devices for heating systems so all space heating and domestic hot water boiler installations in existing non-domestic buildings must now include controls to improve the effective efficiency of the system.

OVERHEATING

An entirely new Building Regulation and Approved Document O has been set up to mitigate the risk of overheating in new homes. It not only looks at mitigating solar gain (heating due to direct sunlight) but also other causes of overheating due to uninsulated heating pipes, cylinders or lack of heating system controls.

The revised Building Regulations document states,

“All new residential buildings, including homes, care homes, student accommodation and children’s homes, must also be designed to reduce overheating, making sure they are fit for the future and protect the most vulnerable people.”

It also highlights that thermostatic radiator valves (TRVs) should be used on heat emitters. Although this in itself won’t prevent overheating bearing in mind solar gain etc, it will go some way to mitigating overheating due to poor responses to heating demand.

Due to the much lower water content of Jaga’s Low-H2O Hybrid radiators and the use of a good quality fast response TRV, thermal comfort and efficiency can be much improved.

The document highlights that passive cooling measures must be implemented “as far as reasonably practicable” to limit unwanted solar gains and remove excess heat before introducing air conditioning or mechanical ventilation systems.

Another feature of Jaga’s Low-H2O Hybrid radiators is the ability to provide ’light cooling’. This means that if cool water (approx. 15°C) can be provided from a heat pump, gentle, non-condensing cooling can be provided with water above the dew point. The advantage here is that there is no condensate being produced so no need for a condensate drain system.

ENERGY-EFFICIENCY

The latest figures show almost half (46%) of the homes in England are now rated C or above for energy efficiency, compared to 14% in 2010 but there is still a long way to go. For existing homes, the uplifts to both Parts L and F mandate new minimum efficiency standards to help further increase this figure. And for new homes, the government has adopted a ‘full fabric specification’ for setting the level of the Fabric Energy Efficiency Standard (FEES).

The updated regulations increase the threshold for fabric efficiency, with new requirements for insulation, thermal bridging, primary energy targets and air leakage testing. For example, most types of new window, roof window and curtain walling must achieve a U value of 1.6, versus 2.2 previously.

A new principal performance metric measuring energy efficiency is introduced in Part L. ‘Primary energy’ will be used in combination with CO2 metrics to assess compliance with this document. Primary energy calculations take into account factors such as the efficiency of the building’s heating system; power station efficiency for electricity; and energy used to produce fuel and deliver it to the building.

The use of electrically powered heating systems (particularly heat pumps) is now incentivised thanks to a change in the carbon factor of electricity.

VENTILATION

Improvements to ventilation standards will also be introduced this year. The new guidance in Part F (means of ventilation) was written as a companion piece to Part L (conservation of fuel and power) to ensure the provision of good indoor air quality (IAQ) in airtight buildings.

Changes will support the safety of residents in new build homes and help prevent the spread of airborne viruses in new non-residential buildings, as well as protecting the buildings themselves from damp, condensation and mould caused by moisture not being able to escape.

For homes, Part F now recommends advanced ventilation solutions, such as mechanical ventilation with heat recovery and continuous mechanical extract ventilation instead of natural ventilation. Natural ventilation is now only suitable for dwellings with a design air permeability higher than 5 m3/(m2·h) meaning many new build dwellings will not be suitable for this technology.

For new offices, there are additional standards for recirculating ventilation systems being introduced, along with the compulsory installation of CO2 monitors.

Ventilation guidelines will include a requirement for trickle vents in replacement windows and a new method for ensuring ventilation is not compromised when energy efficiency improvements are carried out in existing buildings.

In addition to offering efficient, responsive heating and light cooling, Jaga’s Low-H2O Hybrid radiators can also be used to provide mechanical ventilation as prescribed in Part F of the regulations – local control and regulation-compliant Specific Fan Power (SFP) figures can be provided by highly efficient EC fans housed within the radiator casing.

For the full Building Regulations and Approved Documents, visit the government website and see the links below for further reading.

GET IN TOUCH

If you’d like to discuss our heat pump compatible low flow temperature radiators or need support with your building’s mechanical ventilation strategy, please contact our team who will put you in touch with our technical experts.

FURTHER INFORMATION

1. Press release ‘New homes to produce nearly a third less carbon’ https://www.gov.uk/government/news/new-homes-to-produce-nearly-a-third-less-carbon
2. Consultation outcome: The Future Buildings Standard https://www.gov.uk/government/consultations/the-future-buildings-standard
3. Consultation outcome: The Future Homes Standard: changes to Part L and Part F of the Building Regulations for new dwellings https://www.gov.uk/government/consultations/the-future-homes-standard-changes-to-part-l-and-part-f-of-the-building-regulations-for-new-dwellings
4. New Approved Document L: https://www.gov.uk/government/publications/conservation-of-fuel-and-power-approved-document-l
5. New Approved Document F: https://www.gov.uk/government/publications/ventilation-approved-document-f
6. New Approved Document O: https://www.gov.uk/government/publications/overheating-approved-document-o
7. Impact Assessment: 2021 uplift to energy efficiency standards, improved ventilation and new overheating requirement https://www.gov.uk/government/publications/2021-uplift-to-energy-efficiency-standards-improved-ventilation-and-new-overheating-requirement
8. Guidance: Home user guide template and ventilation guide https://www.gov.uk/government/publications/home-user-guide-template