Here, Mark Dowdeswell Senior Category Manager from Uponor discusses how underfloor heating systems can help to meet the latest Part L requirements for low-carbon heating, and summarises the issues to consider to ensure the system can work effectively for the long-term.
In June this year, the one-year grace period for compliance with the revisions to Part L of the Building Regulations 2010 came to an end. As part of the Government’s strategy to deliver zero carbon ready homes by 2025, measures designed to improve the efficiency performance of new homes were introduced to Part L in June 2022 including:
- All new homes must produce 31% less CO2 emissions from new dwellings compared to the 2013 standards.
- New heating systems must be designed with a maximum flow temperature of 55°C.
- Zones within a new home need to have self-regulating control devices for heating systems.
How does underfloor heating help?
Both Part L and the Future Homes Standard emphasise low-temperature heating as the future of heat emitters, and whilst there are several options, such as solar and thermal, heat pumps are emerging as the primary heating technology for new homes to achieve the Government’s goals. As such, heat pump deployment is expected to reach 600,000 per year in 2028.
To work with heat pumps, traditional radiator sizes would need to increase significantly, which is an unattractive prospect, particularly where space is limited, or aesthetics are a priority. Traditional convectional radiators typically have one or two square metres of heat-emitting surfaces in a room and distribute heat upwards through a smaller heat-emitting area, which can lead to temperature differentiation (hot and cold spots) within the room.
Meanwhile, underfloor heating (UFH) systems have a vast heat transfer surface, which provides an even spread of radiant heat across the entire space. Due to their large surface area, underfloor heating systems operate well at lower flow temperatures (between 35oC to 55oC), making these solutions ideally suited to work effectively with air source and ground source heat pumps.
UFH is also an attractive feature for potential buyers. For those who are more environmentally conscious, or looking to reduce energy consumption, a house with a heat pump and UFH combination can tick a big box in their decision making – knowing that they have an efficient and future-proofed, low temperature heating system already in place.
Furthermore, UFH provides a more uniform temperature throughout the space when compared to radiators. Typically, the energy costs will be lower, and the system will require very little maintenance, as unlike a radiator, it does not need to be checked for air in the system or bled.
With mandatory zonal control, a UFH system provides a better thermal environment where different temperatures can be set for different spaces and at different times, thereby reducing energy wastage. It also increases the useable floor and wall space as it is discretely installed under the floor.
However, before incorporating UFH systems into a development, there are some aspects to consider to ensure that the most suitable system is specified. These include:
Wet or dry installations
Both wet and dry UFH installations are compliant with Part L, providing they meet the necessary energy efficiency requirements. However, wet installations are typically more energy efficient as they can be powered by renewable energy sources, rather than the electric supply. Additionally, they can be easily incorporated into the fabric of a new build.
Pipe material
The pipe material used in the installation of UFH is critical because it can affect the efficiency and lifespan of the system, as well as installation times. Pipes need to be durable, versatile, resilient and easy to install.
PEX pipe is a strong and reliable option, which is made of cross-linked polyethylene and is highly resistant to corrosion and scaling. The material’s flexibility also makes installation particularly easy. There are several variations of PEX pipe on the market including products that offer increased sustainability gains for a development, such as the Uponor Blue PEX, where the pipe is designed with a reduced CO2 footprint compared to fossil-based PEX pipes.
While often overlooked, the choice of flow and return pipework that connects the main heat source, or heat pump unit to the heating system of the building can also have a substantial effect on the performance of the system. Opting for a pre-insulated pipe solution such as the Ecoflex Thermo Twin HP, which is designed specifically for heat pumps, can ensure heat loss is minimised for optimum performance.
Controls
To comply with Part L, UFH systems must be equipped with suitable controls. Thermostats that have built-in automatic balancing are ideal as these continuously monitor the temperature inside the home and can auto regulate the space so that the heating system adjusts to conditions such as the weather, structural changes, or changes in usage patterns, all without the need for manual corrections. This can offer up to 20% more energy efficiency than alternative solutions.
Installation time
UFH systems that are easy to install will of course be appealing when taking build schedules and budgets into account. Solutions that can be fitted using a pipe de-coiler require only one person to lay the UFH pipe and for further efficiencies, consider UFH products that remove the need for over-boarding and the floor finish can be laid directly on top of the UFH system.
Reliability
Homebuyers will naturally want peace of mind that UFH will be problem free and developers want to avoid unhappy owners coming back to complain with the quality of the installation. If installed correctly, with the appropriate floor covering and according to the manufacturers guidelines, systems require little maintenance and are trouble free. A wet system should be thoroughly pressure tested after it has been installed and before the floor has been laid. If a screeded UFH system has been specified, the screed should not be laid until all of the pipework has been tested for leaks. By specifying a quality plastic pipe system, corrosion is eliminated and the need for joining (where potential leaks could occur) is also removed, with all connections for maintenance located above the floor finish at the manifolds.
Opting for products from a trusted underfloor heating system manufacturer, with enhanced product warranties will also safeguard investments. For the best specification, it’s important to engage with the manufacturer early on for detailed guidance on the most appropriate products to suit your scheme.
Uponor offers a wide range of tailored wet underfloor heating systems with a 25-year warranty offered as standard for new build developments, as well as one-to-one design, specification and installation support.