A holistic approach to heating efficiency


Ashley Cooper of WMS explains why underfloor heating is in the spotlight following new requirements in the Building Regulations, and how the housebuilders can benefit from taking a holistic approach to
system design.

Following enforcement of the low water temperature update to the Building Regulations and Part L from June this year, the industry is now collectively adjusting to the single biggest change the housebuilding market has ever seen. Every newly built home is now required to prove a 31% reduction in CO2 compared to previous standards and demonstrate a maximum flow temperature of 55°C. Alongside this, to further increase efficiency, new properties must also now incorporate a self-regulating control device which allows for zoning within the property.

While there is flexibility on how to meet the new targets and there are a variety of renewable energy sources available, the Government expects heat pumps will be the primary heating technology for new homes. However, in order for heat pumps to work at their most efficient (COP) level they need to run between 35-45°C. By design, hydronic (water based) underfloor heating can easily achieve this, whereas at flow temps as low at 35°C, it’s very unlikely that radiators would even work!

Larger radiators would not only increase build costs, but they also create an eyesore and interior layout headache for housebuilders and homeowners alike – as such, they will quickly become a thing of the past for new builds.

When it comes to lifecycle comparisons, radiators typically need replacing after around 25 years – whereas we offer a 75-year warranty on our underfloor heating pipework, so is likely to outlive the life of the building itself. In addition, while radiators are typically made from steel or aluminium and can be recycled, the carbon produced during the recycling process is extremely high. So, when you look at the carbon effect of underfloor heating vs. radiators over the lifetime of a building, it’s clear to see why underfloor heating ticks more boxes!

While heat pumps and underfloor heating are the perfect zero-carbon emission pairing, precision system design and installation is vital to ensure the system reaches the required efficiency – otherwise, the knock-on effect will be increased energy bills. The result of good heat pump design is an efficient system which is capable of covering all of a property’s heat demand, regardless of outside temperature. Heat pumps will also last longer if there is less strain on the system, as such, it’s key to view the heat pump heating system design from a holistic point of view, where all parties involved with the proposed installation work together in collaboration on the design.

The foundation of any correct heating and plumbing design is a calculation of all the heat loss figures for a property. Availability of precise heat loss calculations not only leads to the correct specification of all equipment required, but crucially a seamless installation and operation of the finished system.

Some companies may rely on a W/m2 calculation to guess the amount of underfloor heating pipework required; however, we believe this does not provide accurate enough results when dealing with an ASHP systems.
Guesswork can also lead to heat pumps being unnecessarily oversized. If the heat pump is oversized, not only will the initial upfront cost for the unit be higher, so will the running costs for the homeowner.

This is where the importance of a holistic approach really comes into play, and there are many benefits when all parties involved with the proposed installation collaborate on the final design. As such, with this period of change ahead of us, we believe it’s never been more important for housebuilders to work with suppliers which are ready and able to support them to meet the new standards through collaboration and by putting best practice designs at the heart of their offering.

Ashley Cooper is managing director at WMS Underfloor Heating Ltd