13th May, 2023

An introduction to Part L


Part L Building Regulations: What do they mean for domestic installers?

Have you read the Part L building regulations? Don’t have the time? Been left feeling confused? Not sure if, or how, they will affect you or your work? Well, we’re here to help.

In June 2022, updates to the building regulations Part L, which cover the energy performance of new and existing buildings England and Wales, came into force.

Since then, the industry has been in a transitionary period. This means that work on homes with planning approval under the older regulations has been able to proceed – as long as it was started within 12 months of the regulations coming into force.

However, the transitionary period is now drawing to a close. From June 2023, all projects – retrofit and new build – will need to adhere to the new regulations. So, now’s the time to get familiar with them.

Why have these new regs been introduced?

The way that we heat our homes is one of the biggest contributors to carbon emissions in the UK. So, the primary aim of the new regulations is to achieve a 31% reduction of carbon emissions in all new homes by 2025 (a pretty ambitious target).

Part L is all about the conservation of energy, fuel and power. This means that the regulations will have a direct impact on domestic installers. One of the main differences about the new changes to Part L is that it does not only cover new builds, but it also covers existing homes and retrofit installations too.

So, with the deadline for projects under the old regulations fast approaching, we’ve covered the main changes that will affect domestic installers below.

Lower the flow temperature

One of the biggest changes to the regulations is that the maximum flow temperature for newly installed heating systems is now 55 degrees celsius, much lower than the previous standard of 80 degrees.

This lower temperature means that the heat emitters in a home will need careful consideration. Radiators could have to be resized and largened by up to three times to adequately heat a home at this lower temperature. Whereas underfloor heating is already optimised to run at a lower heat, due to the fact it covers a larger floor area and spreads heat evenly across a room or zone.

Where it is not possible for the boiler to run on a 55-degree flow temperature and the radiators and/or underfloor heating are not being replaced, the system should be designed to the lowest temperature possible whilst still meeting the heating demands of the property.

Insulate them pipes

In line with the new regulations, any new pipework will now have to be insulated. This includes primary circulating pipes for heating circuits, including those that pass into voids or ducts, pipework for domestic hot water, all cylinder pipework and all secondary circulation pipework.

All pipes connecting to a hot water storage unit will also need to be insulated for at least 1m from where they connect to the unit.

In existing systems if you update the boiler or cylinder, any new exposed pipework must now be insulated. It’s also worth noting that pipes need to be heat pump ready and have at least a diameter of 15mm. Are you wondering how on Earth this will be monitored in domestic projects? Well, in new builds in particular, photographic proof will be required.

A smarter choice

Heating controls are another key element of the building regulations. New systems in homes with a floor area of 150m2 or greater will now need a minimum of two independently controlled zones with each room, or zone, requiring its own smart or thermostatic controls.

For traditional convectional heating, this can be satisfied through a thermostat or thermostatic radiator valves on all heat emitters in the rooms that do not have a thermostat. For all hot water stores, a timer for heating and timer for hot water is required so that they can be controlled independently of the space heating circuit.

Underfloor heating can be installed in the same way it always has been – no additions required. This is because it is naturally designed and installed into zones. Therefore, underfloor heating manifolds are able to control multiple zones at once, allowing each area – or room – to be warmed to a different temperature depending on the user’s requirements.

In addition, the pump now needs to automatically turn off when heat is not required. So, the system controls should be wired to ensure that when there is no demand for heating or hot water, the heating appliance and pump are switched off.

Helping you to help your customers

As you can see from above, Part L is not just for new builds. Many aspects of it will have a large impact on how engineers design and install new systems. So, it’s important to get a firm hand of these new updates.

Over the coming months, we will be sharing as much helpful information as possible to arm installers with the knowledge they need.

But if you have anything you’d like to know more about or want to ask us a specific question, why not contact our technical team and they will be happy to help.

Need some help?

Contact our technical team for advice today

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