For example, if only one person is at home during the day, then the ground floor could be used as one zone, where the heating is on. The upstairs bedrooms then become a separate zone, where the heating comes on during the evening only and often at a lower temperature to the main living rooms. This allows householders to match their heating use to their lifestyle, which is more energy efficient.
It’s also particularly beneficial when you consider different living arrangements. For example, more and more homes now have ‘granny flats’ or people working in home offices, where the heating may need to be on at different times of the day.
There are also a number of other reasons to consider zone control.
If there is only one room thermostat installed in a property, then the temperature in that particular room will determine whether the rest of the house is receiving heat. This isn’t always effective, as upstairs rooms may already be at a higher temperature due to warm air rising and rooms facing north or south can differ quite dramatically in temperature. Without zone control, central heating systems can be ineffective and inefficient.
How to get in the zone
The changes to Part L of the Building Regulations state that all new systems in non-open plan domestic dwellings must incorporate at least two separate heating zones, with one zone covering the ‘living area’.
Heating zones will often be divided to cover ‘living’ and ‘sleeping’ areas, or upstairs and downstairs. Both zones must have heating control through a thermostat and individual TRVs.
The revised Part L states that all radiators must be fitted with a TRV except those in bathrooms or rooms with a room thermostat. The same applies within existing properties where it is good practice to install TRVs when replacing a boiler has drained down a system.
More advanced zone control can be achieved using a two-port motorised valve and an additional room thermostat. Ideally, a programmable room thermostat should be used which combines temperature and time control. This creates a separate heating zone within the home, with the opportunity for independent temperature and time control.
The motorised valve will control the water flow from the boiler to the heating and hot water circuits. The two-port valve will open or close depending on demand from the additional room thermostat. When the room thermostat calls for heat at the set time, the heating valve will open. Once the thermostat is satisfied, the pump and boiler will switch off to save fuel. This gives far greater control over the temperature reached in that particular zone at that time.
Independent time and temperature control is particularly beneficial in larger properties, as required by Building Regulations. It’s also worth considering for homes that are poorly insulated, as it helps to minimise potential heat and energy loss. Plus, if householders are adding an extension or conservatory, then more advanced zone control is recommended, particularly for conservatories, which can overheat due to solar gain, unless independent temperature control is used.
Staying in control
Any form of zone control will deliver energy and carbon savings, and will allow householders to use their heating system in a more sensible way, by preventing rooms from overheating and unoccupied rooms from being heated unnecessarily. Installing TRVs with a main room thermostat is an easy retrofit solution for the majority of existing homes. For larger properties and extensions, installers would be wise to recommend more advanced zone control that can deliver even greater savings.
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