UNDERSTANDING ZONING

What is Zoning?

Zoning is the ability to control two or more areas/rooms independently from the one boiler, heat pump or heat source or Manual operation could be as simple as turning on / off a valve.
An automated control would be setting temperatures and or time schedules for each zone and controlled via temperature sensors, actuators, relays and or zone valves.
When doing in-slab heating all the pipe circuits start and end at the manifold (Picture left), this gives the ability to zone each circuit.
You can have more than one manifold in a house; you try to make the manifold centrally located as much as possible, so the pipe runs getting to and from each room are reduce as much as possible.
The individual circuits (ports) on the manifold have a Flow (hot) and Return (cool) pipe on the manifold. The return line has a valve and the flow has a flow adjustment meter; To turn a circuit off you close a valve on the return of the manifold. This valve has actuators installed to turn on and off the circuit via automation.
If designed correctly each circuit on the manifold should go to a room with larger rooms having two or more circuits.
Zoning gives the ability to control each room independently, in over 15 years I have never known anyone to really control each room manually from the manifold.
Our automated system is designed for manifolds but can also be used on pumps and or zone valves.

Why zone?

Zoning makes the perfect sense to control each room.

  • Bedrooms lower temperature
  • Bathrooms higher temperature and turn on in the “off” season.
  • Rooms not being used are turned off
  • Rooms with windows facing the sun in winter has passive heating; much less active heating required.
  • Some rooms hold heat better than others

Heat Pumps with Zoning

Heat pumps are ideally suited to zoning.
The Heat Pump output is matched to each home, unlike a gas boiler one size does just about 95% of all houses in Oz. A Heat Pump increases in costs as you increase the capacity.
Suppliers and installers of heat pumps increase the sizing, to factor in having the whole house being heated whenever the heat pump is running.
Also the heat pump is more efficient for heating when the outside temperature is warmer. As the temperature gets colder the heat pump output is reducing.
So running during the day is more effective.
With zoning: bedrooms would use 50% less than bathrooms; and rooms not been used can effectively be turn off.
Zoning can clearly help direct the heat where its needed and programmed to run during the day to have the solar PV offset the running costs.

Selecting Heat Pump Size

If you do need to run at night or in the morning you can target the heating perfectly with zoning.
We size the heat pumps in Australia for the NSW southern Highlands, Snowy Mountains and Canberra regions at 80w/m2 (25.4btu / ft2) (250m2 heated house area heat pump size 20kw), never a problem if the house built well, with an insulated slab. This is well below industry standard.
Good homes well orientated and insulated would be less than 50w/m2 (15.8 btu / ft2) heat pump sizing for colder climates in Australia.