Can I set a different temperature in each room?
The short answer
You can, but with floor heating it rarely pays. Every extra zone needs its own thermostat, wiring and valves on every loop, and Phil’s experience is that people who have six, eight or ten zones end up setting them all the same, because a well-designed floor just runs quietly in the background. A few large zones work better: one per level, or two for a big single-storey home split by how you use it. A spare room can simply be turned off at the manifold. Radiators and split systems are different, because each radiator or unit can be turned up or down on its own.
It’s a natural thing to want. Most of us grew up with an air conditioner on the wall of each room, or ducted air with a switch for the bedrooms, and setting the kids’ room cooler than the living room feels like the sensible, thrifty choice. With air, it is. A heated floor works differently, and the reason tells you a lot about what floor heating is like to live with.
Why does zoning suit air conditioning but not floor heating?
Because air heats up in minutes. A ducted system has flaps in the ducts that open and close each zone, and a split system heats only the room it hangs in, so turning a room on when you walk in and off when you leave makes sense. Phil’s point is that we’re so used to this from air conditioning that installers bring the same idea to floor heating, because they think it’s what people want.
A heated floor is the opposite kind of heater. It works at a low temperature, slowly and evenly, and it holds warmth in the concrete. Switch a room off and it takes an hour or so to come back, so you can’t warm the spare room for a movie the way you would with a split system. The floor is meant to run steadily through the cold months and keep the whole house at an even temperature. That’s how most of Europe does it: Phil points out that a European house usually has one thermostat downstairs and one upstairs, and that’s all.
What happens when every room gets its own thermostat?
Over decades of looking after the same clients, Phil has seen a clear pattern. People who asked for six, eight or ten zones end up, a few winters later, with every thermostat set to the same temperature and the same times. A well-built floor costs little to run and works in the background without being noticed, and the only time you do notice it is when you walk into a room that’s been switched off and the pleasant feeling isn’t there.
Meanwhile each extra zone has cost real money. It needs a thermostat on the wall, cabling back to the controls, and valve parts on every loop in that zone, and it adds one more thing that can go wrong. Phil’s verdict on room-by-room zoning for floor heating: “it’s just a bit of a gimmick, to be honest.” His rule is that the simpler the system, the better. The same thinking applies to leaving rooms out altogether, which people almost always regret, as we explain in whole house or just the living areas.
What works better?
A few big zones, set by how the house is used. In a two-storey home that usually means one zone for each level, because very little of the floor’s warmth makes its way up the stairs and the upper floor behaves differently. In a large single-storey home, two zones, split by which side gets the sun or by how the house is lived in, such as the living areas and the bedroom wing. A self-contained studio or a home office used on its own hours is just the sort of space a separate zone is for.
For a room you hardly use, there’s a simpler trick than a thermostat. Every loop starts and finishes at the manifold, the box on the wall where each room’s flow is set, and in Phil’s words “you can just simply go to the manifold and like a tap turn that particular Zone off”. When the kids move out, the spare room goes off. When they come home for the holidays, it goes back on.
If you’d like the bedrooms a little cooler than the living areas, say so at the design stage, because that’s when each room’s share of the warm water is set. And put the money you’d have spent on extra thermostats into a good controller instead. A better system reads the room temperature where people actually are, not the floor, and can check other parts of the house and the weather outside to send each zone the water it needs. We cover the choices in how to control hydronic heating.
4 min
What about radiators, ducted air and split systems?
Room-by-room control is where radiators shine. A radiator system still has a thermostat controller in the heated area to switch it on and off, but each panel has its own valve, so a room can be turned down or off at the radiator itself. Because every room gets its own radiator sized for it, usually one in a normal bedroom and two or three in an open-plan living area, the rooms also stay in step with each other. For an older Perth home that’s a big part of their appeal, and heating an existing home covers how they’re designed.
With ducted air, the zones are set by the flaps in the ducts and the outlets in each room, and getting the airflow right is a matter of balancing those when the system is installed. Split systems are the simplest room-by-room heating there is, one unit per room, and if you only ever heat one room, a split system is the cheap and sensible way to do it. We compare them with radiators in radiators or split systems.
Other questions people ask us
Can I control the zones from my phone?
Many controllers can be adjusted from a phone. A well-set-up floor rarely needs it, though: it goes on a timer at the start of winter, gets fine-tuned in the first season, and after that it’s left alone.
Will the bedrooms be too warm for sleeping?
Most people like their bedrooms cooler, and a floor can be designed that way from the start. In a large house the bedroom wing can also be its own zone, set lower at night.
Where should the thermostat go?
On a wall in the room or area it controls, where it can feel the warmth people feel. Not in a cupboard or an unheated room, and not reading the floor instead of the room, because the floor’s temperature isn’t what you feel.
Where to go from here
If you’re building or renovating in Perth or the south-west, the 5-minute quote gives you your options in writing within 3 working days, each with its price and a modelled running cost, and you don’t need final plans to start. Tell us how you use the house in your notes, and we’ll suggest the zones. If you’d rather read first, floor heating, explained shows how the whole system fits together.