Experiments with Far Infrared Heating

What with the situation in the world, I've been trying to reduce our domestic gas consumption. Looking through our smart meter readings, our biggest usage is heating (in winter) followed by hot water (showers and baths) then cooking. We have a Tado smart thermostat which turns the heating off when we're out - but I wondered if there was something more efficient we could do.

Burning gas to heat water to pump around a home is… daft. It's noisy, expensive, requires a yearly service, and is difficult to control on a per-room basis. It is a fossil fuel with a tendency to explode. Yuck!

Heat pumps are marginally better. But they require a huge box installed and, possibly, bigger radiators. They still rely on pumping fluids around. Eugh!

So I decided to experiment with Far Infrared Heating. The science is simple - a thin flat panel which pumps out infrared radiation - and nothing else. No light, no whirring fans, no stored oil - just heat.

Before replacing every single radiator in the house, I decided to get the cheapest panel I could find which included WiFi (hey, what else did you expect from this blog?!). This is it:

Boring, innit? And it only cost £100 delivered.

It's the Maclean 360W WiFi heater. As far as I can tell, it's a rebadged OEM heater. It uses the near-ubiquitous Tuya platform, which means there's a basic app and it can be controlled by Alexa.

There's also some on-panel buttons for controlling it, if you don't trust IoT devices.

The controls are physically on the panel. The panel gets painfully hot to the touch so, sensibly, the area around the buttons has no heat. That said, it's easy to misjudge where your finger is going and feel a slight pain. There's an infrared remote control which feels plasticy and clicky and is just grim to use.

It's pretty thin, only 35mm, which includes the power box - but closer to 40mm if you use the included mounting brackets. And it is light - only a couple of kilos. These things are designed to be mounted on ceilings or walls. Mine also came with little feet to make it free-standing.

Thermal Imaging

Using my cheap Thermal Camera, I took a couple of photos of the device in use.

Here's the general heat distribution:

The top of the panel is quite a bit warmer than the bottom. This is also observable through touching the panel briefly. What's more interesting is the right hand side of the panel - where the controls are:

Despite the controls only being in the top corner, the entire column is considerably cooler. Effectively, this is a 50cm panel with a 10cm control space.

What I like about the system

The heating is instant. With a gas-powered radiator, I have to wait for the water to heat up and get pumped to the room. With this, I flick a switch and it is on. You start feeling the heat straight away.

The heat is directional - the back of the panel doesn't get very warm. Unlike a normal radiator which quite often needs a "reflector" to make the best use of the heat.

The aim of FIR is to build up "thermal mass". Rather than heating the air - which can be swept away in an instant - it heats objects which then continue to radiate warmth.

Because each panel is wired in individually, I'm not wasting energy by heating rooms I'm not in. I know I could dial down the radiator valves - or even get smart ones - but this just targets the rooms I'm in. And, when I leave - the heat can be instantly switched off.

Completely silent - no whooshing of gas or gurgling of water. Well, OK, there is a small speaker which beeps whenever it receives a command. And, as with anything, there can be the occasional creak due to thermal expansion. But it's a lot quieter than my existing heating system.

The Tuya app is a little basic, but it works. I can schedule rooms to be on or off, control them directly, or use the built-in thermostat. Or set the heating to come on when the local weather is a certain temperature,

Drawbacks

FIR has a few issues which are worth knowing about.

FIR heats objects and people, not the air. It is a different type of heat to convection radiators. Think of being out in bright sunshine on a cold spring day.

The heat travels in a straight line. So a panel around a corner will only heat things in its line of sight.

Thermostats generally measure the air temperature - so traditional ones won't work. There is a thermostat built in to this panel but it is only really measuring the ambient temperature around the panel.

The heat cuts off instantly. With a gas-powered radiator, the rad stays warm even once the gas has been turned off. With this, you get a few minutes of residual heat before it cools down.

Product specific issues

I deliberately chose the cheapest panel available. Longer term, I think I'd use someone like Warm4Less who offer a much better service.

Anyway, problems with this unit:

• Long shipping times from Poland.
• No wall mounting template - although they did provide screws & rawlplugs.
• Euro-style plug rather than BS 1363.
• No long-term guarantee - although these sorts of panels typically have a 100,000 hour life.
• The LED control panel will dim after a period of inactivity, but never switches off. When the unit is off, the power LED flashes. So you won't want it in your eyeline.
• The panel is pretty shiny, so reflects LEDs from your other gadgets. A matt finish would have been better.
• Only a 2m power cord. That's not really long enough for ceiling or wall mounting without extension leads.
• The Tuya app *sigh*

Tuya App

Tuya are near-ubiquitous when it comes to IoT and Home Automation. The Tuya Smart Life is pretty basic - and really could do with some UI and UX attention to detail. But, it works. Here are the sum total of the controls.

OK, once you're in the belly of the app, you can set actions to happen based on timers, weather, geographic location, and voice commands.

The app also has an Alexa skill which - despite my best efforts - I couldn't get working. I followed the Tuya Alexa Guide but the Echo just couldn't detect the Espressif-powered device. Annoyingly, there are two different official Tuya skills. I tried both of them, but no dice!

Security

The panel only has one TCP port open - 6668 - which is normal for these sort of devices.

As with any IoT device, unless you're prepared to spend ages configuring subnets, you have to take the risk that your devices could get compromised. YOLO!

Alternatives

I deliberately bought the cheapest panel I could find which was free-standing, so I could move it between rooms. There are panels available in all different shapes and sizes. Long, thin panels are great for hanging from a hallway ceiling, for example. There are picture panels if you want to use them as decoration, and mirror panels for bathrooms.

But all of them work in the same way.

Conclusion

Depending on the size and shape of your home, Far Infrared could be a good source of heat. The panels are passive and don't require any maintenance. If/when they break - you won't need a plumber or electrician to replace them. They're a lot simpler to install than a heat pump - and they're thin enough that you can place them in front of your old radiators if you want.

The 360W panel is enough for me to heat my home office. I have it set fairly close to me and it feels lovely. For larger rooms, you'll need much more powerful panels.

True, the cost effectiveness is highly dependent on the relatively price of gas and electricity. But the use of gas is being phased out across the UK and investment in this technology is likely to make it cheaper.

Overall, I'm happy with this experiment. When I'm the only one WFH, I can just heat my office and it will get warm pretty quickly. Most of my electricity comes from our solar panels, which is a much greener and cheaper source than gas.

I think, by next winter, I'll have these panels in every room and the gas heater will only be used for showers and baths.

Further Reading

I found these resources useful:

• ACC Haus "Far Infrared Heating. It’s heating, Jim, but not as we know it! (but you may need more power, Scotty) "
• Why infrared heating wouldn’t work for you…
• Far infrared radiation (FIR): its biological effects and medical applications