Wiring an RF receiver to infrared heaters

[mattnotfat]

You do know that the cost of energy from electricity is about four times the cost of energy from gas?

The general rule I've read is that providing the infrared heaters aren't under-spec'd they should be 'on' one third of the time https://www.acchaus.com/blog/far-infrared-heating-its-heating-jim-but-not-as-we-know-it/ Requirements for the whole house is slightly less Kwh than total CH radiator capacity, so taking that and multiplying by 0.33 for six hours a day gives a consumption about 1/4 Kwh compared to gas, making the cost about the same. Also there should be some savings because I can control each room individually - switch off heaters in unoccupied rooms etc. Plus I'd save an annual boiler service of £90 and could disconnect the Gas completely saving £60 a year in standing charges.

What I'm hoping to find out now is if the room will feel warmer with a better thermostat, or if the Herschel heaters aren't up to scratch - or if the whole infrared thing is really just marketing.

 

[mattnotfat]

Ah, I beg your pardon.

Yes, the receiver is 16A; the thermostat is 3A, so ok for what you want.


What about wiring it like this:

Existing socket unaltered >> one plug >> one cable >> receiver >> both heater cables.

Ok, maybe the way to do it. I think I'll have to get the electrician involved, which is a shame if he can't do it soon I won't be able to get a proper comparison with Dec/Jan usage.

 

[JohnD]

taking that and multiplying by 0.33 for six hours a day gives a consumption about 1/4 Kwh compared to gas, making the cost about the same

If, instead of adding 100kwh of heat to your house, you add only 25kWh, you are adding one quarter the amount of heat, so it will of course be colder.

If you want to make your house colder, you can do it by turning your CH thermostat down, and using one quarter the amount of energy from gas.

This will cost you about a quarter as much as the same amount of energy from electricity.

You will also save on the capital cost of purchasing magic beans.

 

[endecotp]

The general rule I've read is that providing the infrared heaters aren't under-spec'd they should be 'on' one third of the time

A gas CH boiler also doesn’t run continuously.

Also there should be some savings because I can control each room individually - switch off heaters in unoccupied rooms etc.

You can turn off radiators in unoccupied rooms too.

 

[winston1]

I wouldn't say it's a lie. The point is a radiator warms the air, and people feel warm because the air around them is warm. But it takes more energy to warm the air enough to have the secondary benefit of making occupants feel warm. Infrared heat warms the objects in the room, including people directly so should require less energy, but it's debatable how much less.

It definitely IS a lie. Maybe not deliberate, it is quite possible they are stupid and don’t know what efficiency is.

If they mean you feel warmer for the reasons you state they should say so.

Using radiant heat to warm the person rather than the room is so last century. Think open fires in one room and the other side of your body is cold, not to mention going to another room to make a brew etc.

 

[mattnotfat]

It definitely IS a lie. Maybe not deliberate, it is quite possible they are stupid and don’t know what efficiency is.
If they mean you feel warmer for the reasons you state they should say so.

They do cover this on their site, "Most of other forms of heaters are convection heaters which primarily heat volumes of air, which then has to transfer its heat to the building in order to warm the thermal mass. The problem is that hot air rises to the ceiling (where you don’t want it) and easily escapes with draughts and open doors." https://www.herschel-infrared.co.uk/how-do-infrared-heaters-work/

Using radiant heat to warm the person rather than the room is so last century. Think open fires in one room and the other side of your body is cold, not to mention going to another room to make a brew etc.

That is a known point, and it's usually recommended to install IR panels on the ceilings and have multiple smaller panels rather than one large of same wattage, to maximise the line of sight. I'm testing these in my back bedroom, where the computer is, and my legs do feel colder because they're under the desk most of the time - which also means it not warming up all areas of the room so should (in theory) be using less energy than heating the air.

The way I think about it is if the air temperature will be basically the same outdoors in shade or in direct sunlight, but you definitely feel warmer in the sunlight than in shade.

 

[JohnD]

let me check this

do you actually believe that you can heat a room to the same temperature, by putting less heat energy into it?

 

[endecotp]

You’re the victim of a scam, and you’re in denial.

If you want a “more efficient” electric heater, get a heat pump (aircon in reverse) or night storage heaters (more efficient in the sense of heater per £).

 

[ericmark]

Am I missing something infrared heaters do not heat air, they heat by radiation anything in its line of sight, but Salus RT510RF measures air temperature, so in time the infrared heaters will warm up things in their line of sight, and they will in turn heat the air which will in turn cause the wall thermostat to switch, however infrared heaters are normally split into bars and are controlled direct by a human machine interface (switch) to switch them on/off.

The infrared heater can be a really good addition to convected heat, so room can be maintained at say 17°C air temperature instead of 20°C and a PIR can switch on the infrared heater as and when the room is used, however as soon as they switch off it feels cold again, so you can select 1, 2, 3, or 4 bars on a heater, but having a thermostat for all bars or heaters would not really work.

I did use combined infrared heater and lighting at one time (tungsten lighting) and you did get a boost of heat when lights switched on, so the heating was set to 19°C air temperature which felt like 20°C once lights were switched on.

@mattnotfat has also pointed this out, so you would normally have stages of infrared heating, similar to with fan assisted radiators where rather than simple on off it will increase or decrease fan speed, and with infrared heaters it will alter how many are switched on.

Clearly you can use a thermostat to turn off the system in warm weather, but it is not going to control the room temperature switching all off/on. Well it will in a way, but the hysteresis will be huge.

 

[mattnotfat]

let me check this

do you actually believe that you can heat a room to the same temperature, by putting less heat energy into it?

No. To be clear I'm not suggesting a 1kw of infrared heat will majically raise the average measured air temp in the room any more than a 1kw oil rad or 1kw convector. What matters is how warm does the person in the room feel? Like I said before - on a sunny day go from the shade into the sun and you'll feel much warmer in direct sunlight, even though there is a minimal difference between the air temps. Air temp is not the only factor in how warm you feel. In this room right now the infrared heater is warming the surface of the futon sofa, but not warming behind the sofa, so should mean less power is consumed. But, as I said, that can also be a disadvantage because anything 'in shade' - my legs under my desk - won't benefit as much.

I'm fairly sure that in practice an oil filled radiator can be cheaper to run than a convector heater because the convector heater warms up the air, the warm air will go the ceiling and into corners of the room where it doesn't really benefit anyone. It also easily escapes unless you don't keep all the doors and windows closed, and because it creates stuffy air you're more likely to open doors and windows. An oil filled radiator both warms the air but also radiates, and because it retains some heat in the oil it still produces heat when it's not consuming power. That leads to less pronounced differences in room temperature, meaning you can feel comfortable with the thermostat on a lower setting, and use less power.

So yes all electric heaters convert electrical energy to heat energy equally. But how warm you feel can be different depending on the space being heated.

 

[mattnotfat]

You’re the victim of a scam, and you’re in denial.

Hmm. Some angry people on a forum after posting a simple wiring query. I have no idea what I'm supposed to be in denial about. If you want to know my reasons for considering infrared heating, it's in the posts above. You're welcome to disagree. But there's no point in getting insulting.

 

[endecotp]

I'm fairly sure that in practice an oil filled radiator can be cheaper to run than a convector heater because the convector heater warms up the air, the warm air will go the ceiling and into corners of the room where it doesn't really benefit anyone.

Nonsense.

 

[endecotp]

But there's no point in getting insulting.

The main reason to challenge your claims is for the benefit of other people who search for info about these extraordinarily expensive heaters, and find these posts.

 

[ericmark]

There is a problem with infrared heat, it can pass through normal glass, so where the heater is aimed and if curtains are closed or not will make a big difference, but how can one measure infrared heat is a much bigger problem, air thermostats are useless, so is turning a single array on/off, you need to have heaters not a heater and you need to control how many are running.

In the main infrared heat is used where there are rapid air changes, like in a garage where the doors are repeatedly opened, or where the time the area is heated for is limited like in a church, the other way to use is to part heat with infrared heat so convection gives a base heat say 18°C instead of 20°C and infrared heat makes it feel like 20°C, but you don't switch the infrared on/off it is the back ground heat which is controlled.

@mattnotfat has some very good points, the infrared heaters can save energy, by allowing a lower air temperature to be comfortable, but the problem is how to control them, and the whole question of this thread is how to control infrared heaters?

Be it a light bulb or a dedicated heater they can reduce the back ground heat required, and in fullness of time the fabric of the room will raise air temperature, but if the infrared heater is aimed at the floor, then the insulation value of the floor becomes critical with a ground floor, you want the infrared to turn into warm air, not into the ground. So an infrared heater placed either side of the TV would work like the open fire which also gives off infrared heat, but it would depend where the TV is in relation to window, if the infrared is pointing into the house then the energy with in fullness of time heat the air, but aimed at a window and it will pass straight through it in most cases, there is special glass which is not transparent to infrared, think it's called k glass but not sure on that, but most glass it will pass straight through, in which case infrared heating could be very expensive.

 

[SUNRAY]

I worked in a farm building 7x9m, building control panels and the sole heating was a wall mounted 3KW IR heater, I could feel the warmth when directly in the red beam but I froze as were my work pieces and tools. In the office were 4 700W oil filled radiators left over from before the gas boiler was installed, I tried those dotted around the immediate work area instead of the IR and was able to take my coat and gloves off. Obviously they didn't heat the whole room.

I see this in places like Wickes stores where IR heaters provide some red light to make you think one side of you is warm