Ceramic V Oil Electric radiators

[Why Not Indeed]

What in the one room are you heating? I heat myself in my home office with a heated blanket - 40W max.

 

[JohnD]

I know gas is cheaper but am not going to turn off 15 rads at night and 15 rads on next day every time. They are balanced rads so hassle and possible mistakes.
I am comparing 22KW boiler to heat 16 rads when one room is used against a 1KW electric heater. 1KW electric heater will cost max 34p/hr and boiler will cost over £1/hr, with today capped prices.

Anyways, after further consideration, my choice is wall mounted oil rad.

You are making the mistake of thinking that your 22kW boiler constantly runs at maximum power all the time it is switched on. It does not.

It only fires during those periods when both the timer and the room stat tell it heat is required. It modulates the flame size down to adjust power input to (about) that emitted by the radiators.

And it turns off the flame when the temperature of the flow reaches that set on the boiler thermostat.

Incidentally, on my current tariff, I pay five and a half times as much per kWh of energy from electricity, as I do for energy from gas. So I could heat five rooms with radiators for the cost of one heated with electricity. Your tariff may vary.

I control my CH with a programmable thermostat that turns down the target room temperature at night.

 

[Rodders53]

You can fit controls to the radiators and zones to allow timed control of which will heat up and when.

Most radiators have Thermostatic radiator valves and you can get smart ones; that might work for you on an existing bedroom radiator - so that it only heats that room for a period before bed-time (and in morning)?

But for one room on occasional bedroom warming duties... an electric heater of whatever variety you want could do the job --- I'd use a smart switch or plug in timer probably (as I already do for an electric bathroom towel rail). Fan heater would probably be less suitable than a simple panel or oil filled type. Cheapest with a thermostat (and timer included, perhaps) will be my suggestion. If 500 Watt would suffice (probably in many bedrooms) then https://www.screwfix.com/p/glen-215...convector-heater-white-500w-815-x-211mm/992hv is one example.

Here, we have to try to get our bedroom down to a comfortably low temperature for sleeping in almost every day of the year due to heat rising and all CH pipes running through it's floor.

 

[ericmark]

I know gas is cheaper but am not going to turn off 15 rads at night and 15 rads on next day every time. They are balanced rads so hassle and possible mistakes.
I am comparing 22KW boiler to heat 16 rads when one room is used against a 1KW electric heater. 1KW electric heater will cost max 34p/hr and boiler will cost over £1/hr, with today capped prices.

Anyways, after further consideration, my choice is wall mounted oil rad.

I have these

on some of my radiators, in 2019 they cost me £15 each, and I can program them to heat rooms as and when required. OK there is a down side, if boiler is not running they clearly don't work, so work better with a modulating gas boiler than an on/off oil boiler.

So a typical modulating gas boiler has an output of around 8 kW to 28 kW depending on make and model, and so once the home needs less than 8 kW it needs to use a mark/space ratio to further reduce the output.

In the main if the boiler turns off due to the temperature of the return water, then it will turn on again at minimum output, but if some external on/off device has turned it off then on again, then it will turn on at full output, and has to go through the sequence of reducing output from scratch, there may be makes which have better algorithms to stop this, but they don't seem to wave a flag to tell people how good their boiler is, so I am unaware of boilers which have the algorithms.

So if we look at a gas modulating boiler it switches on and pumps hot water around the house which is cooled by the radiators so the return water is cool enough to gain the latent heat.

As each room warms up, the TRV gradually closes, even the electronic heads don't just turn on/off, they slowly reduce the flow, at first the reduced flow in some will cause increased flow in others, but once they can't take the flow the by-pass valve starts to lift allowing hot water to return directly to the boiler, increasing the return temperature, so the boiler starts to turn down, so it can continue to gain the latent heat, until the boiler can't turn down any more.

At this point the boiler uses a mark/space ratio, and can also adjust the length of time for the mark/space (often called anti-cycling) so if it turns on and the hot water returns fast it increases the time before it turns on again, and if the water returns cold it decreases the time with a simple system, but we are not privy to manufacturers algorithms so there may be other considerations as well.

But since it can never turn fully off, we fit an on/off thermostat in a ground floor room with no outside doors, and no alternative heating normally kept cool to turn the boiler off as summer arrives. I am sure you can see the problem, that room often does not exist, so we can use a compromise and use both a TRV and the wall thermostat in the same room, normally the hall, so the TRV allows fast re-heat, but then slows down so wall thermostat only triggered in the summer.

The alternative is to link the TRV and wall thermostat, and by doing that one can take over the boiler output control with the wall thermostat connected to boiler e-bus, OpenTherm is one system, using e-bus control means when the boiler restarts it can do so at low output.

It seems there is no limit to the extra controls we can add, my more expensive TRV's have the option for geofencing, as does my wall thermostat (unfortunately they don't talk to each other) but as will many central heating devices some are better than others, Drayton wiser TRV works out time to heat the room, so you set time you want it warm by, and it works out when to switch on, my cheap Energenie MiHome TRV's have OTT anti hysteresis so the geofencing does not really work, and my Nest Gen 3 does not allow the distance to be set, only the Eco and Comfort temperatures.

I will admit if we had an electric panel heater which incorporated all the controls found in the central heating it could be very good, and compete on a room to room basis, but the Drayton Wiser TRV costs £40, but an inverter driver to allow an electric heater to be controlled like a water filled radiator cost around £150, I am sure it could be done, likely a zigbee control, but the cost to control electric is that high, it would be better to use a centralised electric heater (likely a heat pump) and use water to distribute the heat around the home, and the inverter drive controls the motor speed of the heat pump.

It has already been said, an electric blanket could keep one warm, but why bother even with an electric blanket, just a blanket would do the same, but the whole idea of central heating is we can get up and walk from room to room without wearing out door cloths. I don't want to need to put on a coat to go to the kitchen, neither do I want pipes to freeze.

I remember watching my dad with a leather pad blow lamp and stick of solder wiping a joint to repair a burst in the lead water pipe, don't really want to see those days return, the whole idea of the post war ring final was to electrical heat our houses, but it seems all attempts have proved too costly, central heating using gas and oil has reduced the particular emissions from the solid fuel fires, and not seen smog for years, but gas and oil prices are pushing people back to solid fuel, OK there are some very good solid fuel heating systems, but the cost is silly.

 

[Why Not Indeed]

It has already been said, an electric blanket could keep one warm, but why bother even with an electric blanket, just a blanket would do the same, but the whole idea of central heating is we can get up and walk from room to room without wearing out door cloths

It entirely depends on the circumstances. I sit at my desk most of the day, and cool down as I am not particularly active. When I'm in other parts of the house, I am moving around, so don't feel the need for heating. Other seasons and combinations of people in the house require other combinations of central and local heating, as appropriate.

 

[Harry Bloomfield]

What do you read into this:
"
Do panel heaters use a lot of electricity?
Panel heaters are less efficient than electric radiators because convected heat is inherently less efficient than radiated heat. This means that you'll need to use more power to heat your room with panel heaters than you would with energy efficient electric radiators.
"

Absolute, total lies... All direct electric heating system are 100% efficient, no more, no less. The only exception are ASHP systems, which exceed 100%

 

[RandomGrinch]

All direct electric heating system are 100% efficient, no more, no less.

Well, almost
A few of these ceramic rads are also marketed as 'smart' - having LCDisplays and WiFi - so you may lose a fraction of a watt on radio waves and light!

 

[Harry Bloomfield]

Well, almost
A few of these ceramic rads are also marketed as 'smart' - having LCDisplays and WiFi - so you may lose a fraction of a watt on radio waves and light!

The 'fraction of a watt' will end up as heat, so still 100% efficient.

 

[RandomGrinch]

The 'fraction of a watt' will end up as heat, so still 100% efficient.

Yes, the energy will eventually end up as heat - however, unless fully absorbed, it will not necessarily end up as heat inside the room...

 

[ericmark]

Absolute, total lies... All direct electric heating system are 100% efficient, no more, no less. The only exception are ASHP systems, which exceed 100%

Define efficient. To my mind to heat a room to the temperature required for occupancy unless the room is used 24/7 one takes a ratio of time being heated compared with time being used, so heat for two hours and used for one hour then 50% efficiency.

So if we look at inferred and convection both waste energy. The inferred can be lost through windows, in the same way as we feel the heat from the sun through a window, we can lose heat from the inferred heater, so using inferred in a conservatory would be silly, as so much heat is lost, unless the time the conservatory is used is very short.

So to heat a room for say half an hour, likely inferred is best even if loads of windows, but convection heating needs a lead in time, so the longer it is used for the more efficient it becomes, use a room for 8 hours and heat it for 9 hours and 89% efficiency.

However with this we are assuming the room then cools fully before next use, if the ambient outside is zero, and the room has only cooled to 16ºC then clearly that has to be taken into account, using inferred the room will cool more as the air has remained cool.

So speed does matter, I can maintain my home at 20ºC with a 20 kW boiler with no problem, but if I want to take advantage of geofencing then what matters is the reheat time, so the most efficient radiator type to reheat is the fan assisted radiator, the worst is to use storage radiators, followed closely by under floor heating, but cost means likely the standard radiator is a good compromise, as no noise, and if positioned well we can retain some cool areas near the windows, my old house was hot air central heating was costly to run as warm air was being blown past single glazed windows.

However this house the radiators are at first glance in a daft place, right under the windows, so when the air is hottest it is where the insulation is worst, however against the window is one place we will not place furniture, and standard radiators are large.

So it is a trade off, and in general the more we pay the better it is. I did look at the new Ivector fan assisted radiator from Myson, the 5 speed fan means once the room is reheated noise is very low, but to reheat the room the output is very high for the size of the unit, also even if furniture like a chair is placed in front of it, the heat will still get into the room, and the really big advantage is same radiator can both heat and cool, seems a no brainer this is the future. However then we look at the price, plus of course to use it to cool, it needs some way to get rid of the condensate. The same applies to pipe work.

The other point is there is no restriction of water flow, output is controlled by fan speed, so if the fan is off, hot water is returned to the boiler, not a problem with a conventional boiler, but with a boiler designed to extract the latent heat from flue gases, that return water is too hot, so they would need a heat reservoir to work at top efficiency, which also means fast recovery time, and can use multi fuels, so solar, solid fuel, LPG can all use the same system.

But we return to installation cost, the twin storage tanks my brother-in-law had worked well, but were not light, not a problem as house built with them in mind, as he returned from Germany the geofencing would detect he was at Manchester and used the stored solar energy to reheat the house for his return to Mid Wales, but when he moved, was quoted £24k to install same system in new house, reinforcing floors, etc. And as he said, £24k will buy a lot of oil, at current prices, likely would be over 75 years pay back time, and once one hits 25 years loss of interest on the money spent means it will never pay for its self.


To install good heating systems in a new build, is very different to retro fit, to fit a heat pump with lagged pipe work and condensate pumps in a new build is great, but in an existing house, very different. Heating will never be free, we will always need to pay some thing, and for my three story house I pay as it stands around £320 per year for my heating oil, using all the latest technology maybe I could reduce that by 10% so £32 per year, at 72 I may reach 100, although unlikely, so 28 x £32 = £896 forget inflation as the higher the inflation the more interest I would get on the money if invested instead, so what can I get which will save 10% of fuel bill for under £800, answer very little. Remember already have programmable TRV's in most rooms.

But efficiency must include time and very few things can exceed 100%, Octane rating is one.

 

[DetlefSchmitz]

“When I use a word,’ Humpty Dumpty said in rather a scornful tone, ‘it means just what I choose it to mean — neither more nor less.’

’The question is,’ said Alice, ‘whether you can make words mean so many different things.’

 

[FrodoOne]

Q. Occasionally, I need to heat one bedroom in my house before sleep when alone. I have 16 rads, gas boiler 25KW boiler, surely 1KW (or less) electric heater is more economical than CH. Which type of electric heater shall I buy?

If you need to "heat" just one bedroom (independently of any other domestic heating), the best device is a "Fan Heater"- with this type of design, with a thermostat.
(https://www.cnmonline.co.uk/fiji-fan-heater-2kw.html)
It should need to operate for only about ten minutes to bring the room to an acceptable temperature before you "use" the room and you can use the thermostat to set this temperature.
It does not matter what the "wattage" of the heating device is for "economical" heating.
A 1 kW device or a 2 kW device can heat a room to the same temperature - but the 1 kW device will take (a bit more than) twice as long to do so.

A "flat" fan heater (such as the above) cannot "tip over", as heaters of this vertical design can (https://www.arlec.co.uk/product/2400-watt-oscillating-fan-heater/ )
If a vertical fan-heater does tip-over, unless it has a cut-out which senses that it is in the wrong position, it may cause scorching of floor surfaces or start a fire, if the thermal cut-out (which it should have) does not operate soon enough.

 

[ericmark]

Just been looking at the BBC website, it seems claims like talked about here will fail foul of a new law.

Wonder if that's the end of the Freddy Boswell adds?

 

[Harry Bloomfield]

Define efficient. To my mind to heat a room to the temperature required for occupancy unless the room is used 24/7 one takes a ratio of time being heated compared with time being used, so heat for two hours and used for one hour then 50% efficiency.

I obviously meant 100% efficient, as in transfer of electrical energy, into heat energy. BTW, your Welshpool preserved railway was on TV yesterday, during that program about classic car sales, Mathewsons, Thornton le Dale.