Most energy efficient electric heating?

siulas

I know that in other countries where apartment blocks put together money and install geothermal heat pumps for whole block, has anyone seen anyone do that in here? What would be costs of that?

loyatemu

siulas wrote: »

I know that in other countries where apartment blocks put together money and install geothermal heat pumps for whole block, has anyone seen anyone do that in here? What would be costs of that?

you'd have to retrofit the entire block which would be very expensive, you'd also have to get the agreement of a majority of owners which could be very difficult to achieve (particularly if a lot of the units are rented out and it's the tenants who are paying the bills).

antoinolachtnai

One thing you might be able to do, if you have a balcony or can hang a unit outdoors, is to install a heat pump. A heat pump transfers heat from the outdoors to the indoors. For every kWh of electricity input the heat pump should deliver 2-4 kWh of heat into your living space.They do need expertise to size correctly and get up and running properly.

siulas

antoinolachtnai wrote: »

One thing you might be able to do, if you have a balcony or can hang a unit outdoors, is to install a heat pump. A heat pump transfers heat from the outdoors to the indoors. For every kWh of electricity input the heat pump should deliver 2-4 kWh of heat into your living space.They do need expertise to size correctly and get up and running properly.

What would be rough initial costs of it?

antoinolachtnai

siulas wrote: »

What would be rough initial costs of it?

Hard question. For an air water heat pump I'd say you will be looking 5k at least. If the place suited mounting air conditioner units (an air to air heat pump) on the wall or ceiling that might be a bit cheaper but wouldn't heat hot water at all.

Earthhorse

OP, just to let you know I'm in a similar position to yourself and opted to get the Lucht (Technoterm) heaters. My apartment has storage and electric heaters that are old and need replacement. Like yourself, I did a lot of research and find it hard to come across definitive arguments one way or the other on the matter. So why did I go with Lucht?

Well, first I wanted to get rid of the current heaters because:
- they were old and needed replacement; the storage heaters emit a burn odour that isn't awful but which I'd prefer not to have and also are leaving burn marks.
- the electric heaters in the bedroom create a very dry heat, you can really feel it in your throat and nasal passage.
- the current heaters are ugly and I want something that looks nicer.

Why did I go with Lucht:
- personally, I was convinced, if not bowled over by the economics. Leaving the storage heaters on at the night rate ends up costing more than if you have the Lucht heaters on for every half hour of every hour you're around.
- you have more control over the timing and output with the Lucht heaters.
- according to one commenter on here I think, they don't produce that dry heat.
- they look well.

I have to say my current storage heater does a good job of heating the living area but by the same token we've had a mild winter and the heat does dissipate later in the day.

I'll be more than happy to report my experience back to you once I've been using them for a while.

In the meantime, if you're thinking of getting a space heater, I came across this website: http://thesweethome.com/. They do really in depth reviews of product categories and pick out the best from each one.

Here's their review of the best space heaters: http://thesweethome.com/reviews/best-space-heaters/

Ultimately I may end up getting a wood burning stove dependent on whether I can open my chimney flue back up.

But all this talk of heat pumps and the like is probably not realistic for an apartment situation. The truth is no one is as invested in the practicalities and outcomes of your decision as much as you are and in the electric heating game there doesn't appear to be a standout winner.

antoinolachtnai

Apart from using a lot of electricity, the lucht heaters aren't particularly cheap. Putting a stove in an apartment? It's not a particularly cheap or convenient way to provide heat, especially if you don't have plenty of storage.

I don't know if they are really that much more realistic than a heat pump. Obviously, it depends on the situation.

There certainly aren't any stand-out winners. I would say that if you can do anything to insulate the apartment it could make a big difference to comfort and economy.

Earthhorse

antoinolachtnai wrote: »

Apart from using a lot of electricity, the lucht heaters aren't particularly cheap.

Do they use more electricity than the alternatives? Compared to the alternatives are they particularly expensive?

Putting a stove in an apartment? It's not a particularly cheap or convenient way to provide heat, especially if you don't have plenty of storage.

Storage for what? The wood? And again, particularly cheap or convenient compared to what?

2011

I have a wood burning stove myself. Recently I came up with a great new idea that cuts the running cost of my stove by 50%. I simply burn 50% less wood than before. Sounds ridiculous? Well Lucht heaters use exactly the same technique:

Lucht Economical Radiator 1.8kw
20min of Charge = Gives 1 hour of Heat
(Lucht heater consume 1.8kw for 1/3 part of an hour only. Which equals 0.6kw per Hour)

There is only one downside to this, the heat output is directly proportional to the input. So if I reduce the average input by two thirds I will also reduce the average output by two thirds.

I accept that a Lucht heater is a more aesthetically pleasing, is non smelling, and has better control than a traditional storage heater, but the only way they use less electricity is by switching off which results in less heat being emitted. It is notable that their website does not claim that they are more efficient.

_Brian

Underfloor heating is designed to deliver small amounts of energy over long periods. The energy delivered is so low it is easily lost through inadequate insulation and airtightness.

I wouldn't consider it unless the insulation is excellent and the apartment properly sealed with controlled ventilation, younwill spend a lot of money and he disappointed, I've seen this happen.

76544567

A few years ago my dad installed a heat pump in his living room. It good his overall electricity bill by half. Basically he spent most of his time in The living room so that's where he wanted to heat the most.
He bought the unit for about €300 and you just mount it on an outside wall and make the hole for it.
It looked like one of those air conditioning units that you see in apartments on The continent. About 3 ft long with a remote control and find that can bet set to oscillate or stay still and just blow out air.
For the bedrooms and kitchen he had oil rads on timers.
I often thought I would love to get one of those heat pump units for my.house but never got round to it.
Should look into it.

Also.if you are in a small apartment you should try to have the whole apartment at the same temperature. If you have say the kitchen hit and the bedrooms cold you will end up getting mould in the bedrooms.

loyatemu

antoinolachtnai wrote: »

There certainly aren't any stand-out winners. I would say that if you can do anything to insulate the apartment it could make a big difference to comfort and economy.

it depends on the aspect, but most apartments would be fairly well insulated by virtue of being surrounded by other apartments (certainly compared to a house which has more external walls).

siulas

76544567 wrote: »

A few years ago my dad installed a heat pump in his living room. It good his overall electricity bill by half. Basically he spent most of his time in The living room so that's where he wanted to heat the most.
He bought the unit for about €300 and you just mount it on an outside wall and make the hole for it.
It looked like one of those air conditioning units that you see in apartments on The continent. About 3 ft long with a remote control and find that can bet set to oscillate or stay still and just blow out air.
For the bedrooms and kitchen he had oil rads on timers.
I often thought I would love to get one of those heat pump units for my.house but never got round to it.
Should look into it.

Also.if you are in a small apartment you should try to have the whole apartment at the same temperature. If you have say the kitchen hit and the bedrooms cold you will end up getting mould in the bedrooms.

That sounds interesting, where did he buy it?

antoinolachtnai

siulas wrote: »

That sounds interesting, where did he buy it?

I imagine it was something like this? http://m.ebay.co.uk/itm/Blaupunkt-Air-Conditioning-Heat-Pump-Inverter-System-3-5kW-Cooling-3-8kW-Heating-/112260502522?hash=item1a233f53fa%3Ag%3A3MUAAOSwLF1X7g1V&_trkparms=pageci%253Aa40f7bb8-d8bf-11e6-a951-005056b24358%257Cparentrq%253A92930f761590a78849904094ffba82ef%257Ciid%253A9

It would require professional installation but there are plenty people who would supply and fit one of these.

siulas

antoinolachtnai wrote: »

I imagine it was something like this? http://m.ebay.co.uk/itm/Blaupunkt-Air-Conditioning-Heat-Pump-Inverter-System-3-5kW-Cooling-3-8kW-Heating-/112260502522?hash=item1a233f53fa%3Ag%3A3MUAAOSwLF1X7g1V&_trkparms=pageci%253Aa40f7bb8-d8bf-11e6-a951-005056b24358%257Cparentrq%253A92930f761590a78849904094ffba82ef%257Ciid%253A9

It would require professional installation but there are plenty people who would supply and fit one of these.

I'd say this or lucht radiators are best options, but I believe in long term I would save more money with this sort of heat pump.
Thanks

2011

siulas wrote: »

I'd say this or lucht radiators are best options

Why?

siulas

2011 wrote: »

Why?

I like aesthetics of lucht
from all options listed, heat pump is probably most economical?..

2011

siulas wrote: »

I like aesthetics of lucht

I would agree with you on that front.

from all options listed, heat pump is probably most economical?..

Once properly installed and selected, yes.

antoinolachtnai

Consensus!

Earthhorse

2011 wrote: »

I have a wood burning stove myself. Recently I came up with a great new idea that cuts the running cost of my stove by 50%. I simply burn 50% less wood than before. Sounds ridiculous? Well Lucht heaters use exactly the same technique:

There is only one downside to this, the heat output is directly proportional to the input. So if I reduce the average input by two thirds I will also reduce the average output by two thirds.

I accept that a Lucht heater is a more aesthetically pleasing, is non smelling, and has better control than a traditional storage heater, but the only way they use less electricity is by switching off which results in less heat being emitted. It is notable that their website does not claim that they are more efficient.

I get the point you are making and that in this forum people are going to give the technical answer but although the question is about efficiency I think it's not just about that. Infrared panel heaters and electrical storage heaters are technically as efficient as each other but the latter are better are heating spaces and are more economically efficient.

If I recall from reading at the time the technology in Lucht is that they have rods in the heaters which get heated by the electric heater during the heating cycle and then release that heat as the heater switches off. This does not seem like an astounding claim to me but basically a refining of the idea in electric storage heaters. So they may be no more efficient at converting electricity to heat but they are more efficient at delivering it when needed. It may be truer to say that they are more effective and as a result more economically efficient.

But let's say that Lucht are lying to us and all that talk of rods and heating cycles is stuff and nonsense. In that case, the Lucht heaters are nothing more than a standard electrical heater with an integrated timer and thermostat. If we compare this to your (I assume fictional?) wood burning stove will we really get the same result? Well, perhaps if I were an autustic savant woodsman I might.

I find with my Dimplex heater in the bedroom that I turn it on initially for 20 to 30 minutes then switch it back on and off in 10 to 20 minute cycles. It's a bit of a pain. With the Lucht I should be able to set a temperature and let the technology handle that. With the stove I would need to fit a thermostat and then work out some system of having different sized logs to feed it based on experience. Not going to happen as it's completely impractical.

2011

Earthhorse wrote: »

I get the point you are making and that in this forum people are going to give the technical answer but although the question is about efficiency I think it's not just about that.

Yes, it is also about control and the quality of the heat.


I attempted to address this in a non-technical way here:


http://www.boards.ie/vbulletin/showpost.php?p=102143640&postcount=10

Infrared panel heaters and electrical storage heaters are technically as efficient as each other but the latter are better are heating spaces and are more economically efficient.

More economically efficient? By using off peak electricity?
Please elaborate.

If I recall from reading at the time the technology in Lucht is that they have rods in the heaters which get heated by the electric heater during the heating cycle and then release that heat as the heater switches off.

This idea is as old as time itself. Conventional storage heaters have been doing this for a very long time.


The idea with storage heaters is simple, heat the bricks or rods with cheap rate electricity at during the night, switch off the electrical supply at peak times and the bricks release the heat.


In reality this does not work. Why? Because the heat gets released during your breakfast, by lunch time they are cold, when you get home from work the house is like a freezer. So you switch the heaters on before you get hypothermia at the off peak rate but he heaters emit very little heat. Why? Because the heat is being absorbed by the bricks.

But let's say that Lucht are lying to us and all that talk of rods and heating cycles is stuff and nonsense. In that case, the Lucht heaters are nothing more than a standard electrical heater with an integrated timer and thermostat.

That is exactly what they are along with some thermal mass, they don't claim otherwise:


http://www.yourhome.gov.au/passive-design/thermal-mass

If we compare this to your (I assume fictional?)

Very real in fact.

wood burning stove will we really get the same result?

Yes.

I find with my Dimplex heater in the bedroom that I turn it on initially for 20 to 30 minutes then switch it back on and off in 10 to 20 minute cycles. It's a bit of a pain. With the Lucht I should be able to set a temperature and let the technology handle that.

I'm not trying to be smart, but that is exactly why thermostats were invented. Again this technology has been around for years. I think that what you are really saying is that the attraction for you with the Lucht heaters is superior control. However it is possible to install very sophisticated control systems to any type of electrical heater with a stat per room / zone, control from a smart phone or intruder alarm, set back temperatures, frost protection etc...

With the stove I would need to fit a thermostat and then work out some system of having different sized logs to feed it based on experience. Not going to happen as it's completely impractical.

Agreed, but my point remains the same:
If I use half the quantity of logs the heat output will be halved.
Just like the Lucht heaters if they use half the quantity of electricity the heat output will be halved.


Let me explain:

Energy is measured in joules, (J). As heat is also a form of energy this too can be measured in joules. Electrical power is measured in watts, (W).
A watt is joule per second. So if you take a 3000 watt (3 kW) electrical heater and switch it on for one hour it will use 10.8 MJ ( = 3000 x 60 x 60 joules) of energy. As all electrical heaters are 100% efficient it will emit 10.8 MJ of energy regardless of what type of electrical heater it is. The only difference is that some heaters (such as infra red) have a quicker response. This means that they will heat up and cool down quicker. The Lucht will heat up and cool down slower.


In defence of the Lucht, they look better, may be supplied as standard with better control than some other heaters, they are odourless (I'm told), the heat from them is not as dry as some panel heaters but switching off to make a saving .......

antoinolachtnai

Earthhorse wrote: »

Do they use more electricity than the alternatives? Compared to the alternatives are they particularly expensive?

They use the same amount of electricity and produce the same amount of heat per unit of electricity as a heater you buy for 30 euros in Argos. But they are a lot more expensive than a 30 euro heater from argos. (They do have advantages over the cheap heater certainly.)

Storage for what? The wood? And again, particularly cheap or convenient compared to what?

Electric heating is for all its faults really convenient. The transport and storage is included in the cost of the electricity and the investment you have made in your wiring. For wood, you have to store the fuel somewhere. 4800 kWh worth of timber is going to weigh a tonne and take up few cubic meters. Not only do you have to store it, you have to haul it through your home, and when you are done with it you have to haul the ash out and dispose of it.

76544567

antoinolachtnai wrote: »

I imagine it was something like this? http://m.ebay.co.uk/itm/Blaupunkt-Air-Conditioning-Heat-Pump-Inverter-System-3-5kW-Cooling-3-8kW-Heating-/112260502522?hash=item1a233f53fa%3Ag%3A3MUAAOSwLF1X7g1V&_trkparms=pageci%253Aa40f7bb8-d8bf-11e6-a951-005056b24358%257Cparentrq%253A92930f761590a78849904094ffba82ef%257Ciid%253A9

It would require professional installation but there are plenty people who would supply and fit one of these.

That looks very like it alright.

siulas

antoinolachtnai wrote: »

They use the same amount of electricity and produce the same amount of heat per unit of electricity as a heater you buy for 30 euros in Argos. But they are a lot more expensive than a 30 euro heater from argos. (They do have advantages over the cheap heater certainly.)

This got me thinking...
Is there so much more tech inside lucht than just oil based heater from argos?
Or am I paying a lot more for design and convenience to hang it on the wall?

Earthhorse

2011 wrote: »

Yes, it is also about control and the quality of the heat.

I attempted to address this in a non-technical way here:

http://www.boards.ie/vbulletin/showpost.php?p=102143640&postcount=10

I know. I thanked that post.

More economically efficient? By using off peak electricity?
Please elaborate.

The off peak electricity rate costs less to provide a similar amount of heat. So they are more economically efficient, at least in theory.

In reality this does not work. Why? Because the heat gets released during your breakfast, by lunch time they are cold, when you get home from work the house is like a freezer. So you switch the heaters on before you get hypothermia at the off peak rate but he heaters emit very little heat. Why? Because the heat is being absorbed by the bricks.

It does work, it's just not particularly satisfactory for the reasons you point out.

That is exactly what they are along with some thermal mass, they don't claim otherwise: http://www.yourhome.gov.au/passive-design/thermal-mass

Right so, what's the issue exactly? They claim to work a particular way and you're not disputing that.

I'm not trying to be smart, but that is exactly why thermostats were invented. Again this technology has been around for years. I think that what you are really saying is that the attraction for you with the Lucht heaters is superior control. However it is possible to install very sophisticated control systems to any type of electrical heater with a stat per room / zone, control from a smart phone or intruder alarm, set back temperatures, frost protection etc...

It's not just the superior control but the fact that the superior control ought to result in an economic benefit. I don't dispute it's possible to do all sorts of things with home automation these days but do they come with the benefit of the thermal mass component of the Lucht heaters?

Agreed, but my point remains the same:
If I use half the quantity of logs the heat output will be halved.
Just like the Lucht heaters if they use half the quantity of electricity the heat output will be halved.

Likewise, I'm not trying to be smart either but who has disputed this?

The only difference is that some heaters (such as infra red) have a quicker response. This means that they will heat up and cool down quicker. The Lucht will heat up and cool down slower.

It seems to me that the latter, coupled with the thermal mass aspect (can't stop using that phrase now, it's your fault for teaching me!), will result in a more even heat.

In defence of the Lucht, they look better, may be supplied as standard with better control than some other heaters, they are odourless (I'm told), the heat from them is not as dry as some panel heaters but switching off to make a saving .......

I'm not sure I get the last point. They switch off for two reasons: (1) like all thermostat driven devices once they reach a certain temperature they shut off for a while as the area is now heated (2) during the time they are switched off the rods continue to emit heat. It's the latter feature that is missing from other products (bar ESH, which we've already covered). Perhaps the benefit from point 2 will be negligible ultimately but I don't see why and there's really only one way to find out.

Earthhorse

antoinolachtnai wrote: »

They use the same amount of electricity and produce the same amount of heat per unit of electricity as a heater you buy for 30 euros in Argos. But they are a lot more expensive than a 30 euro heater from argos. (They do have advantages over the cheap heater certainly.)

Okay, but that's not really a fulsome comparison is it? I mean, I linked to a page back there with reviews of various space heaters and some heated the space faster than others, some were nosier than others and so forth. I'm sure they all convert heat at the same rate but that some are engineered better than others.

Electric heating is for all its faults really convenient. The transport and storage is included in the cost of the electricity and the investment you have made in your wiring.

Sure. But I'm already using electric heating!

For wood, you have to store the fuel somewhere. 4800 kWh worth of timber is going to weigh a tonne and take up few cubic meters. Not only do you have to store it, you have to haul it through your home, and when you are done with it you have to haul the ash out and dispose of it.

A wood pile can make for a nice feature in a home or indeed a chest to store it in, which could also double as a seat, can too. My home ain't big so hauling it through won't be impossible. Likewise, disposing of ash will just be another thing I've to dispose of. Plenty of people seem to use wood burning stoves without issue so I don't these as huge obstacles.

Earthhorse

siulas wrote: »

This got me thinking...
Is there so much more tech inside lucht than just oil based heater from argos?
Or am I paying a lot more for design and convenience to hang it on the wall?

I honestly don't want to sound like Mr. Lucht here but I would argue you are paying for a little more tech, the engineering of the product, the installation (and removal of the old heaters) and the product guarantee.

If you take a look back at the link I posted to the review of space heaters you'll see that similar heaters had different performances. It's just not true to say that all electric heaters are as good as each other even if they are all as efficient as each other.

Like I said before, siulas, if you're not in any rush I'll be happy to let you know how I get on with my Lucht heaters. If they're a bag of sh*te I won't hesitate to say so.

DoozerT6

Are heat pumps permissible in apartment buildings? (Due to the external fixtures and fittings).

2011

Earthhorse wrote: »

I know. I thanked that post.

Thanks.

The off peak electricity rate costs less to provide a similar amount of heat. So they are more economically efficient, at least in theory.

Any electrical heater can use off peak electricity. I assume that you mean that only storage type heaters can emit heat without consuming electricity during off peak times? If so as you said yourself "It does work, it's just not particularly satisfactory for the reasons you point out".

Right so, what's the issue exactly?

What I see as a misleading statement from this website:

Lucht Economical Radiator 1.8kw
20min of Charge = Gives 1 hour of Heat
(Lucht heater consume 1.8kw for 1/3 part of an hour only. Which equals 0.6kw per Hour)



Why do I see this as misleading? Let's do the maths,

If the 1.8 kW heater was on for 100% of the time for one hour it would consume 1.8 units of electricity so at a unit cost of €0.17 the running cost is €0.36

1800 watts x 60 minutes x 60 seconds = 6.48 MJ
Therefore it will provide 6.48 MJ of heat to the room at a cost of €0.36

If the 1.8 kW heater was on for 33.3% of the time for one hour it would consume 0.6 units of electricity this would cost €0.10

1800 watts x 20 minutes x 60 seconds = 2.16 MJ
Therefore it will provide 2.16 MJ of heat to the room at a cost of €0.10

In a nutshell a ⅓ of the heat for ⅓ of the cost !!!

Using this amazing technique of turning off the heater the website goes on to demonstrate how much money can be "saved" by tuning off the heater:

EXAMPLE 1:

Using "Balance 10" Saving is €45.90 a month

€45.90 multiply by 8 month = €367.20 << SAVINGS PER YEAR <<


EXAMPLE 2:

Using "Maximum Saving" is €60.60 a month

€60.60 multiply by 8 month = €484.80 << SAVINGS PER YEAR <<


EXAMPLE 3:

Using "Balance 10" Saving is €45.90 a month

Two heaters in use - €45.90 multiply by 2 heaters =€91.80

€91.80 multiply by 8 month = €734.40 << SAVINGS PER YEAR <<

This reminds me of my burning less logs technique :rolleyes:

It's not just the superior control but the fact that the superior control ought to result in an economic benefit.

Agreed, control can save money and add comfort. However control is something that should be added to any heating system.
I have seen nothing to suggest that the controls on these heaters are anything special or new.
Old fashioned stats are still used very effectively.

It seems to me that the latter, coupled with the thermal mass aspect (can't stop using that phrase now, it's your fault for teaching me!), will result in a more even heat.

Just to be clear, thermal mass with storage heaters is about heating up blocks (or rods) so that it will radiate out heat when the electricity is turned off. It will not provide more heat. During the heating up phase little heat is provided to the room as most of the heat is being absorbed by the blocks. Once the power is turned off the bricks cool down and the heat they give off warms up the room. So there is no net heat gain.

I'm not sure I get the last point. They switch off for two reasons: (1) like all thermostat driven devices once they reach a certain temperature they shut off for a while as the area is now heated (2) during the time they are switched off the rods continue to emit heat. It's the latter feature that is missing from other products (bar ESH, which we've already covered).

Yes, this feature is absent from heaters other than storage heaters.
However Lucht heaters are a form of storage heaters. However they do not provide extra heat.

Take the example above:
1800 watts x 20 minutes x 60 seconds = 2.16 MJ
Suppose during the hour 80% of the electrical energy is initially absorbed by the blocks. That is = 2.16 x 0.8 = 1.728 MJ
Then the remaining 20% of heat is released to the room = 2.16 x 0.2 = 1.728 MJ

Then the electrical supply is switched off. What happens? The brick cools releasing the heat into the room. How much heat energy? 1.728 MJ

So the total heat added to the room = 1.728 + 1.728 = 2.16 MJ
Right back where we started....

2.16 MJ energy in (electrical) = 2.16 MJ energy out (heat)

All we have "gained" is the ability to release heat that has been stored using cheaper rate electricity, but as we both agree the result is most unsatisfactory.

As per my earlier posts I do agree that these heaters have some advantages but I in my opinion websites such as the one linked to above are misleading in the extreme.
People then conclude that they will be able to make the above savings while heating their homes to the same temperature simply by swapping one type of storage heater for another.

Earthhorse

2011 wrote: »

Thanks.

No. Thank you.

I assume that you mean that only storage type heaters can emit heat without consuming electricity during off peak times?

Yes.

What I see as a misleading statement from this website:

This reminds me of my burning less logs technique :rolleyes:

That's fair enough, I'm aware a certain amount of the claimed benefits are marketing.

Old fashioned stats are still used very effectively.

I agree with the things you said before this but not sure what you mean by this?

Just to be clear, thermal mass with storage heaters is about heating up blocks (or rods) so that it will radiate out heat when the electricity is turned off. It will not provide more heat. During the heating up phase little heat is provided to the room as most of the heat is being absorbed by the blocks. Once the power is turned off the bricks cool down and the heat they give off warms up the room. So there is no net heat gain.

Yes, this feature is absent from heaters other than storage heaters.
However Lucht heaters are a form of storage heaters. However they do not provide extra heat.

Then the electrical supply is switched off. What happens? The brick cools releasing the heat into the room. How much heat energy?

No, I agree no more heat is generated.

All we have "gained" is the ability to release heat that has been stored using cheaper rate electricity, but as we both agree the result is most unsatisfactory.

I would have thought that this feature is what allows Lucht provide that slightly cosier heat. You have actually switched sides inadvertently there! The Lucht heaters are designed to operate on day rates so it won't be using the night rate. (I accept you can use them at night and will likely use this feature to try and heat the house in the early morning).

As per my earlier posts I do agree that these heaters have some advantages but I in my opinion websites such as the one linked to above are misleading in the extreme.
People then conclude that they will be able to make the above savings while heating their homes to the same temperature simply by swapping one type of storage heater for another.

Most of the literature is aimed at suggesting you'll save 50% on your heating bill. Maybe you will, but as you say a lot of that will come from the thermostat and timers, and I would be amazed if the saving was that good. I think we are on the same page here and anything else will just be splitting hairs.