You’re right. 1kWh of electrical energy delivered always equals 1kWh of heat into the property.

When people talk about ‘efficiency’ they’re often confusing it with heat distribution. Oil electric retains the heat a bit longer, but the above still applies.

Anything else is nonsense.

Your average person on the street knows basically nothing about energy. As proved by the fact they turned down a heat pump which is by far the best way to use electricity for heating.

If they’re that far gone, I doubt you’ll be able to persuade them otherwise. Depends if £200 is worth it to you to shut them up lol.

They're incorrect. For electric resistance heating (including ceramic heaters and storage heaters), 1kW of electricity running through the meter produces 1kW of heat. This is due to the fundamental physics of electricity-to-heat conversion, which is always 100% efficient for resistive heating.

The "trickery" with storage heaters lies in using cheaper off-peak electricity (via tariffs like Economy 7 or Agile) to store heat for later use, potentially reducing costs but not improving efficiency.

Heat pumps are more efficient to heat a space, often around 200%-300% efficient. They don't generate heat directly (otherwise we'd be breaking the laws of physics) but instead transfer it from one place (e.g., outside air or ground) to another. A fridge or an air conditioning unit would do the same, but in reverse

Declining a heat pump upgrade was a missed opportunity. (I wish my landlord would upgrade me, damn.)

As for the AI response, don't take anything a language model (AI) takes as fact, they commonly "hallucinate" facts as they are (at the low level) statistical models which generate words that sound plausible together.

If you're interested in looking more into the information, I'd recommend these two videos on YouTube, they explain the concepts I've went over here very well:

https://www.youtube.com/watch?v=V-jmSjy2ArM
https://www.youtube.com/watch?v=7J52mDjZzto

If you've got any questions about heating feel free to ask, It was an interest of mine for a while.

Edit: phrasing

As many others have said, and you suspected, the tenants and the letting agents have misunderstood the most basic laws of physics.

The promotional wording from Bestheating is carefully drafted to say nothing at all. The wording from Heating Direct is word play: it does not actually say they are more efficient than anything else.

Your broader suspicion may well be correct: there is probably a comfort issue here. Personally I’ve never liked storage heaters. Perhaps the tenants have them on too long (to stay comfortable), so are paying more than they expect. Heating via electricity is always expensive. It would be worth checking that the tenants are on an economy 7 or similar tariff, that they understand how to use it, and you being 100% sure that the heaters are wired correctly so as to use that tariff.

If all else fails, you could offer to swap out just the heaters in (for example) the living room and the primary bedroom. Alternatively, I find oil radiators do a good job comfort vs cost wise but I suspect they’ll push back on that because it’s not a shiny new thing on a wall.

Storage heaters are woeful compared to proper radiators. My partner's landlord refused to put heating in the bedrooms at all until it was pointed out it's a legal requirement by the letting agent. He's put storage heaters in and they heat themselves up, and the air directly above them, and that's it. And cost a ton in the process compared to gas central heating. But he wants to keep his own costs down and that's his only concern.

It is not possible to give a definitive answer what is best between storage heaters and electric radiators because it will depend on a lot of factors including insulation, how much they are home, type of storage heater, and so on.

Ask them what they mean by efficient? Do they mean use less electricity or cost less to run?

People confuse efficiency and cost. If you use 10kWh for your ceramic heaters but 15kWh for your storage heaters then your ceramic heaters are more efficient (typically because you only run them when you are there). But if you were paying 20p/kWh for your ceramic heaters but 10p/kWh for your off peak electricity then you will actually be paying more to run your more efficient heaters. But depending on your usage it could be more efficient and cheaper.

What vintage are the storage heaters and what sort of property is it? A landlord of a 1 bed flat I know replaced one of the 3 antique storage heaters with a fancy modern high heat retention one (Dimplex Quantum) and the tenant was much happier because it was programmable and set and forget,

To answer one of your other questions, ceramic radiators are part radiator, i.e., they radiate heat as well as heating the air. That means if you sit in front of one then some of the heat will be directed at you rather than heating the air. It's a bit like feeling the warm sun on your face on a cold day, or standing near a bonfire on a cold night. So it may be that if you have a storage heater running at 2kWh and a ceramic radiator running at 2 kWh you feel warmer with the latter because 1kWh is going into the room and 1kWh is going directly int room vs 2kW going into the room.

Since when do tenants dictate what upgrades goes into a house. It's you're house and choice what heating system you choose and if the tenants don't like it it's their choice to stay or move.

Take advice from professionals and not tenants. Air source heat pumps might be the best option but it depends on the property and it's current insulation levels. Do your own research and make the best choice for your circumstances and house. Personally I'd never let a tenant dictate their wants on such an expensive upgrade based on their research and beliefs.

I work in emergency accommodation. We have over 300 properties/ rooms to heat. Only one building has heat pumps. They are rubbish (mitzsubishi make). My company only pay to maintain them so the building can keep it's 'green eco-friendly' tag.

All other places have storage heaters. Fck me, they chuck out heat, and according to the MD, they are cheap to run, considering the heat they chuck out, due to being economy 7.

I think an air conditioning unit is the best system for electric heating. The full system is designed to work together.

With air source heat pumps, they're retro fitted to old pipe work, radiators, and trv's. People don't understand how to run them, and 90% of heating engineers just slap in an ashp in and leave the occupier to it.

I know enough about ashp to know i don't know enough. That's why I'm sticking to my 20 year old gas boiler.

Seriously don't listen to AI on these things. Losing heat is what heaters are designed to do. If you keep all the heat in they won't heat anything around them up.

More modern lot20 storage heaters probably would be your best option, along with a better tariff. Air source heat pumps don't have a good reputation ATM. They can be great in the right property with an appropriately designed system, but the odds of getting a salesman who will bung just any system in and run off with the money is just too great IMO.

Electric heating is always 100% efficient. Heat pumps can sort of exceed 100% on paper by moving heat from the outside into the property.

With storage heaters the tariff is the important thing. If they are on a bad tariff they will be too expensive to run. Octopus energy are coming out with a tariff called Snug which I'm on the wait list for. That will charge me 9p a kWh off peak and 25p kWh peak. You get 6 hours at night and an extra hour in the afternoon at a point the supplier chooses between 2 and 4. This is ideal for storage heaters. The down side is many of the lot 20 heaters won't come on in the afternoon unless programmed too. The changing time for when it charges could mean they won't work with the tariff. In this circumstance the older heaters may well be better.

I use storage heating in my 3 bed all electric house and I'm an electrician who works on these systems.

Fit a heat pump. Nobody should be using direct electric heating.

Reading the other comments it seems its not actually about efficiency of electric to heat (100%)

But the efficiency of getting that heat to the person.( Leaks when they are not home. Or instant heat. Or the ability to heat qucikly would affect the tenants )

The air source heat pumps are really only good for well insulated buildings (such as new builds) and ones that have been designed to be air tight (aside from the purpose ventilation).

There's some good info out there and generally they're only as good in efficiency as your average boiler over an entire year (+90%) even though yes they technically can get upwards of 320% efficiency, but only when the outside temperature is ideal for the heat exchange. Too cold and they struggle, using more electricity, plus they're prone to their exchange elements freezing in colder weather which reduces the exchange, thus more electricity used.

They're a good piece of tech but only in new builds or well retrofitted buildings with good insulation U-values.

If your building isn't insulated to current building regulations, then I'd go down the ceramic route. Might make a bit of a difference but as others are saying, 1KWh of heat is just 1 KWh of heat, it doesn't really matter if its quick to dispers or not. The ceramic will help hold the heat as a sink and radiate it but not really worth the money in my opinion. I'd spend it on loft insulation (25% of heat is lost through the roof) and this can be done relatively cheaply (£1100 by contractor) or even less if you want to put the time in to save the cash.

Beware of replacing them for your epc could drop until they reform it. I saw a few posts this week where people have swapped storage heaters for something better only to find their epc dropped a level as they prefer storage heaters at current.

Generally, yes, they’re more efficient and cheaper to run, also more control over them then storage heaters. Older storage heaters are generally not very efficient.. I mean, they didn’t need to be when energy was cheap and the tech wasn’t as good. But newer ones are more efficient than older ones (as you would expect). Tbh it’ll probably be an advantage either way upgrading them to ceramic anyway, again, more control, look better and more attractive to renters..