Electric heating system

For the landlord it really does not matter how good or bad the heating is, what matters is that on the day of viewing it seems as if the heating is really good. So if you have bees knees storage radiators and the prospective tenant has had storage radiators in the past which were rubbish, they will not want the flat.

So gas central heating has a good name, electric has not, so if you have an option to use gas, then use it.

flameport said:

If that is really wanted, then the only sensible option is modern storage heaters such as Dimplex Quantum.
Installation costs will be similar to a gas boiler and radiators, and so will the disruption, as the heaters will require new circuits installing.

Whatever heating system is installed, the insulation of the building will need to be upgraded, including new windows.

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Thanks for your input Flameport. I have lived with storage heaters and it was not a pleasant experience. It was far too hot in the morning and by 8/9 o'clock it was chilly. I appreciate that with storage heaters on an economy 7 rate you get cheaper leccy but isn't it inefficient to heat the flat all day when the tenant is at out at work for most of that time? By contrast, electric radiators could be programmed to come on for an hour in the morning and 3/4 hours at night. would 4/5 hours of well-timed and thermostatically-controlled radiated heat be that much more expensive than 7 hours of night-rate electricity?

Of course, the electric radiators have the advantage of being able to be plugged into the ring circuit so no/little disruption or expense of installation.

You mention the insulation of the building will need to be upgraded. Why? The walls seem pretty thick - about 7-8" at the window recesses. As it is a purpose-built flat I don't think my friend would be allowed to (or would want to) do that unilaterally anyway. Also, why would the windows need to be upgraded? The (probably original) single-glazed units seem to have been well made and well maintained. They close properly and all seals are in place.

bullethead123 said:

would 4/5 hours of well-timed and thermostatically-controlled radiated heat be that much more expensive than 7 hours of night-rate electricity?

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Do the sums. Off peak is around half the price so yes off peak would be cheaper on those figures.

bullethead123 said:

The (probably original) single-glazed units seem to have been well made and well maintained. They close properly and all seals are in place.

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Single glazed windows lose twice as much heat as double glazed. In technical terms, single glazed U value 1, double glazed U value 0.5.

OK, but is the sum as simple as that? During a mild winter's day wouldn't thermostatically controlled direct heat be much cheaper (and more comfortable) than charging up a storage heater overnight? .

winston1 said:

Do the sums. Off peak is around half the price so yes off peak would be cheaper on those figures.

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For a start, whilst 3 or so years ago off-peak E7 was only about a third of the price of peak price, I doubt that you'd find anything like as cheap as half of the peak price these days. I'm currently paying 10.84p / kWh for off-peak, which is about 70% of the 'peak' price of 15.45p per kWh.

In any event, whatever prices one uses, the sums are much more complicated than you imply. Thermostatically controlled heaters will not be using energy for all of a 4/5-hour period for which they were switched on, and it's also unlikley that the storage heaters would need all 7 hours of off-peak electricity to get their bricks heated up.

Just checked out the Dimplex Quantum. seems storage heaters have come on a bit since my student days. One question though, does it need two supplies? A day one and a night one?

JohnW2 said:

For a start, whilst 3 or so years ago off-peak E7 was only about a third of the price of peak price, I doubt that you'd find anything like as cheap as half of the peak price these days. I'm currently paying 10.84p / kWh for off-peak, which is about 70% of the 'peak' price of 15.45p per kWh.

In any event, whatever prices one uses, the sums are much more complicated than you imply. Thermostatically controlled heaters will not be using energy for all of a 4/5-hour period for which they were switched on, and it's also unlikley that the storage heaters would need all 7 hours of off-peak electricity to get their bricks heated up.

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Thanks for your input John. I did do a 5min google to see wot the diff between day and night rates was but came up blank.
There is a lot to consider. Sure am glad I started this thread.

bullethead123 said:

I have lived with storage heaters and it was not a pleasant experience.

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Old storage heaters are totally unlike new ones.

bullethead123 said:

One question though, does it need two supplies? A day one and a night one?

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Yes - there is one supply for the stored heat, and another for the fan, electronic controls and the daytime heating element.

winston1 said:

Do the sums. Off peak is around half the price so yes off peak would be cheaper on those figures.

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It is not as easy as that, I moved out of my parents house in the 70's at that time single glazed with coke fires, my memory of the house was on cool days fire lit at around 5 pm and only on cold days lit in the morning, and the only problem I remember was a cold house, never recall the house getting too hot.

Before my mother died we had to return to the house to look after her, now cavity wall insulation, double glazing, gas fired combi boiler condensating, and radiators and TRV's in every room, and it was realised the problem was the bay window, it was a sun trap, so in the morning the radiator would start heating the living room, then the sun came out, radiator already hot by this time so combination resulted in room hitting 28°C. What was needed was for the radiator TRV to act faster so it turned off the radiator faster when the sun came out, so electronic heads fitted to radiators which reduced the temperature when sun came out to 24°C. Still hotter than wanted but within acceptable limits.

The main problem was bay window and double glazing, but the point is that central heating was OK until house was made more thermal efficient. So a 1980's storage radiator system may have worked, but today when the sun hits the windows, the heating must be able to switch off, not just down.

OK it seems this flat only has one south facing window, so likely OK, but outbuildings, trees, hills all affect the heating plus direction of windows, and we don't tend to fit automatic louvre opener on a house today, only used in green houses, but in real terms the house can become a green house. It clearly depends on the home not all homes have same problem, and even the amount of flies, and security will determine if windows can be left open, on sunny days I will get up at 6 am and open the doors in house to allow house to cool as much as possible, then close again at 8 am to keep house cool, as it is too well insulated to cool down naturally over night.

Living style also changed heating requirements, away at work all day, and home at 6 pm you want a timer on heating, but with a varied return time you want geofencing. It is easy enough to fit either TRV or wall thermostat which can geofence, but most wall thermostats have a limit of around 5 amp some times lower, there are thermostats designed for under floor electric heating which can handle 16 amp, but under floor heating no good for geofencing it is again too slow to react, how much you want to spend is also a limiting factor.

It is all well and good saying what you want is fan assisted twin core radiators in every room to control the temperature nearly spot on and react fast, one core heats other core cools, it seems ideal, until you consider noise of fan running. So every heating system is a compromise, there is no perfect system, and government has not helped, OK good intentions with rules on zone heating, and energy ratings, even my caravan has plastic double glazed windows, and blown air central heating both gas and electric powered.

But I have lived in one house in Wales with gas blown air central heating, very expensive to run as house single glazed and it was blowing warm air past a cold window, and it also made the house very dry. Latter houses in the estate went to circulated water central heating. And if you put 4 thermometers in a room, you will see the room is not at one temperature, mothers house with that bay window the temperature could vary 10°C within the room.

All replies are very interesting but could someone point me in the right direction for info as to how to work our the sizes and number of electric heaters which would be recommended for rooms this size

Room sizes:

Hallway 2m x 1.8m (no outside walls or windows)
Bedroom 2.7m x 4m (one 2.7m outside wall, one window (single glazed) 1.7m x 1.3m) north facing
Kitchen 1.9m x 3.7m (one 1.9m outside wall, one window (single glazed) 0.8m x 1.3m) north facing
Lounge 3.5m x 5m (one 3.5m outside wall, one window (single glazed) 1.7m x 1.3m) south facing
Bathroom 2.5m x 1.6m (no outside walls or windows).

As for room heights, they are all 2.4m high. The flat is on the second floor of a 4 story block and its construction looks to be 1970s brick. All walls not stated as 'outside' are party with other flats.

If you need any further info let me know.
Chris.

Read more: https://www.diynot.com/diy/threads/electric-heating-system.546945/#ixzz6PNDzOKSM

Heat loss calculations are complex and not something that sparks do. You need to ask heating engineers.

As @winston1 said, you need heat loss calcs. Google it- you'll find loads online, you can do the donkey work. Yes they're mostly on central heating sites but they'll give you a number in kwh (or BTU) for the rooms and energy is energy.
Of course your next problem (assuming your mate wants to do a cheap job with miracle panel heaters) is max load.

Keeping it simple in most homes a 2 kW heater will maintain room temperature in each room. So total 10 kW of heating.

Where it gets complex is to say at -10°C outside with a 2 kW heater it will take x hours to raise room temperature to 20°C.

If I look at my old house, as built 1978 it had one 4.5 kW gas fire for the whole of the house, and we lived in the house for a year or two before I fitted central heating, and in spite of knowing I could maintain the house at a liveable temperature with 4.5 kW the central heating boiler was 18 kW and we found it was not big enough so separated the domestic hot water from the main boiler and fitted a Main 7 instant hot water heater as well.

As time went by and cavity wall, and loft insulation added plus double glazing the boiler and gas fire were well over the size needed, it did not need geofencing as with a fan assisted radiator and 4.5 kW gas fire plus standard radiator the living room could go from 10°C to 20°C in around 15 minutes, but this new house, 10°C to 20°C in living room without lighting the open fire takes around 1½ hours.

The reverse is true too, tends to hold the heat, this room now 1:15 am is at 25.5°C and outside is at 12.2°C, the room below me is at 20.6°C clearly heat raises so even the temperatures of the rooms below the flat will make a difference.

My first house we were poor and kept heating low, could not really afford the gas, but it was not too bad until next door moved out, there were cavity walls to outside, but solid walls to next door, and so we were getting heat from next door until they moved out, then our heat was heating next door.

So there is really no calculator to say what is the minimum required, only way is to look at old bills, and if you work out a 468 watt heater is required to keep room at 20°C when -10°C outside it does not really help as you will not find any 468 watt heaters for sale. In all rooms but bathroom 2 kW, bathroom because it needs to be bathroom safe, likely a towel rail, as big as will nicely fit. The heaters will need to be thermostatically controlled so being over sized will not matter.

If you use a hot water system this can reduce maximum load, it is how my central heating works, at just before I am due to arrive home kitchen, dinning room, living room and hall are heated, latter the bedrooms are heated, so the programmable TRV heads prioritise rooms, kitchen first, then dinning, then living room then hall and finally up stairs so a 18 kW boiler can re-heat whole house fast enough.

If you want off peak then you can use a water store and circulate water only when required, and in that case yes you will need to work out how much heat to store, and in that case to reduce size of water store double glazing, cavity wall, floor and ceiling insulation will reduce the size required, but then it would not make sense as gas would be cheaper both to install and run, so to heat on cheap 2 kW per room, and let the thermostat control temperature.

I am not sure if there is a requirement with domestic, with offices you are allowed one hour to get to 20°C. And that is what larger or smaller heaters mean, it alters the time taken to reheat the room.