Vintage electric central heating help

[ericmark]

I saw a lovely system,

the diagram is some what simplified, the water stored the energy, in real life two massive water tanks, upstairs, so if electric fails, you still have thermo syphon to cool the solid fuel fire, and the floor is reinforced to take the weight. It was installed when the house was built, and the owner on moving wanted the same system in new house, quoted around £25k, so did not get it installed.

And this is the problem, what is your life expectancy? Will it pay for its self in that time?

We should use Joules or Calories to measure energy, but for some reason, we use watt/hours, maybe as we end up with smaller units, but my battery stores 3.2 kWh and cost around £1,100 so to have a battery large enough to heat one run using off peak would be a silly price. So we use bricks or water, there was an experiment using some crystals and latent heat of fusion, but it did not get far.

The brick is basic a lump of iron ore bound together with either clay or cement, it is not standard concrete. The the problem is the temperature used, they get very hot, and near impossible to stop the heat escaping, water is not heated anywhere near the same amount temperature wise, so easier to stop heat escaping. But water takes up more room.

So if you heat the store for 7 hours over night, the release rate is often too high for it to last 17 hours, so economy 10 replace economy 7 and at some point one got a boost, however the split rate means higher peak cost, to get the lower off peak cost, and the longer the off peak, the more is costs, I have off peak for 5 hours.

I went to look at different tariffs, and off peak varies a lot, around 6p to 16p per unit, I pay 8.95p, this means it is no easy task to work out costs, and the big question is, do you need all rooms heated 24/7? If a room is only heated from 6 pm to 11 pm, it will loose less energy to heating it 24/7, so many people have replaced the storage radiator with a simple resistive heater, as it is used for such a short time.

The debate is raging at the moment, as heat pumps typically have a lower output to boilers, my boiler has an output of around 20 kW, a heat pump likely would be half of that, so with a boiler one can heat as required, but heat pump can't allow the home to cool, as it would take so long to reheat.

Even gas v oil, the method changes, gas boilers can turn up/down, oil boilers turn on/off.

But the design of the house will make a huge difference to how to heat. There is no right or wrong, and only you can decide what will work for you.

 

[SimonH2]

I saw a lovely system, View attachment 351370 the diagram is some what simplified, the water stored the energy, in real life two massive water tanks, upstairs, so if electric fails, you still have thermo syphon to cool the solid fuel fire, and the floor is reinforced to take the weight. It was installed when the house was built, and the owner on moving wanted the same system in new house, quoted around £25k, so did not get it installed.

That is indeed a nice system. But £25k ? Sounds like someone was taking the p1ss.

 

[Taylortwocities]

That is indeed a nice system. But £25k ? Sounds like someone was taking the p1ss.

That’s what you quote when you don’t want the job!

 

[JohnW2]

The installation looks to me like late 50s. I’ll do the maths for you ….70 years!!!!

Yes, that sounds roughly right, but I suppose could be a little younger than that.

I think STD codes started to be introduced around 1958, but since it took them many years to fully 'roll them out',that doesn't prove very much

 

[JohnW2]

??

No evidence of any RCDs in sight, for a start

 

[ericmark]

That is indeed a nice system. But £25k ? Sounds like someone was taking the p1ss.

The problem is the floor needs to be strong enough, the system I saw up and running, had two massive tanks, I would say likely 100 gallons each, this is some weight, and with solid fuel it must fail safe with a power cut, so up stairs.

Quick internet hunt, this house has a 20 kW boiler, will in the worst weather likely runs for 1/3 of the time, (6.7 kW needed) off peak is 7 hours, so need heat for 15 hours, so 100 kWh required when not drawing from the grid, and 200 gallons would give one 80 kWh so not quite enough, but with better insulation or some other heating as well then it would work.

However in the main the whole idea of the system shown is the ability to use multi-fuels, all to same radiators. Each tank can cost £2000 so that bumps up price as well, for most it is a pipe dream, not a real option, and that is my point, we can select a good system, but a good system at a reasonable price is some thing else.

 

[SimonH2]

and with solid fuel it must fail safe with a power cut, so up stairs

That is the easiest way, not the only one. Its also the simplest system in operation.

However in the main the whole idea of the system shown is the ability to use multi-fuels, all to same radiators.

Indeed, and the hot water.
It also means you can design the heating system according to its needs instead of the limitations of the boiler - in particular the requirement for a minimum flow rate. Modulating pump, TRVs (or electronic controls) on all rads = nice quiet system. Then the boiler loop can be designed to suit the boiler not the limitations of the heating system.

Each tank can cost £2000 so that bumps up price as well

I know - put one in the rental flat about 14 years ago now, and in our own house a few years ago. Flat was an off the shelf one, ours was a custom design* to fit the space - could only fit 170l. Both are just there for the buffer and stored heat - the only heat source is the gas boiler.
* It was during covid, the original supplier just disappeared, the supplier I was working with put me in touch with MacDonald Water Storage and I really could not fault them - even for a custom design and while covid was on, they took my sketch, sent me drawings, and turned around the store in a very good time and at what I thought was a quite reasonable price.

, for most it is a pipe dream, not a real option, and that is my point, we can select a good system, but a good system at a reasonable price is some thing else.

True
But then my viewpoint on costs is coloured by being able to do most of the work myself.

 

[ericmark]

I have looked at tariffs of late, the original tariff I had was 29.57 p per kWh, I went to a split tariff of 8.95 p for 5 hours at night and 31.31 p for the peak supply, if using electric 24/7 at the same rate then average is 26.65 p per kWh, but we tend to use less at night, so to gain from the split tariff one needs to arrange things so the heavy use is at night.

I can see what I use and when I draw from the grid, below 0 is import, above 0 is export, so most of the power I use from the grid is over night. With electric heating however it comes down to when we want to heat the home, my oil central heating switches off at around 10 pm, and back on at 8 pm, I don't like it warm at night, and to be frank when I was working heating came on at 5 pm, the problem with heat storage is to stop the heat going into the house, when not required. In an old peoples home likely they do want 24/7 heating, but most other places they don't, so how does one work out the cost of heating 24/7 v 5 hours, as clearly the fabric of the building also stores heat.

So much is down to how fast heat is lost, I know the flat under the house is very slow to loose heat, or without heating on, to gain heat, it is where I brew my beer, and first 48 hours need beer at 19ºC and this time of year rarely cool enough to start a brew. But rest of house as all above ground level, and heat loss and gain is much faster.

So each home will have a different cut off point where single tariff and split tariff end up costing the same, in terms of hours when home is heated, so a couple who both go out to work, panel heater could be cheaper than a storage heater, as only heat the house for a few hours a day, but a couple with at baby the storage will work better, once the children reach school age again it changes, as even if one adult stays home during the day, they are likely busy, so don't want heating as high.

I was stunned when my daughter told me how much electric costs when it heats the house, clearly I use more in winter than summer July was £41.71 and February (did not have smart meter until end of Jan) was £82.50 in summer half the bill is the standing charge. I may also spend £750 on oil, hard to say, as price varies.

 

[SimonH2]

Each tank can cost £2000 so that bumps up price as well

As people are finding when going for a heat pump install - not only (often) do they have to update all the radiators, they have to find room for a hot water cylinder of some sort. From stuff I've read, these are often stainless, which costs more than copper for an equivalent cylinder.
Was just reading something today that was saying that a typical (if there is such a thing) install still costs in the order of £4k to £5k v.s. £1.5k to £2k for a new boiler, even after the government's £7.5k incentive.

 

[ericmark]

As people are finding when going for a heat pump install - not only (often) do they have to update all the radiators, they have to find room for a hot water cylinder of some sort.

I simply can't understand why anyone would fit a heat pump for heating only. The problem is the cooler the circulating water the larger the surface area you need for the radiator, best seems to be fan assisted radiators, as they can work to heat or cool, be they mounted high or low, so as said every radiator needs changing, and the likes of the Myson iVector is not cheap, clearly extra plumbing is required for the condensate extraction and you really don't want the pumps in view, the problem with fan assisted radiators is they have no TRV's, so the room temperature is controlled by fan speed, and if the fan is not running, hot/cold water is returned to heat pump, so the whole system really needs plumbing in series not parallel so the old pipes are useless.

The heat pump may use ¼ of the power of a burner, or element, but our electric system promotes the use of off peak power, or solar power, cooling is fine, if you need to cool, there is plenty of sun, heating is another story.

So what we look at is how much room one has, installation cost, and running cost, it is a compromise, there is no best system, this is why we have heating and ventilation engineers, I am an engineer but not heating and ventilation, engineer in this country means a University graduate, not the driver of a steam train, although working on a heritage railway, I have to admit it does take some skill.

To fit a modern gas boiler with OpenTherm and linked TRV's on every radiator can't see how one can get it wrong, but that is expensive, so the heating and ventilation engineer earns his money by designing some thing cheaper that will work in the home in question. I found by experiment a TRV in the same room as the wall thermostat can work very well, in some homes, when set up correctly, but it can also fail, one basic system does not suit all.

I think @WiseOwlOls has given up, this is what one would likely find in a museum, Beamish and the like, the old smiths clocks

I remember well, turn the cover to remove it, and then turn the centre knob to release the blades, and you could then put them at the times you wanted, you can also select the days of the week,

you want it to run, most if you pull the whole unit unplugs, so you can do all the settings in comfort, there was often a little red button on side to manually switch on/off, some did not have days of week, but some even have seasons so they could turn on lights earlier in the winter, there were quite a few variations of basic same device.

Above the is a relay, looks like a mercury device, not seen one that size, it was common to use mercury in thermostats, but not seen them before.

Centre is the old Wylex fuse box, they were only rated at 60 amp, in the main limited to 30 amp fuse, but some versions the first fuse next to isolator could take a larger fuse, the fuse carrier could be changed, rewire-able, cartridge, and even a MCB could be fitted in that box, the MCB needed the cover to have the centre removed, and trying to remove the centre often resulted in it smashing, so common with MCB's to see no cover. You can still get them, but at £22 each expensive the older ones had two buttons rather than a switch.

The box will not take a RCD so I had a separate box with RCD's in it this was before the consumer unit was invented.

As to the way forward, hard to say, clearly well past its use by date, it depends on what you want to spend. Or maybe how you want to spend, the more you spend to install new, the less you spend to run it, but we only have three score years and ten, so at 85 you may just leave as it is, at 25 you will likely rip it all out.

Also why you need to change, I know I had mother house re-wired in case I needed to let it out to pay for her care, as to an electrical installation condition report, (EICR) not sure how I would code it, could be just code C3, advise up-grading, but it could be a potential danger (C2) with mercury relays, so if a rented property likely you would be forced to upgrade.

 

[DetlefSchmitz]

I simply can't understand why anyone would fit a heat pump for heating only.

Because otherwise you don't get the grant.

 

[ericmark]

Because otherwise you don't get the grant.

What a stupid system, I thought idea of heat pumps was because of globule warming, clearly not the case, as will globule warming we will need to cool the home as well.

Maybe one can get a 28 sec gas oil (TVO) powered heat pump? Or gas powered? There was at one point a gas boiler with Sterling engine built it. My reason for not liking a heat pump, is in 1978/9 I went through the winter of discontent and I vowed never again would I rely on electric for heating, last house had a gas fire, this house has an open grate to burn wood etc, and the oil boiler is battery backed.

Some people after the Ronan Point collapse were unable to use gas any more, and some don't have storage area to use oil or LPG, so are forced to use electric heating. But a heat pump also takes up space, so selecting how to use electric to heat the home, is not easy, and much hinges around life style, if only need heat 6 pm to 10 pm, then storage heating is not the answer, but with a small baby and wanting heat 24/7 then it may be.

 

[Why Not Indeed]

What a stupid system

There are many layers of "stupid" here.
Air-air HPs are not eligible, Air-water [and presumably, water-water] are.
You have to have an EPC to get the grant, but it doesn't matter what the rating actually is, so what's the point?
The outdoor unit can only be installed under permitted development by an MCS-registered contractor, if you do it yourself you're not entitled to PD.
There are no doubt other WTFs with it.