Total Heating Total Control (THTC)

Total Heating Total Control (THTC)

storage heaters, no longer fit for purpose
Storage heaters….no longer fit for purpose?

Storage heaters were originally developed to use electricity produced at night when demand was low which would otherwise have gone to waste. The heat or charge is built up over night and then gradually released during the day. To encourage people to use this heating system the electricity companies discounted the cost of this night time electricity. Originally they gave 7 hours discounted electricity over night, the cheap electricity, being monitored by a separate meter and this was called “Economy 7”. This is still very much the standard in most of England and parts of Scotland.

One problem with this was that much of the heat, produced, giving a cosy house in the morning (often when people didn’t need it especially if they were out working and the kids at school) often dispersed by the late afternoon and evenings meaning people were either cold or had to find another method of heating to supplement their storage heaters. There are still about 5 million households in Britain using this system. This was even more of a problem in Scotland with it being that bit colder which led to the introduction of a more flexible solution which was called Total Heating Total Control or THTC.

There are over 150,000 households in Scotland who heat their homes using THTC. This is an improvement on Economy 7 as it allows the storage heaters to receive top ups during the day, controlled by a long wave radio signal sent along with Radio 4! The idea is that if the weather looks like it could be particularly cold then the heater will be given a boost as required. However it appears some households under the THTC tariff are set to particular times and come on whether the additional heat is required or not.

Another big plus of the THTC system apart from it heating hot water at the cheap rate, is that there are effectively TWO supplies of cheap rate electricity one is as mentioned above controlled by others for your storage heaters, the second a constant supply of cheap rate electricity used usually for panel heaters in the bedrooms and a focal point fire in the living room where you can use cheap rate heat instantly when you need

Regrettably there are a lot of negatives about storage heaters and THTC, in our opinion much more than the positives.

The three main problems with storage heaters is lack of control, high power usage and the type of heat produced, convected heat (hot air) rather than radiant heat.

Storage heaters do not respond to change in climatic conditions very easily, if you get a mild day you could find that you have wasted lots of money powering up that heater, producing heat which was not needed. Some people have even been known to open the windows to let the heat out. If you then turn your storage heater off overnight and it then turns cold, you have to wait 24 hours for it to build up a full charge again.

Many houses are empty during the day. With the bulk of the heat being available in the morning this is wasted. When people arrive home at night they often might find the heat has all but dissipated and they have to rely on expensive alternative heat sources such as fan heaters to get the room comfortable.

Although benefiting from cheap rate electricity, storage heaters are very hungry for power with a typical heater in the average living room using 3.4 Kilowatts of electricity per hour!

Convected heat is wasted as it rises to the ceiling. giving a warm ceiling but it could be much colder nearer the floor Radiant heat produced by modern heating systems, travels more in a straight line giving a more even and economical heat throughout the room, just like the heat from a fire or stove.

People on Total Heating Total Control, THTC, have effectively three electricity supplies :-

1) The cheaper rate supply that charges your storage heaters, on at night, but sometimes also on intermittently during the day, giving boosts to your storage heater units, sometimes by timer, but often controlled by a radio signal Scottish & Southern Energy ( SSE or Scottish Hydro) decides, supposedly on the basis of the weather, if they should give a boost to the hundreds of thousands of heaters (or not) YOU HAVE NO CONTROL APART FROM THE OFF SWITCH!!

2) The cheap rate supply that controls your panel heaters, focal point fire in the living room (if you have one, usually found hard wired), your hot water and possibly a towel rail in the bathroom

3) The “standard” supply, which is used for lights, television, cooking etc. The only problem is you are not charged a standard rate.You are charged a premium over other non storage heater users, in the region of 20-30% So it is not really a standard supply it is a PREMIUM PRICED electricity supply.

THTC customers are penalised for having access to cheap rate electricity, this seems to happen with any dual tariff supply, but the premium is much higher probably because you have access to something that other storage heater tariff’s don’t have …. A CONSTANT SUPPLY OF CHEAPER RATE ELECTRICITY!

But is the cheaper rate cheap?

The difference between the two rates has reduced over the years the latest rates we got from one of our customers applicable from 1st October 2021was 24.19 pence per unit and 19.34 for the cheaper rate.

Just now energy prices are chaotic , but to put this in a bit of perspective we are currently paying about 18pence a unit for our standard electricity.. Way cheaper than the cheapest rate above.

THTC is known as a legacy tariff and is no longer offered to new customers.

SSE or Scottish Hydro has been taken over by Ovo energy (just the part that suppliers domestic customers) They have announced that they are ending support for THTC in March 2023.

There are lots of things up in the air just now, one thing is for sure, energy prices are getting dearer.

We think there has never been a better time to change from expensive storage heaters to more energy efficient electric heating such as our German Clay core heaters or our Far Infrared heaters

More info on our websites below

Heating Products

Infrared Saunas

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Elsco Heating Ltd

69 Wards Road



IV30 1TE
Phone: (John in  Elgin) 01343 819676

Phone (Dennis in Glasgow) 07526 704204