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Central Heating: Smart Controls to Save Money

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A fully manual central heating can be very inefficient and costly to run. There are a number of measures you can take to improve efficiency and save money.

1 Time Control Clock

Many modern boilers are fitted with an integrated time control clock. Many boilers, especially those more than 5 years old do not have any built in time control.

An independent time control clock is fitted between the fused isolator switch and the electrical connection to the boiler. There are two types of control clock:

Mechanical timer clock.

The Danfoss 103 as shown below was once very popular, and still available if anyone wants one.

Danfoss 103 Mechanical Timer

Danfoss 103 Mechanical Timer

Digital RF* room thermostat.

Digital equipment is now becoming much more affordable. Prices have fallen by 50% in the last couple of years. It is now possible to buy wireless RF thermostats for under £50.00

Danfoss RF Room Thermostat

Danfoss RF Room Thermostat

* RF stands for Radio Frequency [typically 433MHz, with a working range up to 100 meters]

The items above can be combined into a fully digital timer/control/thermostat arrangement [RF programmable room thermostat] as shown below.

Danfoss Prgrammable RF Room Thermostat

Danfoss Programmable RF Room Thermostat

There are three options for the programmable functions. A RF thermostat will only be ONE of the following:

24 hour – one set of time settings will be available for all days of the week. This offers least flexibility of function/lowest cost reduction [if you like a lie in on some days, the heating will come on at the same time regardless]

5/2 day – this offers one set of times for Monday – Friday and the option of different times for Saturday – Sunday. Better than the 24 hour option, but no good if you want to alter different days.

7 day – the best option by far. The 7 day option offers the facility to set different times for each of the 7 days of the week. Fully flexible and gives the option to control heating times around your lifestyle.

The same RF technology is now available for hot water cylinders as shown below.

Danfoss RF Cylinder Thermostat

Danfoss RF Cylinder Thermostat

The standard mechanical thermostat is shown for completeness

Danfoss Mechanical Cylinder Thermostat

Danfoss Mechanical Cylinder Thermostat

The disadvantage of the mechanical setup is that it needs to be hard wired to the boiler controls. The saving in time and materials is much better if a. more expensive,  RF wireless cylinder thermostat is installed due to savings on labour charges.

The most radical and energy saving change to heating controls in recent years are the eTRV [Thermostatic Radiator Valve] and programmable TRV. These two devices offer full automation of each radiator. Before these valves were available it was a major task involving both plumbing and electrical works. at considerable cost, to create separate heating zones.

The eTRV is shown below

eTRV [Thermostatic Radiator Valve]

eTRV [Thermostatic Radiator Valve]

The eTRV is controlled by a remote device similar to a television remote control.

eTRV Remote Control Handset

eTRV Remote Control Handset

The eTRV actuator head can be fitted to many existing standard Thermostatic Radiator Valves. This makes retro-fitting a simple and cheap solution.

Check the link below for the eTRV compatibility guide


Programmable TRV.

The programmable TRV differs from the eTRV in that the time control function is fitted, individually, to each TRV actuator head. The picture below shows a programmable TRV.

Programmable TRV

Programmable TRV

These units again can be retro-fitted to many existing TRVs quickly and at little cost.

The great thing about eTRVs and programmable TRVs is that you can independently switch radiators on and off, regardless of the control settings of the boiler. An example of what can be done is as follows:

Boiler starts at 06:00 and is on until 23:00.

The upstairs TRVs are set to come on at 06:30 and go off at 08:30.

The downstairs radiators are set to come on at 07:00 and go off at 22:00

The upstairs radiators are set to come on at 21:30 and go off at 22:30

From the time settings above the boiler is in operation for 16 hours a day. However 50% of the radiators are only on for 3 hours. The heat demand from the boiler is therfore 100% for 3 hours and 50% for 13 hours.

Typical savings for a boiler consuming 60p worth of gas per hour are 3 x 60p = £1.80 and 13 x 30p = £3.90 total spend = £5.70

If standard radiator valves are installed, without intelligent controls, the same boiler demand would be 16 x 60p = £9.60 almost £4.00 more spent per day, over £27.00 per week, OVER £1400.00 PER YEAR.

With Programmable TRVs and eTRVs costing upto £15 to£40 per unit, they are not cheap. However the cost for a typical property with 3 bedrooms and with 12 radiators would be between £180.00 and £480.00. Still could be £900.00 better off in year one.

Please e-mail me or call me on 07901380746 if you need any further help or advice with heating controls.

Remember once money is spent on wasted energy, you can’t get a refund


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