Central Heating Thermostats

Energy efficiency is the greatest objective of nearly every environmental and cost conscious household today. Achieving that objective requires the installation of appliances and complimentary devices, which conserve heat, prevent heat loss and extract the maximum amount of output from the minimum amount of input.

From the perspective of looking at achieving greater boiler efficiency, it is interesting to examine how introducing complimentary devices improves the overall operation of the boiler and system.

Modern condensing gas boilers are extremely efficient at producing hot water for heating and domestic use. They supply on demand as and when it is required. With a combi boiler, when a demand for domestic hot water creates a pressure differential in the domestic hot water supply, the boiler senses the differential and springs to life producing almost instantaneous hot water.

The boiler responds to a command.

Like a pressure differential, a thermostat provides a command. The command is either to operate the boiler or to turn the boiler off. It can also command valves to open and close.

Some boilers even incorporate a thermostatic control to command the boiler to operate when ambient temperatures fall below a certain level and act to prevent the boiler and its internal pipes from freezing.

A basic room thermostat will monitor the temperature of its surroundings. It can be set to operate at a certain temperature. If the temperature falls below the desired temperature, it will command the boiler to start. As the temperature rises and exceeds the desired level, the thermostat will instruct the boiler to stop.

This simplistic thermostatic operation forms the basis of controlling the environment that the boiler’s central heating facility is designed to satisfy.

It is also the regulating device that maintains an adequate supply of stored hot water in a domestic hot water cistern.

On very basic central heating systems, one wall mounted thermostatic control is fitted in a cool area of the house, for instance in a hallway, and this becomes a point of temperature reference which informs the central heating output throughout the entire house. To work efficiently, the thermostat must be placed where it cannot be affected by a direct heat source, for example, sunlight or a wall heater. From the remote point, the thermostat is wired to the boiler by discreet cabling. The recommended domestic environment temperature is between 18C and 21C. Unless individual radiators are turned off, all rooms occupied or not will be maintained at the reference temperature.

The introduction of a timer into the system can override the thermostat to disable the boiler at certain times during the day, for instance, overnight or when the house is empty during the day.

The incorporation of a timer into a thermostat provides even greater scope for environment control. Modern digital thermostats can be programmed to operate the boiler to maintain various pre-set temperatures throughout the day and on various days. For instance, the programmer may wish the central heating to come on and heat the house to 18C at 7.00 a.m. when they get up, then reduce the temperature to 14C when they leave the house for work at 9.00 a.m. They may also programme the heating to restore the heat level to 18C at 5.00 p.m. when they return from work and reduce it again to 14C when they go to bed at 11.00 p.m. They can also programme different instructions for the weekend and override all settings whenever they wish.

The installation of wireless digital thermostatic programmers enables central heating installers to add controls quickly without the need for extensive wiring. Some modern programmable devices are capable of ‘learning’ about user habits and the environment in which the device is operating. They can be programmed to provide a set temperature at a given time and they then calculate the time at which the boiler should be commanded to operate in order to satisfy the programmer’s request. Eventually, they can formulate a programme based on the user’s preferences and no longer require programming.

Thermostatic radiator valves (TRV) added to radiators enables householders to set individual room temperatures. The valves are easy to install and can be used in any room other than that which incorporates the main thermostatic control device. These devices require no operating power source and work very efficiently by controlling the rate of flow into, and, therefore, the heat output, from the radiator. They are good at regulating temperatures in rooms where extraneous heat sources, like direct sunlight, heat a room at the front or back of the house whilst other shaded rooms are cooler. They do not work efficiently where radiators are housed in screens or when obstructions are placed in front of the thermostats impeding airflow around the device.

Thermostats, which control motorised valves, can regulate the flow of central heating fluid to various areas and rooms in the house. Three-port valves can supply both the central heating and the domestic hot water supply at the same time.

Advances in thermostatic control have led to the development of Remote Energy Management devices that enable householders to set, programme and monitor their heating systems from almost anywhere in the world. The thermostatic device is connected to the home broadband network allowing Wi-Fi access via smartphone, tablet or P.C. by the householder when they are away from home.

As further advances in technology provide greater control over heat and energy management, the opportunity of benefits to consumers will continue to increase.

Remote Diagnostic Boilers

Imagine getting a phone call from your gas supplier informing you that your boiler has been talking to them.

Your boiler has advised them that although it is working satisfactorily at the moment, it is, nonetheless, in imminent danger of a catastrophic breakdown. Consequently, they need to send their engineer around to replace a part. The boiler has informed them which part it requires and they just need to arrange a convenient time to pop round and fit it.

Now. Does that increase your comfort level, or reduce it?

Of course, the self-diagnostic capability of appliances and machinery is nothing new. You probably encounter it when you take your car for a service and the garage simply connects your vehicle to a laptop computer. From this, they can detect most faults and also ensure that the mechanics and electrics are all running efficiently.

If you have a modern, top of the range domestic gas boiler you may well have seen a gas engineer carrying out a similar process.

The boiler’s ability to interact with technology is nothing new. Boilers, sensors, programmers and timers have all been interacting together in the home for many years. The practice of remotely communicating with the domestic boiler has already become well established. A growing number of householders are controlling their heating via smartphone and android gadgets. These devices utilise broadband technology to monitor and adjust boiler function and household temperature settings from almost anywhere in the world. Not surprisingly, adjustments to the householder’s heating controls are now often made from an armchair in the home and sent over a few thousand miles of networks and satellite connections to a receiver a few feet away.

But this next step forward in communication with a remote central monitoring facility, which can be hundreds of miles away, is already past the development stage and being trialled by one major energy supplier.

Remote Appliance Diagnostics Systems or RADS for short are being heralded as the next great innovation to revolutionise boiler operation for householders. Offering a sophisticated electronic control and monitoring service through a remote diagnostics centre, it is claimed that these devices will maximise comfort and efficiency for boiler owners.

There is no doubt that the early identification of impending boiler problems will provide an extra level of confidence for households, particularly during the winter months. Nobody welcomes an unexpected boiler breakdown in the middle of winter.

There are other benefits too. Most boiler owners are familiar with the situation where an engineer has been called out to investigate the cause of a malfunctioning boiler. The diagnosis usually requires a considerable amount of time fiddling with the boiler’s internal components and a certain amount of head scratching. Inevitably, the engineer comes to a conclusion which usually centres on the recommendation of the fitting a new part. Fitting the part is a straightforward procedure. Ordering and getting the part is another matter.

With RADS, a remote diagnosis should ensure that the engineer arrives pre-supplied with the necessary components.

Through a RADS system, the boiler will be in what is referred to as ‘real-time’ contact with the remote monitoring centre. Real-time is one of those phrases that sound high-tech, but simply means connected to and maintaining a regular contact with the centre. This ensures that the boiler’s operational performance can be monitored for unusual working behaviour patterns. This monitoring will eventually produce a boiler behaviour history, which, when combined with information from maintenance and repair history, will provide valuable information for analytics and engineers.

When an actual or potential malfunction is detected by the provider’s monitoring centre, the centre alerts an engineer. Remotely, the provider’s engineer can use diagnostics software and analysis to determine the possible cause of the problem. In doing so, he can pre-source and obtain any necessary parts from the energy provider’s stores.

Meanwhile, the energy provider’s monitoring centre contacts the boiler owner to arrange a convenient time for the engineer to call. This means that the provider’s engineer can attend to the boiler at a pre-determined time, carry out a few checks to confirm the fault, and immediately install any necessary parts. This, of course, can save considerable cost and inconvenience for the householder and also improve the efficiency of the provider’s engineering department.

Many boiler manufacturers are now building boilers with this technology pre-installed in anticipation of an eventual general consumer uptake of the system. Other companies are investing in developments to provide the necessary components to allow existing boilers to be modified to function with RADS.

Along with remotely controlled and monitored smart meters, boiler-monitoring looks likely to become a normal part of an energy supplier’s service.

How far these developments will provide other additional benefits to consumers remains to be seen.

Having remote boiler diagnostics may remove the potential for intervention by the homeowner. The service provided by the energy provider will ensure that the provider’s engineers facilitate repairs and maintenance to their customer’s boilers. This will allow them to monopolise the boiler repair and maintenance trade, with the potential to affect the businesses of many small, independent boiler heating and plumbing specialists.

Along with smart meters, it could also provide a disincentive to energy customers to source competitively priced alternative energy sources and to easily switch between suppliers.

Perhaps the greatest and growing concern for homeowners is the increasing monitoring of their activity by monolithic companies who have become obsessed with collecting and analysing data connected with consumers and their behaviours. This information is often used to influence and change behaviour patterns in a manner that is beneficial to the companies who collect it, or to those who sell it on to other interested parties.

New energy heating and control technology undoubtedly brings many benefits to homeowners and their families, but when the control of that technology is removed from the homeowner, a certain amount of discomfort about the issues surrounding remotely controlled systems will have to be overcome before they are totally accepted without suspicion


The concept of zoning might seem a little complex but in all probability, if your system is a conventional indirect hot water system, you probably have a simple example of a type of zoning in operation. Hot water generated by your boiler is directed to either the domestic hot water cylinder, zone one, or the central heating, zone two. In this case, a motorised diverter valve maintains the zones.

The purpose of zoning is to optimise the domestic heating system to ensure that the different areas within the house are heated only to the required level, which in certain parts might be quite infrequently or even not at all.

In a home where a single thermostat operates to control the entire heating system, the whole house will be heated to the setting on the thermostat regardless of whether all the rooms are occupied or not, or whether they are receiving supplementary heat from sunlight or cooking tasks. The thermostat will take its base setting from its location.

Many thermostats are inadvertently placed in unsuitable positions, for example in a cold hallway or a draught, and often set to achieve an almost impossibly high temperature. This can mean that no matter how hard the boiler works, it can never reach the cut off point.

In this situation, the boiler runs continuously with some rooms cool and others uncomfortably hot.

Changes to the Buildings Regulations have been introduced to reflect the importance of conserving energy by creating zones to maximise boiler efficiency. In new builds and complete installations, the directions are mandatory and in boiler replacement situations, the directions are related to good practice.

Consequently, any new system in a home that is not based on an open plan format must have at least two heating zones. These must be individually controlled by the operation of a thermostat and a zone valve. Radiators must have Thermostatic Radiator Valves (TRV’s) fitted except those in rooms with a room thermostat installed and radiators and towel rails in bathrooms.

When replacing a boiler in an existing system it is now good practice to install TRV’s on all radiators, except those in rooms with a room thermostat and those in a bathroom. These should be installed whilst the system is drained down.

Although the generalised instructions in the Buildings Regulations will provide a good basic system of zoning, it is in a homeowner’s interest to plan and develop a zoning system that reflects the requirements of the house occupants.

Installing a timer in a two-zone system can control when heat is delivered to a particular zone independently of the zone thermostats. An example would be a timer, which responds to the expected household activity in the living or cooking areas of the property during the day and then redirects heat to the bedroom zone area at night.

Rather than settling for a simple two zone system, usually zone one, ground floor, and zone two second and subsequent floors, a multi zone system can be constructed to take into account the life-styles and commitments of various members of the household.

By installing motorised diverter valves, each operated by an individual thermostat and timer, zoning can be fine-tuned to allow each zone, possibly as individual rooms, to be controlled with precision. The motorised diverter valves will open and close to provide heat only when it is required. Consequently, the boiler will operate only as needed and in a controlled and efficient manner.

Motorised diverter valves can be fitted with wireless controls and can be operated and programmed along with their individual thermostats and timers from a central control programmer.

For a complete and remotely controlled system of zone and room control, TRV’s are relatively good at regulating individual radiators. They are also ideal for regulating temperatures in different areas, for example a cooler bedroom for sleeping in and a warm living area for relaxing in.

New wireless controlled examples can be remotely controlled from a central programmer, or by a remote control system.  Honeywell Evo Home has a system that can accommodate the remote control of up to twelve wireless TRV’s through its dedicated software system and hardware. A broadband connection is required.

A system called Heat Genius works in a similar fashion to Honeywell Evo Home, but has the extra option of fitting motion sensors in individual rooms and areas. This allows the system to learn about the habits of the house occupants and predict energy requirements based on this learning.

The system also has adequate provision for build and add on technology as and when it becomes available. Installing a complete Heat Genius package in an average three-bedroom property with seven radiators would cost around £800 including the individual room sensors, the TRVs and the Heat Genius Hub.

The efficiencies and controls afforded by installing the components necessary to produce effective zoning are only part of the practical tasks associated with energy saving. Much of the efficiencies these systems deliver are dependent on the energy usage and awareness of the house occupants. Without a concerted effort to minimise heat loss, use energy with efficiency in mind and learn from the limitations of the installed systems, installing technology without interacting with it is a futile waste of time and money.

Where technology and adaptable human behaviour co-operate, major savings in energy and costs can be readily achieved.

Remote Heating Controls

Imagine the situation. It’s mid January and you are enjoying a spot of snorkeling off the Great Barrier Reef. Then, as you haul yourself into the inflatable, out of the blue you get a text from your daughter saying that she has had a row with her partner and is moving back into the family home, “like, now.

Although the house back in Blighty has been empty for a couple of weeks, the heating has been ticking over to keep the property frost-free.

Still, it is not going to be a very warm and inviting environment for the imminent return of a daddy’s little angel.

No problem, you simply head back to the yacht, log onto the internet and adjust the heating settings via the Wi Fi hub back at home. Then you text your daughter telling her to make herself comfortable and that you will be back as soon as you can get a flight.


Although the scenario might be a little OTT, the practicalities of controlling your domestic heating controls remotely are not. Having discovered that householders might wish to monitor and adjust their home environment from another location, or at least suggest to them that it might be a good idea to, a number of companies are now actively promoting the technology.

British Gas is at the forefront with Hive Active Heating. It is believed that this company has over 50,000 homes across the UK using their system.

Following its purchase of Nest, Google are trying to become a major competitor to British Gas in the UK remote heating control market. Although very successful in the US, some feel that Google’s business model, dependent on collecting personal data, may deter many households in the UK from considering their product. To try to overcome this negative perception, the company has formed a marketing partnership with N.power.

Honeywell, who have long been associated with heating control systems, have their own multi room system on the market.

Also venturing into the UK market is Tado, a successful German company who like to stress their independence from the monitoring suspicions and capabilities of other players in the market.

There are of course other systems available, usually aimed at the dedicated technophiles who like to indulge in creating distinctly personalised systems. These often Heath Robinson configurations of hardware and software probably incorporate considerably more functions than the mass-market products. They are, however, often very sophisticated and subsequently prone to some unexpected behaviour, much to the delight of their assemblers.

Although the major players in the remote heating control market offer pretty much the same technology and features, Hive Active Heating from British Gas is currently the most popular system. Priced at £199 including fitting, it compares favourably against Google’s Nest at £249.

What is more, you do not need to be a British Gas fuel customer to obtain the system; however, there are instances where British Gas might install Hive for its boiler-servicing customers at a more favourable rate. This can sometimes occur in situations where existing boiler controls are faulty.

It is a good idea when choosing a remote control heating system to establish whether the intended system is suitable for your requirements and has functions to control heating and hot water, as some systems are only able to control heating.

So. The first requirement of any current remote access heating system is a broadband internet connection. The broadband router will need to have a spare Ethernet port.

Taking the Hive system as an example, a British Gas engineer will take approximately ninety minutes to install the components.

The engineer will disconnect any existing wired connections from the boiler to the thermostat and connect a wireless receiver to the boiler.

A wall-mounted programmer will be installed in a suitable location.

A dedicated system hub will be plugged into a spare Ethernet port on the broadband router and connected to an electrical supply.

And that is it, although the engineer will demonstrate how to use the system and get it up and running.

The boiler must be set to constantly on at its independent settings to allow the wall programmer to take control over it.

The system can now be operated by either accessing the British Gas website on a PC or Mac, by installing an application on a smart phone or tablet, or by sending a text to the SIM card that is installed into the wall-mounted programmer. This latter option is a useful standby in situations where internet access is temporarily unavailable. The system obligingly sends a return text in acknowledgment. The boiler can still be operated normally by manually adjusting the wall-mounted programmer.

So. What are the advantages?

Well, manufacturer’s claim that users are able to reduce their energy consumption and consequently save money. They suggest that being able to control the heating remotely allows more focused and targeted heating manipulations to fine-tune requirements. This has the advantage over conventional seven-day programme modules of being able to respond to unexpected situations.

The interface also displays usage and trending information.

If you are already in the market to upgrade your heating controls, getting a remote control system installed by British Gas or Nest can be a cheaper option.

With the British Gas system being operated from the company website, users are able to access their energy accounts if they are fuel customers.

It is also suggested that these devices are the harbinger of far more sophisticated systems that will one day control many aspects of home management and daily life.

However, possibly the greatest benefit from these remote control systems is that in the home, the user will no longer need to get up from the armchair to adjust the heating.