Introduction to heating controls


What are heating controls?

Heating controls allow you to easily regulate the temperature of your home. The controls automatically turn the heating on and off based on settings input by the user, to ensure maximum comfort. This process moves away from a fixed, traditional timer system and can therefore be used to better control the temperature within your home.

Thermostats, allowing people to control the temperature of their home, have been around for a long time. Newer heating control systems have evolved to the give residents total control of their heating, and by extension, their bills. The latest technology allows you to automatically control your heating to work around your daily schedule.

Products that make up a heating control system

There are four products that normally make up a full heating control system (based on a home with a traditional central heating system):

  1. A room thermostat
  2. A boiler programmer
  3. A hot water cylinder thermostat
  4. Thermostatic radiator valves

In our experience, many homes currently only have one or two of these.

Room thermostat

Room thermostats take the temperature of the ambient air in the home and feed it back to the boiler to tell it to either fire up to raise the temperature of the home, or to turn off since the home is warm enough and no additional heating is required.

They require free-flowing air so that the sensor can work out the right temperature. You’ll need to ensure that the thermostats are not blocked by household objects like curtains or furniture and avoid placing them near heat-emitting objects (fireplaces, radiators, household appliances etc). It is also recommended to house these in the lounge, since this is where homeowners typically spend most of their time. Having your thermostat in the hallway by your front door, for example, will not give an accurate reflection of the temperature of your home. This is because it’s an area commonly affected by draughts, when the front door is opened and closed.

Boiler programmers

Boiler ProgrammerA boiler programmer is an automated way of turning the boiler on and off. People tend to like their homes to be warm when they wake up or come home from work. There seems little point in heating the home when no-one is there to get the benefit from the heat. A programmer allows you to set very specific time frames for when the heating comes on from day to day.

Let’s take the example of a family that go to school/work during the day. Typically the boiler would come on at approximately 6-7am to heat the house ready for when the family wakes up. This would then go off at about 9 when the people in the home leave for work or school. The boiler could then fire up again about 4pm in preparation for everyone coming home and go off just before everyone goes to bed.

These programmers allow you to set different heating patterns for each day, so if at the weekend more time is spent at home, you could use the programmer to reflect that.

The hot water cylinder thermostat

Boiler thermostat

If you have an older boiler with a hot water tank, a hot water cylinder thermostat is a great way of ensuring the temperature of the water in the tank doesn’t get unnecessarily warm. Storing water at very high temperatures increases your bills, since you need to use more gas (or electricity if you use the immersion heater) to heat it. In addition, unless you’re a fan of a scalding hot shower or bath, you tend to add cold water to wash comfortably, which means you don’t need your water to be boiling in the first place.

The hot water cylinder thermostat is strapped to the hot water tank and has a dial on the front where you can adjust the temperature. Normally this temperature is set between 60 and 650c, which is hot enough to kill any bacteria but not so hot as to scold you when it comes out of the tap. It is a important to check the temperature of the thermostat on your hot water cylinder, since if it is set any higher than 650c, the chances are that you can turn it down and still get nice warm water, but save a bit on your gas bill at the same time.

If you don’t have a thermostat on your hot water cylinder it is certainly worth getting one fitted, since they cost less than £20 and can really help you to use less gas, but we do recommend getting a trained plumber to fit the thermostat.

Thermostatic radiator valves

TRVUsing programmers and thermostats you can, in theory, dictate when you want the heating to come on and the temperature that you want it to be. Thermostatic radiator valves (TRVs) allow you additional control to further fine-tune your heating system.

Much like the main thermostat, these TRVs track the temperature of the room in which the radiator is situated and will turn the radiator down (or off altogether) once it reaches the temperature chosen by you. TRVs allow the temperature of each room to be controlled individually from one another.

TRVs therefore really allow you to fine tune your heating system. For example, a room may have a lot of glazing and get warmer than the rest of your home when the sun is out. In this case, the thermostatic valve can shut off just that radiator, ensuring the occupant maximum comfort.

The future: intelligent heating systems

Heating optimisation works through an intelligent system that can help to save consumers additional money on their energy bills. Most people set their heating to come on at least an hour before they need it (in the mornings and evenings), but an intelligent heating system can sense the time it will take to heat the household to the required temperature, and turn heaters on automatically.

For example, a household might get up at 7am and want their home to be warm for this time. The traditional timer turns the heating on at 6am and works for an hour before everyone gets up. However on warmer days, the warmup time may be shorter than on cold days. An intelligent heating system will take this into consideration and set your boiler to fire up later, meaning less fuel will be used, resulting in savings in energy bills.

You might have a standard programmer that at most allows you to turn your heating on or off two or three times per day. An intelligent heating system can set multiple points where you set the time and temperature requirements for that day. The idea being that one may have different heating requirements for each day of the week.

Certain products on the market can have over 20 built-in plans, with further programmes available for customisation to an individual’s personal needs. For example, if you are a flexible worker, you can set customised patterns to suit your needs on different days. When you go on holiday, you can programme your heating not to come for the time you’re away.

In addition, these intelligent heating systems can be linked wirelessly to your phone or computer, so you can set the heating to come on as you are beginning your commute home. If you go away in cold weather, you can bring the heating on in your home even if you are not there to help prevent freezing.

Many of the intelligent heating features discussed above are now built into new heating control products available on the market today, and over the next few years they will become far more commonplace. All of the features work to more effectively regulate the temperature of your home, helping to minimise the amount of gas and electricity required to heat it.

The importance of heating controls

Installing huge quantities of loft or wall insulation will increase the energy efficiency of your property. However to get the biggest savings on your energy bills, it is absolutely key to be able to regulate the temperature of your home. Thermostats and TRVs are a really important way to help benefit from the increased energy efficiency of the envelope (floor, walls and roof) of your home. If you don’t have them, your boiler will continue to operate as it always has, which means your home will be warmer, but you will be using the same amount of gas.

It is also worth remembering that most of the features discussed will run behind the scenes in your home, so once you have set them up, you can then forget about them.

Finally – and this is one of our favourite tips – turning your thermostat just one degree can cut your energy bills by as much as 10%!




    Room Thermostats


What is a thermostat?

The thermostat is a common fixture in most homes, helping to maintain an even temperature in the house all year round. In the winter, room thermostats (sometimes referred to as roomstats) prevent rooms from overheating. In the summer months, they ensure the heating system does not fire up unless the temperature of the house falls below a preset level.

How do thermostats work?

themrostats keep even temperaturesA thermostat is normally a control unit for a central heating boiler, but these days it can also control electric heating such as infrared panels. You choose the temperature that you would like the house to be at via a dial or a digital display on the thermostat. The thermostat then monitors the ambient temperature of the air and instructs the boiler/heating system to turn on or off accordingly.

If the temperature of the ambient air is lower than the requested temperature set on the thermostat, it will fire a message to the boiler to fire up and send hot water to the radiators to heat the house.

If the air temperature is too high, the thermostat will send a message to the boiler to switch off, which obviously should result in the home cooling down.

Using a thermostat will therefore ensure that the house stays at a regular temperature and rooms don’t overheat. The thermostat will ensure that the boiler keeps a constant temperature in the house, which results in an efficient heating system that will save you money on your gas bills.

How much can a room thermostat save?

A correctly-installed thermostat can save you £100s per year, however you have to know how to get the best out of it. For example, a pre-installed room thermostat can save about £65 for every degree centigrade you turn it down. Therefore if you normally have your home at 230C and then decide to turn the thermostat down to 210C, you should see energy savings of well over £100.

We have written a blog you can read here on the optimal indoor temperature, which discusses some of the common queries people have when it comes to setting their thermostat.

Thermostats do not speed up the rate of heating

One common misconception of thermostats is that if you turn up the dial of the thermostat, the room will heat up quicker. The rate at which a room heats up is dependent on the boiler, the size of the room, the size of the radiator and finally, how well-insulated the room is.

Thermostats and draughts

Roomstats are sensitive little things; if they are hit by prolonged cold draughts they will instruct the boiler to fire up. This means that they have to be positioned very carefully in the house.

For example, we have seen thermostats installed in clients’ hallways just by the draughty front door. This means that they will normally be recording a lower temperature than the actual ambient temperature of the house and will instruct the boiler to fire up, using more gas.

Thermostats are just part of heating controls

Thermostats are just one part of a home’s heating controls, which normally include a programmer and TRVs. They are designed to work seamlessly with the other components, with the thermostat overriding the programmer to prevent overheating. It is important that you don’t situate your roomstat near a radiator with a TRV because they will interfere with one another – that will mean the heating may go on and off unexpectedly.

To learn more abut TRVs, click here.

To learn more about programmers, click here.

Modern intelligent heating controls

nest uk heatingNew intelligent heating controls such as Nest take the idea of the thermostat much further. They allow you to set the temperature of the home from the other side of the world via your phone, but they also take into account things like direct sunlight, which in the past has manipulated the ambient air temperature.

To learn more about intelligent heating controls, click here.

    Heating Programmers


What are heating programmers?

Programmers are a key component of heating control systems in the UK.

Since many homes are unoccupied for parts of the day, there is little point in heating them if no one is there to benefit. A programmer allows the occupant to specify when the heating comes on to match their lifestyle and their heating requirements.

For many people in the UK, this simply means firing up the heating in the winter months for a couple of hours in the morning, so the house is warm when they wake up, and then firing the heating up again in the evening so the house is warm when they get home until they go to bed.

This means that the heating won’t be on in the interim times, for example during the day when they are at work, or in the middle of the night (although some people do like a warm house even when asleep!).

Programmers range massively in functionality and the choice is often dependant firstly on the type of boiler – combi or heat only. A combi boiler produces hot water on demand whilst a heat-only boiler (despite the name), produces hot water that gets stored in a hot water tank until required.

Two-channel programmers versus single-channel programmers

Honeywell two channel programmerWith a heat-only boiler, you need a two-channel system: one channel that allows you to program when the hot water is being produced and the other for the heating in the home.

For a combi boiler, you only require a single channel programmer – since you are only worried about when the heating comes on.

It is not uncommon for us to encounter boilers that have a malfunctioning two-channel programmer, where the heating and hot water are tied to one another – so when you turn the heating on, the hot water is being produced and vice-versa!

Accuracy of heating programmer

Once you have established what type of programmer you need – a single or dual channel system, then you can choose the functionality you need.

Obviously over the course of a week, people’s heating habits change. For example Monday to Friday it might be very similar, however on Saturday/Sunday, you might require the heating to come on later in the morning.

Drayton single channel programmerThere are essentially three types of programmer that each allow you different levels of control. There are one-day programmers that allow you to specify when the heating comes on each day but every days heating pattern will be mirrored.

So with this type of programmer you might opt for something like this.

These are the most basic types of programmer and while they are simplistic so potentially good for some, in terms of energy saving they are not ideal.

The next type of programmer is the 5-2 programmer, this allows you to set two heating patterns, one for a day in the average working week, and the other for a weekend day (i.e Saturday / Sunday).

So with this type of programmer you might opt for something like this.

Depending on the type of programmer you have it may also allow you to set further time slots for the heating to come on – e.g. instead of just heating the home morning and evening, it may allow you to specify 2 hours in the morning, 2 hours at midday and then a few hours in the evening.

The most advanced (but the one than can most accurately match your heating requirements) is the 7-day programmer and most bought today would be of this type. This allows you to set heating requirements for each day of the week independently.

So with this type of programmer you might opt for something like this (based on the fact that this occupant works from home Tuesday and Thursday).

The good thing about the new programmers is that they allow you to dumb down the complexity if you don’t want it – so if your heating requirements are fairly simple you may just wish to go with 5-7 functionality.

The override button

All new programmers will have an override button, which can give your heating or hot water (if you have a heat only boiler) a boost. If you are using a lot of hot water for example (and you have a hot water tank) you can hit the override button and it will fire up the hot water for an additional hour – allowing you to run more showers or baths.

Programmers working with thermostats and TRVs

You can find more information on thermostats here, but they can be used in conjunction with programmers. The programmer means that the boiler will only fire up as per the times set, however if the house reaches a certain temperature the thermostat will instruct the boiler to turn off.

Working together, thermostats and programmers and TRVs compliment each other to help you tailor your heating demands. This means not heating rooms unnecessarily and also no overheating which helps reduce heating bills.

Taking heating systems a step further you might want to consider intelligent heating control systems which allow you to monitor and change the temperature in individual rooms and learning functionality like Geofencing.

Insulated homes need thermostats – not programmers!

One blog we wrote at the beginning of the year that has proved very popular was on whether it is cheaper to leave your heating on 24/7 or use a programmer/timer to control it. In fact – if you have a well insulated house, it is actually cheaper to leave it on 24/7 and just use the thermostat to control it.

Even so, in reality we would advise people to also get programmers because if you are out of the property for an extended period of time it is worth having ensuring the heating comes on occasionally in winter to stop pipes freezing – the cost of which would far outweigh the energy savings!

    Thermostatic Radiator Valves (TRVs)


What are thermostatic radiator valves (TRVs)?

Thermostatic radiator valves are commonly referred to as TRVs and are used to control the air temperature of different rooms – you will normally find them on the side of your radiators.

TRVs are just one of a number of heating controls, which allow homeowners to heat their homes more efficiently. If set up correctly, they allow you to have different heating zones throughout the house, despite only one centralised boiler providing the heat.

How does a TRV work?

The TRV is a self-regulating valve that works by changing the flow of hot water into a radiator. It consists of two parts, the valve head and the valve body, with the head sitting atop the body. When the room temperature changes, a capsule in the valve head contracts or expands, which moves a pin in the valve body causing it either to open or close.

If it gets too warm in the room, expansion of the capsule will cause the pin to close the valve – slowing the movement of hot water into the radiator. Likewise, if the room drops in temperature, contraction of the capsule in the valve head pulls the pin out, allowing hot water to enter the radiator once more.

There tends to be two materials used in the TRV capsules – wax or liquid. On the whole, liquid models are generally considered to be better and their price reflects this. One of their advantages is their responsiveness to changes in temperature – while the wax one is relatively slow to expand or contract, the liquid capsule will change the flow of water into the radiator far more quickly.

Costs of TRVs

A traditional TRV will cost you about £10 – 30 each.

Where not to use a TRV

There are two places that you really shouldn’t install TRVs on the radiators – the first is in bathrooms. This is because the heat produced by the bath/shower will cause the TRV to shut off (it will cause the capsule to expand), just when you need the heat from the radiator to fight off condensation.

We also don’t advise installing a TRV in the same room as your main heating thermostat. The main thermostat will link directly to the boiler, firing it up or turning it down, so by having a TRV in that room they will fight for control – if the TRV wins, the heating in your house will go off!

Smart TRVs

Nowadays you can take zonal heating control a step further with smart TRVs. These electronic TRVs are remotely controlled to constantly monitor the temperature of the room and move the pin up and down accordingly.

They can also be used with the other heating control components to create an intelligent heating system like the Heat Genius system. This obviously adds significant cost to the system, but allows you to accurately monitor and control the temperature of individual rooms in the home all from the touch of the button on your tablet computer or phone.

Are TRVs a good idea?

In properties with a decent number of different rooms, then TRVs are definitely worth considering, especially if there are rooms that are unused and therefore not worth heating in the first instance.

They can produce decent energy savings especially when part of an intelligent heating system.

It is important to maintain them though; many clients we see have non-functioning TRVs.

It is important to ensure that the valve head vents don’t get clogged by dust and other objects since this can obstruct air hitting the liquid or wax capsules that control how the TRV functions. It is also worth checking once a year that the pin in the valve body is still moving freely (these sometimes get stuck).

To do this, unscrew the valve head off the body – this should reveal the pin that moves up and down controlling the flow of water into the radiator. A spring should hold the pin fully extended above the valve – if the pin doesn’t move when you push it, you may need to replace the whole valve assembly.


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