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Control the heating

Control the heating

Control the heating to reduce bills and carbon


When we moved into this house, the central heating and domestic hot water were controlled by a traditional programmer. A great improvement to either leaving the whole system on all the time, just controlled by thermostats, or a manual switch, akin to lighting a fire in the hearth when you get home. There is an uncomfortable period of being cold before the room or house warms up. 

The programmer had settings for Weekdays, and Weekends. An acl Lifestyle (Drayton) Model LP522.  We swapped that out for a similar one, but with the additional function of being able to set each day separately. It was a very easy task as the industry had adopted a standard docking for such things many years before. It was just a case of switching off the power supply, unscrew the retaining screws, clip out from the dock and then clip in the new one, and reverse the procedure. Then set the times you want the heating to come one and the time for the hot water, for each day, and sit back and enjoy being comfortable.

Central Heating Programmeracl Lifestyle (Drayton) Model LP522 Central Heating ProgrammerYou have to guess how long it will take to warm your home to the desired temperature, and add that to the start time whist deciding the settings to apply. In all probability, the only time you would think to change the settings was if you came home and the house was not as warm as you wanted it, so you would start the heating earlier.  Another time to consider changing the settings was if your work patterns changed, resulting in different times of occupancy. Obliviously, the settings are dependant on the occupancy of the house by anyone in the household. 

Cental Heating Programmer Drayton

You can see from the photos that the replacement, a Drayton Lifestyle LP722, is very similar to the one it replaced.

The technology was not changed between one unit and the other, just the functionality of each day programming.

The wiring of the system is the ultimate logic control. Ours is the S Plan wiring with two valves, one for central heating and the other for hot water. The hot water is called on by a thermostat on the cylinder. The central heating is called on by a room thermostat, in our case, in the hall, mounted on the stairs. It is hard wired to the Junction box containing the S Plan wiring.

Cental Heating Thermostat


Smart Controls

 I had been investigating and watching the development of smart controls for some time at this point.

Multiple sensors both inside and out measure the temperatures. Combined with learning the thermal mass of the house and it's heating characteristics.

This was the early days of development by small British companies, and came with the not unexpected large price tag to accompany it.

By memory, slightly vague, only, one of the developers was bought by Honeywell. I currently have no evidence that this happened, but it is not unusual for development companies to be bought up by larger more established companies. This also happened with Nest being bought by Google.

The sensors allow for changing the the time to start the boiler, based on a combination of the outside temperature and the learnt heating characteristics of your home. This improves efficiency and reduces bills, as well as improving the probability of walking into a comfortable home. The unexpected cold snap is catered for by starting heating earlier than the time set to reach comfort level. Conversely, if warmer, it delays the start, avoiding using energy unnecessarily, thereby saving money and carbon.

The advent and proliferation of Smart Phones and GPS together with other technical advances, including increasing broadband speeds and availability, provided another step change in the control of heating. Instead of having sensors to detect outside temperatures the connected controller could use the internet to get data regarding forecast weather and current temperatures in your area.  Also, your phone knew were you were, and could therefore automatically tell your heating controller. The further away from home your are the more time your system has to get to the comfortable walk through the door. As you start to come home your phone's GPS system tells your heating controller that you are on your way. The smart heating controller has learnt how long this journey normally takes and therefore adjusts the start time accordingly. It is not inconceivable to use other data, both learnt and real time to check your predicted journey time. It could use the car's GPS to tell if you are travelling in your car, or other data, for public transport. However, I don't know that they do that yet, using the Internet of Things, along with other data. It is surprising how much joined up intelligence there can be in the background.

I am not suggesting that it does or should do any of the following. Your car's GPS states that it is on the drive. Alternativly, perhaps somebody else is driving it. The seat position may help identify who, but a correlation of speed and direction of the car and a mobile phone will identify the probable driver. You on the other had are at the railway station, you have bought a coffee and paid using a contactless payment system. The retailer has a location, in the station. You have gone through the barrier and your ticket is activated, perhaps even on your phone. The CCTV cameras facial recognition confirm that it is you. The phone's GPS confirms you are in these locations. But wait, you are inside and can't be seen by the GPS Satellites. The station has an internal GPS system developed to help passengers find their pre-booked seats, by following instructions on their smart phones, which has the train ticket. You get on the train, your phone knows which platform and which carriage. Real Time train information can correlate this to the service and the predicted journey times. The speed, route, and stopping pattern obtained from you phone's location can be compared against the planed data and that of the real time information. The prediction of the need for comfortable heat is now accurate to within minutes. The system has learn how long it takes you to get from the home station to your house, however, it cannot predict the non habitual visit to the pub, or to the florist to buy flowers, but both of those are outwith the range to make any difference to the heating call.

Having all the other factors of weather and current temperature to hand, the system can fully optimise the heating up cycle of the system. Inside, there are other monitors of occupancy, which if indicating an empty house, perhaps with the phone left behind, can lead to the heating being switched off. There are plenty of ways to monitor occupancy these days, including the smoke and carbon monoxide detectors, the intruder alarm, and even the wi-fi router.

An article from 2011, 'What is a Smart Building'. Another from 2019. 'The rise of the smart home'. 'Smart thermostats provide several advantages over their traditional counterparts, but there are two main benefits. They are easier to programme and use, and they give greater energy savings. Average gas bills in the UK are £676 a year, and Tado, the smart-thermostat manufacturer, estimates UK customers can save 19% on heating bills. Nest claims that UK customers can save between 8.4% and 16.5%. '


Our next investment in Heating Controls was a Tado Smart Thermostat. Not the version in the link, but similar. The wired version directly replaced the pervious one in the hall and the other object provides internet connection.

Tado Smart ThermostatTado Smart Thermostat


The Tado Smart Thermostat was easy to install in the same place with no additional wiring. The thermostat only controls the heating side and not the domestic hot water, but it is more than just a thermostat. It is also the programmer as it controls the schedule or timings via an App. Accordingly the existing programmer, was turned to always on for central heating, relinquishing control to the Tado Smart Thermostat and App, and the hot water remained with the previous arrangement of programmer and cylinder thermostat.

Tado does now have a hot water controller as well as the central heating. 

Tado has Geofencing, whereas Nest for instance relies on you using an App on your phone to alert it if you are going to be home early or late. Tado interfaces with your phone to assess this automatically.

The Tado App does a lot more than it used to.

However, our family work patterns changed, making Geofencing less of an advantage and Tado changed it's pricing model from a fixed purchase price, including all of the data interfaces, to a hardware price plus subscription.

Accordingly we changed to Nest.


Nest is also a Smart Thermostat and describes itself as a Learning Thermostat. It does not have the same Geofencing as Tado but integrates well with our Nest smoke and carbon monoxide detectors. which include motion detectors. Both Tado and Nest integrate with Google Home, our choice of Smart Home engine. However, I am not sure if Tado was so enabled when we switched over. Apparently that link happened in 2017.

 Google acquired the company for $3.2 billion in January 2014. However, it was not fully integrated until 2018. Snice that time some of the functionality of the Nest products have been lost and I think added security has put significant delays into notifications from the Nest Doorbell and cameras. It is still quick enough to capture nefarious activities, but not as quick as the postman or delivery driver may like. Nest smoke and carbon monoxide detectors used to be able to interface with Philips Hue lights and turn colour enabled Smart LED lights red at the time of an alarm, making the alarm useful for both the visually and hearing impaired person.Nest Learning ThermostatNest Learning Thermostat

Nest does control the hot water in the one App and connects wirelessly to the system so it is easy to move the thermostat to the most convenient location for you, rather than the wires.

Nest is easy to set up and operate. The predicted savings may be less than that of Tado but some of Tado's savings will be based on not heating an empty home.

The family dynamic has changed again, as we are both retired now. Heating predictions are not as relevant in terms of creating savings of money, energy, and carbon. Technology has also moved on.

Watch this place for the next chapter.








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