The need for heating, cooling and ventilation vary depending on where you live in the world. Here in the UK we have a fairly moderate environment where typically cooling is rarely used and thus rarely found in most UK homes. Our heating is switched off over the summer months. As climate change increases, more extreme temperatures become more common and more people in the UK are installing air-conditioning in their homes.
With this in mind we have designed our contextual smart home to work for anyone in any country and to enable use of its many user interfaces to enable and disable both the heating and cooling. Typically they will not both be enabled at the same time though.The best way to save money in your home is to to not use the heating and cooling at all and that is why we have the ability to switch it off completely. When it is enabled, the contextual smart home can minimise costs through very intelligent control based on actual and predicted occupancy and also provide the best possible user experience.
"Heating" is an object modelled by our contextual smart home and it refers to all the space heating devices in our home. If it is set to off, then none of them will operate to heat the home. The only exception to this is when the heating systems are exercised (briefly switched on to run pumps, etc. and to ensure things don't seize up over long periods of inactivity).
The 'Central Heating' in our current home is a set of radiators heated by a gas fired boiler and currently controlled by a single "thermostat" in our home.
"Cooling" is an object modelled by our contextual smart home and refers to all space cooling devices in our home. We don't currently have any cooling installed (fans aside) but, we plan to add air conditioning soon.
There is a big different between using a smart thermostat (or several) and in placing your HVAC under full smart home control. The main difference is where the decisions are being made and the context in which they are being made.
Traditional heating systems have a controller near the boiler (or in an airing cupboard), which provide the scheduling and control, with the thermostat (or thermostats if using several zones) measuring the actual temperature against that requested and providing a (heat request) control signal back to the controller.
The addition of a smart thermostat allows the requested temperature to be varied based on a schedule and in response to other factors that it has visibility of but, a smart thermostat will always have a narrow view and won't have whole home context. In addition, many smart thermostats have scheduling control features but these are essentially duplicated (and wasted) when you have multiple smart thermostats, resulting in a much more expensive solution.
In a contextual smart home, the Home Control System is deciding when the HVAC should be operating, based on whole home context. It will also be determining what target temperatures are required in each zone and have the sensors to know when those temperatures have been achieved. In a new build, this results in a much more intelligent and powerful system, that is considerable cheaper and delivers a much better user experience, which works with all of the user interfaces available and enforces permissions.
For each zone, we use a controller to define scheduled, adaptive temperature targets, avoiding the need for expensive "smart thermostats".
Each controller can be enable/disabled easily using any of our smart home's user interfaces. This basically means we can enable/disable heating/cooling down to zone level if required. Typically, the adaptive controller works on occupancy though, so it just works around us.
The controller allows us to set target temperatures based on adaptive schedules, days of the week, time of year, etc.
Our contextual smart home supports the concept of 'virtual sensors', so it is possible to control a boiler using the 'Average House Temperature', which is derived in real time from all of the relevant connected temperature sensors in the home. This effectively makes the "smart thermostat" redundant, especially when utilising direct boiler control via protocols like OpenTherm. One advantage of using an average house temperature (or the average for a smaller zone) is that it is not wildly affected by things like the front door being opened on a cold day. In the UK, many thermostats are in an entrance hall and opening the front door will immediately cause the heating to kick in, even if the other rooms in the house are already warm enough.
Heating and cooling systems need to be 'exercised' regularly, to ensure things don't settle in pipes and pumps don't seize up. This is particularly true of our current central heating system, which is not used over the summer months.
To avoid any issues, our smart home will over-ride the normal controls and exercise the heating system. It will set a high target temperature (e.g. 30°C) at 7am on a Monday morning and run the heating system for a short time period.
During the summer months, our central heating system is switched off. It is not used at all from about April to October. Once a week, during these months our @smartest_home exercises our central heating by setting a high target temperature and turning on the heating for 10 minutes. This helps keep the pipes clear and the pumps running smoothly, which improves reliability.
