KNX consultant Paul Foulkes explains how building automation systems work, and the advantages of using the KNX standard.
Interview with Paul Foulkes
Paul Foulkes has a background in engineering and also worked as an electrician before developing an interest in building automation systems. When a client's system failed within 2 years of installation and with the system becoming redundant due to the manufacturer no longer supplying parts, he began looking at the alternatives and in 2003 became a qualified KNX installer.
Building automation operates systems within a house in a more efficient manner
A building automation system can incorporate:
- Controls for ventilation, heating, shutters, security, lighting, etc
- Monitoring of temperatures, heat gains, solar gains, VOCs (Volatile Organic Compounds), CO2, heat detection, smoke detection etc.
Take a holistic view before construction starts
A self build house is the ideal opportunity for installing a building automation system. Consideration should be given from the outset, and looking into the future, as to how the house is going to be heated, ventilated and lit, to ensure that the correct cabling is in place.
There will always be the fundamental needs for sockets and lighting in each of the rooms, but then there will be a constant layering of other systems (ie heating, ventilation, air quality monitoring) on top of that to bring them all together, rather than looking at them as separate systems and installations.
“You need to be looking at all of this now and saying I can put in a system that will control all of this the most efficiently.”
Monitoring is an effective way of saving energy
In Paul's own house he has installed a detector in each room which monitors absence and presence, so can be set to control lighting or heating when someone enters or leaves a room.
Monitoring information can be displayed in whatever way you choose, for example Excel spreadsheet or something more graphical, and by monitoring the amount of energy being used you can see the points at which it is being wasted.
If linked wirelessly to a personal device you can also access this information remotely, ie check cameras, switch alarms off or view the monitoring information.
Paul believes the future of energy billing will change dramatically over the next few years, with considerably higher prices at peak times. By monitoring and understanding your energy usage, and with battery storage, you can take back control of the energy that you use.
KNX is a non-proprietary protocol
KNX is not a company that manufacturers a piece of kit. Instead it is a protocol, a standard that is accepted worldwide. There are over 400 manufacturers worldwide so there are always replacement parts available. It has been available for 26 years and new parts that are made today will still integrate with original systems.
KNX isn't a smart home system or a heating control system, it is a building automation system. It is fully scalable so can be used in domestic situations, and all the way up to stadiums and airport terminals.
It uses an addressable bus system, whereby every input and output into the system (ie a switch is an input, an actuator that controls an immersion tank is an output) is a point within the system that can be addressed and linked together.
“The advantage with a bus system is that it can be star wired, it can be Christmas treed, as long as the piece of kit is connected to the bus by two wires then you can address that piece of kit. So as long as you’ve got your wire to any position that you want an input or an output, you can hang what you like off that.”
The flexibility of the system means that it has implications for care of the elderly and assisted living, where the technology can be used to adapt the house to you, rather than you having to adapt to the house.
Help may be required to commission the system
A self builder might be able to lay the cabling ready, as any other cabling would be installed, but it is advisable, and probably cheaper, to have an expert commission the system for you. That involves using a piece of software which they can even do remotely. If any additional switches are required, for example other kit such as a ceiling fan needs adding to a 4 point switch, the person that commissioned the system can programme the kit and post the new 6 point switch for you to install.
Passivhaus doesn't need KNX, but you might still want it!
Passivhaus addresses the heating energy usage and thermal loss within a building, but Paul says what KNX can do is address the lighting, hot water and ventilation to a degree, which make up a massive percentage of the energy being used. By using KNX monitoring and controls you can add the same level of energy efficiency and make savings to those.
Paul also says that with so many Passivhaus buildings being constructed and decorated with such a high quality finish, the KNX system can be a more aesthetically pleasing alternative to traditional switches.
Smart home apps are an alternative for monitoring energy but have their disadvantages
Paul explains that one of the problems with smart home alternatives is that they tend to be provided either for heating or lighting etc and not as an overall approach.
“So straight away you’re already talking about multiple layers. You’re adding in complication and the idea of all of these systems is really to simplify your life. So do you really want your house run by 12 different apps, different systems, or do you want it run by 1 different app?”
Paul also uses the examples of the Apple home care kit and Google's Nest product. His personal view on their business strategy is that they want you to buy new, or upgrade, products on a 2 or 3 yearly basis. An additional problem with this is if you have a system which they decide to stop supporting you could be left with kit that is completely redundant.
Find out more
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The Autonomous House for sale
Owners of The Autonomous House, Mike and Lizzie, are thinking of selling their ultra low-energy eco-build house in Worcestershire. The house was designed to the exacting Passivhaus standard, though is not certified. They also took their project a step further and decided to live off-grid and aren't connected to the mains water or sewage.
It's an incredible and rare opportunity to buy such a house. So if you're interested and would like more information while avoiding the estate agents, then let us know and we can put you in contact with Mike and Lizzie.
The Hub update
Our latest episode of the Long Barrow Passivhaus story takes the opportunity to look at why Alex Baines was keen to use Insulated Concrete Formwork on his project.
We also have a new module on roofing which looks at the different types available, the support required underneath, cold roofs, warm roofs, etc.
If you're not yet a Hub member, then take a look at this video we have made, which tells you everything you need to know about what we can offer, and shows a sneak peak inside.