Self Build EIB/KNX Control Case Study – Review
Submission by Andrew Hempsall and Colin Price – Located in a quiet Derbyshire village, this cottage had been uninhabited for more than 20 years and was virtually derelict when the current owners decided to buy it. The oldest part of the cottage was originally built in 1799 as a single dwelling, and the original parchment title deeds show that the house, garden and orchard were bought for the princely sum of £60.
All the lighting, heating, air conditioning, audio and security are controlled by an EIB/ KNX system that is anything but old cottage. The system’s finish has been carefully selected to bring modern life choices to perfect ‘olde worlde’ surroundings.
Why chose EIB/ KNX – Many systems were considered before EIB/ KNX became the only sensible choice. EIB/ KNX caters for all the intelligent requirements of a modern home including heating, cooling, lighting, enhanced security and remote access. As EIB/ KNX is based on an industrial control platform available and unchanged since 1984, it is already widely known to be absolutely robust and reliable. With over 100 manufacturers and more than 6,000 products, all talking the same distributed intelligence language down the same twisted pair cable, there’s no risk of a single manufacturer going out of business and denying spares for the future, and no single point catastrophic failure can ever leave the house ‘in the dark’.
How it was installed – The owners did much of the work on the cottage over a period of 15 months. They teamed up with a good local electrician and planned the installation carefully. The owner, with a keen technical knowledge, decided to take on the commissioning himself and as long as all the ‘live side’ was done by the electrician then his part-P certificate would be no problem.
Having talked to an EIB consultant engineer, he bought ETS (the EIB/ KNX programming tool) and quickly got trained to EIB Partner level. He knew that if he got stuck or just wanted some advice he could call on a local expert to help out, and EIBShop.co.uk provided him with access to parts from many manufacturers and technical support for them, which was invaluable during the course of the project.
Lighting – The cottage has 45 dimmed and switched lighting circuits that can be used to set moods in each room. Like any lighting control system, this allows for scenes to be set for particular instances, and in addition EIB/ KNX allows lights to be incorporated into other features of a house. Some examples are:
- A welcome home function incorporating a motion sensor by the front door so when you walk into the house at night the lights in the hallway, landing, kitchen and family room light automatically. The owners will never have to ‘stumble’ around a dark building with arms full of groceries.
- A ‘discreet’ scene has been set for the bedrooms. In the master bedroom, the discreet button turns on the wall, landing and bathroom lights at a very low level, effectively lighting a pathway there and back so that they don’t needlessly wake anyone asleep.
- Simulated occupancy where the house repeats previously recorded switch pushes and blind movements when the owners are out. The actions are played back at random intervals to give a very real appearance that some one is always at home.
- A porch light and architectural lighting are programmed to come on at dusk and turn off at a random time in the late evening. The rear courtyard and garden have numerous lighting circuits that allow for scene setting at night depending on how the space is being used. Infrared patio heaters have been built into the garden walls and provide heat for cooler evenings.
The picture shows heating lighting and audio in the convenience of the switches adjacent the dining table. And the occupier has matched the ‘mint’ glass switch frames and a green glass dining table.
Heating & Cooling – The 9-zone wet underfloor heating system is controlled using GIRA Sensor2Plus thermostatic light switches (removing the need for non-matching traditional wall thermostats and light switches), and Theben HMT6 24V AC manifold controllers. The whole EIB/ KNX system works seamlessly lowering temperatures both at night when everyone is asleep and a few degrees lower than normal when the house is known to be unoccupied. This represents a big saving in fuel bills when you consider it is an accepted practice to run wet underfloor systems continuously throughout the winter. The thermostats send a proportional value to the HMT6 manifold controllers which results in a pulse width modulated opening and closing of the manifold values, so delivering very even temperature regulation over time.
The same thermostats also control the room-by-room air-conditioning. If the temperature rises above the setpoint then the heating will have been switched off and the cooling will take over. By use of a dead-zone and hysteresis the thermostats ensure that the heating never ‘fights’ the air conditioning and vice-versa.
Audio – Integrated audio which is controlled via the EIB/ KNX system offers music in the main living spaces and the bathrooms with no evidence of any further wall controllers or switches. The source is selected and volume level set using the same light switches that control the rest of the room functions. There is luxury without the need for a wall full of technology that would spoil the period appearance of the cottage. The preamplifier and controls from WHD are all centrally located, with active speakers in the ceilings providing excellent sound pressure levels in each room.
Remote Access – The whole house can be accessed by an internet connection anywhere in the world using the GIRA HomeServer2 IP addressable controller. With a multitude of high end features such as direct heating and lighting control, security monitoring, remote diagnostics, IP camera viewports, email transmissions for security breaches or activated smoke detectors, this Linux based box is fantastic for higher end EIB/ KNX projects.
In summary, EIB/ KNX can be installed in a DIY project with attention to planning, a good electrician and access to parts and technical support.
Post Script: By the end of the project the owner liked EIB/ KNX so much that he refocused his company, Application Power Hire Ltd, based in the East Midlands, to concentrate full time on EIB/ KNX design and installations.
For more information on EIB/ KNX see – www.eibshop.co.uk
Authors – Andrew Hempsall, of Application Power Hire Ltd, designed and integrated the EIB system into the cottage in this article and has wide experience with high-end EIB/KNX installations – www.aph.info
Colin Price of Ivory Egg (UK) Limited, specialist wholesaler of a full range of EIB and related products, and provider of expertise and technical support – www.ivoryegg.co.uk