As a global community, we’re slowly starting to wake up to the stark realities of the environmental havoc we have wreaked on the world over the last few hundred years.
In September we passed the carbon tipping point of 400 parts per million of atmospheric carbon; on 4th November, the Paris agreement on climate change came into force, obliging almost every nation in the world to commit to action that keeps the rise in the global average temperature at less than 2°C above pre-industrial levels.
Much of this shift towards a more sustainable, low-carbon economy will come from work on critical infrastructure and reducing our dependence on fossil fuel energy sources – indeed, renewables finally overtook coal as the second largest generator of electricity in 2015. However, our homes and the way we construct them will have a huge role in ensuring we enjoy a more sustainable future. The domestic market was responsible for 39,735 kilotonnes of oil equivalent (KTOE) in 2015 alone, outstripping industry (23,469 KTOE) and remaining the second-biggest drain on our overall energy supply (the transport sector, with 54,747 KTOE per annum, has far and away the biggest energy demand).
On an individual level, energy consumption per household is on the rise and increased by 2.6% between 2014 and 2015. With the UK a net importer of energy, it is more sensitive to price fluctuations in its energy supply. This is exacerbated by the poor state of current housing stock in the UK – approximately 6.6 million homes are rated as having poor energy efficiency (achieving band E, F or G on their Energy Performance Certificates).
While there is a clear need for more energy efficient housing in the country, it is on the way to becoming mandatory in London, where the Greater London Authority has decided to press ahead with the Government’s abandoned plan to require new builds to be zero-carbon. This makes it imperative for residential building projects in the capital to consider how to reduce CO2 emissions while keeping energy costs low for the homeowner.
This can be achieved a number of ways, from increased insulation to passive house design, where the property is designed to make maximum use of its environment to heat and cool the space. Another key element of these efforts is the introduction of smart home technologies into the home for the purpose of increasing energy efficiency and stopping occupants from wasting electricity unnecessarily.
How can I create a green smart home?
For new build projects, making a home smart and energy efficient is a relatively straightforward task, as the property can be designed and wired with the required technology in mind. With pre-existing properties, this can be trickier due to the limitations of the property – uneconomical layouts, wasteful heating systems and the construction material used can all play a part in reducing a house’s potential energy-saving ability.
That said, there are a number of retrofit smart technologies now on the market that make existing systems more intelligent and help users to monitor and manage their homes in a more eco-friendly manner. Fibaro, for example, offers active power monitoring from all of its wired devices, with data collated and displayed on the user interface so the user can easily track how much energy each smart device in the home is using.
While heating and lighting are the obvious areas where energy savings can be made with smart technology, there are other areas that could be optimised, such as window treatment, water supply and the management of electricity-intensive technology such as home entertainment systems and kitchen appliances.
What green smart home systems can be implemented?
The smart thermostat is, thanks to high-profile companies such as Nest and Hive, one of the best-known elements of the smart home. These add a layer of intelligence to your heating systems, allowing the user to create set points and keep their homes at a certain temperature during certain times of day. Some systems go further than this and introduce an element of learning, whereby the unit becomes accustomed to a household’s daily habits and begins to program itself to suit users’ preferences.
In some cases, a more comprehensive solution is needed; tying in a smart home control system such as Fibaro with Danfoss radiator valves allows room-by-room heating control even if you have a single zone heating system (a common problem in many existing homes). Integrating a more advanced heating system such as Heatmiser takes this one step further, allowing you to integrate your HVAC with the rest of the smart home without the need for a Nest or Hive device.
For larger properties, smart thermostats allow homeowners to zone their property, so that different areas of the home are only heated when they need to be. By programming it so that the temperature is lowered in rooms that aren’t needed at certain times of day (for example, communal areas during the night), a home can be made much more energy efficient without the need for constant interaction on the part of the user.
Sensors and home automation
An intelligent lighting system is one that only illuminates the areas of the property that require it. The problem with traditional lighting schemes are that the user is responsible to physically switching each room’s fixtures on and off as they need them. Forgetting to turn off a light when you leave a room wastes energy that could be usefully employed elsewhere.
The two main types of sensor are occupancy and vacancy detectors, which perform a similar function but in slightly different ways. An occupancy sensor recognises when someone enters and leaves the room, and switches on and off accordingly. A vacancy sensor will also turn off when motion is no longer detected, but the light will need to be switched on manually when the occupant enters the room. The latter is better for the environment, as it means that artificial lighting is only activated when required, as opposed to whenever someone enters the monitored space.
This type of sensor can be tricky to set up, as it will need to be sensitive enough to detect someone performing a largely stationary activity, such as reading a book or watching television. Using units such as Lutron’s sensors with proprietary XCT signal processing technology mean that this type of ‘fine motion’ activity can be identified, meaning that the lights won’t turn themselves off at an inopportune moment. Likewise, a system that incorporates ambient light sensors ensures that lights come on only when illumination levels in the room drop below a certain level, rather than always coming on every time someone walks into a room.
Motion sensors and smart phone tracking can also be used with heating systems, changing the program to energy-saving mode if no presence has been detected for a prolonged period to reduce energy costs. For properties in hot climates, having south-facing mechanised shades or awnings set to extend or descend when the sun reaches a certain point in the sky can reduce demand on the property’s air conditioning system during the day.
Smart valves are still a fairly new concept when it comes to the residential market, but are set to become more and more popular as households look to reduce their water consumption alongside their gas and electricity usage. While many smart valves will focus largely on leak detection and prevention of pipe bursts, others are designed to monitor water pressure and actively work to maximise the efficiency of water flow and water heating costs.
While a relatively simple device, the smart plug is a quick and easy way to reduce energy usage for several non-smart systems in the home. This is especially valuable for devices such as irons or hair straighteners, which along with consuming plenty of electricity have the potential to be hazardous if left on for prolonged periods of time.
For high energy consumption systems such as home entertainment systems, using a smart power strip can help manage the energy flow and ensure that they aren’t being kept on needlessly. Depending on the model, these can be set so that peripheral systems – such as Blu-ray players, speakers or games consoles – are only turned on when the TV itself is in use. Some also offer a number of non-managed outlets for devices such as set-top boxes and DVRs, which require a constant source of power in order to function.
For charging devices, having a smart plug that can be controlled by a mobile app means that devices can be pre-programmed to turn on and off during the day as required. These units can also provide a fail-safe should an emergency occur, allowing malfunctioning or leaking devices to be turned off automatically when they stop working correctly.
Won’t a smart home actually use more energy?
Despite the obvious ways in which a smart home can be used to save energy, there is a troubling tendency for many legacy systems to use more energy by default. Stand-by power consumption has long been an issue in many properties and has been estimated at around 10% of total residential energy consumption. This is particularly pertinent when it comes to equipment such as home entertainment devices, which come with relatively high energy requirements.
An area where energy usage often passes unnoticed is in a smart home’s technology rack (or head end), which efficiently organises a number of AV and smart home sources in a single location for more effective building management. This will need to be thermally managed in order for the equipment contained to perform at maximum efficiency for its expected lifetime. As many installers put lots of equipment in a central rack, some so-called ‘smart-homes’ can actually consume more energy than a traditional system.
“Many installers leave several components – including multi-channel amps, network switches, AV sources and receivers and processors – switched on constantly,” explains Krystian Zajac, managing director at Andrew Lucas London. “Although some of these are justifiable (it’s good to have your network switch always on, for example), an installer might be able to optimise the programming of the control system so that devices that are not being used are automatically turned off.”
Even if many of the devices in a rack need to remain on at all times, this does not necessarily have to be a massive drain on energy resources. A well-designed rack will introduce a degree of natural ventilation as well as effective airflow management that ensures cold air is taken in and hot air expelled quickly from the unit rather than allowed to circulate. This, coupled with more intelligent device management, can eliminate a substantial amount of the hidden energy costs commonly found in many older intelligent home systems.
While this is an area that will generally need to be left to a specialist, it is worth identifying with your home technology provider whether anything can be done in the proposed rack build to reduce any unnecessary energy use without compromising on device performance.
How can eco-friendly building design complement smart home systems?
Implementing green smart technology into the home can go a long way towards creating a more sustainable property, but it is most effective when the house itself has been designed with energy efficiency at its core. By aligning buildings and positioning windows to make the most of prevailing winds and natural light and heat from the sun in both summer and winter, the energy and lighting needs of the house are reduced. The materials used in construction also play a big part in ensuring that the home is well-insulated and retains heat effectively.
Alternative energy generation is something that many households are considering adopting. In the UK, there has been a large expansion of the use of photovoltaic systems (also known as Solar PV), particularly in the South West of England, driven largely by Government- and community-backed schemes. The Wadebridge Renewable Energy Network (WREN) in Cornwall, which has seen more than a thousand solar micro-installations on properties in the area, is one such example of localised efforts to create a more sustainable energy mix.
As the technology evolves, the price of installing solar panels is beginning to fall, and there are signs that the next generation of solar power for the home could be on the way. Electric car giant Tesla recently unveiled a solar roof which, when combined with the company’s Powerwall solar storage unit, promises to not only power a whole house for a full day, but also be a more inexpensive option than investing in conventional roofing and purchasing power from the grid.
These solar roofing tiles are not yet available commercially but, considering their durability (stronger than a standard tile) and potential affordability, it might be a significant step on the road to more widely affordable solar power for the residential market.
Heating, ventilation and air conditioning (HVAC) systems in the home are also make-or-break decisions that can vastly affect the property’s overall energy bills. Radiant heating systems (i.e. in-floor or in-wall) are generally considered to be more efficient that radiator-based units, while ground source heat pumps optimise the heat distribution in the home, generally costing no more than gas-powered central heating while making the home more eco-friendly.
A smart home that stays sustainable
As the energy landscape of the UK changes, our homes will need to adapt accordingly to reduce our environmental impact. By building our current generation of houses along sustainable lines with smart technology, clever design and a more sustainable mix of power sources, we can save ourselves significant amounts of money in energy bills while reducing our carbon impact in the process. Good for our wallets and for the world at large – what’s not to like?