Smartphones, the internet and the smart energy revolution
Andy Woodham is enjoying an enviable retirement.
Aged 60 he and his wife like to travel as much as possible. In the mean time their home is left empty - which in the winter could mean burst pipes, and an insurance nightmare to return home to.
Not exactly the après ski experience they look forward to.
All this changed, says Mr Woodham, when he joined a field trial for a new smart home energy system called PassivEnergy.
"The benefit to us is that I can control it remotely.
"While we're travelling in Australia or something like we were last winter when the winter was very hard, then clearly being able to check occasionally that the house is OK, the heating system is functioning and checking what the temperature is inside the house is pretty good."
The system lets you to control your heating and hot water from a touchscreen interface at home, online or from an app on your smartphone.
First you set a few basic rules. Then the system will learn how long your home takes to heat up and cool down, when you are most likely to need hot water, and act accordingly.
Passiv Systems founder Colin Calder says the platform has been designed with a simple interface, on top of a back end that can be adapted to manage all energy needs including air-conditioning, solar installations, and heat pumps.
He started the company in 2008 while building a zero carbon home.
"I stood back and thought, this is completely unmanageable.
"If we've got the Kyoto treaty driving us towards a zero carbon house, how can we possibly expect consumers to manage those homes efficiently if we've got all these different systems and they're not integrated.
"If you can't find the solution on the market, go and create it."
Company research found 47% of people have no idea how their heating works. Mr Calder decided making his system accessible from ordinary consumer devices could help.
"Almost everyone has a mobile device. People like to be able to control things with that mobile device.
"So if you're going to be home late because you're going to be out for a meal then you can control your energy consumption on the phone."
Data is sent to company servers - the cloud - every 10 minutes, for analysis and to help with grid and supply balancing.
The intelligence behind the system stays behind.
"To do proper control in the home then the intelligence needs to be in the home.
"We firmly believe that the home can go offline, there are all sorts of security issues, it would be dangerous for people to be in the home when the temperature goes below a certain level."
Critics point to the fact that data held on systems like this could potentially allow hackers to work out when your are most likely to be away from home, leaving it vulnerable to thieves.
But Mr Calder says data is fully encrypted, and as inaccessible to prying eyes as possible. He also says the system can slice up to 23% off your energy bills.
"It's the sort of - why wouldn't I want that? I'm better off, I'm more comfortable and I've got control."
He's not alone in harnessing consumer devices, cloud computing and the internet to create smart energy products.
Across the Atlantic iPod designer Tony Fadell found himself having a similar moment of clarity while designing a green home in Lake Tahoe.
"I was upset. After a series of years of trying to get the right products I just literally threw my hands up and said I'll design my own.
"I saw all kinds of other technologies and industries moving forward as energy conservation was becoming much more important.
"This one device that controls 50% of your home's energy wasn't being innovated at all. It seemed like it was stuck in the 80s.
"You can actually make them consumer friendly and very attractive so people actually want to get their hands on it."
The Nest is a thermostat - "it's really a smartphone mated with a thermostat" - with smart algorithms working around heating, ventilation, and air conditioning.
After answering a few basic questions, it will learn how you heat or cool your home over the course of a week.
It adapts to your households habits, guides you towards good energy management, and senses when you're away from home.
You can access it online or through a smartphone app, and Mr Fadell says average savings are between 15-25%.
"The devices that are out in the home today, almost none of them besides your computer are actually connected so they can't get better over time.
"When you install a thermostat, it's supposed to be there between 10 and 15 years on your wall. Our goal is not to make you change that out more often, it's to change the software inside of it so it gets smarter over time."
The Nest is encrypted to prevent hacking, and relies on the cloud only for updates and data analysis.
"It has to be incredibly simple out of the box," says Mr Fadell. "You can't have sensors being placed everywhere, you can't have all these different components being hooked on to all these different devices."
Cloud computing allows for big data crunching - and detailed analysis of home energy usage.
Opower works with utility companies to provide their customers with home energy reports, online energy management tools and email and text alerts to let customers know when they're running up large bills.
The company estimates it has saved 530m kw hours of electricity. Opower's Ogi Kavazovic says giving consumers access to their data causes changes in behaviour.
"It's only once they have a complete picture of what's going on that the customers start acting on their inherent desire to be more efficient, looking for new products."
The company has recently announced a partnership with Facebook where users can compare their energy use against similar homes, and compete against their friends to see who is the most energy efficient.
Tadj Oreszczyn is professor of energy and environment and director of the Energy Institute at University College London (UCL). He says poor user interfaces have long been a problem.
"I suppose a good way of presenting this is that control systems historically have been produced in such a way that they have been produced by engineers almost for engineers.
"What we haven't been doing is I think putting enough effort into making those interfaces work correctly in ways that are intuitive for people.
Harnessing consumer technologies to improve on this could drive better energy behaviour, he says.
"Energy in buildings has historically not been sexy, I would argue they probably haven't had the best brains applying their expertise to this problem, and the great thing about a lot of the new products now is that some very clever people are starting to think about this all very seriously."
And it's not before time, says Prof Oreszczyn.
"We do have to radically improve the energy efficiency of domestic stock.
"We can't just rely on decarbonising the supply. We have to move to renewables and nuclear, and we have to radically improve the efficiency of the way we use electricity in buildings."
For Mr Woodham the motivation is more immediate.
"It's really good to get back home late at night from a plane from Gatwick, and you've got perhaps not a full tank of water because it doesn't think you need it and a warm house. But the heating hasn't been running for hours."