With increasingly alarming predictions from scientists about the pace of climate change and the very real prospect of energy shortages in the UK within the next few years, we urgently need to reduce CO2 emissions and stop wasting energy.
In these austere times some have said we can ill afford to invest in going green. But in a little-reported speech back in February, it was the Prime Minister himself who said: "Far from being a drag on growth, making our energy sources more sustainable, our energy consumption more efficient and our economy more resilient to energy price shocks - those things are a vital part of the growth and wealth that we need."
But the benefits of conserving energy go beyond economic growth.
Take our housing stock. Our draughty old houses contribute around a quarter of this country's CO2 emissions, and much of this is from heating them. So refurbishing them so they use less energy will be key to meeting the government's emissions targets and playing our part in mitigating climate change.
One of the most effective, albeit least exciting, ways of doing this is insulation - and lots of it.
And insulation won't just help us tackle climate change. It's also the most effective way of easing the misery of fuel poverty, which affects around 6 million homes. That's around a quarter of all households where the stark choice of either heating or eating is a daily reality.
It's estimated that individual households would save up to 40% (an average of £400) a year on their heating bills by fitting solid wall insulation. For example, if all of the 7.8 million 'hard-to-treat' homes - that's solid-walled homes that aren't suitable for cavity wall insulation - were insulated this way, the total energy savings would amount to £3bn. That's a lot of money that could be ploughed back into the economy.
Insulation also makes people healthier. People living in cold homes have been found to have poorer physical and mental health as well as being more likely to have accidents and injuries. Making homes drier and cosier will mean fewer respiratory infections, asthma and other cold and damp-related illnesses - not to mention fewer deaths: around 25,000 people a year die prematurely from living in cold homes.
And of course, healthier people will bring other positive knock-on effects for the economy: fewer sick people means fewer days off work, as well as fewer hospital admissions. For example, in 2010 the Chief Medical Officer released a report estimating that every pound spent on energy efficiency would save the NHS 42p.
So if solid wall insulation has so many benefits, why have so few of us chosen to install it? So far only 2% of solid-walled homes have been fitted with it.
One reason is that until now, it has been an expensive, disruptive business, with residents typically having to move out of their homes to allow the work to happen. But a new partnership between the Sustainable Energy Academy and social housing developer United House has created a revolutionary way of fitting interior solid wall insulation much more cheaply, in a matter of hours. Currently being deployed in the social housing sector, there's huge potential for the process to taken up by private home-owners.
Another reason for slow take-up is that it's simply very hard to persuade people to spend money in order to save money, especially if there's a long payback period in the investment.
But this is changing too. For example there are new Government initiatives like the Green Deal, which lets people pay for the work via a loan attached to our electricity bills. It may have got off to a bumpy start, but it has the potential to play a major role in taking the short-term pain out of energy efficiency measures.
And there are now many more people who are trained to help people make sense of the options available to them, thanks in part to the efforts of organisations like National Energy Action in Newcastle. The charity trains people ranging from health and social care professionals to environmental health advisors on the soft skills needed to persuade home owners to invest in energy efficiency improvements to reduce fuel poverty.
As Carol Hepple, Operations Director of energy advisors Keeping Newcastle Warm says: "There's one of my clients whose house I can't drive past without them offering me a cup of tea. Their house used to be so damp that all the walls were flaking. But within a couple of weeks of having work done, the whole house was dried out, and they started to save lots of money on their fuel bills."
Greening our homes will create a virtuous circle of lower CO2 emissions, more jobs, happier and healthier people with more money in their pockets - and, as Cameron said, boost growth.
So let's get on with it.