Four letters with the power to alter the way we feel about ourselves as individuals, as families and as a society. Home is the place we retreat to when everything else in life crumbles around us; it's how we define ourselves and it's the foundation for everything we do. If we're not happy at home - or, worse still, don't have a home - then we're not happy. It's that simple.
Of course, there are other important facets of life but they're not tied up with as much emotional string. Nobody writes songs, novels or movies about transport, education and healthcare - they write them about home. Coming home, going home, feeling at home.
Yet we're not doing enough to secure the availability of decent, affordable homes in the UK. Ownership is drifting beyond the reach of a whole generation, rents are rising to unprecedented levels and business - and therefore economic recovery - is suffering as a result.
At the same time the general cost of living is rising - food, energy bills, fuel - while salaries have flatlined. The vast majority of people in the UK are feeling the financial squeeze. Shelter have warned of the rising risk of repossession in many parts of the country and, when interest rates finally rise - as they must - this risk will increase. Young people are facing some of the toughest times ahead. Recent graduates are having to deal with escalating debt before they can even think about saving for a deposit. The new crop of full tuition fee students will graduate with around £50,000 of debt each, taking accommodation costs into account.
The cost of having somewhere to call home is high. It's not difficult to see why - everyone agrees we don't build enough homes. There are plenty of reasons we can point to, including whose responsibility it is to house people, the state's or the private sector's. Then there are the developers holding onto land till they can build houses with a high enough value to recover the cost of buying at the top of the market. Whatever the reasons we need more stock and that takes time - it's a difficult problem to resolve.
However, even if we build homes at record levels we won't solve it. In 1968, our best year for housebuilding to date, we still only managed to add around 2% to housing stock. Housing, as things currently stand, relies far more on existing properties than new builds. Of course building more homes - affordable homes in areas where people need them - has to be a long-term priority, but we clearly also need shorter-term solutions.
One such solution already exists and it utilises existing stock. It's an old fashioned notion that's enjoying a modern day resurgence - lodgers.
There are an estimated 15 million empty bedrooms in owner occupied properties in England alone. In the owner occupied sector under-occupancy currently stands at 49%, compared to 10% amongst social renters and 16% for private renters.
Encouraging more people to rent out their spare rooms achieves two things. Firstly it allows the person taking in a lodger to cope with the ever-rising cost of living and also helps them avoid repossession. Secondly it secures a supply of affordable accommodation, largely for the younger generation, who need it most, but also for the increasing number of 40- and even 50-somethings who can't afford to rent alone.
There are other benefits - two people living together have a 40% lower carbon footprint (per person) than they would living separately. You also don't need to look far to find a wealth of research showing why it's not healthy for us to live alone or showing that falling behind on rent or mortgage payments leads to an increase in mental health problems.
So wouldn't it be good if we had an incentive for people to rent out their rooms? The more rooms people make use of the better off people will be - homeowners through extra income and renters from the lower rents resulting from higher availability - and the more housing stock we'll have available in a time of crisis.
That incentive already exists too; it's called the Rent a Room Scheme. The scheme, which was introduced in 1992 to encourage people to rent out rooms in their homes, allows anyone renting out a room in their primary residence - yes, anyone, that includes both social and private tenants (with their landlord's permission of course) - to earn up to £4,250 a year without paying any tax. The problem is it's a benefit that has become seriously eroded by time. The last increase to the threshold, while generous and considered with an eye to the future, was in 1997 under the last Conservative government.
If we want to encourage people to do something using a tax break as the sweetener the tax break has to be viable and meaningful. In other words, the benefit has to be of benefit. Allowing for inflation the threshold would have risen to at least £6,500 by 2013. The average annual rent for a room let to a lodger in the UK currently stands at £5,593 (rising to £7,667 in London, where demand for shared accommodation is highest) - an increase of 103% since 1997 .
By letting the incentive erode over time we allow it to become meaningless. If an incentive becomes meaningless it stops acting as an incentive.
So, the argument is a simple one - we should raise the threshold of the Rent a Room Scheme to bring it into line with 21st century realities. In the Republic of Ireland a similar scheme had its threshold raised to €10,000 in 2008. This would increase available housing stock, help the squeezed middle we hear so much about feel a little less squeezed and provide an affordable source of quality accommodation for those who need it most, where they need it most. A minimum threshold of £7,500 - to account for rooms in the capital - would be appropriate, but we should also factor in annual rises in line with inflation to avoid the benefit becoming eroded again.
For more on the call to raise the threshold visit www.SpareRoom.co.uk/RaiseTheRoofSuggest a correction