Glazing

The glazed areas of our homes can be there energy weak points. We all love big bright rooms with expanses of glazing but the larger the glazed area, the more heat loss there is and so it is often necessary to improve on the minimum requirement required by building regulations to keep the heat in and the bills down.

Building regulations have been revised several times in the last few years (and will doubtless be revised in years to come) with regards to decreasing the U-values of buildings (including windows) for increased energy efficiency.

The current regulations state that windows must have a U value of no more than 1.8W/m²K (previously the requirement was 2.2W/m²K)

Double glazing has been the industry standard for years now on virtually all new builds as it halves the amount of energy lost through glazed areas. To comply with the regulations you would now require a double glazed 28mm unit with a 20mm air gap with a low e-coating.

Triple glazing

The average U-value for a double glazed window is 2.5W/m²K. Triple glazing will reduce the U-value to 2.2W/m²K - better but not massively. The U-value of a single pane of glass i s 5.4W/m²K.

Low-e coatings

Low-Emittance (Low-e) is a term used for a surface that radiates, or emits, low levels of radiant energy.

A specially designed microscopically thick coating of a metallic oxides, is applied to one or more of the inners surfaces of the panes of glass.

These coatings reflect radiant infrared energy, thus tending to keep radiant heat on the same side of the glass from which it originated. The windows are more efficient as the sun's heat is allowed through at the same time as the radiant heat from inside the house is prevented from escaping and is reflected back inside.

The coating is almost invisible so low-e coated glass looks identical to ordinary glass.

There are two types of low-e coating - hard coat low-e and soft coat low-e. An example of hard coat low-e is Pilkington K glass and soft coat low-e is Pilkingon Optitherm

Inert gas filled double glazing

Another method of energy saving in double glazing is to fill the space between the panes with an inert gas such as argon, krypton or xenon instead of air.

These gases are better insulators than air and so help lower the U-value of the unit. A soft low-e double glazed unit filled with argon gas has a U-value of 1.2W/m²K.

Argon is the most commonly used, the others being expensive and only necessary when there is a limit to the thickness of the unit.

Spacer bars

When you've gone to such an effort pulling down those U-values you don't want a weak link in the chain and in the case of windows it could be the join between the edge of the double glazed unit and the frame.

There are now advanced technology bars made of rubber or of plastic which form a tight fit between the two edges and not only help reduce heat loss, but condensation and sound insulation too.

Once only of interest to a small minority, green is the new black as far as self-building is concerned.

With the effects of global warming becoming increasingly apparent, more and more people are seeking greener ways to provide the energy needed to run a home.

Whether it's solar panels, heat pumps, high specification glazing or eco-friendly wool insulation in the loft space, there is little doubt that it is self-builders who are setting the standards for a greener future for the building industry and the way we live our lives.

Underfloor heating for example, has been available for years but, by and large, the self build market has been the industry's bread and butter - with large scale property developers still opting for standard, less efficient radiators.

But it's not all about saving the planet. Incorporating green ideas into a home can lead to reduced running costs and save you money in the medium to long term too. And when you come to sell your home in the future, you can guarantee that the greener it is the more attractive it will be to prospective buyers.

There is a greater sense of purpose from the government to promote green alternatives too with a stick and carrot approach in place.

Building regulations now demand far better energy efficiency while government grants are available for loft insulation right through to solar panels, heat pumps, wind turbines and other microgeneration technologies.

Self-builders are leading the way as far as greener homes are concerned and greenselfbuild.co.uk will be with you every step of the way towards a greener future for you, your family and the wider community.