Insulation
Insulation is one of the most important elements in a person’s home when it comes to saving energy. Insufficient insulation could lead to heat loss in a house of up to 50%. It is vital in both existing and new build houses to have the insulation to the standards applicable.  New houses must comply with Part L of the Building Regulations 2007. While existing houses only need comply with the regulations applicable at the time of construction. However it is strongly recommended to bring your existing house as close to the 2007 regulations as is practically possible.  There are grants currently available to improved the insulation quality in existing dwellings and are shown as follows:

Without getting into the technical calculations of insulation there is a value, called the ”U-value” that governs quality and thickness of insulation in respective areas as indicated below from Part L 2007.

The reason for these U-Values is to set a standard that all insulated areas can achieve, irrespective of what products and type of insulation is used to construct them, i.e. Timber frame or block cavity wall; boarded insulation or beaded cavity fill insulation etc.

HOW DO I DETERMINE IF I NEED MORE INSULATION IN MY ATTIC OR WALLS?
Well because of the vast number of types, quality and products of insulation out there correct thickness requirements should be left to an energy consultant or the manufacturers, especially for new builds.
However for existing dwellings the following guidelines are recommendations that would give your home a better insulated quality and relatively good U-values.

1. Open attics should have a minimum of 250mm quilted insulation. 100mm is to be laid between the joists and 150mm over the joists or equivalent. This alone could save up to 20% on your home heating bill.
2. Solid masonry walls should be insulated internally with 65mm dry lining board or externally with 100mm insulation board or equivalent.
3.  Cavity constructed block walls with no insulation should be pump filled. If the cavity is already partially filled (with aeroboard) one should either fill the remainder with pump fill (if appropriate) or treat as solid masonry above. The thickness of the new insulation will depend on what insulation if any is already installed.
4. Sloped ceilings in dormers and flat roof ceilings should be internally slabbed with insulated slabs. Again the thickness of the new insulation will depend on what insulation if any is already installed.

There are a huge variety of insulation materials out there. The most common ones used in attics include mineral wool, rock wool, sheep wool, polystyrene beads, cellulose fibre and multi-layered foil. Variants in polystyrene, phenolic foam or polyurethane boards are generally used with walls and blown mineral, cellulose fibre or polystyrene beads can also be pumped in.