Insulation in its various guises and uses has featured
in most of the Build Stages that precede this section. However
insulation is just one part of the whole equation that goes
towards the energy requirements for your new home. The SAP
(Standard Assessment Procedure) measures the space and hot
water heating costs per square metre of the floor area, taking
into account a whole host of different factors such as the
size, the heating system and what type of boiler is used with
which type of fuel, the ventilation characteristics plus the
expected occupation and heating requirements. The results
are converted into a rating from 1-100 and, in order to comply
with the Building Regulations, homes must achieve a minimum
SAP value of 60, although most modern houses achieve far higher.
There are three main methods of emonstrating compliance with
the Building Regulations: |
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Key Points |
1 |
When choosing green materials
for your build look for those which take the least energy
in manufacture and which are either recycled or can be
recycled. |
2 |
Sheep's
wool and recycled newspaper products can be used for
insulation. |
3 |
There
is a wide range of good environmentally friendly paints
and stains to choose from. |
4 |
When
choosing applicances for your new home make sure that
they are low energy and where appropiate low water consuming. |
5 |
Many package suppliers offer
an energy efficient upgrade to their standard products
and there are some companies who specialise only in low
energy homes. |
6 |
Alternative water and waste
systems such as reed bed sewage systems and the collection
and cleaning of rainwater for washing machines and flushing
toilets can be considered. |
7 |
A wind turbine could be
useful for a remote and exposed house and might provide
a significant proportion of the home's electricity needs. |
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The most publicly understood method of heat loss calculation
is the ‘U' value, which measures the heat loss in watts
for every square metre of the material in relation to each
degree of temperature difference between the inside and the
outside. The lower the ‘U' value the more thermally
efficient the material is.
The elemental method lays down specific ‘U' value targets
for each element of the building.
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Floors |
Walls |
Standard Roofs |
Sloping Roofs |
Windows |
Flat Roofs |
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0.25 |
0.35 |
0.16 |
0.20 |
2.0 |
0.25 |
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0.25 |
0.30 |
0.16 |
0.20 |
2.0 |
0.25 |
Metalframed windows can have an average 'U' value of 2.2.
In Scotland the level of 'U' value achieved is dependant upon
the type and effciency of the boiler. |
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