A new study from the European Commission’s Joint Research Centre (JRC) concludes that 7% of the EU’s total annual carbon emissions could be saved through the use of three simple measures.

For individual buildings, this represents reductions of between 30-50% in emissions.
In June 2003, the European Commission adopted a Communication on Integrated Product Policy (IPP) with the aim of reducing the environmental impact of products and services throughout their life cycle. Research showed that products from just three areas – food and drink, private transportation and housing –  were responsible for 70-80% of the environmental impacts of individuals and accounted for some 60% of consumer expenditure altogether.

Three parallel projects were launched to analyse the environmental IMprovement of PROducts (IMPRO-Car, IMPRO-Meat, and IMPRO-Building).
The overall goal of the IMPRO-Building project was to analyse the environmental improvement potential of residential buildings, from single-family houses to multi-apartment buildings, including existing and new dwellings in the EU-25 (all the EU countries except Romania and Bulgaria).

This included:
n the assessment and comparison of life cycle environmental impacts of residential buildings
n the identification of the main environmental improvement options, their costs and benefits.

The building stock was split into three distinct types: single-family dwellings (including two-family houses and terraced houses); multi-family buildings; and high-rise buildings. These three building types represent 53%, 37% and 10% respectively of the existing EU-25 building stock. The buildings were also defined in such a way as to be distributed across three main zones in Europe that roughly represent three climate zones according to heating degree days (HDD): Zone 1, Southern Europe (564-2000 HDD); Zone 2, Central Europe (2501-4000 HDD); and Northern Europe (4000-5823 HDD).

For new buildings, the environmental benefits were limited to the construction phase, and these can be achieved by changing the materials used in construction. The results showed that significant environmental improvement can be expected only when substitution leads to the increased use of wood products instead of more ‘conventional’ materials such as concrete, reinforced concrete and brick.

Besides these alternatives, improvement measures should target reductions in future GHG emissions from the buildings. These include employing the concepts associated with ‘passive housing’ and ‘zero emissions buildings’ where the space heating demand is reduced to 20 kWh/m2.

For existing buildings, the focus was on measures that addressed operational use, particularly space heating. So
n additional roof insulation
n additional external insulation and
n weather sealing
were considered. These three measures alone were shown to yield significant environmental improvements. For a majority of the building types analysed, the emissions reductions were at least 20% compared to the base case. When scaled up over the EU-25, the improvement potential was substantial.

For roof insulation and weathersealing, the measures were shown to be economically worthwhile (positive net present value and a high internal rate of return) for the majority of buildings. For external wall insulation, the economic profitability was not so consistent as, in some cases, the subsequent fuel costs savings did not totally compensate for the higher initial investments.

Compared to the two other measures, the application of weatherseals to reduce ventilation brought smaller improvement potential but had a higher economic profitability as a result of very low initial investment.For each measure, the highest improvement potentials from the European perspective were derived from Zone 2, which includes the UK. This is partly due to the larger building stock in use and to the colder climate conditions. The major improvement potentials lie in single-, two-family and terraced houses, followed by multi-family buildings.

Despite important reduction potentials for high-rise buildings, smaller emissions reductions are expected in absolute terms due to the smaller share of these buildings in the overall building stock.

When combining and totalling the building types included in the analysis and relevant retrofit measures, the derived total life cycle emission reduction potential reaches 360 MtCO2eq per year. This corresponds to about 7% of the total direct greenhouse gas emissions in the EU-25 in 2005 (without land use, land use change and forestry). This high estimated emissions reduction potential can be achieved provided that all barriers (e.g. social, economic) are overcome. The initial investment costs may represent one of these barriers. The life cycle costs of the retrofit measures were analysed through the calculated internal return rates and the net present values associated with these retrofit measures.

The current environmental performance of the European residential buildings stock is far from the low-energy standards currently being discussed. If the measures examined were carried out, the emissions of greenhouse gases from these buildings
may be cut by around 30-50% over the next 40 years.