Retrofit Europe’s houses is ‘end of pipe approach… ‘ ( for CO2)

It started dawning, the past weeks, as I was listening to some presentations on several events I visited. Have you ever wondered what in fact it means, renovation or retrofitting houses and buildings for 0-energy performance? A focus on operational energy, for heating and ventilating, has become completely irrelevant. It does not cause any environmental impact anymore, its solar radiation, direct for Solar panels, or indirect by warm outside air for a heat pump or even groundwater. Its hardly interesting to focus on that. All environmental impact has moved to the materials and products that are required to create that 0-energy situation. And not only materials, not in the least the energy invested during production . Embodied energy, for winning, production , transport and construction. Which is still fossil energy, and highly relevant . Research shows that its not the extreme insulation alternative that delivers the highest CO2 reduction, but cavity wall insulation with double glass, with some more PV panels as in the extreme case. Its both 0-energy (operational), but the CO2 result is better.


That of course poses the question, then why still use materials and products that have been produced and transported with fossil energy? Since production and transport, in due time will have to switch to renewable energy based supply as well, to meet the climate and CO2 targets. The whole society has to transform for 100% renewable energy.


A housing retrofit for 0-energy , is in fact a 80% CO2 reduction, not a 100% reduction, and only in the best case as described above. With other concepts and configurations the figure drops to 70 or even 60% CO2 reduction [1} In other words the focus at the building or house is in fact a ‘end of pipe’ approach: fighting symptoms , while the elementary problems in the whole chain are not addressed, which eliminate profits on the building operational side.

Which leads to the conclusion that the first priority , before large scale retrofit of our housing stock, should be at the construction materials and products industry: 0-energy manufacturing. That has a double advantage. : the industry has made the transition to 0-fossil energy production, and retrofits become more profitable in terms of CO2, without rebound effect.

Now if the industry has to invest in renewable energy, there is another advantage: they will look critically to reduction of energy in their own process: developing products that require minimal energy investments. Which will create products with less embodied energy demand, which in turn will reduce the demand for renewable energy production. In other words: prevents a lot of investments in PV panels and windturbines, which would have caused a energy and materials impact themselves again…. etc etc.
get the picture?


And we are not there yet. There is another advantage: All focus now is on retrofitting a house for 0-energy, with random choice of materials and products . You ask and the industry produces, as long as the house will be 0-energy ( operational that is) . As the industry itself becomes responsible for the the impact of their products and processes, automatically they will start of process of product innovation: In design and detailing, but also in materials choice: the industry will choose materials that have a low embodied energy, even if that embodied energy is produced by renewable energy since it saves in investments in renewable energy production. They will look for alternatives for high impact materials, as metal and especially aluminium: it makes no sense anymore to use these if there is a low embodied energy alternative available. ( thin of window frames for instance, but many other applications). Which is a simple and direct profit in terms of CO2/


So count your profits: A energy neutral industry, no rebound in retrofit, a boost for circular building, reduced construction of wind turbines and PV panels, and a shift toward biobased materials ( low embodied energy materials) 4 or 5 flies in one catch.

So if I where the government, I would put all effort on the industry, ( not only in building and construction of course) , instead of focusing on end-products with built in failures. Thats an end of pipe approach. We need a to tackle the problem by the roots.


A few days after this blog was published as a column in a Dutch Building magazine , ( , there was a voting in the EU parliament about the new emission trading system . Which is meant to put a price on carbon and steer the industry in the right direction. What happened is that in the last weeks before the voting the lobby has become that strong that politicians changed their opinion and the ETS system, so that many industries and among these the cement industry, will get free emissions right for the period of 2020-2030 . How on earth is it possible , with the immense task ahead to stay below 2 degrees of climate change, that the EU is given away free emission rights? A free ride for climate change !

Unbelievable, the more since it seems that he industry in stead of chosen politicians make the policies, and with that determine CO2 emissions. Even after Paris.


[1] Environmental impact evaluation of energy saving and energy generation: Case study for two Dutch dwelling types, Michiel Ritzen, T.Haagen, Ronald Rovers, Chris Geurts, in: Building and Environment 108 ·July 2016, DOI: 10.1016/j.buildenv.2016.07.020

Author: ronald rovers