Wood gets a well-deserved A

María Eugenia Velásquez

July 1, 2021
energy-saving concept photo, people holding a wooden toy house

It's no secret that at I'm in we love wood. Its multiple benefits for both the environment and health make it our building material par excellence.

As if that wasn't enough, we now have one more reason to safely say that building with wood is cool, as it helps you get an A energy rating for your home. Read on and I'll tell you why.

What is the energy rating

Since 2013, in Spain, every house or building is required to have an energy rating, which is an official label or code of its energy characteristics.

The energy performance certificate calculates the annual energy consumption for the normal operation of that home, building or premises, and thus marks the "energy class" it has. These classes range from A to G, with A being the highest rating for buildings with excellent energy efficiency and G, as you can imagine, being the lowest rating for buildings that are not energy efficient.

In addition to consumption, carbon dioxide emissions per year and floor area are also taken into account when marking the "energy class".

New laws promoting energy efficiency

With the entry into force on 22 May 2021 of the new Law 7/2021 on climate change and energy transition, the requirements for energy efficiency are higher.

One of the main objectives of this law is for Spain to reach emission neutrality by 2050, i.e. to achieve a zero greenhouse gas balance by then. In doing so, Spain commits to a specific roadmap to fulfil its share of the Paris Climate Agreement, signed in 2015 and subsequently ratified in 2016.

Likewise, on 1 June 2021, Royal Decree 390/2021 was approved, updating the basic procedure for the certification of the energy performance of buildings.

As the same decree states: "The purpose of the approval of this basic procedure is to promote energy efficiency in buildings, as well as to ensure that the energy they use is mainly covered by energy from renewable sources, with the consequent reduction of CO2 emissions in the building sector".

This makes it clear that Spain is taking firm steps towards more efficient and nearly zero-energy buildings, and this is where our beloved wood comes into play.

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Wood for energy efficiency

This natural material that has been used in construction for centuries has many attributes, one of the main ones being its ability to save energy. It is therefore gaining prominence again as a sustainable building material that helps to achieve climate change and energy efficiency goals.

Wood saves energy right from its manufacture, using one-sixth of the energy it would take to make a similar piece of steel and one-quarter of the energy of concrete.

In addition, wood is an insulating material, which is why wooden houses have a good thermal performance. A 100 mm thick timber-framed wall has a capacity to resist heat 3.6 times greater than a 140 mm thick brick wall; and 5.7 times greater than a 200 mm thick concrete wall. This excellent insulating capacity results in less energy needed to heat or cool the spaces.

This, coupled with the fact that wood is a "CO2 sink", storing on average 1 tonne of CO2 per m3, makes it an optimal building material for energy-efficient housing.

In the publication "Energy criteria for timber structures" Julius Natterer, head of the Department of Civil Engineering at the Federal Institute of Technology in Lausanne (Switzerland), concludes that wood has an energy consumption and CO2 emission 12 times lower than steel, 15 times lower than concrete and 52 times lower than aluminium. Not bad eh?

As detailed at the beginning of this post, the energy performance certificate takes into consideration energy consumption and CO2 emissions per year and floor area to determine the "energy class" of your home, so by building with wood you are covered on both counts and therefore increase your chances of getting an "A" rating.

To end this post, I would like to recall this sentence from the book "Structures: or why things don't fall down" by J.E Gordon, Professor of Materials Science at the University of Reading (U.K.) "The twentieth century may be known to posterity as the 'age of steel and concrete'. Or as the 'age of ugliness' or other unpleasant names such as the 'age of waste'. It is not only engineers who are obsessed by steel and concrete, but also politicians and the man in the street seem to have been infected by the same disease".

Will the twenty-first century be remembered as the 'age of wood'? Time will tell, but I really hope so.

If you want to know more about timber construction and passive houses, schedule a video call with us, we'd love to talk to you.

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Are you interested in building a passive house out of wood?
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Are you interested in building a passive wooden house?
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