With the cost of energy rising every year, and with the daily increase of the “energy transition” effort, many houses are designed around one central theme: saving energy. Everybody installs heat pumps and solar panels and ventilation systems and batteries, all to make sure we minimize our carbon footprint. Green is good.
And indeed, green is good. At Lithouse we love green and eco and natural. So we understand that some engineers want to install a full blown computerized ventilation system that promises to extract the very last Joule from the air that leaves our houses. But when the ventilation system costs 25.000 euro in a 150.000 euro house, then we start asking questions.
Questions such as: how many Joules do we save annually with this fancy 25.000 euro ventilation system. How much money do we save that way. And how much does it cost to depreciate, run and maintain the ventilation system. Because ventilation systems have moving parts, and moving parts break.
Off course a top of the line ventilation system saves energy, but the question is: how much does it save, and is it possible to save energy somewhere else? And then we saw an energy efficiency report in a French project, and that made us think. In France, just like in any EU-country, you are by law required to write a report about the estimated energy consumption of your house, and there are rules for the max amount of energy you may consume. Just like in any other EU country.
But for this specific project, the engineers also made a graph of exactly where your house looses energy: through the roof, or the walls, or the floor. And this is what we got:
Wow! Most energy leaves the house via the glass. Actually almost 50% of the energy leaves the house via the glass. And these were triple glass windows, fully specced with Uf-values and insulated frames, and not super extra large, just standard sizes windows.
So we think: if you have 25.000 euro to spend on energy saving systems, why not spend it on top-of-the-line glass and window frames? We never were fans of complicated energy recuperating ventilation systems, but this graph makes it very visible. Better build a damp-open house, spend money on glass, spend money on woodfiber to store energy in the walls, and keep it simple.