Thermal transmittance U vs th. resistance R

To achieve thermal comfort and energy efficiency in buildings, a primary role is played by the thermal envelope: this is required to thermally decouple the indoor environment from the ever-changing external conditions, both in summer and in winter.

The structures of the thermal envelope need to be able to control the amount of heat migrating through them: the thermal resistance and the thermal transmittance are two ways to describe this phenomenon. Read More

Insulation materials: discovering the lambda value

The lambda value of a material indicates its ability to transfer heat: this property is therefore very important in the design of highly performing buildings and passive houses.

The information commonly available is unfortunately quite confusing: with this article, we’ll try and shed some light on the topic. Read More

Certified construction system for Passive Houses

The construction system certification is possibly the least known certification offered by the Passivhaus Institut, and yet it can help spreading passive buildings all over the world.

We worked on the first system certification for passive houses in a warm climate: we try and explain what it’s all about. Read More

The compactness ratio of a building

When addressing the energy efficiency of a building, one of the most important players in the game is the compactness of its thermal envelope.

Is there a way to measure the compactness of a building? Yes: it’s the compactness ratio. Read More

Shedding some light on Earth Hour and the like.

Imagine what would happen if everyone knew as much about insulation as they do about energy saving bulbs. The light bulbs in our homes have changed drastically in the past ten years. The walls, however are the same. Enrico and I decided to take a look at exactly how much energy we can expect to save on a night like M’illumino di meno or Earth Hour. And then, just for fun (!), we decided to compare that saved energy with how much we’d save by adding one single square meter of insulation to the external wall of our outdated apartment building. Here are our results… Read More

The potential benefit of an early ‘Blower Door Test’.

In December we ran a ‘Type B’ Blower Door Test on our CasaClima Class A project, “Conte Re”, under construction near Albinea (in the province of Reggio Emilia, Italy). Many of our colleagues wondered why we decided to run the test so early in the construction process. Here is a brief overview of the benefits… Read More

A Disastrous Case Study: How Replacing Windows Alone Can Lead to Mold

In our previous articles, we have cautioned that an energy retrofit should be approached with an integrated, whole-building approach, and by a professional with experience in calculating and simulating thermal envelopes. The photos below show what happened to one family’s home when they decided to do an independent partial energy retrofit, without consulting a qualified professional. In this case, they decided to replace the old windows of their house with newer, high performance windows, hoping that they would be able to reduce their energy consumption. Read More

BIM Energy Analysis with Archicad 17

As in its previous version, Archicad 17 comes with a built-in energy evaluation tool, that allows designers to develop the building energy concept from the preliminary design phase. The line that divides architectural design and energy simulation seems to be getting thinner and thinner. On one hand, this Graphisoft approach is no doubt cutting edge. However, some large doubts remain: Read More