How to build a well-insulated house?

We often understand home insulation as a strategy to protect ourselves from the cold in winter, but the truth is that building a well-insulated house will provide a suitable indoor climate all year round, protecting us from heat loss in winter and heat gain in summer.

In Spain, we tend to underestimate the effect of insulation, as temperatures in our country are not extreme; however, if we look at annual climate summaries, most Spanish towns spend several months a year where the average temperature does not exceed 10 degrees. For this reason, building a well-insulated house should be the primary comfort strategy. In fact, in terms of energy efficiency, a well-insulated and sealed house can achieve energy savings of around 90%.

While the climatic conditions of the location where a home is situated will define the appropriate type and thickness of insulation, understanding the microclimate of the plot and knowing how to take advantage of solar gains throughout the year will be a relevant factor in adapting to seasonal variations and maintaining a constant indoor comfort temperature.

INSULATION DESIGN IN RELATION TO HEAT LOSS AND GAIN

The first thing to consider when selecting the type and thickness of insulation for our home will be, as we have seen, the bioclimatic design in relation to solar incidence.

If we have a home highly exposed to the sun with large windows, the heat gain will be very high. Therefore, if we apply a large amount of insulation to this home in a temperate climate with mild winters and hot summers, we will be creating an oven effect inside.

Thus, to build a well-insulated house, it will be necessary to consider the orientation of the dwelling, the available sunlight, and the local climate.

AVOIDING THERMAL BRIDGES

Another concept to take into account when building a well-insulated house is thermal bridges.

insulating a home to prevent dampness

The final concept to consider for building a well-insulated house is breathability.

Inside homes, a lot of humidity is generated by the use of rooms such as the bathroom, shower, or kitchen, which must be eliminated. The importance of ventilating the home daily is often emphasized, as excess humidity that cannot be absorbed by the environment is transferred to the building materials.

In recent years, with the development of insulation materials derived from petroleum, it has been common to install plastic insulation such as polystyrene or sprayed polyurethane. While these provide good insulating qualities at a very affordable price, they are plastic materials that do not breathe and therefore do not allow moisture to pass through.

If a material prevents the passage of moisture, it condenses, and condensation inside a home is a breeding ground for mold, bacteria, and viruses. If this occurs inside the wall where it is not visible, as a result of non-breathable insulation, we will be living in an unhealthy environment.

At Slow Studio, we are completely opposed to the use of petroleum-derived insulation, as these are synthetic materials that not only prevent moisture from breathing but are also unsustainable, coming from non-renewable sources and requiring a large amount of energy for their manufacture. This is without considering that many of them incorporate toxic ingredients during their manufacture, installation, or use.

building materials that do not require insulation

While most building materials are not sufficiently insulating in themselves, it should be noted that there are materials that incorporate insulation due to their porous nature, which gives them the ability to store air inside without reducing their strength.

This is the case with straw-bale houses, whose walls are formed by a wooden frame that holds large bales of straw. Straw is considered a material for wall construction but also a material with excellent insulation quality.

Another example of a material that serves both a structural and insulating function is autoclaved aerated concrete blocks. This is a less ecological option than straw construction but somewhat more economical.

In both cases, however, it will be necessary to assess the specific conditions of the plot where the house is to be built to determine the necessary insulation.

how to determine the effectiveness of a home’s thermal insulation?

The effectiveness of a material for building a well-insulated house is measured based on two factors:

types of insulation

Regarding insulation strategies, there are two ways to insulate a home: either by taking advantage of the insulating capacity of the air contained within a material or by taking advantage of its capacity to radiate heat. Thus, the types of insulation are based on:

where is it important to install insulation to build a well-insulated house?

Generally, when we talk about insulation, we think of the wall material; however, it will also be important to protect ourselves from radiant solar heat through the roof, as well as from the cold or possible dampness coming from the ground.

In areas with high solar exposure, it will be necessary to protect the roof from solar heat gains by increasing the insulation thickness or through bioclimatic design strategies, such as the installation of a green roof. This will not only increase the insulating power through the air pockets contained in the topsoil but will also contribute to regulating humidity and cooling the environment.

Exterior walls should be insulated according to their solar orientation; in this regard, we must also take into account the location and size of the windows.

In cold climates, to build a well-insulated house, it will be necessary to leave an air chamber to separate the dwelling from contact with the ground and to insulate the lower part of the flooring to prevent heat loss. This strategy will also be important for homes with basements, where the upper floor must have well-insulated flooring to avoid heat loss through lower floors that do not have sufficient insulation.