Insulate the house from cold and heat it's good for your wallet and helps you live better. In addition to the economic advantage linked to savings on gas and electricity bills, the improvement in terms of living comfort.
If the walls are warm, in the sense of thermally insulated, the windows without drafts and the roof well insulated, you can stay at 20-21 ° C in winter with the heating system at a minimum and the air less dry. You save and you are better off.
But there is also summer, and not having a hot house in July is as important as not having it cold in January. Even in the hot season,thermal insulation. And given that the house cannot be changed according to the seasons, it is good that the type of insulation is designed to be comfortable all year round. Also not to spend what was saved with the boiler on the air conditioner ...
Insulate the house from cold and heat: do I change the boiler or do I coat the facade? Both interventions are important and are also very closely linked. The aspects to consider are the following:
- replacing the heating system is convenient when the old one no longer works well. The new system can be more efficient but a new boiler or one that can last longer is not thrown away, unless the technology is really obsolete;
- the new system, more efficient, will give its best if the house does not have significant heat losses. This happens for example with condensing boilers, which are characterized by a high efficiency at relatively low temperatures and therefore offer excellent performance in well insulated buildings;
- interventions on the building envelope reduce the energy requirement upstream. For this reason, once you have done the thermal insulation and reduced the requirement, you may realize that a less powerful and less expensive boiler is enough.
- the year is also made up of hot periods in which thermal insulation is equally important but depends on devices other than those that produce the heat. A well-insulated building allows you to balance needs and optimize the investment in the boiler and air conditioning.
- the thermal inertia of the building is given by the performance of the envelope, which consists of walls, roof and window systems (glass and fixtures). The windows are important and the double glazing contributes to the insulation, but the lion's share is made by the walls (and the roof in single homes or on the top floor of condominiums).
- the insulating thermal coat involves an initial investment, but has no maintenance costs. The intervention of the thermal coat is most convenient when it coincides with other planned works, for example the renovation of the plaster or the roof, because the fixed costs (scaffolding) do not change.
Insulate the house from cold and heat: how and with which materials? Thinking about the envelope of a building, whether it is to build a new one or to upgrade an existing one, the aspects to consider are the following:
- the best insulation is obtained by coupling materials with good thermal inertia (that is, which accumulate thermal energy and then release it slowly) and materials with good insulating capacity (that is, capable of not being crossed by heat).
- the thermal inertia (indicated by the lambda factor λ) is typical of heavy and dense materials, the insulating capacity (K factor) is instead typical of light materials. The best insulator existing in nature is still air, so the most efficient insulating materials (with reference to insulating capacity, not thermal inertia) are those that trap the most air;
- in a new building, good insulation can be done with heavy thermal inertia materials coupled with an air gap, or with an insulating coat, or even with both. On an existing building, the only conceivable intervention is the thermal hood;
- synthetic insulating materials, expanded polystyrene and polyurethane, insulate well from cold but not from heat because they have a low phase shift value (the speed with which the thermal energy passes through the insulating material from side to side) and are not breathable;
- insulating materials of mineral origin, glass and rock wool, are very efficient but have the problem of releasing microfibers into the air which makes it necessary to encapsulate them in a synthetic casing which makes them non-breathable;
- the insulators of natural origin, wood fiber and cork, insulate a little less from the cold than polystyrene but much better from the heat;
- natural blond cork is also an excellent acoustic insulator;
- the insulators of natural origin are breathable and contribute to the hygrometric balance ensuring better living comfort than synthetic ones;
- cork and wood fiber have a significantly higher cost than synthetic insulation (obviously the cost also depends on the quality of the individual products);
- when you decide to make a thermal coat or to insulate a roof, the cost of the insulating material affects the overall cost less than the fixed costs;
- the cellulose fiber in flakes, made with recycled newspaper, is an excellent insulator and is also economical, but it does not lend itself to the realization of the insulating coat.
At this point the choice is yours. Keep in mind, however, that making a thermal coat is a complex intervention, it is not that you buy the hardware panels and stick them on the facade. The advice is to do a cost-benefit energy analysis of the intervention and then to rely on specialized workers.
You might also be interested in Thermal inertia: definition and materials