What are the best materials for insulation of old houses.

The best materials for insulating old houses depend on the specifics of the building, its construction and budget. Here is a review of the most commonly used materials:

## 1. Styrofoam (EPS)
– **Advantages**: Low price, ease of assembly, Good insulation properties ($$ \lambda = 0,030-0,040 \, W / mK $$
).
– **Application**: Exterior walls.
– **Cena**: 20-40 PLN/m².
– **Comments**: Popular choice due to the favorable price ratio to efficiency. The recommended thickness is 10-15 cm[1][4].

## 2. Mineral wool
– **Advantages**: Good thermal and acoustic insulation ($$ \lambda = 0,035-0,045 \, W / mK $$
), fire resistance, vapor permeability.
– **Application**: Roofs, external and internal walls.
– **Cena**: 30-60 PLN/m².
– **Comments**: Better for demanding buildings “breathing” walls. Installation requires greater precision[1][4].

## 3. Polyurethane foam (PUR)
– **Advantages**: The best insulation properties ($$ \lambda = 0,020-0,030 \, W / mK $$
), tightness and possibility of application in hard to reach places.
– **Application**: Internal and external walls, roofs.
– **Cena**: 50-100 PLN/m².
– **Comments**: More expensive option, but very effective in places with complicated geometry[1][4].

## 4. Ecological insulation materials
– **Options **:
– Wood fibers ($$ \lambda = 0,038-0,045 \, W / mK $$
).
– Hemp wool ($$ \lambda = ok. 0,040 \, W / mK $$
).
– Cork and fiberboard.
– **Advantages**: Natural origin, Room humidity adjustment.
– **Cena**: Higher than traditional materials (depending on the product).
– **Comments**: Perfect for people who value ecological solutions and a healthy microclimate[5][6].

## 5. PIR plates (polysocyanuratic)
– **Advantages**: Very high insulation efficiency at low thickness ($$ \lambda = ok. 0,022 \, W / mK $$
).
– **Application**: External walls and roofs.
– **Cena**: Higher than polystyrene or mineral wool.
– **Comments**: Good solution with limited insulation space[4].

## 6. Extruded polystyrene (XPS)
– **Advantages**: Moisture resistance and mechanical damage.
– **Application**: Foundations, basement walls.
– **Cena**: Higher than EPS (about PLN 40-80/m²).
– **Comments**: Especially recommended for places exposed to moisture[2].

## How to choose the right material?
The choice of material depends on:
1. Technical condition of the building (e.g. the need for breathable walls in old constructions).
2. Budget - foamed polystyrene is cheaper, But ecological materials are healthier and more environmentally friendly.
3. Type of insulated surface - e.g.. XPS for foundations, Mineral wool for walls requiring vapor permeability.

It is worth consulting with an expert before deciding on the selection of material and the insulation method.