New regulations require the construction of energy-efficient homes, which represents a major progress toward sustainability. However, many older buildings fall significantly short of current energy efficiency standards. Owners of these properties must carry out thermal upgrading work. How to carry out thermal insulation step by step? Check in the following article.
What materials can be used when insulating a house?
The most popular insulation materials used in construction are:
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Styrofoam - has a thermal conductivity coefficient of about 0.031 W/mK. It is often used to insulate the facades of houses. It is resistant to moisture and prevents rotting processes. Unfortunately, unlike mineral wool, styrofoam is not resistant to high temperatures. Its main advantage is its low price. However, when installing it, you need to be careful about the right choice of adhesives and avoid solvent-based paints. There are different types of styrofoam, including those dedicated to insulating facades, floors and roofs, and also those with a layer of felt, dedicated to insulating terraces and flat roofs.
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Mineral wool - its thermal conductivity coefficient ranges from 0.031 W/mK to about 0.045 W/mK, making it a very effective insulation material. In addition to thermal insulation, mineral wool also acts as an acoustic insulator, helping to soundproof rooms. It is also the best option for single-family housing, due to its resistance to fire and high temperatures.
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Extruded polystyrene (XPS) - looks similar to styrofoam, but it is more expensive. Its main advantage is excellent water resistance, which makes it often used on flat roofs. In addition, XPS is resistant to corrosion.
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Cellulose fibers - these are modern and environmentally friendly insulation materials that are made from recycled paper. They have excellent thermal and acoustic insulation properties, and are resistant to corrosion and moisture. They are also characterized by their ability to store excess heat and gradually release it into the room. Despite being relatively thin, they insulate very effectively.
Where do you start to thermally insulate a building?
The first step in the process of thermal modernization is to consider replacing windows and doors, especially if the current ones do not meet today's standards. New windows, regardless of what material they are made of (plastic, wood), should have a Uw coefficient of no more than 0.9 W/(m².K), and 1.1 W/(m².K) for roof windows. It is important not to confuse this parameter with the Ug value, which applies only to glazing and is usually lower.
How to choose the thickness of wall insulation?
Replacement of window and door frames should be the first step of carrying out thermal modernization of a building. Thanks to this, the heat is better maintained in the building and heating bills are much lower
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After replacing the windows, the next step is to determine the appropriate thickness of the thermal insulation layer. This task is best left to a professional, as it depends on a number of factors.
First, we take into account the current heat transfer coefficient. Second, we need to consider the thermal insulation of the material with which we intend to insulate the facade.
If you want to get a subsidy to carry out thermal modernization, you must ensure that the heat transfer coefficient U does not exceed the value specified in the current regulations, namely 0.20 W/(m².K). The optimal thickness of insulation materials such as mineral wool or styrofoam should usually be 20-25 cm, although 10 or 15 cm is often sufficient. This depends on the thermal performance of the wall and the properties of the specific insulation material.
Roof insulation - step by step
It is worth paying special attention to the insulation of the roof, since up to 30% of heat can escape through this part of the building. After thermal modernization, the U-value of the roof needs to be equal to or less than 0.15 W/(m²-K).
If you are dealing with pitched roofs, the current standard is to use two layers of thermal insulation - one between the rafters and the other underneath, which overall makes about 30 cm of mineral wool layer. For a roof that has already been insulated before, we can consider additional layers of insulation. For a flat roof, the procedure is usually simpler, but it depends on the specific construction.
Subsidies for thermal insulation
Mineral wool is often chosen for insulating buildings. It protects homeowners from fire and is a godd insulator of heat. In addition, it is great for soundproofing rooms.
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You can get subsidies for home thermal modernization from the Czyste Powietrze program. Financial support can be received by owners or co-owners of residential buildings, including premises in single-family buildings with a separate land register.
The main goal of the program is to improve air quality and reduce greenhouse gas emissions by increasing the energy efficiency of buildings through thermal insulation. The subsidy covers various measures, such as replacing old furnaces, installing heat pumps, CH or DHW systems, mechanical ventilation and photovoltaics. The program covers also the cost of thermal insulation of buildings, replacement of windows and doors, and even an energy audit.
As of January 1, 2019, Czyste Powietrze program includes also a thermo-modernization tax credit, which allows a portion of the cost of purchasing building materials, equipment and services related to thermo-modernization to be deducted from tax. It applies to a spending limit of PLN 53,000, and you need to present VAT invoices to obtain it.
Are you building or renovating a house? Check out our tips on insulation
Compiled by:MAŁGORZATA BUCHKOVSKA
