Thermography in the energy certificate

Depending on the type of property to be certified, the use of thermography in the energy certificate will be viable or not.

The use of infrared thermography in energy audits, in energy certificates of buildings and facilities is more and more frequent since it supports the technician to diagnose energy losses and the owner to visualize them. The thermography in the energy certificate helps the technician to diagnose and locate in a forceful and effective way the direct losses of energy or the state of the insulation that we will later reflect in the Report.

What is thermography?

Thermography is a non-invasive technique that makes it possible to measure temperatures from a distance by capturing infrared radiation from the electromagnetic spectrum "making the invisible visible".

How does thermography work?

All materials that are at a certain temperature above absolute zero (0 K, -273ºC) emit infrared energy. The energy emitted in the infrared band is converted into an electrical signal by the detector (microbolometer), this signal is converted into a black and white or color image.

Infrared radiation is defined as that having a wavelength between 0.78 µm and 1000 µm (microns). Infrared rays are subdivided based on the wavelength proximity to visible light as near, medium, or far.

Thermal imaging cameras detect the invisible infrared radiation emitted by objects and transform it into an image within the visible spectrum in which the color (or gray) scale reflects the different intensities.

The intensity of infrared radiation is a function of temperature but NOT only of it, the surface characteristics of the object, heat and the type of material also influence.

Uses and applications of infrared thermography in buildings and consequently in the energy certificate.

1. Thermal energy leak and loss inspection for buildings (plants, maquiladoras, hotels, government buildings, etc.)
2. Assessment of moisture / leaks for buildings. (Identify parts of roofs damaged by water, quickly and efficiently)
3. Concrete integrity inspections.
4. Inspections on overheated floors, leak location and temperature distribution.
5. Locate damaged or poor insulation.
6. Locate overheated cables, conductors, or pipes.
7. Tightness measures, detection of air leaks "Blower door"
8. QA.
9. Preventive and predictive maintenance.

For the procedure and different technical aspects in carrying out a thermography, guides are already provided at the end of this post. What we are interested in is analyzing the advantages and disadvantages of thermography in the energy certificate:

Advantages of thermography before the energy certificate:

1. Speed in data collection. So we can get faster conclusions.
2. You can see "what the eyes do not see." In this way we can issue a Report with higher technical quality, with more specific and timely results.
3. Data collection can be global, frame "the entire facade" and know the thermal behavior of the facade as its singular points such as thermal bridges.

Disadvantages of thermography before the energy certificate:

1. The measurement must be carried out only at night to avoid direct solar radiation, the greater the difference between the interior and the exterior, the better.
2. Avoid "air speed" (Less than 1 m / s) to avoid convection phenomena.
3. Stable temperature conditions, both interior and exterior in the building. The materials must have stored a sufficient amount of heat.
4. The temperature in the measurement must be at least 10-15ºC. Very important condition.

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The conclusion that we can draw is that the use of thermographic cameras in the energy certificate is initially not viable in the realization of buildings of little entity such as individual homes in buildings given the complexity in data collection and stability requirements in terms of temperature … etc, not counting the cost of the cameras "which are not cheap". Another issue is when an audit or energy certificate of a complete Building is carried out, where the budget assigned for this purpose is higher.

Guides:

1. From Land. Basic Guide to Thermography.
2. From Testo. Practical guide to Thermography.
3. From the IDAE (Infrared thermography - Applications in energy saving and efficiency)
4. From Flir. Infrared manual for construction applications.
5. Examples of thermography in homes. Analysis.
6. Infrared thermography in the diagnosis of the rehabilitation of facades.
7. The principles of thermography. Introduction and application.

From Alava Ingenieros:

1. Building diagnostic thermography
2. Thermal cameras for construction inspections.
3. Guide on thermography for renewable energy and building applications.

Videos:

1. What is infrared thermography?
2. Energy efficient with Flir thermography.
3. Thermography for the energy efficiency of Buildings. (Recommendable)

Error correction: We have to clarify that we are not experts in Thermography and as such, in this article there are some errors that must be clarified since our purpose is to learn. Given this circumstance, a colleague of ours with a lot of experience in the sector has written a post where different concepts are specified and clarified on the portalIntermal Engineers HERE. From OVACEN We want to thank your article for giving us your experience.

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