Finding Energy Losses at Home: Thermal Imaging, Air Tests

A thermal camera shows where heat escapes, and an airtightness test shows where air leaks. Both help spend renovation or insulation money in the right place.

Heating bills are high in winter, rooms have cold corners and draughts, but the cause is unclear. The first reflex is to buy new windows or insulate the walls. Yet the main source of loss may be somewhere else entirely: under the roof, around the floor perimeter, behind electrical boxes. Instrumental checks for energy losses make it possible to decide on the basis of measurement rather than guesswork.

What a thermal camera shows

A thermal camera records the infrared radiation emitted by surfaces and turns it into a coloured temperature map. In an image taken indoors, cold strips show where insulation is weak or interrupted, while warm patches may reveal, for example, the route of hot water pipes under the floor. In an external image, warm areas are where heat is escaping.

Typical problems found with a camera include:

• gaps between insulation boards in a wall, or slumped insulation;
• cold lines along slab edges, beams and columns;
• a cold outline where window and door frames meet the wall;
• areas of roof or attic floor without insulation;
• damp wall areas, since evaporating moisture cools the surface.

The camera gives a temperature map but does not explain the cause. A cold spot can come from moisture, air leakage or missing insulation. Interpretation by an experienced specialist is essential.

The right conditions for imaging

A thermal survey gives reliable results only under certain conditions. The most important is a large enough difference between indoor and outdoor temperatures, so surveys are usually carried out in the cold season, with the house heated for several hours.

External imaging is not done in direct sunlight: a facade warmed by the sun looks falsely "hot". The best time is early morning before sunrise, or evening, once the facade has lost the heat it absorbed during the day. Rain and strong wind also distort results. Shiny surfaces such as metal and glass reflect their surroundings, so readings from them are interpreted with caution.

Before imaging indoors, furniture is moved slightly away from external walls, curtains are opened and areas directly influenced by radiators are assessed separately.

The airtightness test

Much air is lost along invisible paths: behind socket and switch boxes, at ceiling and floor junctions, around pipe penetrations and at the attic hatch. An airtightness test is carried out to measure this.

A fan in a special frame is fitted into the front door, all external windows and doors are closed and ventilation openings are temporarily sealed. By extracting air from the house or blowing it in, the fan creates a steady pressure difference between inside and outside. The amount of air needed to hold that difference is measured and the result is expressed relative to the volume of the house. The lower the figure, the tighter the building.

The test gives more than a number. With the house under pressure, leak points are easier to find: a smoke pencil produces artificial smoke and you watch where it is drawn, while a thermal camera shows how cold air currents chill surfaces.

When a check is most useful

In a new build, the most sensible time for an airtightness test is after the airtight layer is installed but before internal finishes go on. At this stage a gap can be sealed with tape in a few minutes; once plasterboard and paint are on, reaching the same gap means removing finishes. A second, final test can follow completion.

In an existing house, the check should be done before renovation starts. The results show which work will bring the most benefit and let a limited budget be directed to the most effective measures. A repeat thermal survey after renovation is also used to verify the quality of the work.

What to do after the results

• Rank the problems found by impact: large insulation gaps and major air leaks come first.
• Make simple, inexpensive fixes straight away: sealing the attic hatch, closing pipe penetrations, fitting door seals.
• Where there are signs of mould or damp, investigate the source of moisture first.
• For major work, such as facade or roof insulation, prepare a design and cost estimate.
• After sealing the house, check that ventilation is still adequate.
• Keep the image files and report for comparison after renovation.

Zaferoğlu İnşaat plans the scope of apartment and private house renovations based on an assessment of the existing condition. If you have a thermal imaging report, go through it with us and we can rank which losses to tackle first.