Building thermography: cost, process and requirements

Every house loses heat in winter. The question is where and how much. Building thermography shows where heat escapes through the roof, walls, windows and junctions. That tells you where a renovation should start, before you spend money.

What building thermography shows

A thermal camera measures surface temperature. Where warm air escapes or insulation is missing, the outside is warmer than its surroundings. Typical findings are:

• thermal bridges at roof edges, parapets, balcony slabs and floor supports
• leaking junctions at windows, doors and roller shutter boxes
• areas with missing, damaged or displaced insulation
• hidden elements such as timber beams, steel girders or heating pipes in the wall

What it does not show

The thermal image shows surfaces, not the inside of the construction. It does not measure energy consumption or insulation thickness and does not replace an energy performance certificate. A finding is a well founded indication that should be confirmed on site or by a specialist. Ventilated facades, glass and metal surfaces can only be assessed to a limited extent from outside.

When is the right time

A meaningful measurement needs a clear temperature difference between inside and outside, as a guide about 15 K. In Central Europe this is the case from November to March, ideally at temperatures around or below freezing. Measurements are taken at night or early in the morning before sunrise, when the facade has had no sun for hours. Rain, fog, a wet facade or strong wind distort the result, so the exact date is set at short notice according to the weather.

How to prepare your house

• heat all rooms evenly for at least 12 hours beforehand, without night setback
• keep windows and outside doors closed
• leave roller shutters open if possible so window junctions are visible
• tell us in advance about spots you already suspect

From the ground or by drone

From the ground the ground floor is easy to see, but roof surfaces and upper floors only at an angle or not at all. A drone captures the roof and facades from a favourable position at a constant distance. For large buildings, halls and residential complexes this saves a lot of time. The drone does not replace interior images. If you also want interior measurements, both can be combined.

What does a thermal survey of a house cost?

For a single family house, market prices typically range from about 200 to 1,500 euros, depending on the number of images, whether inside and outside are measured and how detailed the report is.

At QopterVision, thermography of a single or two family house with the roof and all facades from outside costs from € 348 including VAT (290 net), including the report. Larger buildings such as residential complexes, halls or schools from € 350 net per building, depending on size and number of facades. Several buildings on the same morning are charged as a day rate. More under the services Building heat loss and Building monitoring with thermal imaging.

What a good report should contain

• a thermal image and a visual image of the same section for each finding
• a temperature scale on every thermal image
• date and time of capture
• the conditions during measurement: outside temperature, inside temperature, wind, cloud cover and precipitation
• the location of each finding on the building

Without the measurement conditions it is impossible to judge whether a finding is real or caused by the weather.

Three questions for your provider

• At what temperature difference is the measurement taken, and is it stated in the report?
• Do I get a visual image and the location on the building for every thermal image?
• What does the report not show, and who confirms a finding?

Want to know where your house loses heat? Send us the address and the approximate size of the building. We will get back to you with a date for the next suitable morning.

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