How it works
We survey at night, an engineer signs off – and we state our limits
01 / Measurement conditions
Why at night, and when is a night good enough?
An exterior thermal survey shows heat loss only when the driving force is large enough and nothing disturbs the surface’s own temperature. By day, solar radiation masks defects, so we work in the evening and before dawn.
| Parameter | Requirement | Why it matters |
|---|---|---|
| Indoor–outdoor temperature difference (ΔT) | at least 10 K, preferably 15 K | Losses only show on the surface when the driving force is large enough. |
| Solar loading | no sun on the facade for many hours: in practice at least 4 hours after sunset, or before dawn | Sun heats the structure and stores heat in it, which masks or fakes defects. |
| Wind | below 5 m/s | Wind cools the exterior surface and lowers contrast. |
| Precipitation, wet surfaces | no rain, dry surfaces | Water and evaporation cool the surface and change how it radiates. |
| Heating | stable operation for at least 24 hours | During warm-up or a change of operating state, surface temperatures are misleading. |
The heating season: roughly late October to March. If the conditions are not met on the night, we reschedule free of charge (up to 2 times [confirm]).
There is plenty to survey in summer too
- Flat roofs: at dusk after a sunny day, wet insulation holds its heat longer.
- PV: in full sun, clear sky and light wind.
- Electrical cabinets: under load (summer is best).
- Cold stores and cellars: all year round.
02 / The survey
One night on site
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Step 1: Walk-through and logging
Indoor and outdoor temperature, wind, humidity, the heating state and the start time – everything goes into the report’s measurement log.
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Step 2: Exterior round
Facades, roof edge, doors, windows, plinth. Each thermal image gets a visual photo from the same position (a photo pair).
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Step 3: Interior images
Wall–floor and wall–roof junctions, doors, docks, column bases, pipes, ducts and cold rooms – without disturbing operations.
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Step 4: Reference measurements
Emissivity and reflected apparent temperature are set; where useful, contact-thermometer checks – see below.
03 / 3D registration
The image lands where it belongs: the 3D heat map
On their own, thermal images are just pictures: it is hard to say exactly where they are and how long a defect runs. So we register the thermal images and their photos onto a 3D model of the building using common points. Every finding then appears in its real place with measurable sizes (m², running metres, gap width), and you can walk around it in a browser.
The 3D model is a decision aid, not a land survey: its geometry is engineering-grade but does not meet design or hand-over surveying requirements.
04 / Reference measurements
How does colour become temperature?
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Emissivity
The camera measures radiated heat; to get temperature we need the surface’s emissivity. We set it per material and record it in the report.
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Reflected temperature
Radiation from the surroundings can reflect off a surface. We measure it with a reference surface (e.g. crumpled foil) and correct for it.
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Contact check
Where possible we check the camera value with a contact thermometer at a chosen point.
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Photo pairs and log
Every thermal image has a visual photo, and the conditions (time, ΔT, wind, distance) are in the report.
05 / Engineering review
Four eyes: whoever compiles a finding does not approve it
The analysing engineer compiles the findings, and a second, approving engineer checks them against the raw data. Every finding gets a location, a photo pair, a likely cause, an estimated loss (as a range) and a fix suggestion.
If an image is ambiguous – because of reflection or wind, say – we do not guess: the finding is marked “to be verified”, with a note on how to settle it on site. The approving engineer is responsible for every statement in the report matching the data.
06 / What the report contains
What lands on your desk
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PDF report
Measurement conditions, findings list with A/B/C priority, finding cards with photo pairs, estimates with assumptions. 10–15 pages for the Quick diagnostic.
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3D heat map
With the 3D package: an interactive model in your browser, with a shareable link.
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Action list
XLSX and PDF: per item the repair, cost band, payback and priority – usable for contractor quotes.
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Raw files
The original radiometric images, unchanged, with the hash manifest.
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Walkthrough
45 minutes (Quick diagnostic) or 60 minutes (3D package), on site or online.
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Scenarios
With the 3D package: what happens if you fix only the A items, or all of them.
07 / Data integrity
The raw data does not change
After the survey we create a hash manifest (SHA-256) of the original radiometric files, and the manifest is part of the report. We hand the files over unchanged, so you – or anyone you show them to – can later verify that the images in the report are the ones captured on the night.
Interior images can contain trade secrets: on request we sign a non-disclosure agreement, your data stays yours, and an anonymised example only appears with your written consent (for instance in the pioneer programme).
08 / Limits of infrared measurement
What a thermal camera cannot do – and what we do about it
A thermal camera measures surface temperature; it does not see through walls. So every report records the conditions and marks uncertain findings as such.
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Emissivity
Shiny metal, glass and lacquered surfaces have low emissivity: the camera reads them colder or warmer than reality.
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Reflections
Shiny surfaces mirror their surroundings (lamps, sky, machines); we filter this with reference measurements and several viewpoints.
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Glass and translucent surfaces
Glass is opaque in the infrared: we measure the glass surface, not the frame behind it.
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Wind and cooling
Wind cools the exterior surface; in strong wind defects blur or disappear.
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Solar loading
A structure warmed by the sun releases heat for hours and can mask defects – which is why we measure at night.
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Hidden defects
Ventilated facades, structure behind cladding, thick insulation: a defect does not necessarily show on the surface. We do not promise otherwise.
09 / How we compute the HUF figures
From thermal image to forints: a transparent calculation chain
The camera shows where a defect is and how big it is, not the watts it loses. The money figure is therefore a model-based estimate using known physical formulas and sourced parameters. Every number is a range, stamped with the energy-price date (here: 2026-10-09).
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Step 1: Defect → W/K
From the defect type and size (m², running metres, gap width in mm) we compute a heat-loss coefficient: separate formulas for insulation, thermal bridges, air gaps and open doors.
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Step 2: W/K → kWh/season
With heating degree-day data for the Nyíregyháza area (ERA5) and your heating set-point, we get seasonal heat, then invoice-kWh and gas m³.
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Step 3: kWh → HUF
We calculate at low, central and high gas prices (net, marginal), excluding the fixed capacity fee; in the report with your own tariff.
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Step 4: Fix and payback
Repair cost is an indicative, quote-based band. Simple payback in months, with A/B/C priority: A ≤ 24 months, B ≤ 60 months, C otherwise.
The uncertainty of a single item is typically ±30–50%, which is why we give ranges. Savings only materialise if the repair is carried out; the survey alone saves no energy.
Estimate – not a guarantee. Figures are model-based and actual values may differ.
10 / Standard principles
MSZ EN ISO 6781-1:2023 – we follow the principles
Our method builds on the principles of MSZ EN ISO 6781-1:2023 on the qualitative detection of thermal irregularities in building envelopes by infrared: documented measurement conditions, a ΔT requirement, temperature values supported by reference measurements, and interpreted results. This is a methodological reference, not a declaration of conformity: we do not claim that we comply with the standard, and we hold no certification.
11 / What it does not replace
What our survey is not suitable for
Not an accredited or certified inspection. The following require statutory authorisation, serve different purposes – proving compliance – and we neither perform nor replace them:
- an energy performance certificate (under Government Decree 176/2008 (VI. 30.))
- an energy audit or energy-specialist (szakreferens) service (under Act LVII of 2015)
- the mandatory electrical safety inspection (under NGM Decree 40/2017 (XII. 4.))
- a fire-safety inspection (OTSZ, under BM Decree 54/2014 (XII. 5.))
- a building-expert or court-expert opinion
- structural, design, technical-supervision or construction work
- use in official or court proceedings, insurance claims or lender submissions – unless we expressly agree otherwise in writing
The report reflects the weather and operating conditions at the time of the survey and does not guarantee that hidden defects will be found. Before implementing any measure from the report, design, contractor and, where needed, regulatory expertise must be engaged.
Questions about the method? Request a quote and tell us about your facility
Before the survey we agree the walk-round, the timing and what the report will show.