Our Services

Thermal imaging survey.
Aerial thermal survey by UAV and hand-held thermographic survey. Radiometric, Cat 2 interpretation.

Angell Surveys carries out thermal imaging surveys and thermographic surveys on UK sites, by UAV where the target is a roof, facade or solar array and hand-held where it is switchgear, plant or an interior. Radiometric long-wave infrared capture maps surface temperature to reveal heat loss, moisture, insulation gaps and electrical hot-spots; every finding is interpreted by an ITC Category 2 thermographer and reported against the environmental conditions recorded on the day.

Cat 2
ITC-certified thermographer
UAV + Hand
Aerial and ground-based capture
Radiometric
Calibrated, temperature-true data
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What it is

In-depth guide: How a thermal imaging survey works →

What does a thermal imaging survey find?

A thermal imaging survey from Angell Surveys identifies defects that are invisible to the naked eye: heat loss and insulation gaps in building fabric, air leakage, water ingress and damp, underfloor heating faults, electrical hot-spots in switchgear and distribution boards, motor and bearing degradation, refractory wear, and module-level faults in solar PV arrays. Each anomaly is classified, paired with a daylight reference image and given a remediation pathway. For the physics and the survey conditions behind it, read the guide on how a thermal imaging survey works.

Every Angell Surveys thermal survey is a thermographic survey in the strict sense — radiometric (temperature-true) capture, paired thermal/daylight imagery, and a written interpretation by an ITC Category 2-certified thermographer. Survey environmental conditions are recorded alongside every image so the analysis can be evidenced to an insurer, building control or an asset owner if it is challenged.

Applications

Where thermal surveys deliver.

Three primary application categories. Most projects combine UAV and ground-based capture for full asset coverage.

Building Envelope

Thermal bridging, missing or compressed insulation, air leakage, water ingress, underfloor heating layout. Residential, commercial, industrial, heritage. Pre-refurbishment, post-retrofit verification, EPC dispute evidence.

Solar PV & BESS

Utility-scale UAV thermography across solar farms and battery storage sites. Module-level hot-spot detection, failed cells, bypass-diode failure, junction-box defects. Aligned to IEC 62446-3 / SEMI PV3 inspection standards.

M&E and Industrial

Electrical switchboard hot-spot scanning under operating load, motor and bearing condition monitoring, district heating route tracing, refractory inspection on industrial process plant.

Roof & Flat-Roof Survey

Drone-mounted thermography across commercial and industrial flat roofs to locate trapped moisture and saturated insulation. Identifies repair zones without removing covering or coring the membrane.

Underfloor Heating Mapping

Pipe-route detection for underfloor heating and district heating circuits without coring or destructive investigation. Critical pre-drilling or pre-fixing where pipework records have been lost.

Confined Space & Hard-Access

Combined with our remote inspection UAV capability to thermally survey assets that cannot be safely accessed on foot — tanks, voids, towers, plant rooms, chimneys.

Standards & Conditions

What conditions does a thermal imaging survey need to be valid?

Thermal contrast is the key variable on every thermal survey — without it, the imagery is not interpretable. Every survey is scheduled to environmental conditions that produce an auditable result, and those conditions are recorded against every image set.

Angell Surveys is a RICS-regulated practice (Firm 681790). Thermographic interpretation is provided by ITC Category 2-certified thermographers under the InfraSpection / ITC standards.

ApplicationRequired ConditionsTime WindowReference Standard
Building envelope>10°C internal/external ΔT; no recent rain; low windPre-dawn Oct–Mar (UK)RICS · BINDT InsT(NDT) · BS EN 13187
Solar PV>600 W/m² irradiance; clear sky; arrays under load10:00–15:00, clear-sky dayIEC 62446-3 · SEMI PV3
Flat roof moistureSunset + 2–3h after sunny day; dry membraneSunset window, May–SepASTM C1153 (informative)
Electrical / M&EEquipment under normal operating load; emissivity controlledAny — coordinated with operatorITC EL Level 2 · NETA ATS
Our Process

How does a building thermal survey work?

01

Scoping & Conditions

Target asset, anomaly classes of interest and environmental window confirmed. Equipment calibration and thermographer Cat 2 evidence supplied at proposal stage.

02

Survey Capture

Radiometric capture under the agreed conditions. Paired thermal/daylight imagery. Environmental conditions logged against every image set.

03

Interpretation

Cat 2 thermographer reviews radiometric data, classifies anomalies by severity, recommends remediation pathway.

04

Report & Issue

Written report with executive summary, anomaly inventory, paired images and recommendations. Suitable for insurer, building control or asset owner review.

Sector Applications
Renewables & Solar Built Environment Industrial Process Utilities & District Heat Heritage Healthcare Data Centres
Scope

What can a thermal imaging survey not tell you?

Thermal imaging shows surface temperature patterns; interpreting them correctly needs the right conditions and references.

Conditions

A usable survey needs a temperature differential across the subject and stable weather; sun, wind and wet surfaces mask or mimic anomalies, which is why survey conditions are recorded.

Emissivity and reflection

Metals, glass and glossy finishes reflect the surroundings rather than emit; readings there are qualitative unless reference emitters are used.

What thermal cannot see

Thermal imaging does not see through walls, insulation or cladding; it infers hidden conditions from surface effects, which then need confirmation.

Radiometric versus visual

Absolute temperatures are only meaningful from radiometric capture with stated parameters; palette images alone are indicative.

Angell Surveys delivers this service across the UK from a London base, under RICS regulation, with the same documented control, check-point verification and QA on every project. Inspection outputs are positional condition records, not measured surveys; where dimensions or clearances are required we add LiDAR or photogrammetric capture specified to a RICS (2014) accuracy band.

FAQ

Thermal imaging survey questions.

What does a thermal imaging survey from Angell Surveys include?
The survey records the radiant surface temperature of the target with radiometric long-wave infrared (LWIR) cameras — a building envelope, a solar PV array, an electrical switchboard, an industrial process or a concealed M&E installation — and classifies the anomalies found: heat loss, insulation defects, water ingress, electrical hot-spots, blocked junctions and faulty PV cells. You receive a report pairing each thermal image with a daylight reference image, the anomaly classification, the environmental conditions recorded at the time of capture, and a recommended remediation pathway. Capture is radiometric and calibrated; interpretation is by a certified ITC Category 2 thermographer.
What is an aerial thermal survey?
An aerial thermal survey is a thermal imaging survey flown by UAV. A radiometric long-wave infrared camera captures temperature-true imagery of roofs, facades, solar PV arrays and plant from above, covering large or hard-to-reach areas in a single flight. Thermal and daylight images are paired and georeferenced, and the findings are interpreted by an ITC Category 2 thermographer against recorded environmental conditions, following BS EN 13187 for building fabric and IEC 62446-3 for PV arrays.
What conditions does a thermal imaging survey need to be valid?
A thermal imaging survey is only interpretable when there is a genuine temperature differential across the subject and the weather is stable. Building envelope work needs a difference of more than 10°C between inside and outside, no recent rain and low wind, which in the UK means a pre-dawn survey between October and March. Solar PV inspection needs irradiance above 600 W/m², a clear sky and the arrays under load, so a mid-morning to mid-afternoon window on a clear day. Flat-roof moisture work is flown in the two to three hours after sunset following a sunny day, on a dry membrane. Sun on the surface, wind, wet finishes and reflective materials all mask or mimic anomalies, so the environmental conditions are recorded against every image set and issued with the report.
What is the difference between thermal imaging and thermography?
They describe the same physics — capturing and interpreting infrared radiation to map surface temperature — but in practice "thermal imaging" is often used for any infrared capture, while "thermographic survey" implies a qualified Cat 2/3 thermographer is interpreting calibrated radiometric data against a documented baseline. Every Angell Surveys thermal survey is a thermographic survey: radiometric capture, Cat 2 interpretation, written analysis tied to measured environmental conditions (ambient temp, humidity, wind, solar load).
What kinds of buildings and assets do you survey?
Three primary categories. (1) Building envelope: detection of thermal bridging, missing or compressed insulation, air leakage, damp ingress and underfloor heating layout — across residential, commercial, industrial and heritage buildings. (2) Solar PV: aerial drone thermography across utility-scale solar farms and BESS sites to identify failed cells, hot-spots, bypass-diode failure and module-level faults. (3) M&E and industrial: electrical switchboard hot-spot scanning, motor and bearing temperature monitoring, district heating pipe-route tracing, refractory inspection.
When is the right time to survey a building thermally?
Thermal contrast is the key variable. Building envelope surveys require a minimum 10°C differential between internal and external temperature, ideally captured pre-dawn between October and March in the UK to minimise solar loading on external faces. Solar PV surveys are conducted on a clear day at peak irradiance (typically 600–900 W/m²) when faulty cells generate measurable thermal contrast under load. Electrical scans are conducted with the asset under normal operating load. We confirm conditions in the proposal stage.
Do you use drones for thermal surveys?
Yes — UAV-mounted radiometric thermal cameras (FLIR / DJI H20T-class) are used for solar PV array surveys, roof and high-level building envelope inspection, district heating pipe-route detection across large sites, and substation/switchyard scanning. Ground-based handheld thermography is used for internal building envelope work, M&E equipment scanning and confined-space assets. Most projects combine both — aerial overview plus targeted ground-level investigation.
What deliverables will I receive?
A written report containing: site overview, environmental conditions at survey (ambient temp, RH, wind, irradiance), camera calibration record, thermographer qualifications, paired thermal/visual images per anomaly, anomaly classification by severity, recommended remediation, and an executive summary suitable for handing to insurers, asset owners or building control. For PV surveys an anomaly map with module-level GPS coordinates and a comma-separated defect inventory. Solar SEMI PV3 / IEC 62446-3 compliance available on request.
Are you RICS regulated?
Yes. Angell Surveys is regulated by the Royal Institution of Chartered Surveyors (RICS) — verify via our public profile at ricsfirms.com/office/681790/Angell-Surveys-Ltd. Thermographic interpretation is provided by ITC Category 2-certified thermographers operating under documented procedure and equipment calibration records.
Related Services
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Aerial Inspection
Drone inspection of structures, roofs, facades and high-level assets — commonly paired with thermal imaging for full visual + radiometric coverage.
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Service
Confined Space & Remote Inspection
UAV inspection of confined and GPS-denied spaces — available with thermal sensor for combined visual + radiometric capture.
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Service
Aerial Survey
UAV photogrammetry for site context, often combined with thermal capture for solar PV and large-area thermal inspection projects.
Learn more →
Request a Quote

Thermal imaging survey, scoped and quoted within 24 hours.

Most scoping responses sent within one business day.

RICS-regulated work, led by Philip M. Angell MRICS.

Discuss your Thermal Imaging Survey Call 020 4652 4948