Turn Testo temperature values into valuable consumer insight in seconds.

  • What this does

    Turn raw temperature data into real heat output (kW), energy (kWh) and cost (£) in seconds. Identify under-performance, verify output and prove results with measured data.

    Try it in 10 seconds

    New to temperature analysis?
    Download a sample Testo data file and upload it to visualise & interact with the results instantly.

    How it works

    1. Attach Testo 115i clamps to flow and return pipework

    2. Record temperature data over your chosen time period

    3. Export the file from the Testo Smart App

    4. Upload the file into the i-HEATPUMP tool

    5. Enter or simulate flow rate to match system conditions

    6. Instantly view heat output (kW), energy (kWh) and estimated cost (£)

    What you can use it for

    • Reduce call backs by proving outcomes

    • Verify system performance during commissioning

    • Quantify the impact of faults such as low flow or poor heat transfer

    • Demonstrate performance to customers in clear terms

    • Compare pre/post intervention results

    • Support reporting and year-on-year analysis

    Output & sharing

    Generate a simple summary view to:

    • support customer discussions

    • include in reports

    • retain for performance tracking

    • evidence improvements over time

Learn more about the Testo 115i - explore the full product details here.

New to temperature analysis?

Download a sample Testo data file and try the advanced tool in seconds.

Sample Testo 115i File
Sample Testo 115i File

Advanced Heat Output Calculator

40 LPM
Markers assume pure water @ ΔT 5°C (approx).
5 °C
Common diagnostics band: 3–7°C.
0% Water
Markers show approx freeze protection for typical glycol/water mixes - for exact values, use your fluid manufacturer tables.
Estimated heat output
14.0 kW
kW per 1°C ΔT
2.8
Supports .csv, .tjf and .json. Uses the user selected glycol level above and the trend flow rate, illustrative COP and electricity price values set below for estimations.
Expected source: Testo export with timestamp + ΔT and/or two temperature channels.
40 LPM
Used for uploaded trend calculations only. Adjusting this slider live updates the graph.
3.0
Used to convert estimated thermal output into an illustrative electrical input. This is not a measured COP.
25.0 p/kWh
Used with the illustrative COP to estimate a running cost. This is not a measured electrical cost.
Samples
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Avg output
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Peak output
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Thermal energy
–
Illustrative elec. input
–
Illustrative cost *
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Start End Duration
– – –
Approximation only (Q = m·c·ΔT). Assumptions apply. For accuracy use a compliant heat meter and manufacturer fluid data. “Illustrative electrical input” and “Illustrative cost*” are based on the engineer-selected COP and tariff, not measured electrical consumption. No warranty is offered or inferred. Use at own risk.

Don’t have Testo temperature probes? Try the basic heat calculator instead.

  • The Basic Heat Output Calculator quickly estimates a heating system’s instantaneous heat output (kW) using three key inputs: flow rate, temperature difference (ΔT) between flow and return, and glycol concentration.

    This allows you to translate what the system is doing into a meaningful heat output figure in seconds.

    Instantaneous heat output is particularly useful when:

    • Commissioning – verifying the system is delivering expected output relative to design

    • Servicing – checking performance hasn’t degraded over time

    • Fault finding – identifying issues such as low flow, poor heat transfer or incorrect settings

    • System comparison – understanding how adjustments to flow rate or ΔT impact performance

    Rather than relying on assumptions or controller estimates, this provides a quick, evidence-based snapshot of actual system performance.

Basic Heat Output Calculator

40 LPM
Markers assume pure water @ ΔT 5°C (approx).
5 °C
Common diagnostics band: 3–7°C.
0% Water
Markers show approx freeze protection for typical glycol/water mixes - for exact values, use your fluid manufacturer tables.
Estimated heat output
14.0 kW
kW per 1°C ΔT
2.8
Approximation only (Q = m·c·ΔT). Assumptions apply. For accuracy use a compliant heat meter and manufacturer fluid data. No warranty. Use at own risk.