What Does The i-HEATPUMP Toolkit Do?

i-HEATPUMP is developing software to assist heating engineers commission, maintain, diagnose and optimise domestic and commercial heat pump systems.

This suite of tooling represents a growing set of field tools being developed into a dedicated heat pump diagnostics platform - this page gives early access to selected features before the full platform release.

We hope you find these tools useful - spotted something off or have a suggestion?

Email info@i-heatpump.com with feedback.

Toolbox

Turn Testo temperature values into valuable consumer insight in seconds.

  • What the tool 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 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 actual or illustrative flow rate to match or simulate system conditions

    6. Instantly view heat output (kW), energy (kWh) and estimated cost (£) for the uploaded temperature data

    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

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
–
Avg output
–
Peak output
–
Thermal energy
–
Illustrative elec. input
–
Illustrative cost *
–
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.

Cable Current Capacity Estimation Tool

  • Electrical installations should be fully de-energised before inspection - follow safe isolation procedures and lock out the supply before working.

    This tool helps you quickly sense-check cable sizing in real-world installations.

    Enter a measured conductor diameter and compare it against typical current-carrying capacity based on installation method, cable type and run length. It also highlights voltage drop and gives an indicative protective device range.

    Why it’s useful

    Cable performance isn’t just about size - it’s about how it’s installed.

    Insulation, grouping, ambient temperature and run length can significantly reduce how much current a cable can safely carry. This tool helps you spot when a cable might be borderline or undersized.

    When to use the advanced options

    Only adjust these if something about the installation isn’t “standard”:

    • COP (heat pump comparison)
      Use when working on heat pumps.
      Helps translate electrical load into an approximate heat output so you can sense-check system size.

    • Additional thermal restriction
      Use if part of the cable is buried in heavy insulation or tightly enclosed.
      Example: cable runs through a loft and is covered by deep mineral wool.

    • Ambient temperature
      Use if the cable is in a hot space.
      Example: lofts in summer, plant rooms, or near hot pipework.

    • Grouped circuits
      Use if multiple cables are bundled together.
      Example: several circuits clipped together or installed in trunking.

    Important

    This is a reference and diagnostic tool for use on site, not a substitute for full design to BS7671 or manufacturer guidance.

Cable Current Capacity Estimation Tool

Estimate conductor size from measured copper diameter, then check simplified current-carrying capacity, voltage drop and indicative protective device size.
Advanced Options
Explanation
Supply voltage
Used to calculate voltage-drop percentage. The default is 240V because many UK sites measure close to this. Lower supply voltage increases the displayed percentage voltage drop.

Voltage drop limit
Selects the pass/fail threshold. Lighting circuits are commonly checked against 3%; other final circuits are commonly checked against 5%.

Grouped circuits correction
Use when multiple circuits run together and cannot freely dissipate heat. More grouped circuits reduce the allowable continuous current.

Ambient temperature correction
Use when the cable is installed in a hotter environment. Higher ambient temperature reduces the cable’s safe continuous current.

Additional thermal restriction
Use only if there is extra heat restriction not already captured by the selected installation method. For insulation-heavy situations, prefer selecting Method 100, 101, 102 or 103 rather than adding this manually.

COP slider
Used only to estimate equivalent heat pump thermal output from the displayed electrical load. It does not affect cable current rating.

Output Summary

Estimated conductor size
2.5 mm²
Maximum continuous current reference
27 A
Cross Sectional Area (CSA)Solid DiameterVolt Drop