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.
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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
Attach Testo 115i clamps to flow and return pipework
Record temperature data over your chosen time period
Export the file from the Testo Smart App
Upload the file into the i-HEATPUMP tool
Enter actual or illustrative flow rate to match or simulate system conditions
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.
Advanced Heat Output Calculator
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Don’t have Testo temperature probes? Try the basic heat calculator instead.
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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
Cable Current Capacity Estimation Tool
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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
Advanced Options
Explanation
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
| Cross Sectional Area (CSA) | Solid Diameter | Volt Drop |
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Traditional Solid Stone U-Value Calculator
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Traditional British stone buildings are often assumed to lose far more heat through their walls than they actually do.
This calculator estimates the thermal performance (U-value) and design heat loss of traditional solid stone walls using the latest Scottish Government validated RdSAP 10 methodology. It can help homeowners, surveyors and heating engineers better understand how wall construction influences overall heat loss and heat pump sizing.
Why it's useful
Older guidance frequently assumed that solid stone walls had very poor thermal performance. Recent Scottish Government research has shown that many traditional stone walls perform significantly better than historic assumptions, particularly where original lath-and-plaster finishes remain.
This tool allows you to quickly estimate:
Estimated wall U-value (W/m²K)
Design heat loss through the wall (W)
Heat loss rate per square metre (W/m²)
This can provide a more realistic starting point when assessing insulation improvements or estimating whole-house heat loss.
When to use this tool
This calculator is intended for:
Traditional sandstone, limestone and granite buildings.
Preliminary heat loss assessments.
Comparing different wall thicknesses.
Understanding the effect of internal lath-and-plaster finishes.
Sense-checking assumptions used in EPCs and heat loss calculations.
It is not intended for cavity walls, timber frame construction or insulated modern masonry.
Assumptions
The calculator assumes:
Uniform solid stone construction.
Steady-state heat flow.
Traditional Scottish wall construction.
Overall wall thickness measured from finished internal face to finished external face.
Where selected, an additional thermal resistance for traditional lath-and-plaster or dry-lining.
Real buildings are also influenced by workmanship, moisture content, exposure, air leakage, thermal bridges and the condition of existing finishes.
Research and methodology
This calculator is based on the Scottish Government validated RdSAP 10 equations for traditional stone walls, which were developed following in-situ heat flux testing of occupied Scottish buildings by BRE.
Validation of RdSAP U-value Calculation Methodology for Traditional Stone Walls in Scotland
The calculator applies the published sandstone/limestone and granite/whinstone equations together with the optional internal lining adjustment described within the report.
Important
This is a reference and educational tool intended to help understand the thermal performance of traditional Scottish stone walls.
It does not replace a full room-by-room heat loss calculation or professional building assessment. Window and door losses, roof and floor construction, air infiltration, thermal bridging, orientation, solar gains and heating system design must all be considered before selecting or sizing a heating system.