Free, in full, and the working is on screen
Not a teaser. Every calculation runs to completion with no account and no time limit, and each tool shows its workings rather than asking you to trust a number.
- U-Monkey — BS EN ISO 6946 with BR 443 conventions, a neutral 300+ material database with no manufacturer favourites, ISO 13788 condensation alongside, and thermal mass. The Building Control PDF is free.
- ΨMonkey — ISO 10211 thermal bridges you draw rather than look up, with fRsi, and published validation against accredited sets.
- WaterMonkey — the full DCLG methodology including Table 2 multiple-fitting averaging, the water softener rule and BS 8515 greywater.
- GlazeMonkey and RenoMonkey for the extension and renovation routes.
- Reference data — SAP junction psi values, thermal conductivities, carbon factors, RdSAP age bands, water-stressed areas, wastewater permits.
If you issue the reports to clients
Monkey Pro puts your practice name, logo and contact details at the head of every report and drops ours to a credit line, with your project number and revision on each one. The maths is identical either way — a subscription never unlocks a calculation, only whose document it looks like. What each tool costs.
Where we are a consultancy rather than a tool
We are an accredited practice as well, so we do SAP, SBEM, energy statements, air tightness and sound testing. If you are a consultant yourself, that is not a pitch — it is a straight answer to what happens when a client asks you for something outside your accreditation, and an offer of somewhere to send it.
Common questions
Is there a catch to the free tools?
No. The calculations are free in full and the U-value PDF is free to issue. We charge for the other Building Control submission PDFs, and a subscription adds your branding. Nothing behind a payment changes a number.
How do I know the psi values are right?
Because we published the comparison rather than asserting it. ΨMonkey has been benchmarked against accredited construction detail sets, with the value table, the agreements and the outliers all shown, including where BR 497 conventions explain a difference.
Can I use the reports under my own accreditation?
The calculations are yours to use as you would any calculation you had run yourself — you remain the author and it is your professional judgement that signs it. Monkey Pro simply makes the document look like yours rather than ours.
Not quite you?
- Architects & technologists — Settle the fabric at design stage, then hand us the compliance.
- Self-builders — What you can produce yourself, what you cannot, and when each is due.
- Developers & housebuilders — Multi-plot compliance, priced by dwelling type rather than by plot.