Terms of Use & Conditions

VentCalc ("the Service", "we", "us") is a software tool that generates indicative ventilation calculations to support early-stage building design, feasibility assessment, and manufacturer enquiry. It is operated as an independent commercial service.

By accessing or using VentCalc you agree to these Terms in full. If you do not agree, please do not use the Service.

VentCalc provides indicative ventilation calculations only. The Service is designed to support:

• Feasibility studies and option testing at RIBA Stage 1–2
• Early-stage design development and concept sizing
• Manufacturer enquiry and budget quotation exercises
• Tender preparation and preliminary scope definition

VentCalc does not:

• Replace professional engineering judgement or consultant design services
• Produce final construction documentation or installation specifications
• Constitute a compliance submission or regulatory approval
• Guarantee fitness for purpose of any specific building or system configuration

All outputs must be independently verified by a qualified mechanical engineer or building services consultant before use in procurement, construction, or regulatory submission.

VentCalc is a calculation software tool. It does not provide engineering, design, consultancy, or professional advisory services.

Outputs are generated automatically based on user-supplied inputs and standard calculation assumptions. The accuracy, completeness, and suitability of outputs depends entirely on the quality and accuracy of those inputs.

Use of VentCalc does not create an engineer–client relationship, a designer–client relationship, or any professional duty of care between VentCalc and the user or any third party.

Where professional engineering input is required, users must engage a suitably qualified and registered engineer independently.

By using VentCalc you accept sole responsibility for:

• Reviewing and verifying all outputs before reliance or onward use
• Ensuring that any ventilation system design meets applicable building regulations, planning conditions, and health & safety requirements
• Engaging a qualified mechanical or building services engineer where detailed design, compliance sign-off, or coordination is required
• Ensuring that drawings, inputs, and project data uploaded to the Service are accurate, current, and properly authorised for use

Final design responsibility, regulatory compliance, and construction co-ordination remain at all times with the consultant, contractor, or project engineer of record.

VentCalc is provided on an "as available" basis without warranty of any kind, express or implied, including but not limited to warranties of accuracy, completeness, merchantability, or fitness for a particular purpose.

To the maximum extent permitted by applicable UK law, VentCalc and its operators shall not be liable for any:

• Errors or omissions in design outputs
• Construction defects or installation failures arising from use of VentCalc outputs
• Regulatory non-compliance or building control rejection
• Financial loss, project delay, or contractual dispute
• Loss of data, loss of revenue, or indirect or consequential loss of any kind

Where liability cannot be excluded under UK law, it is limited to the total amount paid by the user for the specific report or service giving rise to the claim.

PDF reports are available on a single-report or unlimited subscription basis. Payments are processed by Stripe. VentCalc does not store card details.

Single-report purchases are non-refundable once the PDF has been generated and downloaded. Subscription payments are governed by the Stripe billing terms presented at checkout.

If a technical fault prevents PDF generation, please contact us and we will resolve or refund at our discretion.

VentCalc uses automated analysis models (including Claude by Anthropic and GPT-4 by OpenAI) to assist in interpreting uploaded drawings and extracting project data. The following applies:

• Automated interpretation may not identify all information present on a drawing
• Outputs depend on drawing quality, image resolution, and the completeness of visible annotations
• Automatically extracted values are indicative pre-fill suggestions only — users must review and confirm all inputs before calculating
• No guarantee is made as to the accuracy of automatically extracted room counts, areas, equipment tags, or flow rates

All outputs are indicative and intended for early-stage feasibility and design support only.

All software, calculation logic, branding, and PDF templates are the intellectual property of VentCalc. You may not reproduce, resell, or reverse-engineer the Service or its outputs for commercial distribution.

You retain ownership of any drawings or project data you upload. By uploading, you confirm you have the right to share that data with a third-party processing service.

These Terms are governed by and construed in accordance with the laws of England and Wales. Any disputes arising from use of VentCalc shall be subject to the exclusive jurisdiction of the courts of England and Wales.

We may update these Terms from time to time. Continued use of the Service after changes are posted constitutes acceptance of the revised Terms. Material changes will be flagged on the Service.