Easy Heating Engineer

Easy Hot Water

Hot water cylinder sizing, reheat time and running cost. Please read and accept the following to continue.

Data privacy

This tool runs entirely on your device. Everything you enter — inputs, calculations and results — stays in this device’s browser storage and is not sent to any server or third party. There is no account, no tracking and no analytics. Nothing is shared unless you choose to share it yourself by producing a report or sending an email.

Disclaimer & competence

This tool sizes domestic hot water cylinders and estimates reheat time and cost to assist competent persons. It is a calculation aid only. It does not constitute engineering certification, a design, or a substitute for professional judgement, and it does not by itself satisfy any MCS, Building Regulations or other regulatory requirement.

Results depend on the information entered and the published data cited, and must be confirmed against current manufacturer data for the actual products installed. The user is responsible for checking all inputs and outputs, for working within their demonstrated scope of competence, and for compliance with current UK legislation, standards and manufacturers’ instructions. To the fullest extent permitted by law, the author accepts no liability for any error, omission, or any direct or indirect loss or damage arising from use of this tool or reliance on its output.

Copyright

© 2026 Easy Heating Engineer. All rights reserved. This tool may not be reproduced, redistributed, or modified without written permission. Sources (CIBSE, BSI, CIPHE, MCS and manufacturer data) are cited for reference only.

Backups. Your work is stored only on this device. Clearing the browser’s site data, uninstalling the app, or losing or resetting the device will delete it, with no means of recovery. Saving the report as a PDF keeps a copy of the results.
Easy Hot Water
Easy Heating Engineer

Easy Hot Water

Hot water cylinder sizing, reheat time and running cost.

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© 2026 Easy Heating Engineer.
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build 2026-10-17f