Unvented hot water cylinders: frequently asked questions

This unvented hot water cylinder’s frequently asked questions webpage is designed to answer the most common questions people have about unvented cylinders, how they work, where they are used, and what to consider before choosing one. Unvented hot water cylinders are a popular choice for homes, flats, commercial buildings, offices, hotels, schools, and properties that require reliable mains pressure hot water.

Unlike traditional vented cylinders, an unvented hot water cylinder is connected directly to the mains cold water supply. This allows it to deliver hot water at higher pressure to taps, showers, baths, and other outlets without needing a cold water storage tank in the loft. This makes unvented cylinders ideal for properties where strong hot water performance is required across multiple bathrooms or outlets.

Unvented cylinders can be heated in different ways depending on the system design. Direct unvented cylinders use electric immersion heaters, while indirect unvented cylinders are heated by an external heat source such as a gas boiler, oil boiler, heat pump, or solar thermal system. Most indirect cylinders also include backup immersion heaters for additional flexibility.

Popular pressurised hot water cylinder FAQs

This unvented hot water cylinders FAQ section is intended to provide clear and straightforward answers to key questions, including how unvented cylinders work, installation requirements, sizing, water pressure, safety controls, maintenance, running costs, direct and indirect options, and whether an unvented hot water cylinder is suitable for your property. Whether you are replacing an old cylinder, upgrading your hot water system, or planning a new installation, these frequently asked questions will help you understand the advantages and limitations of unvented hot water cylinders

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