How do you calculate hot water cylinder size?
Calculating the right hot water cylinder size is one of the most important decisions in any hot water system installation. An undersized cylinder leads to frequent cold water during peak demand; an oversized one wastes energy heating water that is never used. The correct approach balances property size, number of occupants, peak demand periods, and […]
Who can install an unvented cylinder?
In the United Kingdom, unvented hot water cylinders must by law be installed by a qualified engineer who holds a current Unvented Hot Water (G3) qualification. This is a legal requirement under Part G of the Building regulations (Approved Document G). Why a G3 qualification is required:Unvented cylinders operate at mains pressure and store water […]
What size unvented hot water cylinder do I need?
Choosing the right size unvented hot water cylinder is essential for reliable hot water supply and energy efficiency. Unvented cylinders operate at mains pressure and store a set volume of hot water that must meet peak demand between recovery periods. Here’s our guide to selecting the right domestic hot water cylinder. Start with the property, […]
Top-rated indirect hot water cylinder brands for UK homes: Key considerations

The UK market for indirect hot water cylinders is led by a handful of specialist manufacturers, each with distinct strengths in material quality, energy efficiency, warranty provision, and installer support. What to look for in a top-rated indirect cylinder: OSO Hotwater consistently ranks among the top-rated indirect hot water cylinder manufacturers in the UK. Manufacturing […]
Welcome to our new members of the Sales team
🎉 Welcome aboard! 🎉 We’re delighted to welcome Gary Muir and Richard Stubbs to the team as our newest members of the Sales team. Both bring a wealth of experience, energy, and enthusiasm, and we’re really looking forward to the expertise and fresh perspective they’ll add as they get started. At OSO, collaboration and support […]
LG acquires the OSO Group

LG Electronics Inc., a global leader in home appliances and consumer electronics with sales of USD 64 billion and headquartered in Seoul, Korea, announced today that it will acquire all shares in OSO Group AS – the European market leader in stainless steel, smart and energy-efficient hot water tanks. Focusing on heating OSO Group will […]
Energy transition at ISH 2025 – Join OSO Hotwater!

OSO Hotwater is taking a lead in the the energy transition with innovative products, and is present at ISH 2025!OSO Hotwater will present innovative solutions that help decarbonize buildings and energy systems designed for various markets across the worldEngage with experts to find optimum solutions for your need. We look forward to meet you at […]
The future role of hot water cylinders in balancing grid demand
The Hot Water Association (HWA) and Energy and Utilities Alliance (EUA) were hosted by Pauline Latham MP at the Houses of Parliament on 5th December to launch the HWA’s new report on Connected Homes The Connected Homes report was commissioned by HWA to demonstrate the opportunities for stored hot water cylinders in decarbonisation and renewable energy in the electricity grid […]
4 WAYS OF SAVING ENERGY ON WATER HEATING
OSO are being asked regularly and understandably about water heating costs and general energy costs. We do have some advice. Some things are easy and will save a small amount of money, others require a rethink about your habits but could save a considerable amount. There are some obvious things that are well known. […]
ONE SIZE DOESN’T FIT ALL
One size doesn’t fit all Isaac Occhipinti, Head of External Affairs, HWA The domestic hot water cylinder industry is a crowded market, the overwhelming majority of unvented cylinders look the same, and in most cases they are fitted in the same way, but there are many differences that the installer and end user should be […]