Installed by Gas Safe and G3 certified engineers, fully compliant with current regulations
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Suitable for 1-2 bedroom properties with 1 bathroom
Suitable for 2 bedroom properties with 1 bathroom
Suitable for 3 bedroom properties with 1-2 bathrooms
Suitable for 4-5 bedroom properties with 2 bathrooms
Suitable for 4-5+ bedroom properties with 2 or more bathrooms
An indirect unvented cylinder uses your existing boiler to heat stored water, delivering mains pressure hot water to every tap and shower in your home. It’s the most popular choice for London homes with a gas boiler, offering excellent efficiency and consistent performance throughout the day.
At Master Gas London, every indirect unvented cylinder is supplied, installed, and fully commissioned by Gas Safe and G3 certified engineers across London, Essex, and Hertfordshire. All prices shown on this page are fixed and include installation, so what you see is what you pay.
By law, unvented cylinders must be installed by a qualified G3 engineer. Choosing an uncertified installer invalidates your warranty and puts your household at risk. With Master Gas London, the work is done correctly, safely, and to your manufacturer’s exact requirements.
Barking and Dagenham
Barnet
Bexley
Brent
Bromley
Camden
Croydon
Ealing
Enfield
Greenwich
Hackney
Hammersmith and Fulham
Haringey
Harrow
Havering
Hillingdon
Hounslow
Islington
Kensington and Chelsea
Kingston upon Thames
Lambeth
Lewisham
Merton
Newham
Redbridge
Richmond upon Thames
Southwark
Sutton
Tower Hamlets
Waltham Forest
Wandsworth
Westminster
Basildon
Braintree
Brentwood
Castle Point
Chelmsford
Colchester
Epping Forest
Harlow
Maldon
Rochford
Southend-on-Sea
Tendring
Thurrock
Uttlesford
Broxbourne
Dacorum
East Hertfordshire
Hertsmere
North Hertfordshire
St Albans
Stevenage
Three Rivers
Watford
Welwyn Hatfield
An indirect unvented cylinder stores and heats water using your boiler via an internal coil, rather than an electric immersion heater. It connects directly to the mains supply, which means you get high pressure hot water throughout your home without needing a cold water tank in the loft.
A direct cylinder heats water using an electric immersion heater only. An indirect cylinder is heated by your boiler, making it significantly more efficient for homes already on gas. Most indirect cylinders also include an immersion heater as a backup for added reliability.
Yes, it is a legal requirement under Part G of the Building Regulations. All unvented cylinders regardless of type must be installed and commissioned by a qualified G3 certified engineer. Every installation carried out by Master Gas London meets this requirement as standard.
The right size depends on the number of bedrooms and bathrooms in your property. As a general guide, a 150 litre cylinder suits a two bedroom home with one bathroom, while larger properties with multiple bathrooms typically require 210 litres or more. Use the quote tool on this page to get a recommendation based on your specific property.
Yes, all prices shown include the cylinder, installation, and full commissioning by a G3 certified engineer. There are no hidden extras. If any additional work is identified during installation your engineer will discuss this with you beforehand.
