There are two common types of water heaters used in residential applications today – vented and unvented. While vented hot water heaters are perhaps the more common of the two, unvented water heaters are quite popular. They provide good flow rates at taps and appliances, and require less installation space than conventional gravity systems (vented hot water heaters). Also unlike conventional gravity hot water systems, unvented water heaters do not have a feed and expansion tank located above them, and there is no need for a vent pipe. In a gravity system, the vent pipe is open to the atmosphere and prevents unwanted pressure build-up within the system. The key difference between the two types of systems is the fact that unvented boilers are sealed. This is also why installation of these systems is strictly controlled by part G3 of the building regulations. It should also be noted that direct unvented water cylinders require the skills of a plumber qualified to work on unvented heaters and a part “P“ registered electrician, as their function requires both skill sets.


  • Potentially better flow rates and stronger pressure at taps, showers etc.
  • This is a very quiet system.
  • Ideal if you have more than one bathroom.
  • Reduced risk of water contamination.
  • It’s space-efficient and can be installed anywhere from the loft to the garage.

At JK Plumbing and Heating we are BPEC G3 qualified, meaning we can safely install all unvented hot water systems, service & provide repairs.

We also carry out yearly services to make sure everything is working as it should be.

JK plumbing & heating have both qualified plumbers and electricians to handle these situations call for a quote today or contact us by email.

We cover the South East which includes all of East Sussex, Heathfield, Horam, Broad Oak, Cross in hand, Crowborough, Uckfield, Hailsham, Eastbourne, Lewes, Brighton, Seaford, Newhaven, Haywards Heath, Burgess Hill, Hastings & Battle. Kent Tunbridge Wells, Pembury, Sevenoaks, Ashford & Maidstone. West Sussex, Surrey & Mid / South London. This includes postcode areas TN, BN, RH and Inner & Outer London.