Combi boiler versus hot water tank

[Dr De Soto]

We currently have a regular condensation boiler, with a water tank in the loft and a hot water tank in an airing cupboard. We want an extension and the builder has advised us to switch to a combi boiler and get rid of the water tanks in the loft and airing cupboard (it will create storage space, for one thing).

Are there any disadvantages to combi boilers? Are these now the norm in houses, or do lots of people still have hot water tanks?

[jimbo1964]

No disadvantage at all from what I've experienced. Very economical and hot water whenever you want it.

[HunterHtingSolutions]

Hi Dr De Soto,

I get asked this question a lot! Both have their pros and cons....

Advantages of keeping the hw cylinder and tanks....

-No pressure loss with multiple tap/shower operation

-If boiler breaks down you have the option of immersion backup for hot water

Cons

-Tanks take up a lot of room

-Unless you introduce shower pumps (pricey and don't always last that long) pressure is never going to be great for showering

-Have to heat cylinder capacity for hot water....You may not use it all

-Unless you seal the heating system open systems are more susceptible to forming 'sludge' in the system

Pros of a combi

-You only pay for what you use (hot water)

-If you have good water pressure on your incoming main you can have a powerful shower without the need for pumps

-Get rid of hw tank, cold water tank and F&E tank

Cons for a combi

-Only one tap operation so if you are having a shower and someone opens a tap it will affect your shower

-If you remove hot water cylinder you lose your airing cupboard for drying clothes etc. (Although there are options like putting a small rad in there or a dual towel warmer so you can use during the summer also)

-If the boiler breaks down you have no heating or hot water

Bottom line is if your water pressure from the main is poor a combi may not be the best choice. If you have poor water pressure you can usually enhance this by running a new incoming main from the outside stopcock (recommend 32mm minimum)to inside the property.

I personally think unvented hot water cylinders are usually the best on the market for delivering efficiency and a powerful equal flow between hot and colds so you can use multiple taps and still achieve equal pressures (provided you have a good water flow rate and its been done properly!) You still get rid of the tanks in the loft but you just have a boiler and a cylinder (your existing boiler would still be compatible with this).

Think I've waffled on enough!! If you have any further questions please don't hesitate to contact me on 07986296453.

Good luck with the extension!

Kind regards,

Billy Hunter

Hunter Heating Solutions.

[Dr De Soto]

Thanks for that detailed answer Billy, very helpful.