Combi vs System boiler?

[Steve Bennett]

Hi all,

I am a new member this is my first post, I am researching boilers and need some advice please.

I have a 5 bed house with 3 bathrooms and 17 radiators, and a traditional tank based boiler on it's way out. All we are looking for is to be able to have hot water when we want it, at any time, as efficiently as possible. Our options seem to come down to one of the following :-

1) A big Combi suitable for a large house, such as a Worcester Highflow floorstanding
2) A System boiler requiring a tank, such as a Worcester 24i Greenstar System

However with Option 1 the limitation seems to be only running one tap at a time as it heats as it goes, which sounds a bit restrictive. Option 2 means it's possible to run out of hot water in the tank, which is a possibility if the kids have a bath then my wife wants one later.

My question is - do I have to choose between either running one tap at a time or potentially emptying the hot tank - surely there is an all inclusive option? Or, what does everyone advise is the best solution? Is it better to get a System boiler and then just leave it on 24x7 or is this really expensive to run?

I have seen a couple of other posts on this, some responders talk about 20mins waiting time to heat a tank, but mine takes over an hour. Is this normal? or is my current one just really inefficient? This might influence the decision!


Thanks
Steve

 

[Atouchofgas]

With the size of house and bathrooms, I would advise boiler and if water pressure is ok put in a unvented hw cylinder

 

[IDCHAPPY]

Even a storage combi might struggle with the demand. Go as above 🙂

 

[Riley]

️Agreed, defo unvented if you can

 

[IDCHAPPY]

Ps. please consider other brands. Worcester isn't the only and best brand of boiler out there 😉

 

[Unregistered]

Thanks for the responses - very helpful. With the unvented cylinder then does this mean : old boiler, immersion cylinder, cold water tank and refill tank all come out, new boiler, cylinder go in and no tank needed in the loft?
I'm not convinced about water pressure where we are, we are on top of a hill and only been in a few months now but flushing the toilets doesn't push water out as powerfully as our old house, not sure if that means anything or not!

 

[Riley]

Your flush is not affected by water pressure. Only how quickly the cisterns fill. Get a GSR engineer in to test the set up for you.

 

[Unregistered]

Thanks

 

[Millsy 82]

If your hot water pressure/flow is enough now and you have no problem with it you can install an efficient vented cylinder (they are not as good as an unvented in my eyes but if everything works as it should why change)

I wouldn't go combi in that sized house my self.

 

[lame plumber]

If anyone quoting for the work suggests a combi, bin them!

 

[AWheating]

As suggested an unvented cylinder would be a good solution. Test you cold water pressure and dynamic flow rate to see if you can have one. A combi in a house with 3 bathrooms with a family is a bad idea.

 

[Roger Welton]

I would agree with all thats been said already, not a combi, and not a worcester.

Unvented cylinder if the incoming main is up to it, or vented if not.