Combi vs standard boiler?

swagman

I'm trying to compare quotes for a central heating upgrade to a condensing boiler. One engineer recommends a combi boiler and sealed system, another a standard boiler, open system. Which advice is most appropriate?

The house has 10 rads, bathroom with shower, bath and sink, cloakroom with sink and a kitchen with sink. The bathroom is a long run from the boiler.

The combi man argues that the output of the boiler will be chosen to fit the demand and that the sealed system will boost CH circulation. He also warns that the sealed system may cause leaks on old pipework (some of it underfloor), but that this is only a slightly greater risk than after the flushing out of any existing system.

Anyone have an opinion on these arguments? Thanks.

Canucklehead

Good evening: My OH, Corgi Guy, says don't go with the combi as it wouldn't meet your HW demands and recommends a regular boiler with an unvented cylinder on a sealed sytem (although you would still need good mains pressure...leaky pipework could result from this option as well).
You can find more info on specification and installation here http://www.energysavingtrust.org.uk/uploads/documents/housingbuildings/ce29.pdf
HTH

Canucklehead

alanobrien

What really matters is how you use your hot water.
If you had 2 bathrooms or a bathroom and a shower room them a combi probably wouldnt be the way to go, if you have one bathroom its not an unreasonable offering. Flow rates are limited but that is offset to some extent by not having a storage system so bills should be lower.

I had a similar dilemma - old system converted to pressurised with pipework underfloor in concrete.
It really is cross your fingers and hope for the best time!

Personally i would go for a storage system (pressurised system boiler) every time but that's just me.

elite_2

I think these points are right - I'm sure I'll be corrected if not...

Combi:

+ Instant hot water
+ Unlimited hot water
- limited flow (can only supply one bathroom) - you may get a cold shower if someone switches the washing machine on while you're in it

Conventional:

+ Can supply multiple locations with hot water
- Hot water has to be timed (a waste if you don't use it, annoying if you need hot water now)
- The amount of hot water available is limited by the size of the tank.


I'm sure there are more...

EliteHeat

Just to complicate things; there is no reason why you can't have both - a combi is perfectly capable of heating a hot water cylinder of any description.

And I'll bet that no one suggested that as an option

Sharra

I'm no expert, but when we had our boiler replaced, our guy said that there is more to go wrong on a combi, so you could be looking at higher repair bills in the future.

Canucklehead

Good evening: Just to add to the mix... in a previous thread the OP mentioned he was looking at a oil-fired condensing boiler and provided details of a quote...he also wanted to future proof for solar heating.

http://forums.moneysavingexpert.com/showthread.html?t=525573

Canucklehead

swagman

Canucklehead wrote: »

Good evening: in a previous thread the OP mentioned he was looking at a oil-fired condensing boiler and provided details of a quote...he also wanted to future proof for solar heating.

http://forums.moneysavingexpert.com/showthread.html?t=525573

Canucklehead

Yes, it is an oil fired system and we started off thinking of adding solar. The combi quote man says that it will soon be possible to connect solar panels to combi boilers, so a combi with no hw cylinder would not rule out solar panels in the future.

Canucklehead

swagman wrote: »

Yes, it is an oil fired system and we started off thinking of adding solar. The combi quote man says that it will soon be possible to connect solar panels to combi boilers, so a combi with no hw cylinder would not rule out solar panels in the future.

Good morning: Alpha has been doing a package called SolarSmart since 2006...it uses a gas fired combination boiler http://www.alpha-boilers.com/index.asp?wpid=143&backpointwpid=

My OH, Corgi Guy, went on a training day at the Alpha headquarters here in Kent more than 1 year ago.

HTH

Canucklehead

mopsey

Alpha CD50 combi is a top boiler.
Not sure if they do an oil fired version though.

Canucklehead

mopsey wrote: »

Alpha CD50 combi is a top boiler.
Not sure if they do an oil fired version though.

Good evening: Alpha doesn't do oil but makes a good product.

Canucklehead