Three bathroom: megaflow, heatstore, or big combi?

alexanderalexander

Hello all,

I've had my house massively extended, increasing it from one bathroom to three! So far I have kept my existing small combi boiler, but as expected it's not providing anywhere near enough hot water for three bathrooms. I've spoken to a plumber who has suggested three options and suggests they'd all be much of a muchness in terms of their efficacy:

• Add a megaflow to my existing combi boiler. The disadvantage is that I have two separate bits of kit (boiler and Megaflow) to maintain or replace when they're worn out, but it would "only" cost about £1200 compared to around double that for the other two options.
• Swap my boiler for one with an integrated hot water tank (I think it's known as "heatstore"), such as an Ideal Istor.
• Swap my boiler for a high-capacity combi boiler (such as a Worcester Greenstar Highflow 550CDi) -- my plumber says I have very high mains water pressure so this would work.

Does anyone have any thoughts as to which would be the most sensible? I have to say I'm finding it hard to get my head around how a megaflow actually works -- is it seamlessly integrated with the boiler system? Ease of use (no faffing around turning different apparatus on/off, or timing hot water etc.) is important to me.


Very grateful for any help.

Alex1983

Id go the mega flow route, assuming as you say the cold mains is good, zone it off you current heating system and just let your current combi run either a kitchen hot tap or one bathroom.

Istors are possible the worse thing ive ever worked on.

Highflows are good but only provide hot water at 20l per minute for a limited amount of time and then they fall back to a normal combis flow rate and they are very expensive.

SuzieSue

Alex1983 wrote: »

Id go the mega flow route, assuming as you say the cold mains is good, zone it off you current heating system and just let your current combi run either a kitchen hot tap or one bathroom.

.

I agree with this. The other main advantage over the other 2 options is that you will be able to have hot water from the megaflo even if the boiler breaks down.

Typhoon2000

An unvented cylinder for sure. There are other brands just as or more reliable for less than a Megaflow.

alexanderalexander

Thank you very much to everyone for this help. It sounds like everyone's agreed that a Megaflo (or alternative brand of unvented cylinder) would be best.

fezster

Joule cylinders are highly rated and much cheaper than a Megaflo branded unit. I have the latter and wouldn't spend the extra on it.