Green star 30i v 8000

[bsr]

Hi, any idea on the differences between the 30i and 8000 system boilers? Both at 30kw. From the specs the 30i is smaller and has the traditional Worcester rotary knobs, the 8000 is bigger and has a fancy display... Anything else? I prefer the LCD display but not for £400!

Am I right in thinking I can't have the 8000 series auto top up of system water on the system boiler (only combi)?

Do they both have the same pump, top opening HEX etc?

Thanks

 

[muggles]

Longer warranty on the 8000 and much better modulation - minimum output is 3.0kW Vs 7.15kW on the 30i so the 8000 will be more efficient in real world conditions.

8000 is front access, 30i has the vertical heat exchanger.

Do you actually need 30kW? That'll run about 30-35 radiators so is for enormous houses.

No auto top up on system boilers, although I've heard horror stories about that feature anyway...

FWIW I wouldn't have either of them, there are better boilers out there...

 

[bsr]

Thanks Muggles. It's a 150m2 detached four bed, with a poorly insulated flat roof extension, and currently has a 30kw installed. The calculators are generally recommending 24 or 30.

Was thinking Worcester as I can use Boxt who are generally 1k cheaper than local installers and offer a year interest free. I'd personally prefer something with a stainless HEX and Opentherm but Boxt are the easy option.

 

[muggles]

Wow, ok at 150m² you absolutely do not need 30kW. You're more likely to need around 10-12kW. I've recently carried out a heat loss calculation on an old property with solid brick walls & single glazed sash windows. 290m², which came out at 22.6kW. Over 100w/m² is virtually unheard of even in really old manor house type properties, there's almost no way you need 200w/m².

If you just want an easy Boxtit-and-scarper installation then fine, you'll get what you pay for and you may as well just go for their cheapest option. It'll be lobbed in in minimum time with minimum care by a badly-paid subcontractor who you'll never ever see again. If you want a good quality installation that will last for years and be cheap to run you need to be prepared to dig a little deeper initially to reap the rewards later on. The Vokera Pinnacle is an excellent system boiler with a 12 year warranty, stainless heat exchanger, and OpenTherm that's about £800 cheaper than the Worcester, and you'll find that the installers offering them generally know their stuff.