Worcester Bosch Greenstar 30i

[Nick Allen]

Hi,

Is the WB Greenstar 30i big enough for a 4 bed house with two bathrooms?

Got one heating engineer telling me it is and one saying it’s not.

Thanks

 

[Hason]

Depends on pressure of mains water /flow rates/expectations etc, if you can get a cylinder with system boiler atleast your have a back up of hw via immersion heater.
Good luck

 

[muggles]

You need to get a heat loss calculation done to determine the required heat output for your house. My own 4 bed semi needs 14kW so a 30kW would be inefficient. Sticking a finger in the wind won't get you the most efficient result

 

[Nick Allen]

So I just did a quick heat loss calc on the house and it looks like we need 13kw for the heating.

When I use the boiler size calculators on WB, Valliant and others, they are recommend between 30kw and 36kw.

What am I missing that means we need over double the output of the heating according to the manufacturers websites?

Thanks a lot.

 

[Dan Robinson]

Marketing

Plus they're crap.

 

[muggles]

Are they sizing for hot water rather than heating? If you're looking at combi boilers and expecting them to run two bathrooms, you're going to be very disappointed. Combi boilers are designed to run one outlet at a time... you need a system boiler and a hot water cylinder

 

[boilerdoktor]

Nick, the average house kw for heating is between 5 and 10 kw. So most boilers will kill it. So you need to look at the hot water solution. To heat two showers at the same time on average flow you ll need 34 kw plus. This though is dependant on your dynamic water pressure on the incoming cold mains. You could get a 60 kw boiler ...if your dynamic pressure can’t support two showers and drops off your wasting your money

 

[boilerdoktor]

The wb cdi classic is a vision of beauty and reliability....look no further than the 34 cdi classic. Fitted by a wai you ll get up to 10 years warranty