Worcester 25Si or 30Si?

[darnok]

Being in a need of a compact boiler, I ordered a Worcester 25Si for my 2 bed (6 radiator) house. However 30Si was delivered instead and re-ordering will delay installation and subsequent jobs. Can anyone voice an opinion on disadvantages of going with a more powerful boiler? 25Si and 30Si have the almost the same specs, 30Si has better DHW Flow Rate and Output BTU/H, hence I presume is more power hungry. Will that make a big difference to heating bills? Is there anything else I need to worry about?

Many thanks!

 

[JayPage]

did you pay the extra cost for the bigger boiler?

 

[Gasguru]

They'll be no difference to the heating bills, but you may have to pay for a upgrade to the gas pipework if it's a marginal size at the moment. Of course you may already be having the gas pipework redone since so many are undersized to start with.

 

[darnok]

The 30Ai "upgrade" is free, but I do worry the pipework will be an issue. For the 25Si, the installers toyed with the option of running pipes around the house, then had another look under the kitchen cupboards and decided only few smaller pipes need to be replaced. I wonder how much more bandwidth would be required for 30Si, I dread running pipes all around the house just for that...