2 boilers or 1?

[Jamesxyz]

I've just purchased a house which we are in the process of converting from two flats into a single property. The flats had two separate gas meters, although both running off a single supply from the road.

My plumber has removed one of the meters and joined the gas supplies from outside the property as this was a requirement from my mortgage company.

Originally it would have been a large Edwardian house that was converted into two flats by boxing in the stairs. As one property it will be a 5 bed house about 3000 square feet in total over three floors.

Currently there are two combi boilers, one supplying the downstairs heating, hot water and a single bathroom (we will eventually remove this bathroom). The second boiler supplies the 1st & 2nd floor heating, plus two bathrooms.

My long term plan had been to replace the whole system with a single boiler downstairs, however typically the upstairs combi boiler has just died and is not repairable, which has forced me to make a decision now.

Obviously the cheapest short term solution will be to replace the upstairs combi and keep two separate boilers.

My question is what is the downside of having two combi boilers as opposed to one large conventional boiler? Presumably it costs more to run and I guess it will be twice the servicing costs?

 

[Dan Robinson]

Double the servicing and repair costs are one downside. Low end efficiency (where the boilers spend most of their lives) is also an issue.

I would be more worried about taking the gas meter over its rated output with two combi's.

For now I would temporarily link the two systems to one boiler.

Then in the refurb, bring that to a plant area and run the house in two zones with an unvented cylinder and system boiler.

 

[heatservice]

You could joint the 2 heating & HW systems to one boiler but your HW might suffer if you have long pipe runs between the boiler and some of your hot taps,the size (the heat output) of a combi boiler is more about the volumn of HW it can give you so a 31Kw combi will give more litres per min than a 24Kw model, but remember a 31Kw model most likely will only give you 24Kw max for your heating so you really need to consult a good heating engineer to check your heating requirements and your water pressure and flow rates before deciding