Large combi advice

[oilman]

EH?

Er.....would you like to elaborate?

 

[gsportgeorge]

^^^ exactly

A plain boiler costs about the same as a combi - so you get all that other stuff in a combi at its true worth.

But installation costs of a (combi?) boiler + unvented may be £2000 more than a combi alone. Then it isn't 3kW to heat the HW, it's 25kW.

Conventional boiler + vented HW tank + a shower pump will be cheaper, more reliable and give you less grief when something goes wrong.

I cant really understand this.

My investigations so far suggest a combi is only £50 or so more expensive than the equivilent conventional boiler... but a cheap hot water cyclinder is over £100
Thats before you factor in controls and extra pipe work and a circulation pump and now a shower pump has crept in there too

But the main concern is the fuel costs...

 

[oilman]

Fuel costs will be more influenced by reducing the temperature and/or heat losses than by anything else.

As for costs, take another view, heating is a major capital investment, and the equipment could/should last thirty years if properly maintained. Don't skimp at the start.

 

[gsportgeorge]

Not using 3kw of power to heat up some water only to let it cool down again seems like a fair saving to me... We just dont use much hot water...

 

[oilman]

Maybe YOU don't use much hot water. Are you going to have guests? Your house is large if 14 rads is anything to go by. The system should last some decades. You may not be there when the system has many years life left. A combi is not a good choice for a large house. When you need to supply water for several taps at once, the supply pipe and the boiler and winter are the limiting factors.

However, have a combi, then you can get to know your boiler repair man fairly well.

 

[PEDANTICVINDICTIVEMAN]

Nothing wrong with a correctly installed decent qaulity combi.

 

[fathertobe]

Apologies for dragging up old thread but ...

I wish people would come back with their final decisions.

 

[sturharv]

Don't worry he'll be back with a new thread which may read:

"WHY CAN'T I RUN A BATH AND WASH THE POTS AT THE SAME TIME!!!"

Does he know what combi's are like in large houses....

 

[gsportgeorge]

At the time of the last post I hadnt yet bought the house it was to go in...

Before the original owner moved out, she had used a government scheme to get a small combi fitted and radiators on the ground floor. Unfortunately the location of the boiler was really inconvenient and had to be moved anyway...

My choice in the end (last winter) was to fit a WB Greenstar cdi 35 condensing combi in a new location and trade the brand new "old" boiler for some help with fitting the new one... Split the 22mm flow and returns to 2 22mm's and a 15mm just outside the boiler.

Started putting a good thick layer of insulation in the roof (one room/half done) and have added a few more radiators in the active bedrooms.


My reasoning for this was that the disruption of putting a hot water tank somewhere (where when there is no attic space that isnt habitable rooms?) was not worth the possible savings.

I would also dearly like to switch to ideally a wood burning combined heat and power unit someday so I dont see this as a "final solution"...



The greenstar has run fine for just over a year now (flashing SE at me for a service). We do have a slight issue with hot water flow but this is more down to the 15mm inlet pipe which serves the whole house and needs changing when I get round to ripping the kitchen out (inlet is plastered in behind the kitchen sink...)


I really did appreciate all the help and suggestions that people gave here and it did lead me to consider every alternative. If I had had more money and some wasted loft space I probably would have fitted a pressurised HW cyclinder with a spare heating coil so I could add solar tubes at a later date...

George