Should I replace my boiler - vokera 20/80 r.s. Flowmatic

[Jonyboymickle]

Hi,
First post on here but had site recommended for great advice!!

I have a vokera 20/80 r.s. flowmatic, there are no functional problems with it at the moment but I have been told that I should replace it as it's about 21 years old and will be quite inefficient.

I live in 100 year old terraced house with 3 meter high ceilings and I find it very hard to heat up in less than a few hours, I have got the relevant efficiencies for stopping the heat loss from the house (as much as I can with its age) but the boiler has to be on for a very long time to get the heat up once it gets there it's great but it's time for bed then and it all gets turned off.

I stared researching looking at the btu output on the radiators and it looks to me that the old single panel radiators don't produce enough heat for the size of the rooms so I am going to look at changing some to double convecting radiators which should heat the rooms up quicker and the thermostat will flick the boiler off quicker being more efficient but getting warmer quicker.

My gas bills are pretty big at the moment costing around £140 per month so the question is am I best investing in a new boiler which could be very costly or just change some if the radiators and keep the boiler as it runs perfectly?

I have no idea what to do so any help or advice would be massively appreciated

 

[btgriff]

Simply changing the radiators wont result in any saving on your gas bill. If you have bigger radiators then the house gets to the required temperature quicker, but it still loses heat at the same rate. Your boiler will still burn the same amount of gas to keep the required temperature.

To answer the question of whether it's worth changing your boiler more information is needed, but here's the method. Lets make some assumptions:
Your current boiler is 65% efficient.
Your £140 per month gas bill is only for the central heating.
The £140 per month is average over the heating season (6 months).

So your £140 multiplied by 0.65 gives you £91 of 'heat' per month. For a modern condensing boiler at 90% efficiency what amount of gas needs to go in to get £91 of heat. 91 divided by 0.9 gives us £101. Meaning a saving of around £40 per month, which would be £240 over the assumed heating season.

When I looked at this myself I found a saving of about £40 a year by changing the current boiler (79% efficient); I decided to improve the insulation and draught proof the house.

 

[Smackhead]

I have recently sorted it! I have also 100 year old mid Terrance with 2 below ground cellars, two beds. Needed to change system of electric immersion tank , back boiler and radiator position and radiators. Enquired everywhere this is the cost ideal logic 35kw condensing boiler Honeywell wireless thermo, 3 single large rads 2 double rads 4 x temp control valve, flush and inhabitor, plus rad valves.£1040 HPM Bolton
Copper piper pack of 22mm pack of 15mm plus extra two or three and connectors and associated stuff £325 local
Labour to pipe gas from cellar to upstairs bathroom to mount boiler, replumb one line system to a two line flow!! Remove immersion tank and back boiler re position all radiators.gas safe boy £900 haslingden boy took him 8 days at 5 hours per day.
Not bad eh