Replacing old Baxi floorstanding boiler with a HE Combi

[tahir2]

Hey guys

Amazing forum, the amount of high efficient condensed knowledge here is astounding. Love the interwebz...

Was looking for a bit of expert advice (be free to disagree, some of this is subjective and personal preference after all.)

OK my dilemma is that I have a very old Baxi floor standing boiler that works absolutely perfectly. I just bought this property a 4 bed mid terraced house with.

Current specification is:

1x conventional Baxi floorstanding boiler (don't know the model number but pic below)

10x radiators of various shapes and sizes

Water storage system with two tanks in airing cupboard in bathroom

The house ground floor, 1st floor and an inclination to do a loft conversion in the future (maybe 2-5 years)

Area of the house is approx: 14m x 5m

1x large lounge

1x bathroom (with electric shower pre-installed)

3x double bedrooms

1x single bedroom

Considering at the moment I have no issues with the old Baxi boiler, it works and heats the home like a champion in winter, is it worth getting it replaced? The reason for replacement would be to lower the gas usage (and therefore gas bill) and just to be greener I guess. Plus the water storage system can be slightly inconvenient at times.

 

[dcawkwell]

To be green keep the old boiler that will go on forever.
Spend the money on insulation(free at the moment, offers for loft and cavity wall). Double glazing.

Modern controls. Wall thermostat, thermostatic valves.
Fully pumped system, hot water tank thermostat. Perhaps replace
tank with unvented cylinder that will be better insulated and heat up much quicker if good mains and pressure.

With the above a mid terraced house will be pennies to heat.

 

[tahir2]

Thanks for the reply.

At the moment the house has lots of loft insulation and no option for cavity wall insulation.

I like the idea of thermostat valves, can you elaborate on the unvented cylinder? I think the house has one already - a big tank with lots of green insulation around it. Apologies not that conversant with plumbing/heating terminology. Ask me about computers though and I won't shut up

 

[dcawkwell]

Thanks for the reply.

At the moment the house has lots of loft insulation and no option for cavity wall insulation.

I like the idea of thermostat valves, can you elaborate on the unvented cylinder? I think the house has one already - a big tank with lots of green insulation around it. Apologies not that conversant with plumbing/heating terminology. Ask me about computers though and I won't shut up

In which case you probably have a hot water tank with a cold loft tank feeding it (gravity hot water).
An unvented cylinder takes feed directly from the mains cold. So you have
mains pressure hot water. If you find the hot water is fine keep with it.
Replace with the hot water tank if and when. Sounds like your cylinder is fairly new if it has the green insulation so should keep the heat.
Only need to be heated for an hour or two in the morning and again
in the evening.

 

[tahir2]

Anyone think different?

The cost savings long term won't outweigh the costs involved in replacing the system I currently have?

 

[kittedup]

Agree with everything that has been said.

That boiler could go on another 20 years.

Update all the system controls (trv's, room/cylinder stat), chemical flush and fit a filter and you'll be getting the best out of it.

Most important get the thing serviced every year.

Ted

 

[Agile]

That kind of boiler is about 60% efficient if you are lucky! That means it wastes 40% of the fuel.

But unless the bills are over 800 pounds a year it will not give a useful financial return by replacing it.

Properly insulated and used you should be able to get your gas bills down to about 600 p.a.

But replacing the boiler will save the planet but cost you about 1500 if you are in a cheaper area.

Tony

 

[tahir2]

If it is indeed around 60% efficient (it is quite old and my winter bill was a decent chunk - we are quite careful with our usage as well) then it may be cost effective to get the old system replaced.

£600 pa sounds about right and possibly £800 if it is a particularly harsh and prolonged winter.

With a new system at around 90% efficiency, with thermostat valves I would expect something like a 30% reduction in cost of gas usage for the boiler. If I do a 70/30 split (boiler + gas cooker and oven) that is an average:

£700 gas pa.
Minus 30% for the gas cooker £490

With a 30% saving = £147 saving per annum with a HE boiler

It would take approximately 13 years to recoup the costs. On the plus side it adds value to your home, it is better for the environment and the energy companies make less money (the robbing s.o.bees) ...

Best quote so far I have had to replace the system add a Baxi Platinum 28 HE, flush system and add thermostat valves = £1700.

Would want to add a magnaclean to that - £1800 total.

I could go for a Potterton Gold and save a couple hundred quid, as been told it is the same as Baxi Duotech but cheaper or knock another £150 and get a Biasi 28 Riva Plus HE. Problem with gaining knowledge is that sometimes it leads to indecision... too many variables!

 

[Agile]

Even if you do a lot of cooking its unlikely the cooking bill will exceed 5% of the gas bill.

Tony

 

[tahir2]

Rejigging the figures allowing for a 90/10 mix instead (just to err on the safe side.)

£700 gas pa.
Minus 10% for the gas cooker £630

30% saving with new system: £189

Would pay for itself in 10 years rather than 13 years - saving immediately and increasing the value of the property.

Cheers Tony!

 

[hammerswinger]

Don't believe for one minute any of that high efficiency mumbo jumbo, we replaced our old band G combi boiler (below 70% efficiency) & replaced it with a band A (above 90% efficiency) condensing combi 2 years ago, our usage has remained unchanged but the bills have not changed in the slightest!


Cheers.

 

[ALEC1]

to get the most out of condensing boilers you need to use compensation controls, these force the boiler to operate as the lowest temperature required to mantain a comfortable temperature..

You also need to engage with the controls to reflect your life style..

 

[hammerswinger]

Even with those controls I don't believe for one minute they are anywhere as efficient as they would have you believe.

It's just like the MPG figures that they give for vehicles, you can never achieve them either....mumbo jumbo I tell you


Cheers.

 

[ALEC1]

which compensation controls do you have experience with..

 

[hammerswinger]

None of them.

As we replaced a less than 70% efficient boiler with one that is said to be 91% efficient (say 20% minimum difference) I would have expected to see at least some reduction in gas used....maybe it does use a tiny bit less but not really noticeable on the bills...certainly not a 20% saving.


Cheers.