A tale of two boilers...

[Terry Fields]

Well, mine and my next-door neighbours...

I don't know the make and model of next door's condensing boiler, but it was installed in their kitchen in last three years, replacing a back-boiler. At the same time, a living-flame gas-fire was installed in the lounge.

A couple of summers ago they had the loft insulation increased to

270mm, while SWMBO and I added 100mm of space blanket to the massive 25mm that the house was originally built with.

Our boiler is a 30-year-old Glowworm.

The recent snow that has fallen on the roofs has resulted in an opportunity to see how the two houses compare in terms of heat losses.

Surprisingly, the snow coverage has remained the same, suggesting not much difference in the heat losses into the lofts.

More surprisingly, the areas of snow that have melted around the chimney stacks is quite different: about 4' of clear area around my neighbour's stack, almost no clear snow around mine.

From these observations I suggest that their 'living flame' gas fire is pumping more total heat up the chimney than my back-boiler, and that the 'waste' heat from my set-up is staying mostly within the house, keeping it warm.

It would appear that my setup, taken a whole, is 'wasting' somewhat less heat than my neighbour's modern efficient system...and as this is the season of highest heating demands, perhaps there is less to gained overall by going 'modern' than claims might suggest...

TF

[A.Clews]

Thus spake Terry Fields ( [e-mail]) unto the assembled multitudes:

I too have a back-boiler Glowworm of what must be similar vintage. Apart from making kettling noises, and despite not having been serviced for several years, it seems to work just fine (touch wood). I was told last time that they're so simple they don't actually need much in the way of maintenance, but I feel I've taken that a little too literally :-)

My house also is well-insulated (windows, walls, roof) and I do wonder just how much better more modern setups really are. I've been tempted to go for this 400 quid scrappage thing but I'm inclined to think "if it ain't broke don't fix it" which is more than can be said for most modern boilers which seem to last only a few years.

[Terry Fields]

Our boiler was last looked at four years ago, and the service engineer said the same thing about their reliability, going on to mention that his dad's Glowworm was 43 years old and never gave any trouble.

At the start of the heating season I clean out the jockey tank, and add inhibitor. Among other things it helps keep the kettling to a minimum.

I also have my doubts about whether the scrappage scheme was 'worth it'; when it was proposed, the Glowworm wasn't on the list...

[tony sayer]

Too much duffo electronics in them!..

[CorporalJones]

multitudes:

My boiler was fitted in '92, a Wickes 50,(nothing fancy that I cannot sort out myself) I too have been looking at the scrappage scheme. Apart from a thermocouple on average every 3 years (about a fiver)and a gas valve coil 2 years ago it has kept my house warm enough,the scrappage site shows it as 65% efficient. If I was to replace it with an "A"rated boiler how long would it take to recuperate my costs of spending 2k+ (would do it myself as I did the last one but the regs dictate otherwise, although I have no intention of moving and when I am dead I don't think I will gave a toss) compared with the existing which is still working fine. I see this scheme as a government boost to the plumbing trade so they can get VAT income to the detriment of the householder. As a stealth tax I have to give them 10 out of 10 for their deviousness. Come the election I know who I will not be voting for!

[robert]

One should always be careful ( the press especially the green press arent) about drawing conclusions from the relative amounts of snow/frost on roofs.

I would expect a major factor besides insulation to be how much the top floor is heated. Factors such as using a bedroom as a study etc could make a big difference.

I am however urprised to see on a row of 4

[Bob Eager]

Also, what does the neighbour have the boiler output temperature set to? Wouldn't that make a difference?

[Peter Andrews]

What regs say you can't fit your own boiler? The regulations say that you must be competant - I also fitted my own Potterton Netaheat in 1989 and I've only had to change one PCB (£55 exchange and the cowl (can't think of the precise description) over the flame at under £2. I intend to keep it as long as possible. I'm sure that any CO2 gain will be lost in the manufacturing of the any replacement therefore the longer it's delayed the better my contribution - same reason that I still run a 10 year old car.

Peter

[js.b1]

Correct.

The big problem with GCH is the lack of real radiant heat sources. DFE are a joke because their efficiency does not truly reflect the rest-of-house heat drawn up the chimney.

A colleague got a 26" IPS monitor, glass with radiant embedded elements, combined the two with a 3hr video of a real fire and it provides a radiant focal point. Thus far the monitor panel is not suffering, but it is very effective compared to the electric versions which are a pretty sad effort. If the monitor panel does suffer he will rip apart one of the cheaper fake electric fires and fit an LCD in there.

Places in Germany do carry a storage heater embedded into a fire - that gives cheap 4-5p overnight charge plus boost capability, which some have hacked apart to fit a TFT panel into with video of a real fire (or goldfish bowl which must look quite funny).

[YAPH]

Whilst living flame types are notoriously inefficient there's also the difference that their fire almost certainly uses the unlined flue, heating the brickwork directly, whilst your back boiler will have a flue liner, giving some decoupling between the flue (and the heat being lost up it) and the masonry of the chimney stack.

[Doctor Drivel]

Their setup is better if they do not used the inefficient gas fire.

[Doctor Drivel]

If you are competent you can fit it. You do not need certification or qualifications.

[Doctor Drivel]

The wall gets heated and heat conducts up the brickwork.

[Terry Fields]

That's quite possible, unfortunately there's no way of estimating the variables such as convection and radiation from the liner.

The exit temperature at the chimney cowl can't be very high, though. as pigeons park themselves on it and don't seem to get cooked!

TF

[Terry Fields]

I've never seen that on the semis or maisonettes round here.

[The Natural Philosopher]

is pretty obvious that they have left the party wall as a cold bridge..carrying the internal masonry up into the roof space without insulating it.

Obviously a strip of celotex each side of it is the way to go.

I have the same sorts of issues with chimneys here..they are warm in my 'cold loft' when fires run. and snop around thenm is somewhat more melted.

Anther reason to use insulated flue liners maybe?

[Harry Bloomfield]

Doctor Drivel explained :

Are they not cavity walls, with no CVI?

Ours is and heat rises straight up the cavity and melts the snow in a strip directly above it.

[Doctor Drivel]

It would be worthy getting rid.The payback would not be that long. Also there is not much life left in it.

[Doctor Drivel]

That will solve nothing.

Why would you want to stop wasted heat entering the loft? If anything that is what you want, rather than it going out to atmosphere.

[A.Clews]

Thus spake Terry Fields ( [e-mail]) unto the assembled multitudes:

That's made me feel even better :-)

I did add new inhibitor in the summer, a bottle of Fernox. I find the kettling is a little less severe if I have the boiler 'stat turned down a bit, but it does mean the rads don't get *really* hot. But then, the house is comfortable with the room 'stat set at 19 or 20 degrees.

Oh well then, that's cemented my decision! :-)