Do we need a new central heating system?

[Blankiefan]

We've had two different people look at it and they've been very non-committal. Maybe you can help.

Moved into the house 9 months ago. Old house (1920z). 5 beds, attic converted but bugger all insulation up there. Cavity wall downstairs.

Boiler is 20 years old. Had it checked when we moved in and was told it was fine. Had it services since. Radiators have thermostatic valves (about half don't work so rads are always full on). Rads upstairs constant need aired. Boiler broke down last month - needed a new fan (£170 inc fitting).

Just got our gas bill - £1200 for 5 months. Now - I was home on maternity leave with pfb so heating was on full blast all day / evening (probably 5am-midnight).

So - what do you think - do we just fix it up or scrap it and get a new one.

It sounds very inefficient - can you not get valves fixed?

Fix it up meaning replace all thermostatic valves, find the leak that's causing the air in the upstairs rads and insulate (which we'll do regardless).

We may also replace two rads downstairs with bigger ones as our living room could be cosier...

Get it priced up and then see how attractive a prospect it looks.

Have you considered improving your insulation upstairs? This could reduce your costs.

If I was you if just get a new boiler etc. yes its expensive, messy and a pain but your going to need to do it shortly anyway and in 4 years you'll have saved the money on your heating bills!

Yup, I'd be looking at a replacement boiler before a replacement system. And I'd be looking hard at sorting the insulation in the loft extension. In the meantime, train your family to keep all the internal doors shut, and only heat the room you're in.

replace the TRVs - they only have a limited life anyway.
find the leak in the system and fix it.
possibly flush the system; chemical flush maybe?
insulation

all these things need doing regardless. Then consider a new boiler.

also you really didn't need the heating on all day all winter unless you are in a sunless valley in the north of Scotland or the baby was ill.

Does "full blast all day" mean it hasn't even got a room stat?

Insulate the loft urgently

Get it chemical cleaned and a system filter fitted

Fit new TRVs while it is drained, but look at the rads first in case any are undersized or rusty and need changing.

Sorry to hijack but I was looking at a place with oil chs which had been put in 50 years ago. Had planned to leave pipework but plumber friend of friend has recommended replacing boiler and all radiators at the same time as we would rewire it (not living there). Does that level of replacement sound appropriate for a system of that age?

we've just replaced a 30 year old oil boiler. the reduction in oil consumption (and noise) has been phenomenal - as we hoped, of course. Should pay for itself in about five years even if oil prices don't rise - yeah, right. Do it.

replace all radiators? Not so sure about that, but the system will certainly need a full flush including a chemical one. If the radiators leak then certainly replace them. And have a filter added too; lots more gunge was still coming out of our system via that. The boiler guarantee is also conditional on a flush.

I was told that modern radiators do a much better job of heating the room rather than just the radiator. Could just be spin. I don't know.

modern radiators usually have fins, which increases their output. Modern condensing boilers run at lower temperatures, which reduces their output.

Also, old systems were often planned to warm the rooms to quite modest temperatures, or were fitted with small rads to keep the price down. On the other hand, if you have fitted cavity wall insulation, and thicker loft quilt, the heat loss will have reduced.

So it is often worthwhile recalculating and upgrading your radiators. My house quite deliberately has rads 50% bigger than the calculation, so they can warm the rooms fast after the house has been empty, and have plenty of reserve for abnormally cold weather. TRVs prevent the rooms getting too warm and wasting energy. If you have lived in the house for a year or two you should have a fair idea of which rooms need bigger rads.

A lot of the work in installing a new system is taking up the floors to run new pipes. If your pipes are copper, and not microbore, they can probably mostly be re-used with new radiators and boiler.

A modern programmable room thermostat will greatly improve comfort and economy in your house, and can even be set to turn up the heat the day before you come back from your winter holiday.

All of that can be done without needing to change the boiler. If you have a first-class older boiler like a Potterton Profile, its reliability will be better than anything you can buy today, as long as you have a good independent engineer who can still get the parts. Once it becomes irreparable, and you buy a modern condensing boiler, it might save you 20% or more off your gas bill. This will however take years to pay back the purchase price.