Need to replace central heating system and finish off double glazing but we
can't afford to do both, so which should be the priority?

Most of the house was DG'd about 10 years ago except for (for various
reasons) 3 windows. These have got - at best - about 4 years life left in
them, but they are draughty and when the wind blows in a certain direction,
the curtains move quite considerably.

We also have a 10-year old Baxi Bermuda 552 back boiler (rest of the
pipework and rads that make up the CH system are 33 years old - original
install when the house was built) that is kettling badly - so much so that
we have to turn up the telly volume to get over it.

We only have one header tank up in the loft and have what I believe is
called a "primatic system" (draining down CH system also takes domestic hot
water) so we can't add any sludge remover or corrosion inhibitor.

Current (and most likely future) gas prices are making it more economically
viable to replace the boiler now before it finally dies. Putting a new
boiler on to 33-year old stuff that's full of sludge and whatever doesn't
seem to be a good idea though and, given that modern rads seem to be more
efficient, I'm thinking we'll go for a whole new system. An added bonus
means that, as the new boiler will be in a different room, we could block up
the 8-inch diameter air vent that the wind literally howls through into our
living room and round our feet - bloody Vladivostok, I'm telling you.

So, what's the priority - CH or DG?

Cheers,

Mogweed.