No experience of owning/running a warm air system myself, but my folks had
this type of heating in their bungalow years ago. Warmed the place up ok
but made everyone nod off for some reason - and before you ask, no it wasn't
on high heat levels and neither was the (gas) boiler leaking gases... I
think it may have something to do with air ionisation (+ve charge ?)
Very practical in some ways - no radiators to worry about, lose room/wall
space or decorate, but vents in floors/walls/ceilings to aid airflows.
Unforced air in under floor heating ducts was the first carbon fuel mass
heating system in the UK (or whatever it was called then) in about 100 AD.
Before that, having the cows underneath the bedroom was considered as
good as it got.
Still more interesting than a Combi, even today.
It's difficult to get the ducts in once the house is finished so you
generally don't see them as retro fits.
We had a Wimpey house in York (new in 1972) which had been designed to
accomodate it, the boiler was in a cupboard in the middle of the house (so
wasn't balanced flue) at a point where the corners of the rooms came
together and the rooms could be supplied by short stub ducts. The "little
bedroom" was on the end of a long duct and didn't get much heat at all.
The bathroom and the toilet simply weren't heated, I doubt that would be
really acceptable nowadays.
The ducts had been joined by erm, well, ducting tape which had
deteriorated quite a lot during the four years we were in the house.
I had worries about the heat exchanger becoming perforated and alllowing
combustion products into the heated air. Doubtless there are ways of
ensuring safety in this regard. But I'd ask for a Corgi certificate from
The manufacturer is still in business:
Overall we were more than satisfied, it was a bit like having a big fan
heater in the room. However ours had simple on/off controls so when the
big fan started up it was quite noticeable, I think there are modulating
controls available nowadays.
We were also more than satisfied with the next house we got which had wet
When I worked for an Electricty Board, we installed a lot using a central
electric night storage heater.
My recollection is that the system was relative expensive to instal. Putting
individual night storage heaters in every room would have been cheaper, but
early 1970s stoarge heaters were big and ugly. The systems we put in
therefore tended to be in high quality new builds, where it was simpler to
fit the ducting and appearance was important. Modern storage heaters are a
lot less obtrusive.
ISTR that there were also problems with some systems, although I think those
were gas fired ones, which gave the concept a bit of a bad name. A couple of
my factories still use the same type of electric night storage heater that
was used as a central unit for hot air domestic systems and, apart from
needing to change a mains switch once, they are still going strong 15 years
Until recently we had a warm air system in the house we're about to move
out of (when we manage to get a buyer). The house was just a couple of
years old when we bought it in 1970. The heating system had good and bad
points, for our needs the good outweighed the bad until the system
finally died a year ago. It was quick acting, easy to maintain (but the
filter did need frequent cleaning) and the air grills occupied much less
valuable wall space than radiators. Warm air has earned a reputation of
being noisy and expensive to run but we found costs quite reasonable.
The noise was noticeable without being unduly obtrusive, the sound of
the fan first thing in the morning wasn't enough to wake us up like an
alarm clock but was enough to gently stir us from a state of drowsiness.
I've known radiators to make as much noise.
The biggest drawback was that there was no heat in the bathroom or
smallest bedroom but this was a fault of the spec. builder's penny
pinching design rather than a weakness of warm air heating in general.
When we built an extra room over the garage it was, of course, out of
the question to extend the heating system into it.
The thing that finally did for our system was a leak in the flue and not
a fault in the heating unit itself. We (unwisely) had a BG maintenance
contract for the system and the annual inspection revealed a leak in the
flue in the loft. BG promptly disconnected the supply to the heater,
slapped a "Do Nor Use" notice on it and claimed that it was not covered
under the contract, relying on some very vague wording in their terms
which they claimed excluded flues from the cover. They quoted about £500
to repair the flue which they said would need a lot of work to bring it
even close to current requirements. I couldn't find anyone else who was
even interested in touching the job.
I expect the generous ventilation in our loft might have reduced the
danger of fumes from the leaky flue. I think the more scary aspect of an
old warm system would be the possibility of a leak in the heat
exchanger, this would provide a direct path between the combustion
products and the warm air circulating through the house.
We already knew that major spare parts for the old International Janitor
"boiler" were no longer available so we felt that it would be more cost
effective to replace the whole system with radiators, especially since
we were already planning to move and an obsolete warm air system would
not be a good selling point.
It's possible that the warm air system might meet your needs, but even
if it does it could be near the end of it's useful life like ours. If
you make an offer on the house you should allow for the cost and
disruption of replacing the heating system. With luck you might even
manage to use the existence of the old warm air system as a lever to get
the price down by more than the cost of replacement.
"If you make an offer on the house you should allow for the cost and
disruption of replacing the heating system."
I can't believe this. Why didn't you just get a new replacement modern
modulating unit? See my other post for details. So replaced a radiatorless
system with rads, which will eventually leak and stain and look ugly.
You wouldn't say that if you'd seen the original installation. The
position of the unit on the ground floor was such that the flue took 2
right angle bends in the void between the ceiling and floor above before
going up through the airing cupboard followed by a couple of 45 deg.
bends before escaping through the roof. There was no way that any new
unit could utilize that flue and comply with current regs. To
re-position the heater unit to meet flue requirements would have
involved the installation of extra heating ducting which would have been
very disruptive. If we were to spend a substantial sum on upgrading the
heating then we also wanted it to heat the 3 rooms which were not fed by
the original system, this would have involved even more serious surgery
to walls and floor joists. Much more than a case of _just_ getting a new
replacement modern modulating unit.
Whilst it might have been possible to get a good warm air system it
would have been much more expensive than a radiator system. We had
already planned to move house within about a year and I'm quite sure
that we would not have recovered our costs on the selling price. So
despite having been happy with the warm air system while it lasted, it
just had to go.
The popular perception of warm air heating systems is that they are
noisy and inefficient, this may or may not be justified but your average
house buying Joe public expects to see a modern combi system and will
regard anything else (no matter how superior it might be) as a negative
point. Hence replacing with a radiator system was the most cost
effective solution for us.
It is. Do you search the internet for these cheap rads that inevitably
fail? And haven't you heard of inhibitor which will prevent corrosion?
Perhaps you'd also give details of how you prevent room to room
transmission of noise at a reasonable cost with a ducted system?
*Why don't you ever see the headline "Psychic Wins Lottery"?
Dave Plowman firstname.lastname@example.org London SW
I lived in a rented house for a couple of years with a WAU.
The house was built by Anglia Homes in 1969, and I think it
was around 1983 when I was living there. Like others said,
one problem is the rooms which are not heated because they
are away from the centre of the house where the ducting is,
the bathroom and one bedroom in our case. Bathrooms can't
be heated by WAU's because of the recirculatory nature of
the system; smells from all rooms get distributed around
the whole house (which could also be a problem if you had
just one smoker -- confining to their bedroom wouldn't work).
Also, you'll probably find your hot water is heated
expensively by electricity.
I quite liked the system, in particular the fast warmup.
We didn't need it on a timeswitch for evening use -- it was
fine to just turn it on when you arrived home. However, it
caused some other members of the household serious problems.
The air in the house gets very dry, and this was a problem
for a couple of contact lens users. Someone else with
various allergies had problems with the dust it stirred up.
(I found it was missing its dust filter, but fitting one
didn't help a lot.)
All the houses on the estate had been fitted with WAU's
originally. By 1983, this house was one of the very few
left which still had one. I still knew the people in that
shared house after I left, and when the regs started requiring
CORGI checks on gas appliances for rented properties, it had
to be taken out as the landlord had great difficulty in finding
anyone who would check and service a WAU, and the cost was high
enough for it to be worth replacing the system with radiators.
I actually serviced it a couple of times when I lived there,
and the firm that made it in Luton was still selling them and
all the spare parts in the early 1980's. Actually, their
customer service was excellent, but I don't now remember who
they were (they were in the Cosgrove Way industrial estate).
Had one in a small town house about 35 years ago. Warm-up was
fast, lack of radiators made room layout easier.
Every room was heated, including kitchen and bathroom, but these
two had no direct return duct.
The system was noisy, both air movement and fan vibrations;
adjusting dampers and fan speeds never made much difference. In
three years we got through two transformers and a fan motor.
In a family house noise transmission along the ducts could be a
problem, conversations could be heard around the house.
Water heating was by a large instantaneous gas heater, which gave
Chris J Dixon Nottingham UK
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