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Default Why did warm air central heating go out of fashion?

It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy
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On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy


Wummin prefer radiators. Or brainwashed into thinking they 'need'
radiators by various house-flipping tv programs.

Warm air systems had one major defect, you still needed to use
electricity to heat the hot tank, even if you had a gas-powered
system.

Also, I'm not sure how you would meet modern fire regs if you had
ducting in the void between ground floor and upper floor with its
potential to assist the spread of fire and smoke.
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On Monday, 26 October 2020 at 10:51:58 UTC, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy


I think they tended to use a lot of space with ducting and the only ones I remember were electric powered which involved having a large heater unit somewhere taking up most of a cupboard. Electric heating probably made sense when we were being told nuclear energy would be too cheap to meter but that soon changed. I would imagine there was quite a lot of heat loss in the ducting and insulating the lot was probably time consuming and expensive compared to lagging a couple of pipes. I do not think they were an easy install for retro fitting compared to installation in a new build. At the same time gas was getting comparably cheaper with North Sea gas coming on tap and at the same time gas boilers getting more compact

Richard
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Default Why did warm air central heating go out of fashion?

On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy


It's partly to do with comfort, warm air circulating can feel like a
draught. We used to set ours at 25c but also needed a radiant heater in
addition to feel comfortable.

Stub duct systems can be economical to instal but if long duct runs are
needed that can get expensive to install.

I guess its mostly that in the UK most peoples idea of central heating
is a boiler and rads.(up to now at any rate)

Underfloor is mainly for new builds or major refurbs where it can be
more advantageous.

In the end it is just changing trends.
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On 26/10/2020 10:56, Andrew wrote:
On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in
- much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be
because they made a great place for spiders to hide!

Andy


Wummin prefer radiators. Or brainwashed into thinking they 'need'
radiators by various house-flipping tv programs.

Warm air systems had one major defect, you still needed to use
electricity to heat the hot tank, even if you had a gas-powered
system.

Some gas systems had a hot water heater integral to the warm air unit.

Also, I'm not sure how you would meet modern fire regs if you had
ducting in the void between ground floor and upper floor with its
potential to assist the spread of fire and smoke.




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In message , Andrew
writes
On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in
- much cleaner, and easier to manage.
Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.
But there was a time when hot air systems were popular, and I think
still are in the USA.
Does anyone know why they went out of fashion? It can't just be
because they made a great place for spiders to hide!
Andy


Wummin prefer radiators. Or brainwashed into thinking they 'need'
radiators by various house-flipping tv programs.

Warm air systems had one major defect, you still needed to use
electricity to heat the hot tank, even if you had a gas-powered
system.

Also, I'm not sure how you would meet modern fire regs if you had
ducting in the void between ground floor and upper floor with its
potential to assist the spread of fire and smoke.


Mother in law had it in a mid 60's flat. Central storage bank, asbestos
insulation! off peak electric. Immersion for hot water.
Not noticeably noisy and the ducting tucked away in the ceiling void.
Downsides, cost cf gas, inlet and exhaust well away from windows leading
to cold exterior walls/condensation and black mould:-(

Leasehold property so insulating cavity not really doable.

Gas boiler plus double glazing a big improvement but subsequent tenants
failed to ventilate to save gas plus airing washing indoors continued
the mould problem.

I used the ducting to feed room air to a heat recovery/vent system which
helped but the flat was sold on so I don't know the current situation.

--
Tim Lamb
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Default Why did warm air central heating go out of fashion?

Tricky Dicky submitted this idea :
I do not think they were an easy install for retro fitting compared to
installation in a new build. At the same time gas was getting comparably
cheaper with North Sea gas coming on tap and at the same time gas boilers
getting more compact


There were gas heated versions of hot air systems. Those I came across
had been Those I came across had been condemned, because the burned
compartments eventually leaked into the air sections.
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On 26/10/2020 11:38, Chris Hogg wrote:

Basically a large oil-drum type cylinder with some baffles and
perforations in the lower part,A side arm
did have a water jacket in the pretence of heating the DHW. It was
situated in a broom-cupboard-sized room in the centre of the bungalow
with vents in and out of the three adjacent rooms - kitchen, sitting
room and hall. Very primitive, antediluvian even, with the only
control being a knob to regulate the flow of oil and hence the degree
of heating.



We had that only gas powered (but with an electric fan[sol if either
fuel supply failed])and we were in a flat not a bungalow, so we didn't
have that at all (just something similar) ;O).

Three short ducts to Living room, hall, kitchen. No heating upstairs.

Called the heating unit "the Dalek"

Cat LOVED the vent she/he (various cats, all seemed the same), not so
daft on it when it was actually blowing but the area around it must have
got toasty.
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On Mon, 26 Oct 2020 10:51:53 +0000, Vir Campestris
wrote:

It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

I thought it was because they wrecked the furniture.
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On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!


Not sure they were ever that popular - although there was a time some
places were built with central columns to allow installation of the
heater and easy ducting.

I would guess that the fact much of our building stock is quite old and
predates CH of any sort, a wet system is a much easier retro fit. Is
also generally more space efficient, and runs quieter with no fans etc.

Still popular in the US though - probably partly helped by many places
seeming to have basement space to install them, and larger properties in
general, so loss of space to ducting is probably of an issue.

There is still at least one major provider of the kit for UK installs
though:

http://www.johnsonandstarley.co.uk/p...rm-air-heating




--
Cheers,

John.

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On Mon, 26 Oct 2020 10:51:53 +0000, Vir Campestris wrote:

It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy



Two weeks before Chernobyl and not related, we had a serious house fire.
The house was gutted by a fire storm caused by our recently serviced Creda
ducted warm air heater and circulated through under floor ducts. The
property was a 4 bedroom dormer-bungalow. The ducts made it so easy to
propagate the fire to every room within minutes. The family was very lucky
to escape any injury and special thanks go to our Dobermann who alerted
everyone to the pending disaster.
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In article ,
Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.


Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.


But there was a time when hot air systems were popular, and I think
still are in the USA.


Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!


The trunking takes up a great deal of space. Maybe not a problem in a US
house, but in the average UK one likely is.

--
*Am I ambivalent? Well, yes and no.

Dave Plowman London SW
To e-mail, change noise into sound.
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On 26/10/2020 14:32, Dave Plowman (News) wrote:
In article ,
Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.


Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.


But there was a time when hot air systems were popular, and I think
still are in the USA.


Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!


The trunking takes up a great deal of space. Maybe not a problem in a US
house, but in the average UK one likely is.


In the US they can duct cooled, dehumidified air around in the summer.

--
Max Demian
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On 26/10/2020 13:10, Jeff Layman wrote:
No idea, but it would it be any different from heating/cooling through
ducting in commercial buildings?


They tend to have a more sophisticated fire detection systems, like
a building fire alarm to start with !. This should shut down the
HVAC immediately.
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On 26/10/2020 11:57, Harry Bloomfield wrote:
Tricky Dicky submitted this idea :
*I do not think they were an easy install for retro fitting compared
to installation in a new build. At the same time gas was getting
comparably cheaper with North Sea gas coming on tap and at the same
time gas boilers getting more compact


There were gas heated versions of hot air systems. Those I came across
had been Those I came across had been condemned, because the burned
compartments eventually leaked into the air sections.


A bit like the exhaust heat-exchangers on my Type 3 VW fastback :-(


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On 26 Oct 2020, Vir Campestris wrote

It used to be we had open fires. But then hot water radiators came
in - much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I
think still are in the USA.

Does anyone know why they went out of fashion? It can't just be
because they made a great place for spiders to hide!


I grew up in Canada in the 1950s and 1960s with oil-fired, forced hot
air heating, with a furnace and large oil tank in the basement, and a
fan forcing the hot air through ductwork running to each room.

It worked fine[1], but I can think of a couple of disadvantages for a
lot of the UK housing stock: it would be a bugger to retrofit in
solid-wall house (rather than building it in too a stick-built/balloon-
framed house), and the furnace, tank, and ductwork took up a lot of
room. That's not much of a problem if you have a full-size basement,
but otherwise it needs a lot more space than a boiler in a cupboard
feeding CH pipes and radiators.

[1] Our cat certainly liked it: she'd lie on top of the hot-air
outlet.

--
Cheers,
Harvey
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On 26/10/2020 10:56, Andrew wrote:
....
Also, I'm not sure how you would meet modern fire regs if you had
ducting in the void between ground floor and upper floor with its
potential to assist the spread of fire and smoke.


Intumescent fire stop grilles or spring loaded shutters with fusible
links will stop fire spreading through ducts. Shutters linked to a smoke
detector will stop smoke spreading.


--
Colin Bignell
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On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!


Very difficult to retro-fit, so only really used in new builds. With
those, if you are going to go to all the trouble of fitting the ducting,
air conditioning makes more sense. It is much more energy efficient and
can cool in the summer as well as heat in the winter.


--
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In message , Vir Campestris
writes
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!


We used to live in an early 60s place that had it. To describe it as
heating was getting close to misleading advertising, more like a slight
warm draught. Even if it had worked anything like, it was very
difficult to control compared to a radiator with a thermostatic valve,
basically vent open/vent closed. It got replaced with a conventional
gas fired CH system.

Adrian
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On 2020-10-26, Brian Gaff (Sofa) wrote:
Noisy?
I would imagine if we go down the reversible heat pump route, then some
kind of air moving system is going to be needed again?
Brian


Out of fashion where? I understand that in Sweden they are the norm -
air ducts to take take warmed fresh air to each room and air ducts to
take exhaust from rooms. Air in and out are controlled with heat
exchanges and heat is recovered from the warm house exhaust air.
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"Vir Campestris" wrote in message
...
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think still
are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!


I'll tell you why. To be blunt - because it didn't f***ing work ;-)

The house that my parents bought (new build) in 1972 had a huge
floor-to-ceiling gas boiler for ducted-air central heating. It needed its
foam air-filters cleaning out of dust every week. It made a very loud noise
and so was relegated to the downstairs cloakroom, away from any room that we
used. That room was lovely and warm - so a lot of heat was being "wasted"
instead of heating the rest of the house. The house was always cold, because
what came out of the floor ducts was a feeble breath of air that was barely
tepid. The only room that was warm was the lounge, because that had a gas
fire in it. Ducted air also made the house dusty - it kept dust in
circulation which would otherwise sink into the carpet and remain "hidden"
until the room was hoovered. Being facetious now, it was also a "great" way
to spread nasty smells around the house: one time there was a horrible
sweaty-foot smell in some of the bedrooms, which we eventually traced to the
duct in my sister's room where she'd shoved an unwanted cheese sandwich as a
prank ;-) My parents were on the point of having the ducted-air system
replaced with a conventional radiator system, because we all hated it so
much, but then dad got a new job so we moved and passed the problem onto the
new owner.

I'm sure ducted-air technology (insulation of ducts, efficiency of boiler)
has improved a *lot* in 50 years, but can it *really* heat a house up as
quickly and to such a high temperature as hot-water radiators (fed from a
boiler that is powered by whatever fuel is currently not condemned)?

When we were house-hunting the other year, we looked at one house where the
owner was proud of the energy-efficient heating system. But through the
whole house we were conscious of a continuous moaning noise which I presume
was the noise of the air fan being propagated along the ducts. I stood in
front of a duct - yes, the air was almost stone cold, just like it had been
in my parents' house.

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"Andrew" wrote in message
...
On 26/10/2020 10:51, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think still
are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy


Wummin prefer radiators. Or brainwashed into thinking they 'need'
radiators by various house-flipping tv programs.


Men do too. We want to be comfortably warm and not to be left shivering if
the sun goes in.

Warm air systems had one major defect, you still needed to use
electricity to heat the hot tank, even if you had a gas-powered
system.


My parents' house with ducted air had a little gas "boiler" in the airing
cupboard which just heated the water for the cylinder. I imagine one that
could have heated the water on demand rather than for heating a cylinder
would have been a lot bigger.

Also, I'm not sure how you would meet modern fire regs if you had
ducting in the void between ground floor and upper floor with its
potential to assist the spread of fire and smoke.


That's a very good point. I hadn't thought of that...

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On Monday, 26 October 2020 10:51:58 UTC, Vir Campestris wrote:
It used to be we had open fires. But then hot water radiators came in -
much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be because
they made a great place for spiders to hide!

Andy


IMLE noise & dust. Then there's fire.


NT


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HVS wrote:
On 26 Oct 2020, Vir Campestris wrote

It used to be we had open fires. But then hot water radiators came
in - much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I
think still are in the USA.

Does anyone know why they went out of fashion? It can't just be
because they made a great place for spiders to hide!


I grew up in Canada in the 1950s and 1960s with oil-fired, forced hot
air heating, with a furnace and large oil tank in the basement, and a
fan forcing the hot air through ductwork running to each room.

It worked fine[1], but I can think of a couple of disadvantages for a
lot of the UK housing stock: it would be a bugger to retrofit in
solid-wall house (rather than building it in too a stick-built/balloon-
framed house), and the furnace, tank, and ductwork took up a lot of
room. That's not much of a problem if you have a full-size basement,
but otherwise it needs a lot more space than a boiler in a cupboard
feeding CH pipes and radiators.

[1] Our cat certainly liked it: she'd lie on top of the hot-air
outlet.


In places that still have oil heating, the tank goes outdoors now.
The house I was born in, the tank is still inside, and it's
been highly reliable compared to the track record of
outdoor tanks. But if you want to save space on a 200 gallon tank,
you can do it.

The places using oil heating, would not be using it if natural
gas was available. The price of oil is astronomical. And electric
heating is similarly stratospheric pricing, so a non-starter
as an option. Electric heating was tried here (because, well, we
got a bunch of nuclear reactors and what are you doing to do?),
and a few people at work were always bitching about theirs.
The elements used to fail in the electric furnace. You won't
find many electric furnaces today (Bill Gates maybe?).

The biggest liability with oil heat, is leaking oil and cleanup cost.

And before we got oil, some of the houses were still using coal.
I was lucky as a kid, I was down at my friends house when
a coal truck came up and delivered a load of coal. And we
watched while my friends dad shoveled coal through a basement
window, into the basement :-) Some of the members of the
family, use to have arguments about which person was
supposed to be cleaning out clinkers. Well, all that
changed when the oil came along. The coal room was re-finished
and became my friends bedroom. And we were careful to *never*
mention he was sleeping in the coal room. It's not like
he had a choice in the matter (big family).

*******

As for the routing of ductwork, my house has a 10"x20" rectangular
cross section pipe running along the spine of the house (in
the basement). There is also a steel I-beam that runs the length
of the house and it's near that pipe. Whereas other houses used
sistered wooden beams nailed to one another for the spin, this
house series they used a steel beam instead.

Smaller round pipes (6" diameter) feed from the 10"x20" galvanized
sheet metal pipe, and the round pipes run between floor joists.
This reduced the impact of the heating distribution in the
majority of the room area. The basement has the penalty of headroom
dropping to 6'3" below the rectangular pipe. Whereas the rest of
the basement has a ton of headroom.

In two story houses, the round pipes may be replaced with a
rectangular cross section pipe running vertically up the
walls. Which makes for a long run of pipe, and makes it
hard to balance the system. Each run of pipes has a "vane"
inside the pipe, and a lever on the outside which you can
rotate. You adjust the lever to get the degree of heat
you need in the room (with the second floor ones being
at a disadvantage because of the flow resistance). In the
dead of winter, the people on the second floor are freezing
to death :-) That's why they get extra blankets up there.
In late fall and spring, everything is fine.

The hot air vents go on the outside walls. The cold air return
are on the inside walls. The cold air returns get little
attention, so it's hard to say whether the flow rates
are really all that balanced between the two sides.
If you don't get that part done correctly, the furnace
starts sucking air through any available crack, from
basement air. Which isn't always the best thing.

The only draft in the house, comes from wall sockets. And
todays R2000 techniques (sealant and proper boxes for outlets)
helps control that kind of leakage. In the old days, the
build quality wasn't all that good on that sort of detail.

The combustion furnace has a range of delta_T it can handle.
You can damage the heat exchanger if the conditions are
not properly met. The speed of the motor (four speed motors
being typical) helps set the delta_T. The door of thr furnace
states how much temperature difference is allowed between
the "heat" central pipe and the cold air return pipe
(aka "ambient"). The speed requirements for heat and AC
are different. In some cases, the same speed used for
both, in other cases, one season runs the motor faster
than the other season. If you get this wrong, you can
crack the heat exchanger. (You would think moar air
for heat distribution would always be good, but
that's not the case.) Part of checking an air circulating
furnace, is making sure some wacko hasn't buggered the
delta_T. (Two furnace techs can get into a fight about
which wacko did it :-) That's why they work in pairs.)

Paul
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Adrian wrote:
In message , Vir Campestris
writes
It used to be we had open fires. But then hot water radiators came in
- much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be
because they made a great place for spiders to hide!


We used to live in an early 60s place that had it. To describe it as
heating was getting close to misleading advertising, more like a slight
warm draught. Even if it had worked anything like, it was very
difficult to control compared to a radiator with a thermostatic valve,
basically vent open/vent closed. It got replaced with a conventional
gas fired CH system.

Adrian


One thing I've noticed, is the home heating people aren't
very good at design.

The ductwork on houses is seldom all that good. A long narrow
pipe is expected to deliver the same air as a short larger pipe.
All sorts of non-intuitive stuff going on.

If you had a saleman come into your house today, he'd
sell you a 60,000 BTU furnace, because he'd tell you
that the "longer run time gives more efficient heating"
and would save you a tiny bit of money. But at the
expense that if you put your toes over the register,
you can't really "feel" the heat.

I've had both a 60,000 BTU furnace (current one) and
an 80,000 BTU furnace, and the 80,000 one really
did "warm toes".

You can't go too high though, because the ductwork
is designed with a certain size of furnace in mind.
If you connected a 120,000 BTU furnace, the delta_T
between the hot air output and the cold air return
would be too high, and the heat exchanger would melt.
The furnace has a four speed motor, to allow some
adjustment to flow rates (most of the time it runs
on high or just-below-high). Each pipe arm has at
least one damper on it, a vane with a rotating lever
to set the airflow in the pipe. But this is not designed
to make large corrections, only small ones. For example,
if you had two identical runs of pipe, the dampers
could make fine adjustments so the airflow was
made equal. But you can't balance 10sqin of pipe
with 40sqin of pipe, just using dampers. If you
damp down the 40sqin pipe to 10sqin, now there's
too much overall resistance to airflow and the
furnace overheats.

After a while, you'll realize that every analogy
in the air circulation system, has an equivalent
one to a water based system. Many knobs. Maths.
And occasionally, a result.

To show you how stupid people can be, on a hot air
system, the hot vents go on the outside walls, the
cold air return is on internal walls. Yet, one house
I was in, they reversed that, and put the wrong
pipes on the respective walls. Naturally, the
results are far from ideal. Miserable even. Any time
the exterior walls get cold (due to the weather
conditions outside), those walls will suck the
life out of you. If you're sitting in a chair, you
move away from the wall :-) Because cold air will
be streaming down the wall at you.

Paul
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Brian Gaff (Sofa) wrote:
Noisy?
I would imagine if we go down the reversible heat pump route, then some
kind of air moving system is going to be needed again?
Brian


Yes, a hot air furnace has an air handler. With
a motor. It makes a noise.

Years ago, before the air handler was introduced,
they did make hot air furnaces that worked by
convection. They are quiet. But, they also have
their own sins.

The house across the street back home was heated
that way. Convection heating.

The oil furnace in the basement (i.e. good combustion temp)
has a huge flared pipe on the top. On the first floor is a
floor grate. It was maybe five or six feet in diameter.

You could feel a steady flow of warm air out of that pipe
while the furnace was operating. But the airflow is also
in the wrong place, because it's in the center of the house.
The walls are cold. You also need an opening into the
second floor, so that sets the plan for how the second
floor is laid out. You can't close the bedroom doors up
there, or no warm air will get into the bedrooms.

The air handler solves this problem. It doesn't rely on the
generous nature of convection air movement. It has the power
to move the warm air where it is needed. The noise,
what little there is, is the price you pay for that
solution.

With the air handler, I can have the warm air rise along
the exterior walls, reducing the "cold wall effect". And in
principle, with good design execution, I can even warm areas
which are an extreme distance from the furnace. With the
old convection furnace solution, standing on the grate
"was a good time", sitting in an upstairs bedroom, not
so much.

Our old church had the convection heating. It had
something like three 130,000 BTU furnaces. And big grates
in the floor for the heat to rise. And considering the
size of the church (and my poor memory of the specs),
I think that system did an excellent job, because
there were no barriers to air movement. If the air
was stratified in there, you didn't notice it. But those
furnaces also used a lot of oil, and the church wardens
were constantly complaining about the expense. They
couldn't possibly afford to use oil for that today.
The church wasn't exactly R2000, so it's not a surprise
it took thousands a month in heat. All the glass on the
place was single-glaze. I doubt the walls had much in
the way of insulation. You'd think Satan would keep
the place warm, but the church was designed to keep
Satan out.

Paul
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On 26/10/2020 20:13, Jim Jackson wrote:
On 2020-10-26, Brian Gaff (Sofa) wrote:
Noisy?
I would imagine if we go down the reversible heat pump route, then some
kind of air moving system is going to be needed again?
Brian


Out of fashion where? I understand that in Sweden they are the norm -


They are not.
All the houses I visited had UFH, many pure electric. Sweden has nuclear
and hydro power. Go figure.




--
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H.L. Mencken, A Mencken Chrestomathy
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On 26/10/2020 22:28, NY wrote:
I'm sure ducted-air technology (insulation of ducts, efficiency of
boiler) has improved a *lot* in 50 years, but can it *really* heat a
house up as quickly and to such a high temperature as hot-water
radiators (fed from a boiler that is powered by whatever fuel is
currently not condemned)?


Oh yes. And much quicker too. As any large supermarket demonstrates.

But that means a high peak power and it is always a bit noisy.
Simply put wet radiators are adequate, cheap and quiet for reasonably
high water temps. At lower temps UFH allows a greater 'radiator' surface
area and is more even in its heating, but is an impossible retrofit in
most cases.

But it is pretty cheap on new builds. The cost of laying plastic pipe in
screed or between joists is no worse than running copper.


--
€śPuritanism: The haunting fear that someone, somewhere, may be happy.€ť

H.L. Mencken, A Mencken Chrestomathy


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Vir Campestris wrote:

I had a gas-powered one in a small town house nearly 50 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;
cleaning filters, 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 have
been a problem, conversations could be heard around the house.

Water heating was by a large instantaneous gas heater, which gave
no trouble.

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.
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On Monday, 26 October 2020 22:32:40 UTC, NY wrote:
Wummin prefer radiators. Or brainwashed into thinking they 'need'
radiators by various house-flipping tv programs.


I think women prefer heating to be invisible and want magic underfloor heating that warms the room but isn't too hot underfoot.

Men do too. We want to be comfortably warm and not to be left shivering if
the sun goes in.


We also like being able to put our socks and pants on the radiator in the morning :-)

Owain

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On Mon, 26 Oct 2020 15:49:45 +0000, Andrew wrote:

On 26/10/2020 13:10, Jeff Layman wrote:
No idea, but it would it be any different from heating/cooling through
ducting in commercial buildings?


They tend to have a more sophisticated fire detection systems, like a
building fire alarm to start with !. This should shut down the HVAC
immediately.


Mine didn't.
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nightjar wrote:
Very difficult to retro-fit, so only really used in new builds. With
those, if you are going to go to all the trouble of fitting the ducting,
air conditioning makes more sense. It is much more energy efficient and
can cool in the summer as well as heat in the winter.


In a new build you can (and indeed have to) insulate such that you don't
need a lot of heat in the first place, which removes the need for a giant
furnace and duct system. Although central air has its advantages - can use
heat pumps to heat and cool. I wonder if we'll start seeing that coming
back for cooling purposes.

Theo


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Tim Streater wrote:
On 26 Oct 2020 at 20:13:19 GMT, Jim Jackson wrote:

On 2020-10-26, Brian Gaff (Sofa) wrote:
Noisy?
I would imagine if we go down the reversible heat pump route, then some
kind of air moving system is going to be needed again?

Out of fashion where? I understand that in Sweden they are the norm -
air ducts to take take warmed fresh air to each room and air ducts to
take exhaust from rooms. Air in and out are controlled with heat
exchanges and heat is recovered from the warm house exhaust air.


The obvious way to do it when you have a larger temperature variation than we
experience. Such heating systems are fairly common in the US of A, too.


Some parts of the USA are hot enough, the AC is duplicated or
triplicated. In the event that the AC dies in one "zone",
the people in the house "evacuate" to the side of the house
with the working air conditioning. It's a bit like
living on Mars.

HVAC people work long hours in summer. Up for 8AM in the
morning (or as early as consumers would allow), heading
home at 10PM. That means five days a week of 14 hours.
That's because they're banging in new installs, and
they try to schedule two installs a day, and they get
****ed if the morning install takes too long and
that makes the afternoon install go forever. In heating
season, there's still work, but not 14 hours worth. They
can fit just the heat in winter (if there is a heat exchanger
failure and it's leaking CO), and wait until summer
to finish the install and put in the AC components.
It's hard to do a refrigerant fill when it's cold outdoors.

Only the R2000 homes here have air-to-air heat exchangers.
The windows don't open. To get fresh air, an air handler
brings in fresh cool air, and as the stale house air
leaves the house, the heat from it is transferred into
the inlet air. These can be relatively large boxes in
the basement, so you don't end up with a lot of storage
area in the basement, and there is a lot of HVAC equipment down
there. All done for bragging rights. The one good part of the
R2000 program, is some of the techniques were inherited
in ordinary home construction (acoustic sealant and plastic
sheeting around electrical boxes in walls for example,
no cold air leakage). Not too many people would necessarily
buy into the double-glazed-windows-that-don't-open.

Paul
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In article ,
Theo wrote:
nightjar wrote:
Very difficult to retro-fit, so only really used in new builds. With
those, if you are going to go to all the trouble of fitting the ducting,
air conditioning makes more sense. It is much more energy efficient and
can cool in the summer as well as heat in the winter.


In a new build you can (and indeed have to) insulate such that you don't
need a lot of heat in the first place, which removes the need for a giant
furnace and duct system. Although central air has its advantages - can use
heat pumps to heat and cool. I wonder if we'll start seeing that coming
back for cooling purposes.


If you have a well insulated house in the UK, just how often would you
need air-con?

--
*A bartender is just a pharmacist with a limited inventory *

Dave Plowman London SW
To e-mail, change noise into sound.
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In article ,
Paul wrote:
Some parts of the USA are hot enough, the AC is duplicated or
triplicated. In the event that the AC dies in one "zone",
the people in the house "evacuate" to the side of the house
with the working air conditioning. It's a bit like
living on Mars.


The US is a bit like the UK. Why insulate a house (making it cost a lot
more) when energy is cheap enough to cool it? Rather like their
excessively large engined cars.

--
*A picture may be worth a thousand words, but it uses up a thousand times more memory.

Dave Plowman London SW
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"Dave Plowman (News)" wrote:
If you have a well insulated house in the UK, just how often would you
need air-con?


The problem is heat sources inside the house. If it's 25-30C outside and
someone's had a shower, you're roasting a joint in the oven, and the kids
are using their 600W gaming PCs, that's heat input and nowhere for it to go.

Plus solar gain (windows etc) can be a problem, even if you're well
insulated.

Theo
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NY wrote:
"Vir Campestris" wrote in message
...
It used to be we had open fires. But then hot water radiators came in
- much cleaner, and easier to manage.

Nowadays we seem to be moving towards underfloor heating - where
effectively the entire floor is a radiator. Efficient, but slow to
respond.

But there was a time when hot air systems were popular, and I think
still are in the USA.

Does anyone know why they went out of fashion? It can't just be
because they made a great place for spiders to hide!


I'll tell you why. To be blunt - because it didn't f***ing work ;-)

The house that my parents bought (new build) in 1972 had a huge
floor-to-ceiling gas boiler for ducted-air central heating. It needed
its foam air-filters cleaning out of dust every week. It made a very
loud noise and so was relegated to the downstairs cloakroom, away from
any room that we used. That room was lovely and warm - so a lot of heat
was being "wasted" instead of heating the rest of the house. The house
was always cold, because what came out of the floor ducts was a feeble
breath of air that was barely tepid. The only room that was warm was the
lounge, because that had a gas fire in it. Ducted air also made the
house dusty - it kept dust in circulation which would otherwise sink
into the carpet and remain "hidden" until the room was hoovered. Being
facetious now, it was also a "great" way to spread nasty smells around
the house: one time there was a horrible sweaty-foot smell in some of
the bedrooms, which we eventually traced to the duct in my sister's room
where she'd shoved an unwanted cheese sandwich as a prank ;-) My
parents were on the point of having the ducted-air system replaced with
a conventional radiator system, because we all hated it so much, but
then dad got a new job so we moved and passed the problem onto the new
owner.

I'm sure ducted-air technology (insulation of ducts, efficiency of
boiler) has improved a *lot* in 50 years, but can it *really* heat a
house up as quickly and to such a high temperature as hot-water
radiators (fed from a boiler that is powered by whatever fuel is
currently not condemned)?

When we were house-hunting the other year, we looked at one house where
the owner was proud of the energy-efficient heating system. But through
the whole house we were conscious of a continuous moaning noise which I
presume was the noise of the air fan being propagated along the ducts. I
stood in front of a duct - yes, the air was almost stone cold, just like
it had been in my parents' house.


Electrostatic air cleaner. Can be fitted to the side of your
HVAC equipment in the basement. Some will also have a humidifier
added to the furnace to set the RH in heating season. Takes
a 1/4" line to the cold water, to fill the reservoir for it
automatically. When I bought the house here, one of the first
things I did was turn off the humidifier (then when the furnace
was replaced, no humidifier at all was fitted to the replacement).

Heating a home quickly... goes against the mantra of efficiency.
The salesman today will try to sell an undersized heating
system. For a person like yourself, simply buy the next size up.
If the salesman wants to sell 100,000 BTU, tell him to install
a 120,000 BTU unit. That will give "toe warming capability".

I can make it uncomfortably warm here, if there's a reason,
but that's just a waste of natural gas. With the old 80,000
BTU furnace, I could make you uncomfortable in about
20 minutes.

You can have any furnace you want, if you have the ducting
for it. If the ducting is pathetic (say, a series of 3" diameter
pipes for some reason), then you cannot run a lot of BTUs
and you'll be sucking your paws for heat. Bad ducting is
the single biggest reason for not being able to fix stuff
on these systems. The upstairs was cold on the home I was born in,
and we actually retrofitted a couple additional registers.
One was added to the back porch, and you could dry winter
clothing on a drying rack above the vent. A register was
added to the upstairs stairwell and hallway. These were possible
because some walls needed to be opened up, and ducting could
be added. Another register was added to the other side of the house,
and that one could be done because there was a duct pipe to
extend to operate it.

*******

There is also an operational alternative, where the call-for-heat
and call-for-cool alternate, and this is done as a way to "force"
the humidity. It's an energy waster, but if you want a particular
humidity, there are controllers for these systems that will
do the programming for you. And control both the temp and
the percent humidity. Here, in my zone on the map, there
is little call for this, maybe early fall or late spring
might call for operation that way. Other times of the year,
straight heating operation or straight cooling, is enough.
I couldn't be bothered adding that to the system I've got.

It's not practical to air condition below about 70F or so,
There's a risk of freezing up the A-coil in the furnace stack,
which isn't good for it. If the RH is 60% in fall, the
air temp is 72F, there's no "runtime" on AC to dry out
the air. The alternate programming solves that, by
heating the house up to maybe 76F, then air conditioning
it for a while (dries the air), heat it up again to 76F,
cool it down again, and eventually the RH is 50% which
is good enough. While this is going on, the RH outside
the house is 90% and the air there is unusable as a fix.
(Opening a window would not help in fall.)

*******

If you tried to retrofit ducting in your radiator homes,
you would reach the wrong conclusions about hot-air systems.
They work just fine... if the ducts are designed into
the house structure, and if the person doing the design
work, actually cares about a result. There is a lot of
slipshod work, where you're standing on a ladder looking
at something and going "what were they thinking". Some
of the ducting looks "designed", but there is always
a bit that looks like "bodged". Like it wasn't on the
plans and someone penciled it in at the last moment.

Paul
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