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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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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 |
#2
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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 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. |
#3
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Why did warm air central heating go out of fashion?
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 |
#4
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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. |
#5
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Why did warm air central heating go out of fashion?
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. |
#6
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Why did warm air central heating go out of fashion?
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 |
#7
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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. |
#8
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Why did warm air central heating go out of fashion?
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. |
#9
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Why did warm air central heating go out of fashion?
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. |
#10
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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! 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. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#11
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Why did warm air central heating go out of fashion?
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. |
#12
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Why did warm air central heating go out of fashion?
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. |
#13
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Why did warm air central heating go out of fashion?
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 |
#14
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Why did warm air central heating go out of fashion?
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. |
#15
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Why did warm air central heating go out of fashion?
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 :-( |
#16
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Why did warm air central heating go out of fashion?
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 |
#17
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Why did warm air central heating go out of fashion?
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 |
#18
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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! 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. -- Colin Bignell |
#19
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Why did warm air central heating go out of fashion?
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 -- To Reply : replace "diy" with "news" and reverse the domain If you are reading this from a web interface eg DIY Banter, DIY Forum or Google Groups, please be aware this is NOT a forum, and you are merely using a web portal to a USENET group. Many people block posters coming from web portals due to perceieved SPAM or inaneness. For a better method of access, please see: http://wiki.diyfaq.org.uk/index.php?title=Usenet |
#20
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Why did warm air central heating go out of fashion?
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 -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "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! Andy |
#22
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Why did warm air central heating go out of fashion?
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. |
#23
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Why did warm air central heating go out of fashion?
"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. |
#24
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Why did warm air central heating go out of fashion?
"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... |
#25
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Why did warm air central heating go out of fashion?
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 |
#26
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Why did warm air central heating go out of fashion?
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 |
#27
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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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 |
#29
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Why did warm air central heating go out of fashion?
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. -- €śPuritanism: The haunting fear that someone, somewhere, may be happy.€ť H.L. Mencken, A Mencken Chrestomathy |
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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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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Why did warm air central heating go out of fashion?
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. |
#38
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Why did warm air central heating go out of fashion?
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 To e-mail, change noise into sound. |
#39
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Why did warm air central heating go out of fashion?
"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 |
#40
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Why did warm air central heating go out of fashion?
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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