Hoping to get a few viewings of potential house purchases in next week,
One of the potential houses has a warm air heating system (by the looks of the photos the house may date from the 1970/80's but hard to tell.) Now I've no experience of these things - I assume there is a heater (gas I would guess) and the air is circulated around the house via ducting.
No, they don't seem that common, which maybe an indicator of something to avoid - then again some technologies can be perfectly good, but just don't succeed for fashion or whatever reason.
Anyone have experience of these sorts of systems - good, crap ok?
My aunt's town house was heated this way - probably built in the '70s too. What I noticed was that there seemed to be very little thermal inertia so that the heater and circulating fan were cycling on and off most of the time. Seem to remember some rattles in the ductwork as well. Worth bearing in mind that if you are sitting in a (even a slight) breeze you will need higher temperatures than if the air is sensibly still. Look for dust on surfaces near the vents. How easy is it to get new filters, and to change them?
I've lived with gas warm-air heating since the house was built in 1971. Advantages are almost instaneous heat, cheap to run and very reliable if serviced regularly. Downside is that, depending on heating unit, thay can be quite noisy - a large fan drives the air around. Also room temperature is not as stable as with a wet system. Gets warm when fan is running then temperature drops gradually until thermostat kicks in. In addition, not all rooms tend to be heated. You may find that bathroom is not on the system - we use an electric heated towel-rail.
Quite a few people around us have converted to radiators, but we're quite happy with our system. Guy who services ours (the very common Johnson & Starley) reckons newer systems are much better but we'll have to wait until original heating unit gives up before we can find out!
I can't answer for old systems apart from a rather inefficient gravity fed 'Agavector' that my inlaws had in the last house, but I installed modern stuff upstairs here under modern isulation, and its very very fast to warm up apart from one room with fairly low power for the volume and an awkward location (in a recess effectively) .
Modern thermos seem to cycle anyway - leastways with te CH off the thermos will cycle at or around teh room temp when the tem is not changing. They have some bimetal strips or summat, and anyway I don't notice any cycling hwn in use.
I got them after installing air blowers in an office premises we had once - they wer marvellous for space heating a large space lacking decent insulation with few cold spots.
I hate rads aesthetically, and the blowers are less obtrusive watt for watt.
The noise is something you get use to - its no worse than the boiler fan, or a bathroom fan, in a next door room.
After UFH, its about my favorite form of heating really. The very slight breeze seems to get a btter air mix with fewer cold spots, and it's - like UFH - not so much 'cosy' as 'comfortable and unobtrusive'. That is you don't walk in to a room and say 'thats nice and ciosy' you walk in and don't notice its being heated at all, unless you just came from outside.
If we want 'cosy' we use the aga, or the open fires.
Crap, had mine replaced with a modern combi system, took months of spare time to remove all the ducting, flue, asbestos! etc, then repair celings, floors blah, blah, then redecorate.... End result was worth it though.
My mum's house still uses this as the main heating. It was built in 1967. She also has supplemental heating via gas fires in the upstairs bedrooms, which are not on the ducted system. In her house, the gas heater and fan are centrally located and blow at floor level into the hall, lounge and dining room. From a cold house, turning on the heating seems to warm up much quicker than our house with rads. The upstairs, of course, relies on the downstairs warm air rising. One of my childhood memories is defrosting my feet sitting by the vent in the hall after a good snowball battle.
So you condemn the whole idea because your system was either installed by a cowboy, very old, or you didn't know how to use it or maintain it ?....
Perhaps you just like great big sheets of metal attached to your walls whilst taking up space that could be used for furniture, not to mention the problems of running pipe work in a 'conversion'.
Forced air was the first mass heating system in the UK in the 1950s. Today well over a million systems are in use. They are now gaining ground again after a bad image as some systems were just plain bad.
You have no rads on walls to leak water. Johnson & Starley make replacement units that are state of the art with electrostatic air filters, variable speed fans, modulating gas burners, sophisticated electronic controls, electrostatic air filters (recommended for asthmatics) , precise electronic temp control etc. etc. The modern units are much quieter and do not cause draughts. You can always add a heat recovery fresh air vent unit too. Fresh air all the time in the house.
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registers and grills are also available to totally revamp the whole thing. It is usually cheaper to run than boilers systems. J&S have an add on condensing unit that is inserted into a conventional flue in the loft to improve efficiency. Some USA units by Lennox and Trane have built in condensing in forced flues.
It may be worth looking into heat recovery and vent units that integrate with the system. More expense, but far superior comfort conditions and a great selling point. Make sure the unit has a summer switch, so the fan circulates air on hot days. They really do drop the internal house temperature quite a bit.
It's difficult to get the ducts in once the house is finished so you generally don't see them as retro fits.
We had a Wimpey house in York (new in 1972) which had been designed to accomodate it, the boiler was in a cupboard in the middle of the house (so wasn't balanced flue) at a point where the corners of the rooms came together and the rooms could be supplied by short stub ducts. The "little bedroom" was on the end of a long duct and didn't get much heat at all. The bathroom and the toilet simply weren't heated, I doubt that would be really acceptable nowadays.
The ducts had been joined by erm, well, ducting tape which had deteriorated quite a lot during the four years we were in the house.
I had worries about the heat exchanger becoming perforated and alllowing combustion products into the heated air. Doubtless there are ways of ensuring safety in this regard. But I'd ask for a Corgi certificate from the seller.
The manufacturer is still in business:
Overall we were more than satisfied, it was a bit like having a big fan heater in the room. However ours had simple on/off controls so when the big fan started up it was quite noticeable, I think there are modulating controls available nowadays.
We were also more than satisfied with the next house we got which had wet central heating.
When I worked for an Electricty Board, we installed a lot using a central electric night storage heater.
My recollection is that the system was relative expensive to instal. Putting individual night storage heaters in every room would have been cheaper, but early 1970s stoarge heaters were big and ugly. The systems we put in therefore tended to be in high quality new builds, where it was simpler to fit the ducting and appearance was important. Modern storage heaters are a lot less obtrusive.
ISTR that there were also problems with some systems, although I think those were gas fired ones, which gave the concept a bit of a bad name. A couple of my factories still use the same type of electric night storage heater that was used as a central unit for hot air domestic systems and, apart from needing to change a mains switch once, they are still going strong 15 years after installation.
System was originaly installed in 1969 when the house was built. I had the original WAU replaced when I moved-in in 1993. The replacement unit cost a bloody fortune to run and maintain, only one company in this area had qualified service engineers; I take it you know there are additional exams required to service/repair WAU's?. The all too few who are qualified (in this area) charge a bloody fortune to cover the additional exam costs. Unless a WAU is fited with dust filters, your ceilings will require redecoration every few years; ballancing the air flow so one part of the house is not baking hot while another isn't freezing is a pain in the A.
WAU's are bloody good if they are designed, installed and maintained by professionals who care, if not, they're crap!
Until recently we had a warm air system in the house we're about to move out of (when we manage to get a buyer). The house was just a couple of years old when we bought it in 1970. The heating system had good and bad points, for our needs the good outweighed the bad until the system finally died a year ago. It was quick acting, easy to maintain (but the filter did need frequent cleaning) and the air grills occupied much less valuable wall space than radiators. Warm air has earned a reputation of being noisy and expensive to run but we found costs quite reasonable. The noise was noticeable without being unduly obtrusive, the sound of the fan first thing in the morning wasn't enough to wake us up like an alarm clock but was enough to gently stir us from a state of drowsiness. I've known radiators to make as much noise.
The biggest drawback was that there was no heat in the bathroom or smallest bedroom but this was a fault of the spec. builder's penny pinching design rather than a weakness of warm air heating in general. When we built an extra room over the garage it was, of course, out of the question to extend the heating system into it.
The thing that finally did for our system was a leak in the flue and not a fault in the heating unit itself. We (unwisely) had a BG maintenance contract for the system and the annual inspection revealed a leak in the flue in the loft. BG promptly disconnected the supply to the heater, slapped a "Do Nor Use" notice on it and claimed that it was not covered under the contract, relying on some very vague wording in their terms which they claimed excluded flues from the cover. They quoted about £500 to repair the flue which they said would need a lot of work to bring it even close to current requirements. I couldn't find anyone else who was even interested in touching the job.
I expect the generous ventilation in our loft might have reduced the danger of fumes from the leaky flue. I think the more scary aspect of an old warm system would be the possibility of a leak in the heat exchanger, this would provide a direct path between the combustion products and the warm air circulating through the house.
We already knew that major spare parts for the old International Janitor "boiler" were no longer available so we felt that it would be more cost effective to replace the whole system with radiators, especially since we were already planning to move and an obsolete warm air system would not be a good selling point.
It's possible that the warm air system might meet your needs, but even if it does it could be near the end of it's useful life like ours. If you make an offer on the house you should allow for the cost and disruption of replacing the heating system. With luck you might even manage to use the existence of the old warm air system as a lever to get the price down by more than the cost of replacement.
I lived in a rented house for a couple of years with a WAU. The house was built by Anglia Homes in 1969, and I think it was around 1983 when I was living there. Like others said, one problem is the rooms which are not heated because they are away from the centre of the house where the ducting is, the bathroom and one bedroom in our case. Bathrooms can't be heated by WAU's because of the recirculatory nature of the system; smells from all rooms get distributed around the whole house (which could also be a problem if you had just one smoker -- confining to their bedroom wouldn't work). Also, you'll probably find your hot water is heated expensively by electricity.
I quite liked the system, in particular the fast warmup. We didn't need it on a timeswitch for evening use -- it was fine to just turn it on when you arrived home. However, it caused some other members of the household serious problems. The air in the house gets very dry, and this was a problem for a couple of contact lens users. Someone else with various allergies had problems with the dust it stirred up. (I found it was missing its dust filter, but fitting one didn't help a lot.)
All the houses on the estate had been fitted with WAU's originally. By 1983, this house was one of the very few left which still had one. I still knew the people in that shared house after I left, and when the regs started requiring CORGI checks on gas appliances for rented properties, it had to be taken out as the landlord had great difficulty in finding anyone who would check and service a WAU, and the cost was high enough for it to be worth replacing the system with radiators.
I actually serviced it a couple of times when I lived there, and the firm that made it in Luton was still selling them and all the spare parts in the early 1980's. Actually, their customer service was excellent, but I don't now remember who they were (they were in the Cosgrove Way industrial estate).
Had one in a small town house about 35 years ago. Warm-up was fast, lack of radiators made room layout easier.
Every room was heated, including kitchen and bathroom, but these two had no direct return duct.
The system was noisy, both air movement and fan vibrations; adjusting dampers and fan speeds never made much difference. In three years we got through two transformers and a fan motor.
In a family house noise transmission along the ducts could be a problem, conversations could be heard around the house.
Water heating was by a large instantaneous gas heater, which gave no trouble.
"If you make an offer on the house you should allow for the cost and disruption of replacing the heating system."
I can't believe this. Why didn't you just get a new replacement modern modulating unit? See my other post for details. So replaced a radiatorless system with rads, which will eventually leak and stain and look ugly. Amazing!
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