simond said:
Warm Air was, and remains one of the most effective, and efficient forms of space heating available.
The comments about dust are misguided, newer systems with varispeed fans, pulsing burners (they do not modulate, Dr D) tend to lower the air velocity.
Warm air systems do not create dust, the dust is already there. For those particularly sensitive to dust, an electrostatic filter can be fitted which removes particles as small as tobacco smoke.
Many public buildings and offices are heated by warm air. I don't recall anyone complaining about it while shopping in Tesco. Or working in the office.
I haven't seen a flue heat recovery unit attached to a WAU, Dr D. Are you thinking of their Reno branded condensing boilers with a Gas Saver attached?
The other day we fitted a J&S Economaire 90 (largish Warm Air modulating system with room sealed flueing) and a Vaillant 937 for hot water only. So the customer kept warm air (because they liked it) and had mains pressure HW.
They also had a route for heating their future loft extension via the Vaillant, but it is currently just used for HW.
Yes forced air is brilliant. The heat up rate is fantastic. They do have modulating burners, mainly on US models.
A full vent and heat recovery twin duct forced air system beats most others by a mile. Gills and registers can be hidden I have seen the behind coving and beams. I have also seen warm air from a conservatory ducted into he system using solar gain.
Yes, the Vaillant combi can do rads as well or maybe Myson fan heaters or small air-handing unit.
Yes, the units do not create dist and the use of laminates away from carpets has made a difference in many homes - forced air or not.
In the USA they tend to have a forced air system and a separate integrated burner gas water heater. Some have high flow Rinnai multi-point water heaters. Condensing units are common, by Lennox, Trane, etc. I personally would look into using a boiler (combi or otherwise) and a copper coil in an air handling unit. A decent controller can keep the boiler flow down to minimum levels, that does not give draughts, promoting condensing efficiency.
J&S did an add on box for conventional flues that was a part of their heat recovery and vent system that integrated into a normal forced air system.
J&S also did some very small units that fitted under stairs and in lofts - not sure if they still do. I recall one of these in house in the loft doing only the upstairs with grill via the ceilings and another downstairs under eh stairs. Two separate systems with individual temp and time control.
Grills and registers can be auto closed too - control by a local room stat. Very easy to do. If I recall correctly I think you need a VAV system for that to get full benefit, although it will work on most modern system irrespective.
Forced air is probably the most common sort of heating: in offices, supermarkets, and even in your car.
For those wanting an overview of forced air dispelling the myths:
http://www.sbfaq.borpin.co.uk/dokuwiki/doku.php?id=sbfaq:heating:warm_air
For those who say the value of your house drops with forced air, have a vent and heat recovery unit fitted and call it Fresh Air Ventilation Heat Recovery, then it sells. Fresh air speaks for itself and heat recovery is eco. You always have fresh air run through the house, which keeps the house fresh. A great bonus as is the free cooling in the summer.