ST BiPAPs: why so expensive?

S8 VPAP Auto 25 BiLevel Machine: $1375 on cpap.com
S8 VPAP ST BiLevel Machine: $2799 on cpap.com

So, the ST is about twice the price of the 25. Why?

The form factor is the same: size, weight, etc. My guess is that the major difference is firmware only, since according to ResScan 3.7 the data reporting is the same.

Does anyone know why the ST is twice the price of the 25? There may be an extra sensor, perhaps, but my guess is that it is PURELY firmware.

Can anyone shed more light? I'd love to be proved wrong...

BTW, my nice doctor prescribed me a 25 rather that the AutoSet II when I told him about my interest in the expanded data capabilities. He said he was interested in the technologies as well, and that we could discover the information together. I love my doctor! It's a shame more aren't like him...

The blower itself has to be more sophsticated, to allow for constant, precise pressure variations. In most modern bilevel machines, most of the work of delivering two pressure steps is done through modulating the blower output (usually) through varying motor speed.

Varying motor speed a great deal also means a more sophisticatd motor drive amplifier (MDA) to provide precisely controlled power to the motor. Most of these MDA's are polyphase AC drivers as the motors are essentially polyphase AC motors (no brushes or commutators to wear out or fail).

I would also think, as you mentioned, the sensors also have to me more complex, and operate accurately over a wider range of conditions. Precision sensor require relatively expensive precision analog electronics to support them.

The most expensive machines, the ST and SV machines, may also use a rather sophisticated 'door' that swings open and closed to modulate air pressure. Although simple in concept, the door has to be carefully made to last a long time, and is probably loaded with some sort of linear motor to control opening/closing speed.

Lastly, they don't sell as many of these high-end machines, but have to put substantially more R&D into designing them. The higher cost reflects attempts to recover these R&D costs, as well as the higher economy-of-scale costs associated in manufacturing them.

I think the blower is same but the liAbility involved requires a very high STD of accuracy
ST machines cost more because of this.

The vpap III S & ST models are identical inside except for the software. The lTer vpaps shd be simar,

DSM

Pls excuse the muddled aspects of my prior post - i did it using an iPhone whilst in the passenger seat of my Daimler Double Six traveling at 120 kph whilst wife was driving us from Sydney to Jervis Bay (3 hrs drive south).

Was just trying out if such a thing could be done - all in all it worked pretty well (but it got a tad muddled despite the wonderful suspension on the car - pls forgive me RG I promise it will be less muddled next trip )

DSM