yes. also, the engine power is often used to run the
air-conditioner as well, which reduces the power available to power
the bus.
some non air-con buses are still around from the old days as it
would be uneconomical to retire them simply because they are non
air-con. some of the buses have already been converted to air-con,
while some are not converted due to:
to be retired soon
(Scanias from 2006, Volvo B10M Mk2 from 2007)
used to meet certain
service's requirement of having non air-con buses (the reasons
behind this is disputable of cos, like low demand, high rate of
concession usage, industrial services etc)
the last of non air-con buses (assuming no new non air-con buses
come along), Volvo Olympian 2-axle double deckers with Alexander
body, will be retired in around 7 years' time, but they only number
about 100 and the majority have settled down on Jurong Industrial
services.
