I understand why new furnaces are more efficient, but why AC?

[Mark]

Ummm.... maybe to save you operating costs? A new unit could save you a substantial amount on your electric bill over a 10-15 year old one.

[Bill]

It is mostly in the electric motors which are used for the compressor and fans.

Actually house electricity is not very "efficient" for running an electric motor. So what they do is make their "own electricity" to run the electric motors. Then design the most efficient electricity/motor pair.

For example electric motors run more efficiently on 3 phase electricity, they may convert the house electricity to a form of 3 phase electricity for the electric motors.

Or they can control the "speed" of the electric motors. Rather than on full blast or off, they can run these are various speeds. If just a little cooling is needed, slower speeds will do the job.

They basically put their thinking caps on and come up with ANYTHING which will save a bit of energy. With modern electronics and computer control, all sorts of things are now possible...

Here is one which says... "Daikin's Reluctance DC motors utilize powerful neodymium magnets that are

10 times more powerful than conventional magnets. By maximizing torque, Daikin's reluctance DC motors can boost efficiencies 20% higher than conventional motors." This one says... "Regular A/C units have a compressor that switches on whenever the room gets too warm and runs at full power until the room is cool enough, then shuts off. The inverter makes it possible to run the compressor continually at a lower power to maintain the room temperature eliminating the frequent stopping and starting required by standard systems ." On "Variable Frequency Drives"... Variable Frequency Drive Technology Can Save Over 30% In Energy Costs...

[mm]

Thanks and thanks to all of you.

[dlzc]

[e-mail]...

The ozone hole is a natural, recurring event. The size of the hole, the date of start, the duration, and the minimum ozone value obtained... are a function of the contaminants in the "ozone layer". This includes chlorine- and bromine-containing compounds, as well as water vapor.

The fluorocarbons are next. We keep making inert compounds that can only leave our biosphere via the (nearly the) same energetic radiation that makes ozone. All because without the chlorine, bromine, or flourine there, they are too flammable for safety.

David A. Smith