Systems are pretty similar, but does the NAH have an ECO(nomy) button for the climate control system? In the TCH this button limits the air conditioning power in the summer and uses an electric heating element to reduce the need using the engine coolant for heating in the winter. Seems to save a few MPG.

No econ switch or electric heater in the NAH.

I didn't think the TCH had the electric heater - only the Prius. I don't think there's any economy gain anyway with the electric heater as the power for that has to come from the battery which has to come from the ICE - there's no free ride. I thought the electric heater was more of a comfort feature to produce heat before the coolant has a chance to warm up.

The TCH does have the electric heater. I thought it was a comfort feature that was enabled when not in ECO mode. Turns out it is only used in ECO mode! Apparently it will allow the ICE to come up to temperature faster, using less fuel. The heater isn't as vigorous in ECO, and the heat doesn't come on any faster in ECO mode. I'd never guess the electric heater is there except for reading the service manual.

The Altima does not have an "ECO" mode like the Camry, but the AC/Fan cycles depending on battery charge in a quasi-ECO way, as it’s normal operation.

My understanding is the Camry AC/Fan runs at full blast (depending on setting) unless it is in "ECO" mode.

So the Camry is full blast or ECO, while the Altima is a compromise in-between.

The TCH fan is auto speed (unless manually overridden).

The TCH in ECO mode will let the AC run full power (or near it) as long as the interior temp is 75 or greater. Then it throttles down to save energy. The result is that in demanding conditions (hot and sunny) you can't get the temperature to drop below 75 in ECO mode. You don't broil, but you don't freeze either.

Setting the temp control at its extremes or turning on the defroster automatically cancels ECO mode. In a IMHO design flaw, the ECO button has no memory, so turning off the defroster or resetting the temperature leaves ECO off. The ECO button seems to be an afterthought as it is located virtually under the dashboard to the left of the steering wheel instead of being in the climate control cluster. Very inconvenient.