I am considering buying a Prius, and am wondering about the heater in the passenger compartment. Does the heater provide good heat when the ICE shuts down, as at a light? I could imagine the heat fading as the temp drops in the heater core, or possibly the engine itself. Does the system have an electric circulating pump, so you can get to the heat that is in the engine block? What happens when the block starts to cool?

Thanks in advance,

gary

The Prius has an electric coolant circulation pump, plus it has electric heat elements that can supplement the engine heat when needed. If the engine gets too cold or battery gets too low it will start up and warm itself back into the optimum operational range.

2001 Prius Photos       2005 Prius Photos
1992 Mitsubishi Delica Diesel-WVO Hybrid Photos

Prius sold in some markets have supplementary electrical resistance heaters, but after all these years since 2001 S. Calif. purchase, I still don't know if mine has them. It has kept me plenty warm when the outside temp. was -19F. There is a electrical motor to circulate the hot coolant to the heater core.

Before the gas engine cools off enough to short-change you on heat, it will restart for one of the other two reasons (low HV battery voltage or low intake manifold temperature).

DAS

edit: And Schwa replies first, by a nose!

At least he can be confident that he got a reasonably correct reply in that we covered the same points without seeing each other's post.

You know you're a Prius nerd when...

2001 Prius Photos       2005 Prius Photos
1992 Mitsubishi Delica Diesel-WVO Hybrid Photos

Thanks for your answers. I'm in Raleigh NC, so I won't be in an extreme case.

Just being careful.

Thanks again,

gk

On the 2005, you set the climate control to the temperature you want -- The car keeps it there, hot or cold, engine running or not.

With regard to automatic climate control that the Prius has. This was really the only way they could have a vehicle that is a no compromises car when compared to a traditional vehicle. Consider that cabin heat is "waste" heat from the engine and air conditioning is provided by a compressor. Since the vehicle shuts down the ICE when it is both in the correct operating temperature and when electrical demand is not such that the ICE needs to tend the battery, that meant that the climate control system had to be much more advanced to provide a competitive driving and comfort experience.

As such a Prius in winter with a fully warmed engine will most likley turn off at a stop but heat will continue to come into the cabin because the coolant is already quite warm and the coolant continues to circulate. In the summer, electric air conditioning will continue to work at stops because there is plenty of battery power to run the a/c without the ICE running, especially at a typical non traffic jam stop. The system will regenerate that power lost to a/c through normal driving. On top of that the a/c system uses a variable speed compressor, so compressor speeds are retarded when demand for cool cabin air diminishes as the cabin reachs the setpoint.

If this vehicle use traditional cabin temp controls it would be impossible to get competitive mileage with the ICE running all the time to provide waste heat and a/c compressor operation.

It has been said:
Hybrid drivers come in 3 flavors, greenie, techie and cheapie. Pick any 2.
2005 Prius, Melinium Silver over gray, package 5 (AI)