It is my understanding that model Y comes with the octo valve heat pump while the model X uses resistance heaters. The question is does the heat pump improve range in cold weather significantly versus the resistance heater of Model X. Model X long-range of 350miles may not make it to North side of Dallas from south side of houston (295 miles). Asking another way, how much does the use of resistance heat strips reduce the range in say 30 to 40 degree weather? I guess I have to ask the same question about the use of air-conditioning for more likely 95 degree weather?