There are a few Carrier models that are Energy Star certified while Trane has quite a few. In terms of which is better, it really depends on your specific needs and what you're looking for in a furnace. With that said, here's a general comparison of the two brands.
Carrier is known for their top-of-the-line customer service, so if you're someone who likes to have peace of mind knowing you can always reach out to customer service for help, then Carrier may be the brand for you. On the other hand, Trane furnaces tend to have slightly higher energy efficiency ratings than Carrier models, so if saving money on your energy bills is a priority, then Trane may be the way to go.
In terms of specific models, the Carrier Infinity 96 Gas Furnace is one of the most popular models among homeowners. It has an annual fuel utilization efficiency (AFUE) rating of 96%, which means it's extremely efficient. The Trane XC95m Gas Furnace is also a very popular model with an AFUE rating of 95%. So again, it really comes down to your specific needs and preferences as to which brand and model is best for you.