How does Garmin connect calculate work? I use and have a 4i power meter connected. I’m hoping the newer is it comes from the power meter. I care because I use the caloric data for diet.

Heart rate is used for calculating the Calories. Power from the power meter only tells how much power goes into the pedals. It tells little about the efficiency of the pedaling, about the work of the body, arms (and of the brain too). The heart rate does.

I don’t believe this is accurate. Using a power meter, multiply average power x 3600 s./hr x hours. The result is both work and calories per the connect app.

This makes sense because for semi/elite athletes work and calories is nearly 1:1.

Please double check how the application incorporates power from a power meter

Thanks

As I wrote, power meter is not accurate either since it does not take in account many factors influencing the work done by the body. Heart rate does.

BTW, this is a user forum. If you want to speak to Garmin, I recommend sending them your idea through Share Ideas | Garmin, or contacting them through https://support.garmin.com 

Read some more details why relying simply on the power meter is not sufficient, for example here: Are Calorie Counters on Cardio Machines Accurate? (verywellfit.com) 

Another detailed analysis of the methods used by Garmin is at https://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html, but it is already a little bit outdated. However, you can see that the data from power meters is being used too by relevant models and when available, but it is only one of the factors used for the calculation (and it is right so).