This is the first white paper in our “Researcher-in-Residence” series. A PDF version of this white paper is available in the free course, “What Data Tells Us About Teaching & Learning Clean Energy Skills“.

In this article we examine three years of Heatspring data from 2021 to 2023, and over 26k students and 50k enrollments, to see trends in course content, emergent learning patterns and what habits lead to building understanding.

Heatspring is an online learning platform with over 249 courses, 153 free and 96 paid, that focus on upskilling and reskilling people for jobs in the growing climate-tech economy. With courses on topics like solar, batteries, and  heat pumps, they provide solid foundations while also helping prepare students for rigorous nationally recognized certifications. The Heatspring course catalog is relevant to both tenured professionals looking to dive deeper into a particular domain of expertise and folks who are new to the space and want to build a foundational understanding.

Growing Demand for Clean Energy Courses

The Inflation Reduction Act (IRA) passed on August 16, 2022 and represents a massive sustained investment in clean and renewable energy. In the past year there has been a 37% increase in clean investment projects (source: Rhodium Group). We see a similar trend on Heatspring with average monthly enrollments up 15% and monthly unique students growing 21% from 2022 to 2023.  Heatspring has emerged as a valuable resource to support workforce development through curriculum aligned to areas of investment resulting from IRA.

Heatspring enrollments grouped by quarter reveal several trends. First, there is a consistent wave pattern with high volume in Q1 and Q4 and lower enrollments in the middle of the year.  Second, overall enrollments are growing at 21% across quarters, with the largest quarter over quarer jump immediately after the IRA passed in Q3 2022. Q1 is consistently the busiest quarter for enrollment. This tracks with individual preference to beginning the new year with growing new skills and business plans for hiring and training plans as part of wider strategic initiatives. 

What is popular

The top ten courses at Heatspring from 2021 – 2023 are a mix of foundations courses providing an introduction to solar power and PV installation (a) along with rigorous bootcamps (b) designed to help pass national certifications and credentials.  While the top ten is dominated by PV related courses, we see in 2023 a battery storage fundamentals course crack the list (c).

When are they learning?

When we aggregate enrollments by day of week we see that the heaviest engagement occurs at the beginning of the week and tapers through Friday with the weekend being very quiet. Perhaps this is not surprising given our busy work weeks and the energy it takes to focus and study.

When adjusting for US time zones which accounts for nearly 80% of traffic, a clear pattern emerges.Students are primarily studying from 8 am to 3 pm.  If we break it down by state nearly 40% of traffic is from West coast and Mountain time zones which indicates there are a significant number of students that are up early in the morning studying before work. 

When looking at a sample across a number of Heatspring’s most popular courses, study session times range from 14 minutes to 6.5 hours with an average of a little over an hour and half.  Longer study sessions tend to occur early in the morning with shorter sessions in the evening. Students with engagement and completion rates above 70% were logging into Heatspring at least three times a week. Students with sessions greater than three hours had consistent time ranges.  This data reinforces the importance of establishing a habit, creating a schedule and building a consistent routine when completing a course.

How are they learning: Video completion and engagement

Let’s dive in and take a look at how different types of learners are engaging with and completing content. We are going to focus on three profiles of students: Student 1 is new to heatspring and browsing across mostly freely available courses. Student 2 has registered for a specific course and is building expertise in a single topic.  Student 3 has been on Heatspring for several years, engaged with hundreds of videos across multiple courses.  

This visual is a horizontal heatmap of a video, where the left side is when the video begins and right side when it finishes.  Refer to the illustration below that explains the color coding of the heatmap. These colors reveal patterns in watching, rewatching and engagement. 

Student 1: Browsing Heatspring
Engagement summary: This viewer has spent 51m38s watching 9 videos. Their average engagement is 13.3%. Their first view was Sep 2023.Discussion: These students are new to Heatspring and evaluating content quickly. They often have low completion rates and skip across videos. Short green lines indicate keyboard or mouse skipping over a video. Short green lines indicate keyboard or mouse skipping over a video

Student 2: Building Expertise
Engagement summary: This student has spent nearly 70 hours watching 96 videos and their average engagement is 68.4%.Discussion: These students have drilled down into a single course and have higher completion rates. They also review and rewatch videos which is an indication of an engaged and active learner.
Student 3: Dedicated Learner
Engagement summary: This viewer has spent 109h24m watching 462 videos. Their average engagement is 79.2%. Their first view was Nov 2021.Discussion: These students have developed several habits that lead to high video engagement which is sustained over a multi month and often multi year span. These are students who frequently log in multiple times a week and multiple times a day. Simply maintaining a schedule adds up to form a habit.    A common behavior within this group is to break up longer videos and watch or rewatch over multiple sessions. In the example on screen, they started the video at 8:30 am, and came back to rewatch and finish 3 hours later. This “same day completion” of videos is a pattern among highly engaged students.


  • Move from browsing a higher number of courses on the surface, to narrowing down on a single domain to drive toward completion to build out your understanding on a topic. Successful students grow understanding through high completion and  engagement  
  • Set a schedule that works for you.  Many students on Heatspring have chosen to start the week strong with a combination of a longer early morning session and a shorter evening session.
  • 34% of Heatspring learning happens on mobile devices.  Use a combination of computers for deeper study and focus with mobile as refreshers/review when you are on the go or have 5-10 minutes free.
  • Successful students will watch an entire video, then rewatch shorter segments that contain technically dense information or key information.  Rewatching short segments is a form of reflection and review that can help reinforce new concepts.
  • Break up longer videos, greater than 30 min, into segments but try finishing in the same day to keep it fresh and top of mind. Watching and rewatching is a form of reflection and active engagement that helps transfer complex topics into longer term memory.