We are often faced with options when selecting a roof on which to place solar pool heating panels. Sometimes the optimal roof is too small to accommodate the number of panels that we suggest for ideal performance.
In the images below, there are two viable options for solar pool heating, the south and the east roofs. There are trade-offs that need to be considered, so we prepared two design options for our customer for discussion.
The south roof is optimal for solar pool heating. However, this multi-gable roof can only accommodate four panels totaling 160 square feet of collector area. That’s well below the desirable coverage which is 80-100% of the pool surface area. However, panels are well hidden from view here, it is the best orientation on a per square foot basis, and it is close to the pool equipment.
On the other hand, the east roof can accommodate a far greater collector area. We have pictured and proposed 384 square feet of collector area. That is almost two and a half times the coverage we can fit on the south roof. While the east roof is not as productive in terms of output per square foot, there is so much more area with which to work. Since the roof has a gentle pitch, the afternoon sun will still be able to hit the panels, providing plenty of heating performance throughout the day. On the downside, the panels will be somewhat visible from the pool deck, which might bother some people (not all). Also, the plumbing run to the pool equipment is a bit farther. Of course, a larger system is more expensive, too.
Ultimately, in this situation I would have to recommend the east-facing system. Despite the added cost and reduced efficiency, the south-facing solar pool heating panel system is just too small to produce enough heating performance for most consumers. While the larger system is 2.4 times the size, the cost is only 66% more. The marginal cost of adding more panels goes down significantly as the size increases. In this case, the customer is replacing old panels from another manufacturer that were placed on the south roof, so we will wait to see what they decide, and I’ll update you in the comments below when they do!