Why don’t we use glazed solar pool heating collectors in Florida? It isn’t a common question, but it’s one that we get occasionally, especially from our northern friends.
The idea behind a glazed collector is that the glazing creates a greenhouse effect that increases the temperature of the collector surface. The main problem is that the cost of the collector is relatively expensive. The added heating performance is not worth the extra money. Unglazed collectors are much more cost effective at heating Florida pools.
In cooler climates, it may make sense to try and trap heat along the collector surface. In Florida’s climate where the ambient temperature is relatively warm and wind chill is not a major factor during daytime heating, glazing is not as effective.
Local Expert Knowledge Gets You The Right Solar Collector
Sadly, a local competitor didn’t get the memo and is offering a glazed collector. While there isn’t much wrong with the product itself, it’s simply not suitable for the environment.
The Florida Solar Energy Center (FSEC) rates glazed and unglazed collectors and lists the former for solar water heating applications and the latter for solar pool heating.
When the desired outlet temperature of a solar thermal system is close to the ambient temperature, unglazed collectors work great. This is why unglazed collectors are specified for pool heating in Florida. If you need a large temperature rise and there is a big difference between the ambient and outlet temperatures, you need glazing. For example, in domestic water heating systems, the ambient temperature may be 75ºF while the heated water needs to be 130ºF or more. Glazing is perfect for these applications.
The flow rate in glazed collector applications is also drastically lower. You need time for the water to heat up substantially. In pool applications, you want lots of flow with a small temperature rise on each pass.
Final Verdict on Glazed vs Unglazed Solar Collectors
The obvious choice in Florida is an unglazed solar panel for solar pool heating. Will a glazed collector work? Sure, but you will need a similarly sized system at a much higher cost.
Glazed collectors also have higher repair and replacement costs, and specialized techniques and products are required for service. That means you are beholden to the dealer for that particular product.
Unglazed collectors are very common in Southwest Florida. There are many dealers and many products. Most dealers can service all brands.
The only answer is to use an unglazed solar pool heating panel in Florida. Don’t let an unscrupulous or unknowledgeable dealer tell you otherwise.