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Getting the Truth Out There - Part 2


Following up on my previous post about getting the truth out there.

I find it frustrating, being a person who cares about making sure a solar system is capable of doing a good job and lasting a long time, to see poor quality solar design and poor quality work being done. As bad as some contractors are, the consumer has to bare some of the responsibility for this happening. Those who only look for the cheapest price or who want to deal in cash to avoid taxes, only encourage disreputable contractors, corner cutting and undersized systems.

Another group of consumers just want to have something and believe that something is better than nothing. Disreputable solar salesmen allow this to happen, believing that a small sale is better than nothing. Unfortunately undersized systems will disappoint because they don't have the ability to do the job - this is especially apparent with solar pool heating systems. It takes a massive amount of heat to heat a swimming pool (a clue to this is that natural gas pool heaters are 3 -5 larger than home furnaces and 10 - 15 larger than home water heaters). An undersized solar system just hasn't the ability to heat a pool properly. Solar pool heating systems are big - starting at a minimum of 50% of the pool's surface area. To draw an analogy - 50% of the pool's surface is like a 4 cylinder engine in a full-size car - it gets the job done but it's not really peppy. If you want pep, you have to go with 75% of the pool's surface area (6 cylinder engine) or 100% of the pool's surface area (8 cylinder engine). This is also only true if the conditions that the pool and the roof area see are perfect. Pools or collectors that are shaded and/or facing more than 45 degrees off of Solar South will all mean you need to start with a larger system.

I recently had an experience with person who really wanted a solar system. I quoted a gentleman at his home earlier this year who had a reasonable site with large enough back roof facing South-East. When I was finished providing the first quote, his neighbour across the street eagerly asked me for a quote to heat his pool. Unfortunately his front (South-East facing) roof was not suitable and the other roofs were broken into small steep sections which meant that a properly sized system couldn't be installed. He wasn't happy with my evaluation and subsequently request a quotation from another solar company (selling a low-efficiency rubber collector) who was happy to fit several small areas of solar collector onto his roof. While we were installing the solar system for our customer, the neighbour came over to complain that his (rubber) solar system wasn't doing the job. Surprise, surprise.... I could also tell from the road that the solar plumbing was also going to severely restrict the flow of water through his filter - this could lead to pool water problems and pump problems.

Something else we’re seeing in the area is solar companies trying to sell evacuated tube collectors to heat outdoor pools. While this can work (for a while) if the system is properly sized and installed, the snake-oil types selling them claim they are more efficient than unglazed collectors at heating outdoor pools, which is completely untrue. Evacuated tube collectors will deliver about 60% of the energy of an unglazed collector per square foot (or meter) of gross area when heating outdoor pools. (The appropriate measure of a solar pool heating system is its gross area, because the solar systems are so large it's hard to fit them on roofs.) This means in order to deliver the same amount of heat as an unglazed collector system, an evacuated tube collector system must be substantially LARGER. The snake-oil types like to point out that evacuated tube systems can deliver heat even when it's well below freezing outside. This is true but completely misleading because 99.99% of people do not operate their outdoor pools under freezing conditions. When the weather is bad, outdoor pools lose heat far faster than any solar system can recover - unglazed or evacuated tube. When the weather is nice (which is when pool owners want to heat & use their pools) an unglazed collector solar system will out-heat, by a wide margin, an evacuated tube system of the same size.