An Introduction to Pool & Spa Heaters
Early Romans elevated bathing from a pesky chore to a daily pleasure by simply warming the water. Wood fires under the floor heated their pools like a kettle on stove heats water. Newer technology heats water directly which may affect the pool but more importantly, warms us.
There are four very different ways to heat water; all have a strength, all have a weakness. The two passive methods are solar collection and heat exchange (heat pumps), Two aggressive methods are gas flame and electric resistance.
Gas and electric heaters work quickly but are priced only for occasional use.
An electric heater works like the electric hot water heater in your home and is just as expensive to operate. Routine repair is limited to replacing a $45 (US) heating element. Installation cost of less than $700 is offset within a decade when the spa is used more than 3 or 4 times a week.
Raising a home spa to the optimum 105 degress (Farenheit) with electricity takes 7 hours and costs about $8 for the experience. Gas can heat a spa in 30 minutes for less than $2 but at almost $3,000 is three times more expensive to install.
Gas heaters require a Propane tank (usually leased) or connection to a Natural Gas line (where available) and are fast and reliable on the job. When spontaneity is a legitimate write-off in your lifestyle, the gas heater is for you.
The most common complaint about gas involves contractor 'spa package' systems. On paper, the system is always 'adequate'. In reality, even a slightly dirty filter will slow water flow enough to cut off the heat. As any experienced serviceman will tell you, when you can't get a gas heater to fire, first clean the filter.
Be wary anytime you deal with 'specialty product' factory reps. Nation-wide service networks are troublesome for small manufactureres to maintain and opportunism often goes unpunished. The factory tech involved in this heater renovation (photo, left) offered to help out a commercial property for a few days on other PVC pipe work and submitted a bill for $600 an hour labor, ten times what the factory paid. The customer appealed to the service manager who denied any responsibility for his behavior. The tech invoked Florida Mechanic's Lien Law and collected his bonanza. Now, he's anxious to get to your job.
Heat pumps and solar heaters may be slow to warm water but are far more economical to operate.
Heat pumps work like an air conditioner in reverse, raising water temperature 10 degrees for about $10 a day. Much depends on your average ambient temperature and maintaining a tropical 74 degrees over a mild Florida Winter will cost a minimum $125 per week.
At $3,000 to $4,500, heat pumps are the most expensive to install but also the most efficient to run. A quirk of heat pumps is that they cease to function in temperatures lower than 37 degrees.
Solar power may one day save the planet, but is currently the least effective pool heating system. It costs little to run and the expense is in initial set-up of 4' X 20' rubber panels at $250 each and the larger pump and plumbing necessary to hoist water up to your roof. Running a solar system when the temperature drops may help prevent freezing, but dissipates heat as fast as a cloudless, sunny day can absorb it.
Don't skimp on solar equipment. A miser's mistake is to undersize with anything less than a 1.5 HP motor and the 2" suction- side plumbing necessary to feed it sufficient water. Total area of panels should equal the surface area of the pool. A 16' X 34' pool needs a minimum 7 panels.
(photo, right) One owner installed a sufficient number of solar panels, one skimped. Guess who complains that solar heat just isn't all it's cracked up to be.
(photo top, right) Afforable heat requires a pool blanket. Annoying to work with and nothing more than bubble wrap, a black cover is the most effective but sells poorly because it's considered ugly. A clear cover is the least visible and the least useful. A blue cover sells best; somewhat invisible, somewhat efficient but absolutely necessary to retain heat overnight in an idle body of water.
Pool heater repairs, routine maintenance and heater sizing are further explained with color photos, drawings, graphs and simple text in the 690 page Pool School PRO CD
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