Category Archives: Pool Heaters

Heaters for swimming pools category

How to Select a Solar Pool Heater

solarheaters chematic

Typical Schematic of a Solar Pool Heating System. Solar systems are longer lasting and more reliable than gas and heat pump pool heaters.

The cost of a solar pool heating system ranges from $3,000 to $4,000 to purchase and install. The return on investment (ROI) is realized in 2 to 7 years depending on local cost of fuel.  Solar systems are longer lasting and more reliable than gas and heat pump pool heaters. The return depends on many factors which one should investigate before selecting a solar pool heating system.

  • Evaluate your site’s solar resource
  • Determine the correct system size
  • Determine the correct orientation and tilt for the collector
  • Determine the system’s efficiency
  • Compare system costs
  • Investigate local codes, covenants, and regulations.

DIY Solar Pool Heater with Topsflow pump

The Department of Energy provides guidance and information on selection, design, and installation of solar pool heating systems.

 EVALUATING YOUR SITE’S SOLAR RESOURCE

The site’s solar resource plays a very big role in design of a solar heating system. How much of the sun’s energy reaches the site at which your pool rests will determine the design and the efficiency of the solar pool heater.

Solar pool heating systems use both direct and diffuse solar radiation. Even if you do not live in a climate that is warm and sunny all the time the radiated energy is adequate to provide the heating needs of a small pool. A building site facing south with unshaded areas is a good candidate for a solar pool heating system.  Consider asking your local supplier for a solar site analysis.

SIZING A SOLAR POOL HEATER

Several factors contribute to the sizing of a solar pool heating system. The size of the pool, the duration of use in a year, the average temperature of the duration, the desired pool temperature, the solar resource available determined from site analysis, the design characteristics of the system such as orientation and tilt of the collector, the efficiency of the collector and heat loss prevention.  A knowledgeable contractor with the right tools should be able to demonstrate the basis for his design.

As a thumb rule the surface area of your solar collector should equal 50%–100% of the surface area of your pool. Areas with cloudier and cooler weathers may demand a higher ration between the area of the collector and the pool. A larger collector extends the duration of the pool’s usage.

In example, year-round use of a 15-by-30-foot outdoor swimming pool in Florida would typically require a collector with 100% of the pool’s square footage.  This computes to 450 square feet of collector area. In northern California, where the swimming season is six to eight months the collector sizes are about 70% of the pool area.  Pool covers play an important part in decreasing the area of the collector required.

The size of the pool pump for a solar system will depend largely on the collector’s ability to provide the heat required.  In comparison to a conventional pool heating system a solar system demands a larger pump to move the pool’s water to and through the collectors.

Most Energy Efficient Natural Gas Swimming Pool Heaters

The efficiency of natural gas swimming pool heaters are measured by their output in Btu (British thermal unit) and is determined by a standard test. Heater efficiency is the ratio of usable output to energy input. For example, an 80%-efficient heater uses $80 worth of useful heat for every $100 worth of fuel. Therefore, it wastes 20% of the fuel.



Find out why Gas Pool Heaters are the most effective for heating your swimming pool
 

The efficiency of a gas swimming pool heater is displayed on their nameplate. The manufacturer may also provide its efficiency percentage.It is not unusual to find gas pool heaters with 89%–95% efficiency. The Department of Energy has computed the savings one may obtain by installing a 95% efficient gas pool heater for every $1,000 in annual pool heating costs.

Table 1. Costs of Outdoor Pool Gas Heating by Location*

LocationSeasonTemperature
78°80°82°
Miami1/1–12/31$2136$2848$3600
w/cover1/1–12/31$416$584$800
Phoenix3/1–10/31$1384$1776$2216
w/ cover3/1–10/31$96$168$256
Dallas4/1–10/31$1512$1920$2456
w/ cover4/1–10/31$184$280$408
Atlanta4/1–10/31$1704$2248$2880
w/ cover4/1–10/31$320$424$592
Los Angeles5/1–10/31$1864$2376$2904
w/ cover5/1–10/31$168$304$472
Kansas City5/1–10/31$1434$1872$2384
w/ cover5/1–10/31$288$416$544
New York5/1–9/30$1448$1904$2384
w/ cover5/1–9/30$208$296$400
Chicago5/1–9/30$1621$2072$2536
w/ cover5/1–9/30$216$296$384
Denver5/1–8/31$1757$2120$2498
w/ cover5/1–8/31$123$168$243
Boston5/1–8/31$1712$2096$2504
w/ cover5/1–8/31$232$328$461
Minneapolis6/1–9/30$1331$1776$2176
w/ cover6/1–9/30$192$248$384
San Francisco6/1–8/31$1560$1856$2168
w/ cover6/1–8/31$192$320$472
Seattle6/1–8/31$1525$1784$2056
w/ cover6/1–8/31$304$424$552

*Figures based on a 1,000 square-foot, outdoor pool heated with an 80% efficient natural gas heater at $.80 per therm and uncovered for 8 hours per day – source-Dept. of Energy.

If you’re replacing a gas pool heater, you can use the following formula to determine your annual cost savings with a higher efficiency gas pool heater model:

Current Annual Cost x [1 – (Current Efficiency ÷ New Efficiency)]

INSTALLATION AND MAINTENANCE

Proper installation and maintenance of your gas pool heater can optimize its efficiency. It’s best to have a qualified pool professional install the heater and even perform complicated maintenance or repair tasks.

Read your owner’s manual for a maintenance schedule and/or recommendations. You’ll probably need to tune up your pool heater annually. Also, scaling in the burner or heat exchanger may decrease efficiency over a period of time.

With proper installation and maintenance, gas pool heaters typically last five or more years. Reading reviews of gas pool heaters are a good source of information.

Solar Pool Heaters

Solar Pool Heater System Schematic

Solar Pool Heater System Schematic

Solar pool heaters can significantly reduce swimming pool heating costs. They are competitive with with both gas and heat pump pool heaters, and they have very low annual operating costs. In some climates they are the most cost efficient.

HOW THEY WORK

Most solar pool heating systems include a solar collector, a filter, a pump and a flow control valve.  A functional description of each is described below.

  • A solar collector — the device through which pool water is circulated to be heated by the sun
  • A filter — removes debris before water is pumped through the collector
  • A pump — circulates water through the filter and collector and back to the pool
  • A flow control valve — automatic or manual device that diverts pool water through the solar collector.

The pump directs the pool water through the filter and then through the solar collector(s).  The collector heats the water and returns it to the pool.  In very hot climates, using the collector(s) at night can cool the pool.

The sophistication of solar systems vary and may include sensors and automatic controls to increase or divert the flow as needed to maintain the temperature of the pool. The sensors direct the flow and when the collector temperature is similar to the pool temperature, filtered water simply bypasses the collector(s) and is returned to the pool.

The Solar pool collectors come in many forms and are made out of different materials depending on their use. If they are used only when temperatures are above freezing, then you may only need an unglazed collector system. Unglazed collectors are generally made of heavy-duty rubber or plastic treated with an ultraviolet (UV) light inhibitor to extend the life of the panels. Because of their simple design and inexpensive parts, unglazed collectors are less expensive than glazed collectors. The unglazed systems work for indoor pools in cold climates if the system is designed to drain back to the pool when not in use. Even if you have to shut the system down during cold weather, unglazed collectors may be more cost effective than installing a more expensive glazed collector system.

Solar Pool Heater Collector

Solar Pool Heater Collector

Example of how a solar collector works.

Glazed collector systems are generally made of copper tubing on an aluminum plate with an iron-tempered glass covering, which increases their cost. In colder weather, glazed collector systems—with heat exchangers and transfer fluids—capture solar heat more efficiently than unglazed systems. Glazed collectors may be used year round in many climates for pools and to heat water for domestic use. Galzed and Unglazed collectors should be equipped with freeze protection if used in cold climates.


Interesting DIY Solar Pool Heater Video