Are Gas Pool Heaters A Good Buy?

Whilst gas pool heaters are still very popular they are not as friendly to the environment as solar heating and heat pumps because they are considerably less energy efficient.
Against this we have to accept that lots of gas pool heaters are sold because they have advantages over the competition:

• Relatively cheap to buy and install - Whilst the cost will always depend of the size of heater required, models for above ground pools are available under $1000 and for in-ground pools under $1500. Installation can be done by anyone who is reasonably handy apart, of course, from the gas and electric connections which must be done by a competent professional.
• High capacity - One major benefit of gas pool heaters is that they have a high capacity (up to 400k BTU/hr for residential pools) and can therefore heat the water relatively quickly. This makes them the best option if you only heat your pool occasionally.
• Energy Efficiency - Most residential gas pool heaters now have an energy efficiency rating of between 80 and 85% a figure which has improved considerably in recent years. The top rating for a gas pool heater is presently 95% but whilst this saves on running costs you have to pay more for such an efficient heater.
• Reliable - Whilst gas heaters are constantly being improved the basic technology is well understood and tested. A properly maintained heater should give you many years of worry free pool heating.
• Not affected by the weather - A gas pool heater will operate in all weather conditions.

Ideally gas pool heaters should use natural gas but most ranges include versions for use with propane. This choice does not affect the performance of the heater but has a large impact on running costs. Propane can cost up to twice as much as natural gas so is never the preferred option.
Gas pool heaters are available in both electronic and millivolt versions. Electronic heaters are the most popular as they feature efficient electronic ignition and sophisticated digital controls. However to power these functions they need an electricity connection. If providing an electrical connection is a problem then the answer is a millivolt heater. These use a pilot light (which wastes some gas) and have simple controls but do not need electricity.
You can choose between popular models from all the major manufacturers including Raypak, Jandy (Laars) and Hayward.
The main competition these days comes from pool heat pumps. These cost considerably more, are less powerful, are electrically powered and don't work in very low temperatures. Their big advantage is that they move heat from the air to the water rather than generating it. This gives them an energy efficiency rating of several hundred percent and makes them cheap to run.
Although this article is about gas pool heaters it has to be said that a heat pump must be considered if you heat your pool all the time during the season. If you don't heat your pool constantly you will probably find that, taking into account up-front costs, running costs and heating power, a gas pool heater is the best option.