Boston Heating Supply has a selection of Thermo-Dynamics brand oil-fired pool heaters. The prices range from about $3,500 to $5,000, depending on the model, as of March 2015. Five models are available from the website.
It is important for the pros and cons of different pool heaters to be assessed before purchasing, as well as temperature preferences. Some heating methods are more expensive to install, but less expensive to maintain or operate in the long term. Other methods of heating are inexpensive at first, but rising costs of fuel can make the long-term cost of heating a pool increase over time.