The last type of hot tub comprises all types of in-ground spas, including those installed as part of a pool-spa combo. This is the most expensive type of hot tub, not so much because of the price of the actual spa equipment, but due to the installation requirements. Installation of an in-ground spa requires excavation, as well as fairly extensive plumbing and electrical work. It must be done by a professional contractor and is considered by most municipalities as a building project, requiring a permit and approval by city hall. On the other hand, this is the only type of spa practically guaranteed to raise the property value of a home.
In-ground hot tubs are generally constructed of gunite (pneumatically applied concrete) or standard concrete, sometimes with a decorative tile overlay. They have limited seating options, primarily offering bench or step-type seating. They are also often larger than above-ground spas, seating up to 16 people. However, they have fewer jets, with limited types and configuration options.
Although in-ground spas cost more to operate than above-ground spas, they do tend to heat faster and maintain their temperature better, and they are considered more aesthetically pleasing. Because the heating and filtration elements on in-ground spas are not attached to the spa itself, heating can be accomplished with either gas or electric systems. While electric is cheaper initially, propane or natural gas heaters are the most economical long-term choice.
Installing an in-ground spa is a major decision, because of both cost and permanence, and should be well-researched. Careful selection of location and finding a good contractor are essential to making an in-ground spa work for you. Although they carry a hefty price tag, the increase in property value, as well as the enjoyment you will derive from your spa, may well justify the investment. You'll want to ask around and interview neighbors about pool and spa contractors.