Gas hot tubs or gas-fired hot tubs use small swimming pool heaters to heat the water (around 100,000 BTU). These heaters can be natural gas or propane gas. Gas hot tubs heat up extremely fast so the water temperature goes from ambient temperature to hot tub temperature (100-104 degrees) in about 30-60 minutes. They heat the water at a rate one degree or more per minute which is extremely fast especially when compared to an electric hot tub.
Here are some of the advantages of a gas hot tub:
Ideal for In-Ground Spas – gas spas are a great option for a fully in-ground hot tub application because the equipment for an in-ground is usually separate from the hot tub shell itself and placed in what they call an equipment “doghouse” or equipment skid. In this application the hot tub equipment is usually pieced together a la carte and the hot tub itself is more of custom built design rather than an off the shelf, portable hot tub. Having an equipment doghouse makes it easier to hide the large gas heater so that it is cleaner looking.
Heats Faster – as referenced above a gas heater can heat the water nearly 20 times faster than an electric heater.
Here are some disadvantages of a gas hot tub:
Bulky and Unsightly – gas heaters are large boxes that are about the size of a portable air conditioner and have to be installed externally from the hot tub. They take up space and aren’t pretty to look at. They should also be left open for fumes and exhaust (they can’t be fully enclosed)
Expensive – the gas heater component of the hot tub alone runs between $900-$1200 which doesn’t include installation cost which involves plumbing it to the hot tub by a certified technician. There’s also the cost of running a gas line from the gas supply (meter) to the heater by a licensed professional. These costs can make a gas hot tub prohibitive.
The second and much more predominant is electric hot tubs. Electric hot tubs are the standard now a days. Nearly 100 spa manufacturers today build their hot tub models with integrated electric heaters. The heating element (usually 5.5 kw) is tied directly to the hot tub’s spa pack (motherboard) and housed inside a 12-18” stainless steel tube. They are referred to as high-flow-thru heaters because there is a large volume of water constantly circulating through the stainless tube and over the heating element. The thermostat tells the heater when to turn on and off as the water is circulating and to keep it up to the desired temperature.
Here are some of the advantages of an electric hot tub:
Superior Selection – as mentioned above almost every make and model of hot tub comes in either 110v/15amp or 220v/50amp electrical. You are sure to find the right size, shape, jetting, seating configuration, and specifications you desire if you go with an electric hot tub. Gas hot tub will almost require a custom built set up or you can buy an electric hot tub and convert it to gas but it will void the warranty and incur all expenses associated with a gas hot tub install (must purchase gas heater, run gas line, and professionally hook up the tub to the gas heater)
Cheaper Maintenance & Repair – replacing a heating element in an electric hot tub is typically a few hundred dollars and easy to do. Replacing a gas heater is a $1000 or more expense.
More Efficient – Hot tub in the last two years have come a long way in energy efficiency. Radiant heat from the self-contained equipment helps keep the spa warm thereby reducing heating expense. Well insulated hot tub covers and premium insulation around the hot tub shell and on cabinet walls help hold the heat thereby reducing energy costs even further. Basically, a well insulated hot tub with a decent hot tub cover on at all times (except during use) equates to a very reasonable monthly expense ($15-$25 per month depending on size). k
Here are some of the disadvantages of an electric hot tub:
Slower Heating – there’s no comparison between the rates in which a gas hot tub can heat up as compared to an electric hot tub. Most 220v/50amp electric hot tubs have a 5.5 kw heater which heats around 3 degrees per depending on ambient temperatures. 110v/15amp electric hot tubs have 1.5 kw heater which heats dramatically slower than that.
One can draw their own conclusion as to what makes more sense to own but the industry has clearly migrated to electric hot tubs by default. For more information on how to research and compare hot tubs before purchasing please visit our hot tub buyer’s guide pages. You can also click on the pink boxes at the top right of every page to get a free local quotes from dealers in your area.