If you're thinking about adding a spa to your backyard, your first concern is likely how much electricity does a hot tub use and how that's going to look on your monthly power bill. It's a smart thing to check before you buy, because while the upfront cost of the tub is one thing, the "subscription" to keep it hot and bubbly is another story entirely.
The honest truth is that there isn't a single magic number that applies to everyone. However, for most modern, well-insulated tubs, you're usually looking at an extra $20 to $60 a month. That range is pretty wide, though, because a lot of factors come into play—everything from where you live to how often you like to soak.
The main factors that drive your energy bill
When you look at your hot tub, the biggest energy hog isn't actually the jets; it's the heater. Keeping a few hundred gallons of water at a steady 100 or 104 degrees takes a significant amount of work, especially when the air outside is chilly.
Quality of insulation
This is probably the biggest factor in the "how much electricity does a hot tub use" equation. High-end hot tubs are usually filled with high-density spray foam that traps the heat inside the cabinet. Cheaper models might only have a thin layer of insulation or none at all. If the heat can escape through the sides of the tub, your heater has to kick on much more often to compensate. It's a bit like the difference between wearing a heavy down parka and a light windbreaker in the middle of winter.
Your local climate
It sounds obvious, but a hot tub in Minnesota is going to cost way more to run than one in Arizona. When the temperature differential between the water and the air is 80 degrees, the laws of physics are constantly trying to pull that heat out of your water. If you live somewhere with harsh winters, you'll see your electricity usage spike during those months as the heater fights against the freezing air.
Frequency of use
Every time you open the cover, heat escapes. If you're a "once a week" user, your costs will be lower than if you're out there every single night with the jets on full blast. When the jets are running, the water is being agitated and more surface area is exposed to the air, which leads to faster cooling. Plus, the pumps themselves use electricity, though usually far less than the heating element.
Breaking down the monthly costs
Let's get into the nitty-gritty of the math. Most standard hot tubs use about 2,000 to 7,500 kilowatt-hours (kWh) of electricity per year. If you want to figure out what that means for your wallet, you need to look at your power bill and see what you pay per kWh.
If your tub uses an average of 300 kWh a month and your local rate is $0.15 per kWh, you're looking at roughly $45. If you have a super-efficient tub and live in a mild climate, that might drop to $20. But if you've got an older, poorly insulated tub in a cold climate, it's not unheard of to see that number climb toward $100 during a blizzard.
Inflatable vs. hard-shell hot tubs
If you're looking at those portable, inflatable hot tubs because they're cheaper to buy, you need to be careful. Inflatables are notorious for being energy vampires. Because they're essentially made of vinyl and air, they have almost zero insulation value.
While a hard-shell tub might use its thick foam to keep the water warm for hours after the heater shuts off, an inflatable tub starts losing heat the second the heater stops. In many cases, owners of inflatable tubs find that they end up paying the difference in purchase price back to the electric company within a year or two. If you're wondering how much electricity does a hot tub use when it's an inflatable model, the answer is usually "a lot more than you'd expect."
The "always on" vs. "heat as you go" debate
A common mistake new owners make is turning the heater way down when they aren't using the tub, thinking they're saving money. In reality, it's usually much cheaper to keep the tub at a steady temperature.
Heating several hundred gallons of water from 80 degrees back up to 102 takes a massive amount of energy and can take several hours. It's much more efficient for the heater to kick on for a few minutes every hour to maintain the temp than to run for five hours straight right before you want to jump in. Most experts suggest only lowering the temp if you're going away for a week or more.
Practical ways to lower your electricity usage
If you've already got a tub and you're shocked by your bill, or if you're trying to prep for a new one, there are a few things you can do to keep costs down.
- Invest in a high-quality cover: About 90% of a hot tub's heat loss happens through the surface of the water. A thick, well-fitting cover with a good seal is your best defense. If your cover is heavy, waterlogged, or cracked, it's not doing its job anymore and needs to be replaced.
- Use a floating thermal blanket: These look like heavy-duty bubble wrap and sit directly on the water underneath your main cover. They provide an extra layer of insulation and significantly reduce evaporation.
- Check your filters: If your filters are clogged, your pump has to work twice as hard to move the water. This increases wear and tear on the motor and pulls more juice from the outlet.
- Be smart about the wind: If your tub is in a windy spot, it'll cool down much faster. Putting up a privacy screen or some landscaping to act as a windbreak can actually make a noticeable difference in your heating costs.
Does the age of the tub matter?
Absolutely. If you're buying a used hot tub from ten or fifteen years ago, don't expect it to be efficient. Energy standards for spas have changed significantly over the last decade. Newer models often feature multi-speed pumps that can circulate water at a very low wattage and heating systems that are designed to be much more precise.
If you're asking how much electricity does a hot tub use because you're looking at a "free" tub on a local marketplace site, just be aware that the monthly "rent" in the form of electricity might make that free tub the most expensive thing you ever own.
The bottom line on hot tub energy consumption
At the end of the day, a hot tub is a luxury item, and it does come with a recurring cost. However, for most people, the $1 or $2 a day it costs to run a modern spa is a small price to pay for the relaxation and physical benefits it provides.
As long as you buy a tub with decent insulation, keep a good cover on it, and don't try to fight the physics of heat by constantly turning the thermostat up and down, your electric bill should stay perfectly manageable. It's all about being a little proactive with maintenance and making sure you aren't literally letting your money evaporate into the cold night air.