The short answer: for a modern, well-insulated hot tub in North Carolina, most owners can expect roughly $20-$50 a month in added electricity — about a dollar a day, give or take. Older spas, poor insulation, heavy use, or bargain covers can push that higher. And thanks to our mild winters, running a hot tub here costs meaningfully less than it does up north.
Your exact number depends on a handful of factors you can actually control. Here is what moves the needle.
What Determines Your Hot Tub’s Energy Cost?
Insulation quality. Full-foam insulation between the shell and cabinet is the biggest efficiency difference between spas.
Cover condition. Heat escapes from the water’s surface first — a dense, well-sealed cover is your number one defense.
Hot tub size. More water takes more energy to heat and hold at temperature.
Temperature setting. Every degree you maintain costs energy; small reductions add up.
Outside temperature. Cold snaps make the heater work harder — a smaller issue in NC than in most states.
Your electric rate. NC residential rates hover around the low-to-mid teens per kWh; check your bill for your exact rate.
Should You Leave a Hot Tub On All the Time?
Yes — and this surprises most new owners. Hot tubs are designed to stay on 24/7, and it is the most efficient way to run one. Once water reaches temperature, holding it there takes only a small amount of energy. Cooling the spa down and reheating it costs more, because heating cold water is far more energy-hungry than maintaining warm water — and a full reheat can take four to twelve hours, so the spa would not even be ready when you want it.
The smarter play is to leave it on and manage the temperature:
Use economy mode during low-use stretches — it limits heating to filtration cycles.
Drop the setpoint a few degrees during the week if you are a weekend soaker, then bump it back up a few hours before you get in. Just do not go below 80°F.
Keep it heated in winter. Warm, circulating water also protects your plumbing from freeze damage during cold snaps — repairs from frozen pipes are expensive and usually not covered by warranty.
What Is the Cheapest Way to Cut Hot Tub Energy Costs?
Start at the top: your cover. The water’s surface is where heat escapes fastest, so the cover does more for your power bill than any other accessory.
Choose a cover with high-density, tapered foam — it retains heat better and sheds rain and the occasional NC snow.
Make sure it fits snugly and seals well. A sagging, waterlogged cover is an energy leak; covers typically last five to seven years before they need replacing.
Add a floating thermal blanket under the cover. It sits right on the water, holding in heat and reducing condensation.
Beyond the cover, keep your filters clean (a clogged filter makes the pump work harder), run filter cycles on a sensible schedule — twice a day for about two hours is the standard starting point — and use your spa’s freeze-protection setting during winter cold snaps. Prefer to hand it off? Our SpaPro service keeps your spa running at its best.
Does North Carolina’s Climate Help?
It genuinely does. Heating costs climb as the gap between your water temperature and the outside air widens. An owner in Minnesota fights sub-zero air for months; in most of North Carolina, winter lows are far gentler and shorter-lived. That means lower winter heating costs and a spa you will comfortably use all twelve months — arguably the best climate case for hot tub ownership: cool enough to crave a soak, mild enough to keep it affordable.
Shopping with efficiency in mind? The American Whirlpool and Vita Spa models on our floor are built by MAAX with insulation engineered for climates far colder than ours.
Frequently Asked Questions
How much does a hot tub raise your electric bill?
For a modern insulated spa in NC, plan on roughly $20-$50 a month depending on size, settings, and usage. Energy-efficient models with quality covers land at the low end.
Is it cheaper to turn a hot tub off between uses?
Almost never. Reheating cold water costs more than maintaining temperature, and it takes hours. Lower the temperature instead of shutting down.
Do energy-efficient hot tubs really make a difference?
Yes. Full-foam insulation, efficient pumps, and a quality cover compound over years of ownership — often the difference between a spa you barely notice on the bill and one you do.