Once you own a cold plunge, the running costs are filters and water care. You can buy them once a year or as you run out.
This article does the math for one brand. For what each accessory does, start with the cold plunge accessories buying guide.
Short answer: the annual package saves about $40 over buying the same items separately. It only covers a full year if you change filters monthly.
What the package includes
The Renu Annual Maintenance Package costs $299 and contains:
- 12 Renu certified filters
- 4 two-packs of oil and dirt buoys (8 buoys)
- 4 chlorine-free sanitizer sticks
It fits the Cold Stoic Classic, Cold Stoic 2.0, and standard Siberian. Renu sells a different package for the Cold Stoic 3.0 and Aurelius.
Run the numbers
| Item | Bought separately | Cost |
|---|---|---|
| 12-pack of standard filters | $67 | $67.00 |
| Oil and dirt buoys, 2-pack | 4 x $39.99 | $159.96 |
| Sanitizing Spa Stick | 4 x $27.99 | $111.96 |
| Total | $338.92 | |
| Annual package | $299.00 | |
| Saving | $39.92 |
Prices from Renu Therapy’s site, October 8, 2026. That’s a discount of about 12%.
Will it last a year?
Here’s what the spec sheet won’t tell you. “Annual” depends on how often you change filters.
Renu says its filters last 2 to 6 weeks in home use, and that most customers change them every 2 to 3 weeks.
| Filter change interval | 12 filters last |
|---|---|
| Every 2 weeks | 24 weeks |
| Every 3 weeks | 36 weeks |
| Every 4 weeks | 48 weeks |
| Every 6 weeks | 72 weeks |
The sticks are simpler. At 3 months each, 4 sticks cover 12 months.
So at the pace Renu says most customers keep, you’d need a second 12-pack of filters ($67) before the year is out. Budget $366, not $299.
When to buy as needed
You get smaller payments and no leftovers by buying as you go. You give up the $40 saving.
It makes sense if you’re new and don’t know your filter pace yet, or if you’d skip the buoys. Without buoys, 12 filters and 4 sticks cost $178.96 bought separately, well under the package price.
When the package makes sense
Buy it if you’ll use all three items and your tub is on the compatibility list. My rule of thumb: buy as needed for the first 3 months, count the filters you used, and then decide.
Check the model first
The standard filters don’t fit the Cold Stoic 3.0, Aurelius, or Siberian Pro. Renu says so on the filter page. A discount on the wrong filters is no saving.
For choosing the tub itself, see the cold plunge buying guide.
Bottom line: the package is a modest discount, not a full year for most owners. Count your filters before you commit.
Sources
- Renu Therapy, Annual Maintenance Package product page (price, contents, compatibility), accessed October 8, 2026: renutherapy.com
- Renu Therapy, 12-Pack Maintenance Filters product page (price, compatibility, 2 to 6 week life), accessed October 8, 2026: renutherapy.com
- Renu Therapy, Oil & Dirt Absorbing Buoy (2-pack) product page (price), accessed October 8, 2026: renutherapy.com
- Renu Therapy FAQ (filter change frequency), accessed October 8, 2026: renutherapy.com
- Renu Therapy, Sanitizing Spa Stick listing (price, lifespan), checked September 2026