Intro
The Epic 8520 and Epic 8640 are the same robotic cleaner platform from Polaris, built on identical cyclonic vacuum technology and running the same cleaning modes. The choice between them comes down to pool length, cable reach, brush configuration, and whether you want a caddy included.
Both climb walls, clean floor, wall, and waterline, and use a large canister filter with a transparent lid rated for 4 liters of debris. Neither model is a step up in cleaning technology over the other — the differences are sizing and hardware for reaching a bigger pool.
If you know your pool's length and whether you already own a caddy, the decision is straightforward. The rest of this page lays out where the two units actually diverge.
Side by side
| Spec | Epic 8520 | Epic 8640 |
|---|---|---|
| Pool Size | Up to 40 ft | Up to 50 ft |
| Brush System | Front Dual-Traction Double Helix Brushes | Double Helix Brushes (front and rear) |
| Cable Length | 50 ft | 60 ft |
| Cable Type | Standard (No Tangle-Reducing Swivel) | Swivel (Tangle-Reducing) |
| Shipping Weight | 30 lb | 40 lb |
| Shipping Dimensions | 22 × 21.5 × 14.5 in | 22 × 22 × 18.5 in |
| Caddy Included | No | Yes (Premium) |
On everything else the spec sheets list the two are identical: cleaning coverage and modes, wall climbing, cyclonic vacuum, pool surfaces, filter type and 4 liter canister, 120V / 60 Hz power, 22 lb cleaner weight, and 16 W × 17 D × 12 H in product dimensions.
Epic 8520
The Epic 8520 is sized for pools up to 40 ft and ships with a 50 ft standard cable — no tangle-reducing swivel. Its brush system is described as Front Dual-Traction Double Helix Brushes, and it's the only one of the two with a published Filter Size, listed as Large. It does not come with a caddy, and its shipping weight is 30 lb with shipping dimensions of 22 × 21.5 × 14.5 in.
Epic 8640
The Epic 8640 is built for pools up to 50 ft and pairs that with a longer 60 ft cable that includes a tangle-reducing swivel — a meaningful difference if your cleaner will be uncoiling and recoiling cable across a longer run. Its brush system is listed as Double Helix Brushes on both the front and rear. It ships with a Premium caddy included, and its shipping weight (40 lb) and shipping dimensions (22 × 22 × 18.5 in) are larger, consistent with the caddy in the box.
The verdict
Choose the Epic 8520 if your pool is 40 ft or under and you don't need a caddy — it covers that size with a 50 ft cable and costs less to ship. Choose the Epic 8640 if your pool runs up to 50 ft, since the 8520's cable and rated pool size top out shorter. The 8640 also makes sense if you want the included Premium caddy and prefer a tangle-reducing swivel cable over the 8520's standard cable, regardless of pool length.
