Pentair WhisperFlo VST
#1 in Large PoolsFull review
For in-ground pools that need a bit more than a 1.5 HP pump, especially ones replacing an old WhisperFlo, where a simple keypad pump is enough.
Amazon $1,559$1,559
3.6/5
A high-flow smart pump for big pools with water features on a Pentair-footprint pad; most pools need less.
- 3.9 HPRated power
- 7.3WEF
- 39% aboveAbove ENERGY STAR minimum
- 5 yearsWarranty
Check price at Amazon$1,875
Price checked October 27, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Enough flow for large pools, spas and water features
- Drops into a Pentair WhisperFlo or IntelliFlo footprint without replumbing
- Built-in Wi-Fi with run-dry alerts, no extra hub to buy
Cons
- Priciest pump among the online brands
- No freeze protection listed
- Supply voltage not stated on the listing
The CircuPool SmartFlo Adaptive Flow family
Every CircuPool SmartFlo Adaptive Flow model we rank, smallest first. Ratings compare each against its own pool type.
| Model | Rated power | Rating | Price |
|---|---|---|---|
| CircuPool SmartFlo AF 1.3H | 1.3 HP | 3.0/5 | $1,275 |
| CircuPool SmartFlo AF 2.2H | 2.2 HP | 3.4/5 | $1,475 |
| CircuPool SmartFlo AF 2.2P | 2.2 HP | 2.8/5 | $1,475 |
| CircuPool SmartFlo AF 3.9P (this one) | 3.9 HP | 3.6/5 | $1,875 |
How it scores
The rating comes from 5 measured or published factors, each scored 0-100 against fixed reference points for its pool type. How we rank explains each one.
Specifications
| Model number | UAF3.9P-1100-5A |
|---|---|
| Efficiency ratings | |
| Pump type | In-ground (self-priming) |
| Motor | Variable speed |
| Rated horsepower (DOE) | 3.9 HP |
| Hydraulic horsepower (DOE) | 1.8 HP |
| Weighted energy factor (WEF) | 7.3 kgal/kWh |
| ENERGY STAR minimum for its size | 5.2 kgal/kWh |
| ENERGY STAR certified | Yes |
| Pump | |
| Pipe size | 2 in |
| Size (W × D × H) | 23.8 × 10.9 × 12.8 in |
| Controls | |
| Freeze protection | No |
| Wi-Fi | Built in |
| Warranty and models | |
| Warranty | 5 years |
| Warranty terms | 5-year manufacturer warranty with US-based support, as listed for any buyer. |
| Also sold as | LINGXIAO Relaax390-VS, Key Lander SWP390-VS, LX SWP390-VS, Iliving ILG8PP390-VS, Aqua Expert VSP39-Pro |
| Released | 2026-04 |
Alternatives in this pool type
Jandy ePump 2.7 HP
#3 in Large PoolsFull review
Jandy’s large-body flagship for big custom pools, where flow and a huge basket matter more than footprint.
Jandy (find a dealer)
Pentair IntelliFlo3 VSF 3 HP
#4 in Large PoolsFull review
For large pools or pools with spas and water features, where an owner wants app control and constant-flow filtering without buying an automation system.
Amazon $1,750 Leslie's $1,719.99$1,719.99
Compare
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