Fortress Power Envy 8K
For grid-tied homes with moderate backup needs that want an outdoor hybrid with export and US-based support.
Wind & Sun $3,735$3,735
The Fortress Power Envy 8K is the better hybrid solar inverter overall, rated 4.0 to 3.5. The Fortress Power Envy 8K leads on warranty, features and solar input. The PowMr SunSmart 8KP wins on value. The PowMr SunSmart 8KP costs $2,916 less ($819 vs $3,735).
PowMr SunSmart 8KP
For off-grid homes that want a lot of split-phase power and solar input for little money. Permitted installs that need a UL listing should look elsewhere.
Amazon PowMr $819$819
Prices were last checked October 23, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Fortress Power Envy 8K for warranty (10-year warranty vs 1.5-year warranty), features (UL 1741 listed, Wi-Fi app, parallel stacking, grid sell-back, generator input, battery communication vs Wi-Fi app, parallel stacking, battery communication; not UL 1741 listed) and solar input (13,000 W of panels, 600 V max, 2 MPPTs vs 10,500 W of panels, 500 V max, 1 MPPT).
- Choose the PowMr SunSmart 8KP for value ($102 per kW of continuous output vs $467 per kW of continuous output).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 120/240 V split-phase hybrid solar inverter; a clear win is highlighted. How we rank explains each one.
| Factor weight | Fortress Power Envy 8K | PowMr SunSmart 8KP |
|---|---|---|
| Overall rating | 4.0/5 | 3.5/5 |
| Value 30% | 47 $467 per kW of continuous output | 100 $102 per kW of continuous output |
| Solar input 20% | 74 13,000 W of panels, 600 V max, 2 MPPTs | 51 10,500 W of panels, 500 V max, 1 MPPT |
| Efficiency 20% | 63 94% peak efficiency, 70 W idle | 45 93% peak efficiency |
| Features 15% | 100 UL 1741 listed, Wi-Fi app, parallel stacking, grid sell-back, generator input, battery communication | 45 Wi-Fi app, parallel stacking, battery communication; not UL 1741 listed |
| Warranty 15% | 100 10-year warranty | 6 1.5-year warranty |
Specifications
| Fortress Power Envy 8K | PowMr SunSmart 8KP | |
|---|---|---|
| Output | ||
| Output voltage | 120/240 V split-phase | 120/240 V split-phase |
| Continuous output | 8,000 W | 8,000 W |
| Surge | 16,000 W | 16,000 W |
| Peak efficiency | 94% | 93% |
| CEC efficiency | 96.5% | - |
| Idle draw | 70 W | - |
| Transfer time | 20 ms | 10 ms |
| Parallel units | Up to 10 units | Up to 6 units |
| Solar | ||
| Max PV power | 13,000 W | 10,500 W |
| Max PV voltage (Voc) | 600 V | 500 V |
| MPPT range | 170 to 500 V | 125 to 425 V |
| MPPT trackers | 2 | 1 |
| PV current per tracker | 25 A | 27 A |
| Runs without battery | Yes | - |
| Battery and grid | ||
| Battery voltage | 48 V | 48 V |
| Battery types | Lithium, lead-acid | Lithium-ion, lead-acid |
| Max charge current | 167 A | 160 A |
| AC charge current | - | 100 A |
| Battery communication | Yes | Yes |
| Grid sell-back | Yes | No |
| Generator input | Yes | No |
| UL 1741 | UL 1741 SB | No |
| Build | ||
| App monitoring | Included | Included |
| Enclosure | IP65 (NEMA 4X) | IP20 |
| Dimensions | 29.5 x 20.5 x 11.23 in | 472 x 412 x 130 mm |
| Weight | 110 lb | 35.3 lb |
| Warranty | 10 years | 1.5 years |
| Released | 2023-06 | - |