Fortress Power Envy True 12
For grid-tied or off-grid homes that want one outdoor inverter to back up the whole house and export to the grid, with US-based support.
Current Connected $4,898 Wind & Sun $4,898$4,898
The Fortress Power Envy True 12 and the Growatt SPE 12000 US are evenly matched, rated 4.2 and 4.2. The Fortress Power Envy True 12 leads on warranty, solar input and features. The Growatt SPE 12000 US wins on value. The Growatt SPE 12000 US costs $3,129 less ($1,769 vs $4,898).
Growatt SPE 12000 US
For off-grid homes that need whole-house 240 V power and a big solar array at a very low price per kW.
Self2Solar $1,769$1,769
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 True 12 for warranty (10-year warranty vs 5-year warranty), solar input (21,000 W of panels, 600 V max, 3 MPPTs vs 18,000 W of panels, 550 V max, 2 MPPTs) and features (UL 1741 listed, Wi-Fi app, parallel stacking, grid sell-back, generator input, battery communication vs UL 1741 listed, Wi-Fi add-on, parallel stacking, generator input, battery communication).
- Choose the Growatt SPE 12000 US for value ($147 per kW of continuous output vs $408 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 True 12 | Growatt SPE 12000 US |
|---|---|---|
| Overall rating | 4.2/5 | 4.2/5 |
| Value 30% | 58 $408 per kW of continuous output | 100 $147 per kW of continuous output |
| Solar input 20% | 88 21,000 W of panels, 600 V max, 3 MPPTs | 68 18,000 W of panels, 550 V max, 2 MPPTs |
| Efficiency 20% | 63 94% peak efficiency, 70 W idle | 67 95% peak efficiency, 75 W idle |
| Features 15% | 100 UL 1741 listed, Wi-Fi app, parallel stacking, grid sell-back, generator input, battery communication | 82 UL 1741 listed, Wi-Fi add-on, parallel stacking, generator input, battery communication |
| Warranty 15% | 100 10-year warranty | 44 5-year warranty |
Independent measurements
Fortress Power Envy True 12
| Tested by | Efficiency | Idle draw | Conditions |
|---|---|---|---|
| The Solar Lab | - | 80 W | About 80 W idle measured off-grid on battery only. |
Growatt SPE 12000 US
No independent test published yet.
Specifications
| Fortress Power Envy True 12 | Growatt SPE 12000 US | |
|---|---|---|
| Output | ||
| Output voltage | 120/240 V split-phase | 120/240 V split-phase |
| Continuous output | 12,000 W | 12,000 W |
| Surge | 20,000 W | - |
| Peak efficiency | 94% | 95% |
| CEC efficiency | 96.5% | 94.5% |
| Idle draw | 70 W | 75 W |
| Transfer time | 20 ms | 20 ms |
| Parallel units | Up to 10 units | Up to 9 units |
| Solar | ||
| Max PV power | 21,000 W | 18,000 W |
| Max PV voltage (Voc) | 600 V | 550 V |
| MPPT range | 230 to 500 V | 60 to 480 V |
| MPPT trackers | 3 | 2 |
| PV current per tracker | 25 A | 27 A |
| Runs without battery | Yes | Yes |
| Battery and grid | ||
| Battery voltage | 48 V | 48 V |
| Battery types | Lithium, lead-acid | Lithium, lead-acid |
| Max charge current | 250 A | 250 A |
| AC charge current | - | 250 A |
| Battery communication | Yes | Yes |
| Grid sell-back | Yes | - |
| Generator input | Yes | Yes |
| UL 1741 | UL 1741 SB | Yes |
| Build | ||
| App monitoring | Included | Optional add-on |
| Enclosure | IP65 (NEMA 4X) | IP20 |
| Dimensions | 34.2 x 20.5 x 11.2 in | 550 x 465 x 150 mm |
| Weight | 127 lb | 47.4 lb |
| Warranty | 10 years | 5 years |
| Released | 2023-04 | 2025-09 |