| according to furnace manufacturer's recommendations | 5 | other |
| along with a disposable filter | 2 | other |
| furnace → have → filter | 11 |
| furnace → use → filter | 4 |
| furnace → have → permanent filter | 3 |
| negative | neutral | positive |
| 0.267 | 0.674 | 0.059 |
| Raw frequency | 18 |
| Normalized frequency | 0.387 |
| Modifier score | 0.875 |
| Perplexity | 479.574 |