WaterFurnace 3 Series Geothermal Filter Replacement Guide
Maintaining the correct air filter in your WaterFurnace 3 Series geothermal heat pump is one of the easiest ways to protect system efficiency, improve indoor air quality, and avoid unnecessary service calls.
This guide covers common WaterFurnace 3 Series filter sizes, replacement intervals, and how to choose a high-quality geothermal filter for long-term performance.
WaterFurnace 3 Series Filter Size Chart - Vertical Units
| Unit Size | Typical Filter Size | Thickness | Purchase Link |
|---|---|---|---|
|
2 Ton |
20 × 24 × 1 | 1” | View on Amazon |
|
3 Ton |
24 × 24 × 1 | 1” | View on Amazon |
|
4 Ton |
28 × 30 × 1 | 1” | View on Amazon |
|
5 Ton |
28 × 30 × 1 | 1” | View on Amazon |
|
6 Ton |
30 × 32 × 1 | 1” | View on Amazon |
WaterFurnace 3 Series Filter Size Chart - Horizontal Units
| Unit Size | Typical Filter Size | Thickness | Purchase Link |
|---|---|---|---|
|
2 Ton |
18 × 24 × 1 | 1” | View on Amazon |
|
3 Ton |
18 × 32 × 1 | 1” | View on Amazon |
|
4 Ton |
20 × 37 × 1 | 1” | View on Amazon |
|
5 Ton |
20 × 37 × 1 | 1” | View on Amazon |
|
6 Ton |
20 × 20 × 1 and 20 x 22 x 1 | 1” |
20x20x1 View on Amazon 20x22x1 View on Amazon |
Why Filter Maintenance Matters for the 3 Series
The WaterFurnace 3 Series is designed for reliable, high-efficiency geothermal performance. A clogged or incorrect filter restricts airflow, forcing the system to run longer and work harder than necessary.
- Reduced heating and cooling efficiency
- Higher monthly energy costs
- Increased wear on blower components
- Potential coil freezing or overheating
How Often to Replace a WaterFurnace 3 Series Filter
Most homeowners should replace their geothermal air filter every 3–6 months, depending on filter quality and household conditions.
Homes with pets, allergies, or heavy dust may benefit from more frequent replacement.
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