When installing a dryer, one of the most important considerations is properly venting the dryer exhaust. The dryer vent removes lint, moisture and other byproducts of the drying process and expels them outside of the home. Most dryer manufacturers recommend venting the dryer exhaust outdoors, rather than allowing the moisture and lint to recirculate back into the indoor air. There are two main options for routing the dryer vent – either vertically through the wall behind the dryer, or horizontally through the floor underneath the dryer.
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Wall Venting vs. Floor Venting
Wall venting and floor venting each have their pros and cons. Factors like dryer location, home construction and layout will help determine which option makes the most sense. Here is an overview of the key differences between dryer wall venting and floor venting:
Wall Venting
- Shorter vent length – Wall vents provide a more direct path outdoors.
- Better airflow – Shorter vent length and vertical path improve airflow.
- Easier access – Wall vents are easily accessible for cleaning.
- Neater appearance – Wall vents are hidden behind the dryer.
- Limitations – Wall venting may not be possible with some exterior wall or siding types.
Floor Venting
- Flexibility – Floor vents work with any wall type and dryer location.
- Longer vent – Requires elbows and longer run to reach outdoors.
- Reduced airflow – Long vent path can allow lint buildup.
- Difficult access – Accessing floor vent for cleaning is more difficult.
- Visible vent – Floor vent is visible rather than hidden.
While wall venting is often preferable due to better airflow, floor venting can allow more flexibility in dryer placement. The key is following proper floor venting guidelines to maximize airflow and prevent lint buildup.
Floor Venting Guidelines
Here are important guidelines to follow when floor venting a dryer:
Use Rigid Metal Vent
Flex foil or plastic vents are not recommended, as they are more likely to sag, trap lint and reduce airflow. Rigid metal venting is required for optimal airflow.
Minimum Vent Size
The vent diameter should be at least 4 inches. Larger vents can further improve airflow.
Shortest Vent Length
The vent run should be as short and straight as possible. Elbows and length over 35 feet can reduce airflow.
Proper Slope
The vent should slope downwards toward the outlet at 1/4 inch per foot. This allows lint to exit rather than accumulating in the vent.
| Total Vent Length | Recommended Downward Slope |
|---|---|
| 14 feet | 3.5 inches |
| 18 feet | 4.5 inches |
Adequate Access
The floor vent should be easily accessible for periodic cleaning and inspection.
Weatherproof Termination
The outdoor vent cap should have a backdraft damper and be weatherproofed to prevent rodents, insects and moisture from entering.
Seal Connections
All vent connections should be taped to seal out lint leaks and moisture.
Following these best practices for floor venting will help ensure good airflow and prevent lint buildup problems.
Floor Vent Style Options
There are three main floor vent configurations to choose from when planning a dryer floor vent:
Center Vent
A center vent is installed in the floor directly underneath the dryer. This provides the most direct path outdoors.
Side Vent
A side vent runs from the dryer to the nearby wall. An elbow fitting is used to route the vent downward through the floor.
Bottom Vent
A bottom vent attaches to the bottom-rear of the dryer and vents directly down. This style requires access underneath the dryer.
The style used will depend on the dryer location, room layout and construction. Side vents tend to be the most versatile floor venting option.
Planning Floor Vent Installation
Proper planning is crucial when installing a dryer floor vent. Here are key steps:
- Confirm the flooring – Subfloors like concrete are easiest to vent through. Wood may require extra framing.
- Choose vent location – Balance direct path outdoors with accessibility.
- Frame opening – Cut hole in subfloor and frame to vent diameter.
- Install duct – Run rigid metal duct sections to the outdoors.
- Add vent fittings – Attach elbows and terminate with a dampered vent cap.
- Seal floors – Seal openings around vent to prevent moisture issues.
- Make accessible – Leave vent exposed or use removable panels for access.
Taking time to properly plan the floor vent layout will ensure smooth installation and good dryer performance.
Considerations for Existing Homes
Adding a dryer floor vent in an existing home brings some additional considerations:
Structural Concerns
Cutting openings in existing floors must be done carefully to avoid compromising stability. Consult an engineer or architect first.
Moisture Barriers
Take precautions when penetrating foundation walls or below-grade moisture barriers.
Utilities
Watch out for plumbing, wiring and other utilities when cutting openings through existing floors.
Finishes
Removing floor and wall finishes to install the vent may drive up cost and work.
Accessibility
Make sure the vent termination is accessible for cleaning from outdoors.
Appliance Location
The washer/dryer may need to be moved to align with the vent location.
Professional Help
Consider hiring a contractor experienced in retrofit floor venting.
With careful planning and skilled installation, an effective floor vent can often be added to an existing home.
Conclusion
Floor venting for a dryer is a perfectly acceptable option when wall venting is not possible. By following best practices like rigid metal ducting, adequate slope and proper termination, a floor vent can provide effective exhaust of lint, moisture and heat. Carefully planning the vent layout and installation is key to success. With some extra care and proper materials, a floor vent can be installed in existing homes as well. Just be mindful of structural concerns, moisture barriers and accessibility. Overall, a properly installed floor vent allows flexibility in dryer placement with minimal impact on drying performance.