Ventilation FansRange Hood
Zephyr AK8400BS-ES Ventilation Fan Manual
Setup, everyday use, maintenance and troubleshooting for the 190 CFM range hood with light, with verified specifications.
- Airflow190 CFM
- Sound2 sones
- Efficacy3.9 CFM/W
- Duct size6 in. round
About the Zephyr AK8400BS-ES
The Zephyr AK8400BS-ES is a 190 CFM range hood with light certified under the ENERGY STAR program.
It is rated to move 190 cubic feet of air per minute. Its sound rating is 2 sones, which is quiet to moderate — audible, but easy to talk over. It connects to a 6 in. round duct.
The integrated LED light produces 460 lumens and draws 6.5 W, with an efficacy of 71.8 lumens per watt, a 3000 K color temperature, and a CRI of 83. It is not dimmable.
Fan efficacy is 3.9 CFM per watt, which means the motor draws roughly 49 W at 190 CFM. That efficacy is higher than 28% of the 86 Range Hood models in our database.
Specifications
| Brand | Zephyr |
|---|---|
| Model number | AK8400BS-ES |
| Fan type | Range Hood |
| Rated airflow | 190 CFM |
| Fan efficacy | 3.9 CFM/W |
| Sound level (highest rated) | 2.0 sones |
| Number of speeds | 2 |
| Duct connection (round) | 6.0 in. |
| Integrated light | Yes |
| Lighting technology | LED |
| Light output | 460 lumens |
| Light power | 6.5 W |
| Luminaire efficacy | 71.8 lm/W |
| Color temperature | 3000 K |
| Color rendering index (CRI) | 83 |
| Rated light-source life | 49,000 hours |
| Dimmable light | No |
| ENERGY STAR Most Efficient | No |
Safety information
- Turn off power at the circuit breaker before installing, wiring or cleaning the fan, and confirm it is off with a non-contact voltage tester.
- Install and wire the fan in accordance with the instructions and local electrical and building codes. If you are unsure, hire a licensed electrician or HVAC contractor.
- Always duct the fan to the outdoors. Never terminate exhaust in an attic, crawl space, soffit vent or wall cavity — trapped moisture and grease cause mold, rot and fire risk.
- Never leave cooking unattended, and keep grease filters clean — grease buildup in the hood or duct is a fire hazard. In a grease fire, turn off the burner and smother the flames with a lid or baking sheet; never use water. If the fire does not go out immediately, leave the house and call the fire department.
- Do not use the fan to exhaust explosive or flammable vapors.
Installation and first-time setup
- Confirm the mounting height
Install the hood at the height above the cooktop specified in the installation manual — commonly 24–30 in. — to balance capture and head clearance. Gas cooktops often need more clearance than electric.
- Check the airflow
Building codes typically require at least 100 CFM for kitchen exhaust. This hood is rated at 190 CFM; heavy cooking or high-output gas burners benefit from more capture.
- Route the duct
Connect the 6 in. round duct with smooth metal duct, sealed with foil tape. Avoid plastic or foil flex duct, keep elbows to a minimum, and terminate at a wall or roof cap with a backdraft damper.
- Mount and wire
Secure the hood to studs or blocking with the supplied hardware and connect power as the wiring diagram shows. Install the grease filters before first use.
- Test
Run each speed and the light, and check outdoors that the damper opens.
Using your range hood
Getting the best capture
Switch the hood on a few minutes before you start cooking so an air current is established, use the rear burners when possible because they sit directly under the hood, and leave it running for 10–15 minutes after cooking to clear lingering moisture and odors.
Using the light
The integrated LED light produces about 460 lumens from 6.5 W. The light is not dimmable, so do not connect it to a dimmer switch. The fan and light can usually be wired to separate switches.
Care and maintenance
| When | What to do |
|---|---|
| Every month | Remove the metal grease filters and wash them in hot, soapy water or in the dishwasher if the manual allows. Dry before reinstalling. |
| Every 3–6 months | Replace the charcoal filter if the hood is installed in recirculating mode. |
| Every 3 months | Wipe grease from the hood interior, fan housing and underside with a degreasing cleaner. |
| Every year | Check outdoors that the damper flap opens freely and the exterior cap is clear of lint, nests and debris. |
| As needed | Clean the light lens. The light source is rated for about 49,000 hours. |
| Every few years | Inspect accessible duct runs for disconnected joints, crushed sections or condensation. |
Troubleshooting
Weak airflow and excess noise are almost always caused by the duct system rather than the fan. Turn off power at the breaker before removing the grille or touching the motor.
| Problem | Possible cause | What to try |
|---|---|---|
| Fan runs but moves little air | Damper stuck closed; duct crushed, disconnected or too long; dirty grille or filter. | Check the exterior damper and cap, inspect the duct, and clean the grille or filters. |
| Louder than expected | Restrictive or undersized duct; loose grille; housing not secured. | Use duct at least as large as the collar (6 in. round), tighten the grille and mounting screws. |
| Rattling or flapping sound | Backdraft damper fluttering in wind; loose duct. | Secure the duct and check that the damper closes fully; a wall cap with a better damper may help. |
| Water dripping from the grille | Condensation in an uninsulated duct; duct sloped back toward the fan. | Insulate the duct in unheated spaces and slope it toward the exterior. |
| Fan will not start | Breaker off; switch or timer failed; motor plug loose in the housing. | Check the breaker, test the switch, and with power off confirm the motor is plugged into its receptacle. |
| Cold drafts from the fan when off | Damper not closing; unsealed housing. | Free or replace the damper and seal around the housing. |
| Smoke and odors escape the hood | Fan started too late; front burners used; filters clogged. | Start the hood earlier, cook on rear burners, use a higher speed and clean the filters. |
| Light flickers or buzzes | Incompatible dimmer; loose connector. | Use a compatible dimmer or a standard switch, and reseat the light connector with power off. |
Energy use and running costs
Ventilation fan certification lists airflow and efficacy rather than annual energy use. From 190 CFM at 3.9 CFM/W, the Zephyr AK8400BS-ES draws roughly 49 W. The table estimates yearly use at an average electricity price of $0.17 per kWh.
| Scenario | Power | Energy per year | Cost per year |
|---|---|---|---|
| Cooking, 1 h/day | 49 W | 17.8 kWh | $3.02 |
| Light on, 3 h/day | 6.5 W | 7.1 kWh | $1.21 |
The motor is only part of the cost: every cubic foot exhausted is replaced by outdoor air that must be heated or cooled. Run the hood while cooking and for 10–15 minutes afterward, then switch it off.
Frequently asked questions
How many CFM is the Zephyr AK8400BS-ES?
It is rated at 190 CFM.
How loud is the Zephyr AK8400BS-ES?
It is rated at 2 sones, which is quiet to moderate — audible, but easy to talk over. Restrictive ductwork can make any fan louder than its rating.
What size duct does the Zephyr AK8400BS-ES need?
It has a 6 in. round duct connection. Use duct at least that size all the way to the exterior cap; reducing it cuts airflow and raises noise.
How much electricity does the Zephyr AK8400BS-ES use?
With an efficacy of 3.9 CFM/W it draws roughly 49 W at 190 CFM. Running one hour a day costs about $3.02 a year at $0.17/kWh.
Does the Zephyr AK8400BS-ES have a light?
Yes. It has an integrated light producing about 460 lumens at 3000 K; it is not dimmable.
Can the Zephyr AK8400BS-ES vent into the attic?
No. Range hood exhaust must be ducted to the outdoors through a wall or roof cap with a damper. Venting into an attic or soffit deposits grease and moisture in the building.
Sources and disclaimer
Specifications on this page come from the ENERGY STAR certified ventilation fans dataset published by the U.S. Environmental Protection Agency (record certified March 9, 2023), retrieved October 7, 2026.
The setup, operating, maintenance and troubleshooting guidance is written by ManualHarbor's editors for this specific product type and configuration. It is an independent guide — not a reproduction of the manufacturer's manual — and ManualHarbor is not affiliated with Zephyr. Always follow the safety instructions, installation requirements and warranty terms supplied with your unit, and contact Zephyr or an authorized service provider for warranty repairs and replacement parts.
Running-cost figures use assumed U.S. average utility prices and are estimates for comparison only. See our editorial methodology for details.
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