Nadair SD-659-22SF Super Duty HEPA Central Vacuum Power Unit, 659 AW, 22L

Quick Summary

The Nadair SD-659-22SF is a Super Duty central vacuum power unit with 659 airwatts, 144.9 inches of water lift, and 135.8 CFM of airflow. Its 22 L aluminum canister, hybrid filtration, self-cleaning True HEPA filter, and soft-start/stop motor technology make it a substantial whole-house vacuum option.

Authorized Nadair Dealer Ace Vacuums can help you compare this central vacuum system with your existing piping and choose a compatible hose and attachment kit. The unit is designed for residential installation and includes a 15-year parts warranty on the motor, body, housing, electronic module, and dust bin, plus one year of labor.

Quick Highlights

• 659 airwatts with 144.9 inches of water lift and 135.8 CFM airflow
• 65 dB operating noise with noise-isolating foam and an included external muffler
• 22 L / 5.8 gal bottom-load aluminum canister
• Hybrid operation with a disposable bag or bagless cyclonic filtration
• 15-year parts warranty plus one year of labor for residential use

Product Overview

The Nadair SD-659-22SF is built around a 6.6-inch, two-stage Ametek Lamb by-pass semi-commercial-grade motor. It produces 659 airwatts, 144.9 inches of water lift, and 135.8 CFM, giving the central vacuum power unit strong suction and airflow for connected cleaning inlets.

This model uses a hybrid filtration design. You can operate it with a disposable triple-layer filtration bag or without a bag, while the True HEPA self-cleaning polypropylene filter remains installed. Nadair states that the filtration system filters up to 99.99 percent.

The 22 L / 5.8 gal aluminum canister loads from the bottom for easier removal wherever the unit is installed. Aluminum is rustproof, lightweight, and smooth, while dual side air intakes make it easier to connect the unit to an existing piping network.

At 65 dB, the SD-659-22SF includes noise-isolating foam and an external muffler for additional sound reduction. Soft-start/stop technology is designed to extend motor life by 20 percent, and a three-second delay helps clear the hose and piping after shutoff.

Expert Recommendation

This model suits homeowners who want a durable central vacuum power unit with hybrid filtration, a 22 L canister, and a residential warranty that covers the motor and main housing components for 15 years. It is also a practical choice when the home already has compatible standard 2-inch outside-diameter PVC central vacuum piping.

The smaller ST-700-25H provides 700 airwatts and higher 140.2 CFM airflow in a 25 L canister, while the HD-750-22H offers 750 airwatts, 146 inches of water lift, and 141.2 CFM at the same 22 L capacity. Those models may be a better fit for shoppers prioritizing higher published performance numbers over the SD-659-22SF's True HEPA self-cleaning filtration claim.

If you want more capacity, the SD-659-32SF keeps the same 659 airwatts, 144.9 inches of water lift, 135.8 CFM, and 65 dB rating while increasing the canister to 32 L. Ace Vacuums can help size the unit for the home and piping run rather than relying on a square-foot coverage estimate.

Best For

Hybrid Filtration

The unit can run with a disposable bag or in bagless mode, while its True HEPA self-cleaning filter stays installed for both operating options.

Allergy-Conscious Households

Nadair states that the cyclonic self-cleaning filtration system filters up to 99.99 percent, and the included True HEPA filter supports the hybrid design.

Existing Piping Networks

Dual side air intakes and compatibility with standard 2-inch outside-diameter PVC central vacuum piping support replacement or new installation work.

Noise-Aware Homes

The 65 dB noise rating is paired with noise-isolating foam and an external muffler for additional noise reduction.

Frequent Whole-House Cleaning

The 22 L / 5.8 gal bottom-load canister provides substantial collection capacity and is designed for convenient removal.

Long-Term Residential Use

Soft-start/stop technology is designed to extend motor life by 20 percent, and the residential warranty provides 15 years of parts coverage on listed components.

Not Ideal For

• It is not ideal for shoppers who want a complete cleaning package because the hose and attachment kit are sold separately.
• The unit requires a dedicated individual 15 A branch circuit and qualified electrical installation, so it is not a plug-in replacement for a portable vacuum.
• Homeowners who prefer the highest published airflow or suction numbers may prefer the HD-750-22H or another higher-output Nadair model.
• The 22 L canister requires installation space and may not be the right choice if a larger 32 L canister would better suit the cleaning schedule.

Key Features

• 659 Airwatts: The two-stage motor system is rated at 659 airwatts for central vacuum cleaning.
• Strong Suction: Published performance is 144.9 inches of water lift and 135.8 CFM.
• Hybrid Filtration: Use the system with a disposable bag or without a bag using the cyclonic filtration design.
• True HEPA Filter: One True HEPA self-cleaning polypropylene filter is included and must remain installed.
• 22 L Canister: The 22 L / 5.8 gal aluminum canister uses a convenient bottom-load design.
• Soft Start/Stop: The motor starts and stops gradually, with Nadair stating that this extends motor life by 20 percent.
• Noise Isolation: Noise-isolating foam and an external muffler support the 65 dB silent-system design.
• LED Indicator: The LED indicator displays unit status and reminds you to empty the canister.
• Dual Air Intakes: Dual side air intakes simplify connection to an existing piping network.

What Makes This Model Stand Out

The SD-659-22SF combines a semi-commercial-grade Ametek Lamb by-pass motor with a hybrid filtration system that can be used bagged or bagless. That flexibility lets homeowners choose the operating method that best fits their routine while keeping the included True HEPA self-cleaning filter in place.

Its design also addresses everyday ownership details. The bottom-load aluminum canister is easy to remove, the LED provides a canister-emptying reminder, soft-start/stop technology is intended to extend motor life, and the included external muffler works with internal noise-isolating foam to reduce operating sound.

Product Comparisons

SD-659-22SF vs HD-750-22H

Both models have a 22 L canister and a 65 dB rating. The SD-659-22SF provides 659 airwatts, 144.9 inches of water lift, and 135.8 CFM with filtration stated up to 99.99 percent, while the HD-750-22H provides 750 airwatts, 146 inches of water lift, and 141.2 CFM with filtration stated up to 99.97 percent.

SD-659-22SF vs SD-659-32SF

These two Super Duty models share 659 airwatts, 144.9 inches of water lift, 135.8 CFM, and a 65 dB rating. The SD-659-22SF has a 22 L / 5.8 gal canister, while the SD-659-32SF increases capacity to 32 L / 8.45 gal.

Central Vacuum vs Portable Vacuum

A central vacuum power unit sits in a garage or basement instead of being carried from room to room. Its exhaust can be vented outdoors, and the user handles the hose and cleaning tools rather than moving a heavy portable machine.

Bagged vs Hybrid Operation

The SD-659-22SF can use a disposable bag or operate without a bag using its cyclonic filtration system. The True HEPA self-cleaning filter must remain installed in either mode and must not be washed.

Questions Buyers Commonly Ask

Can this central vacuum use my existing piping?

The unit fits existing standard 2-inch outside-diameter PVC central vacuum piping meeting ASTM F2158. Ace Vacuums can help check the piping run and confirm the rest of the installation requirements.

Can I use it without a disposable bag?

Yes. This is a hybrid system that can be used with or without a disposable filtration bag. The True HEPA self-cleaning filter must still be installed when operating bagless.

Is the filter washable?

No. The Super Duty True HEPA self-cleaning polypropylene filter must not be washed because washing may clog it and void the warranty. Clean or replace it when the canister is emptied or after every three bags, following the manual's care instructions.

Does the system include a hose and tools?

No hose or attachment kit is listed as included. The hose and tools are sold separately and must match the home's low-voltage or electric inlet configuration.

How much installation space does it need?

The unit measures 13.25 inches deep by 25.39 inches high by 17.25 inches wide. The manual calls for a well-ventilated, weather-protected location with 6 inches of clearance on all sides.

Technical Specifications

Installation Notes

• Install the unit indoors in a well-ventilated, weather-protected location; do not install it outdoors.
• Maintain 6 inches of clearance around all sides of the power unit.
• Connect it to a dedicated individual 15 A branch circuit at 110-120 VAC and 60 Hz. Do not use an extension cord or adapter.
• Use the 72-inch grounded power cord and have electrical work handled by a qualified electrician. The warranty requires proof of purchase and an installation invoice from a qualified electrician.
• Exhaust venting outdoors is recommended where the installation allows it.
• The unit fits standard 2-inch outside-diameter PVC piping. Low-voltage wire is needed when using a hose with an on-off switch.

Maintenance Tips

• Empty the canister or replace the disposable bag two or three times per year, with actual frequency depending on use.
• Use FD-22.5L-3NAD bags for the 22 L canister when operating in bagged mode.
• Clean or replace the True HEPA filter whenever the canister is emptied or after every three bag changes. Do not wash the filter.
• Replace the True HEPA filter every year to maintain the warranty requirements.
• Keep the True HEPA self-cleaning filter installed at all times, including during bagged operation.

Ideal Buyers

Perfect for:

• Homeowners replacing an existing central vacuum power unit with compatible standard 2-inch PVC piping
• Households wanting the choice of disposable-bag or bagless operation
• Buyers who value a True HEPA self-cleaning filter and a stated filtration rate of up to 99.99 percent
• Residential users who want a 22 L aluminum bottom-load canister
• Homeowners prepared for dedicated-circuit electrical installation and separate hose and tool selection

Why Buy from Ace Vacuums

When you purchase from Authorized Nadair Dealer Ace Vacuums, you receive:

• Genuine Nadair central vacuum power units
• Expert help sizing the right unit for your home and piping
• Guidance on matching hoses and attachment kits to your inlets
• Genuine Nadair replacement bags and filters
• Knowledgeable customer support before and after the sale

Available Online & In-Store

The Nadair SD-659-22SF is available online and in-store through Authorized Nadair Dealer Ace Vacuums.

Visit Our Showrooms

• Fairfax, VA: 11110 Main St, Fairfax, VA 22030
• Leesburg, VA: 300 Fort Evans Rd NE, Leesburg, VA 20176

Call 703-997-9292 (ext. 1 Fairfax, ext. 2 Leesburg). Both stores are open 7 days a week to compare central vacuum systems and talk with our specialists.

Comparison Table

Pros and Cons

Pros

• 659 airwatts with 144.9 inches of water lift and 135.8 CFM airflow
• Hybrid bagged or bagless operation adds filtration flexibility
• Included True HEPA self-cleaning filter with filtration stated up to 99.99 percent
• 22 L aluminum bottom-load canister with dual side air intakes
• Soft-start/stop technology and three-second hose-and-piping clearing delay
• 15-year residential parts warranty on listed major components, plus one year of labor

Cons

• Hose and attachment kit are sold separately
• Requires a dedicated individual 15 A branch circuit and professional electrical installation
• The True HEPA filter must not be washed and requires annual replacement for warranty maintenance
• A 22 L canister may provide less capacity than the 32 L Super Duty models

Frequently Asked Questions

What is the Nadair SD-659-22SF?

It is a Super Duty Series central vacuum power unit with a 659-airwatt, two-stage Ametek Lamb by-pass motor. It has a 22 L aluminum canister and hybrid bagged or bagless filtration.

How powerful is this central vacuum system?

Nadair rates it at 659 airwatts, 144.9 inches of water lift, and 135.8 CFM of airflow.

How loud is the SD-659-22SF?

The rated noise level is 65 dB. Noise-isolating foam and an included external muffler are part of the unit's noise-reduction design.

What type of filter does it use?

It uses a cyclonic self-cleaning hybrid filtration system and includes one True HEPA self-cleaning polypropylene filter. The system can be used with or without a disposable bag, but the HEPA filter must remain installed.

Can the True HEPA filter be washed?

No. The manual specifically says not to wash the True HEPA filter because washing may clog it and void the warranty.

When should I replace the filter?

Clean or replace the filter each time the canister is emptied or after every three bag changes. Replace the True HEPA filter annually to keep the warranty in effect.

Which bags fit this model?

The 22 L SD-659-22SF uses FD-22.5L-3NAD bags. The provided manual information identifies these bags as packs of three.

How often should the canister be emptied?

Nadair's manual recommends emptying the canister or replacing the bag two or three times per year. Actual timing depends on how much the system is used.

Does it include a hose?

No hose is listed as included. The hose and attachment kit are sold separately and must match the home's inlet system.

Will it connect to standard central vacuum piping?

Yes. The unit is listed as compatible with standard 2-inch outside-diameter PVC piping meeting ASTM F2158. The existing piping and low-voltage connections should be checked before installation.

What electrical connection does it need?

The manual requires a dedicated individual 15 A branch circuit at 110-120 VAC and 60 Hz. Do not use an extension cord or adapter, and have the electrical work completed by a qualified electrician.

Can it be installed outside?

No. The manual calls for a well-ventilated, weather-protected location and says the unit should not be installed outdoors. Outdoor exhaust venting is recommended where practical.

How much clearance is required?

The manual calls for 6 inches of clearance around all sides. The listed dimensions are 13.25 inches deep by 25.39 inches high by 17.25 inches wide.

What does the soft-start/stop feature do?

It starts and stops the motor gradually. Nadair states that this technology extends motor life by 20 percent, and the unit also has a three-second delay to help clear the hose and piping.

What does the LED indicator show?

The LED indicator displays the status of the power unit and provides a reminder to empty the canister.

What does the warranty cover?

For residential use, the warranty provides 15 years of parts coverage on the motor, body, housing, electronic module, and dust bin while you own the unit, plus one year of labor. Proof of purchase and an invoice for installation by a qualified electrician are required.

Is this a bag-only central vacuum?

No. It is a hybrid central vacuum system that can operate with a disposable bag or without one. The True HEPA self-cleaning filter must be installed in both modes.