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Harmonic Heating & Air Conditioningstarstarstarstarstar4.9 / 5

233 Total Reviews /files//harmonic-logo-footer.png630-999-9008$10S187 Schoger Dr Suite #54, Naperville IL

4SCU20LX Pro Series 20 SEER Split AC

The 4SCU20LX variable-capacity air conditioner is the perfect example of Armstrong Air’s commitment to providing you with maximum control of your home temperatures' energy use and air quality. With its ability to adjust cooling output with extreme precision' the 4SCU20LX can keep your home exactly how you want it from summer to summer. All while using up to 50% less energy than a standard air conditioner.

Pair this model with a Pro Series™ variable speed furnace and a Comfort Sync thermostat' for optimum performance. With the Pro Series' you’re in control of every aspect of your home’s climate' as well as your energy costs.

  • Comfort Sync Thermostat When you pair this model with the Comfort Sync thermostat' the system will continuously monitor internal components for optimum performance. Comfort Sync puts you in total control of your home environment with remote temperature adjustment from anywhere in the world' even your couch' via smartphone app. When Comfort Sync detects that repairs and regular maintenance are needed' it alerts you or your dealer instantly' so your perfect environment never ends.
  • True Variable-Capacity Cooling Rather than running at one or even two speeds' the 20LX Inverter-Driven Scroll Compressor changes its speed in small' precise increments and adjust cooling up and down like a dimmer switch. So temperatures are held exactly where you want them' even in extremely hot weather.
  • Integrated Compressor Protection Integrated Compressor Protection: The combination of both high and low pressure switches give additional reliability to each Armstrong Air cooling unit. The high pressure switch prevents operation in the event that refrigerant pressures exceed safe levels' protecting the compressor. In the event that your unit does not have enough refrigerant' the low pressure switch prevents the unit from drawing in moisture and other contaminants while operating.
  • MHT™ Technology Armstrong Air’s proprietary heat transfer system. The coil features rifled tubing to enhance refrigerant flow' while lanced coil fins increase surface contact between metal and air. They combine for maximum heat transfer and efficiency.
  • Sound Reduction A swept-wing fan blade design reduces turbulence' while a heavy-duty compressor blanket further reduces sound levels.
  • Communicating Control Board Your Armstrong Air® 4SCU20LX continuously monitors internal components for optimum performance and fault prevention' and notifies you and your dealer if repairs or maintenance are needed.
MODELCooling Cap.
Charge Oz.
Line SizeDimensions
Weight Lbs.
4SCU20LX124P24.0 20.0 113 3/8-3/4 27.5x37.8x35.8 243
4SCU20LX136P34.4 20.0 134 3/8-7/8 27.5x37.8x35.8 245
4SCU20LX148P46.0 20.0 154 3/8-7/8 43.75x27.8x35.8 287
4SCU20LX160P57.0 19.0 207 3/8-1-1/8 43.75x27.8x35.8 321

Warranty Information

  • All Parts for 120 months - With prompt online registration
  • Compressor for 120 months -

Available Documents


We customize your comfort by making your home smarter, healthier and more efficient. Your peace of mind is as important to us as your comfort.

That's why every product us backed by warranties as robust and dependable as the products themselves.

Every piece of heating & cooling equipment is eligible for a 12-Year Parts Warranty, when you join the "Rock*Star Maintenance Program".

All other products are eligible for the 12-Year Parts Warranty.

Ask for details, terms, and conditions. All product warranties are registered by Harmonic within 30 days of purchase.

on all equipment repairs, indoor air quality & comfort items

Including humidifiers, air filters, air cleaners, thermostats and more! 12 year parts and labor warranty requires joining Rock*Star Maintenance Program. Ask for details, terms, and conditions.

The "Exclusive 12-year Parts & Labor Warranty" covers parts and labor cost from the time of purchase. "Exclusive 12-year Parts & Labor Warranty" requires annual maintenance to be performed by Harmonic Heating & Air Conditioning beginning immediately from the time of purchase. Maintenance must be performed annually during the initial 12-year coverage term in order to uphold warranty status. If annual maintenance is missed or not performed by Harmonic Heating & Air Conditioning, the "Exclusive 12-year Parts & Labor Warranty" becomes void immediately. Warranty coverage defaults to a 10 year part warranty and a 2 year labor warranty from the time of purchase. Warranty is registered to the purchaser and is not transferable.


when you purchase a Furnace or Air Conditioner from Harmonic!