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4.8 out of 5 stars. 9 reviews
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Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater

  • New Arrival

Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater

Item # 615818299

Keystone Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater
Keystone Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater
$799.99
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  • New Arrival

Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater

Item # 615818299

Keystone Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater
Keystone Keystone Single Zone Core 9,000 BTU 230 V 400 sq. ft. 21 SEER2 Ductless Mini Split Air Conditioner & Heater

$799.99
or
or
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$34/mo.†  suggested payments with 24 Months Financing or earn $39 in Rewards+ on this purchase.
Valid 11/02/2026 - 11/29/2026

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The Keystone Core 9,000 BTU Mini Split AC and Heating System delivers quiet, energy-efficient comfort for bedrooms, offices, and other spaces up to 400 sq. ft. This 230V Energy Star-certified ductless system includes indoor and outdoor units and is designed for professional installation to help ensure proper setup, optimized performance, and reliable long-term use. With up to 21 SEER2 efficiency, advanced inverter technology, and an optimized R32 refrigerant system, it continuously adjusts output to help reduce energy use while maintaining steady indoor comfort without bulky ductwork.

Built for dependable year-round performance, this mini split operates in outdoor temperatures ranging from 5°F to 127°F for reliable comfort through changing seasons. Indoor sound levels as low as 28 dB make this Core system quieter than a whisper. Multiple modes including Cool, Heat, Dry, Fan, Turbo, Sleep, and ECO allow for customized comfort throughout the day.

Wi-Fi, enabled and app control provides convenient remote access. Keystone customer service helps coordinate professional installation to save time and effort, while durable construction and an up to 7-year warranty support trusted, reliable performance.

  • Ultra High Efficiency for Real Energy Savings: This Energy Star-certified Core series delivers up to 21 SEER2 performance, using advanced inverter technology to continuously adjust output, reduce energy waste, and keep temperatures steady.
  • Powerful, Consistent Heating That Eliminates Cold Spots: Designed to maintain consistent operation in temperatures ranging from 5°F to 127°F, this 230V mini split AC provides stable heating and cooling for bedrooms, offices, and spaces up to 400 sq. ft.
  • Whisper Quiet Indoor Operation: Indoor sound levels as low as 28 dB make this Core system quieter than a whisper, ideal for bedrooms, offices, and any environment where peace and quiet matter. You feel the comfort, not the noise.
  • Complete Mini Split System for Small Rooms: This 9,000 BTU system includes indoor and outdoor units for spaces up to 400 sq. ft.; professional installation is required for proper setup, optimized performance, and long-term reliability.
  • Smart Comfort Controls: Multiple comfort modes, including Cool, Heat, Dry, Fan, Turbo, Sleep, and ECO, give users full control of their environment. Inverter precision minimizes temperature swings for steady, reliable comfort.
  • Year-Round Build Quality You Can Trust: Constructed with high-grade components, an optimized refrigerant system, and backed by an up to 7-year warranty, this unit is designed for reliable seasonal use and consistent year-round performance.
  • Efficient R32 Refrigerant System: This Core mini split uses R32 refrigerant to support dependable cooling and heating performance, while the optimized system design helps maintain efficient, consistent comfort season after season.
  • Professional Installation Made Easier: Keystone customer service helps coordinate professional installation, saving you time and effort while helping ensure your system is properly set up for efficient, reliable performance.
  • *NOTE item is shipped in 2 separate boxes*

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Reviews

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1 to 4 of 9 Reviews .
1 – 4 of 9 Reviews
Review 1

Good for smaller areas

a month ago
Easy to use and a great value for the price. I’m impressed so far. It provides strong, consistent cooling, operates relatively quietly, and has been a good addition to smaller spaces. I would definitely recommend it to anyone looking for an affordable mini unit with good cooling performance. It's easy to operate, and I really like having the ability to adjust the temperature and fan settings to my preference. I haven't been able to test the heat yet since it hasn't been cold enough.

Originally posted on Sampling program

Review 1

Really cools

a month ago
This Keystone mini split unit is perfect for our above garage bonus room. It’s the perfect coverage size to keep the area cool or warm. The unit was easy to install and quite durable. There is little noise or vibration sounds.

Originally posted on Sampling program

Review 1

Works Well!

a month ago
I am so happy to have this split AC/Heat unit! We didn’t have any heat going to our house and now I can easily take the chill off in the mornings. Set up was pretty simple and it’s even easier to use than i expected. I am also extremelly happy it does both AC and Heat. It wont work for the whole house but is perfect for our living room

Originally posted on Sampling program

Review 1

Quiet and efficient unit

a month ago
I am very happy with the keystone core mini split. It came well packaged with clear installation instructions. It is a great size for my bedroom and it is nice and quiet when I use it. It is well worth the money because it will reduce my power bill while keeping us more comfortable.

Originally posted on Sampling program