Top 10 Best hard start kit in 2026

Last Updated - 6/9/2026

🏆Best Choice

AMI PARTS

SPP6 Hard Start Capacitor Replacement 115V Thru 288VAC Hard Start kit for air Conditioner Units from 4,000 to 120,000(1/2 Thru 10H.P.),Increases Compressor Torque 500% by AMI PARTS

9.8

ChoiceComparer.com Score

9.8

/ 10

Outstanding

Main highlights

•【Parts Number】: The SPP6 Compressor Hard Start Booster Capacitor can save stuck compressor by increasing the compressor’s starting torque by 500%
•【Replaces part numbers】: SPP6, TJ90HS6,AP4502872,35702, DST-6, ERPP6, HS6, HS650
•【Superiority】: The solid-state relay and hard start capacitor no loose parts or complicated wiring. Just wire it across your run capacitor. Saves you a service fee from the appliance guy! Inexpensive way to fix or repair
•【Quality Guaranteed】: The replacement part is made from high quality material and well-tested by the manufacturer.Be sure to disconnect the power supply before starting maintenance
•【Excellent After-sales Service】:We are full of confidence in the quality of Our SPP6 Compressor Hard Start. We have a professional feedback team. You can give us feedback at any time during this period, and we will provide you with a satisfactory solution within 12 hours, Don’t hesitate to solve the dryer problem easily

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$14.99

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Sealed Unit Parts Co., Inc.

SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque

9.7

ChoiceComparer.com Score

9.7

/ 10

Outstanding

Main highlights

•Relay/capacitor hard start kit 500% incr starting torque
•Increased compressor starting torque. Designed for use on permanent split capacitor single phase a/C and heat pump systems
•The country of origin is china

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$14.62

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Seentech

SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque for Air Conditioner - Compatible with HVAC Compressor – Replaces SPP6, TJ90HS6,AP4502872,35702, DST-6, ERPP6, HS6, HS650

9.5

ChoiceComparer.com Score

9.5

/ 10

Outstanding

Main highlights

•MODEL NUMBER: SPP6 Hard Start Kit for Air Conditioner - REPLACES numbers: SPP6, TJ90HS6,AP4502872,35702, DST-6, ERPP6, HS6, HS650
•COMPATIBLE BRANDS: It can be used for various air conditioning compressors from 4000 BTU window units to 120000 BTU commercial units.
•PREMIUM QUALITY: The SPP6 Hard Start Kit is made from durable high quality material and well-tested by the manufacturer - Ensure long-lasting and effective performance.
•EASY TO INSTALL: The motor start capacitor and PTC thermistor in series, no loose parts or complicated wiring. It only needs to be connected in parallel with the run capacitor. It is easy to install, saves time and effort, and can save you a large amount of maintenance costs.
•𝗖𝗢𝗡𝗙𝗜𝗗𝗘𝗡𝗧 𝗣𝗨𝗥𝗖𝗛𝗔𝗦𝗘𝗦: Enjoy a 30-day return window on your purchase. Your satisfaction is our priority. If you have any questions, please don't hesitate to contact our customer service team.

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$13.87

$19.67

-29%

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Supco

Supco RCO810 3 n' 1 START Hard Start Kit , Black

9.4

ChoiceComparer.com Score

9.4

/ 10

Excellent

Main highlights

•110 To 125Vac
•Includes Relay, Capacitor, And Overload Device
•Totally Pre-Wired
•Brand Name: Supco

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$15.60

$21.25

-27%

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AMI PARTS

AMI PARTS SPP6 Hard Start Capacitor Replacement 115V Thru 288VAC Hard Start kit for air Conditioner Units from 4,000 to 120,000(1/2 Thru 10H.P.),Increases Compressor Torque 500% 2pcs

9.2

ChoiceComparer.com Score

9.2

/ 10

Excellent

Main highlights

•[Data Specification]：The SPP6 Compressor Hard Start Booster Capacitor can save stuck compressor by increasing the compressor’s starting torque by 500%. Made exactly fit for air conditioning compressors from 4000 BTU window units to 120000 BTU commercial units
•[High Compatibility]：The capacitors are used for starting and running of AC motors with frequencies of 50Hz/60Hz and are widely used in central replacement air conditioners, heat pumps, condenser fan motors, refrigerators, washing machines and compressors
•[Part Numbers]: TJ90HS6, AP4502872, HS6, HS650, 35702, DST-6, EPP6, HS6, HS650. The SPP6 replacement part is made from high quality material and well-tested by the manufacturer.Be sure to disconnect the power supply before starting maintenance
•[Superiority]: The solid-state relay and hard start capacitor no loose parts or complicated wiring. Just wire it across your run capacitor. Saves you a service fee from the appliance guy! Inexpensive way to fix or repair.Warning! - Danger of electric shock To prevent serious personal injury caused by electric shock, ensure that the power supply of electrical appliances is switched off
•[Excellent After-sales Service]: We are full of confidence in the quality of Our SPP6 Compressor Hard Start. We have a professional feedback team. You can give us feedback at any time during this period, and we will provide you with a satisfactory solution within 12 hours, Don’t hesitate to solve the dryer problem easily

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$19.99

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FRIOCASA

FRIOCASA SPP6 Hard Start Kit for Air Conditioner, Replacement 115V Thru 288VAC, Hard Start Capacitor Units from 4,000 to 120,000(1/2 Thru 10H.P.),Increases Compressor Torque 500%

9.1

ChoiceComparer.com Score

9.1

/ 10

Excellent

Main highlights

•Part Number: SPP6 hard start capacitor, suitable for rated voltage of 115 to 288 VAC for the starting motor, increase the starting torque of the compressor by 500%
•Multiple Compatibility: Suitable for various air conditioning compressors, including 4000 BTU to 120000 BTU air conditioning units, hard start kit can be used for refrigeration compressors, heat pumps, and other heavy duty or frequently started motors
•Easy and Convenient: two wire installation, Just wire it across your run capacitor. The start relay adds new life to old refrigerators and freezers by providing additional power to the compressor, avoiding low voltage starting problems
•High Quality Materials: Replacement partsare made of high quality materials and arefully tested by the manufacturer to ensurethe durability of the product. Helps with "hard start" issues, where the AC power supply is difficult to connect and suddenly shuts off after a short period of time
•Attention: Please be sure to disconnect the power before starting use to avoid the risk of electric shock

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$11.99

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Powswopx

2 Pack SPP6 Hard Start Capacitor Replacement 115V Thru 288VAC Compatible with Air Condtioning Units from 4,000 to 120,000 (Supco Relay 1/2HP-10HP 500% Increase Starting Torque)

8.9

ChoiceComparer.com Score

8.9

/ 10

Great

Main highlights

•【Part number】: SPP6 Hard Start Capacitor Replacement. SPP6 compressor hard start boost capacitor can save compressor aging by increasing compressor starting torque by 500%. Made exactly fit for air conditioning compressors from 4000 BTU window units to 120000 BTU commercial units
•【Fit】: Compatible with TJ90HS6, AP4502872, HS6, HS650, 35702, DST-6, EPP6, HS6, HS650. Widely used in air conditioner start capacitor, Air conditioner soft start, AC hard start kit, AC capacitor, hvac capacitor, hvac hard start kit etc. Compatible for All PSC Single Phase AC115V-288V
•【Easy to Fix】: Connect the two wires from the SPP6 in parallel with the run capacitor(one wire each side)without removing any original wires. Only need to be connected in parallel with the running capacitor.Easy to install, saves time and effort and can save you a large amount of maintenance costs
•【Note】: Use special"piggy back"terminal of the SPP6 if all the run capacitor terminals are being used. Install only on PSC units equipped with run capacitor⚠Be sure to disconnect the power supply before starting maintenance. Danger of electric shock To prevent serious personal injury caused by electric shock, ensure that the power supply of electrical appliances is switched off
•【Package Includes】: 2 X SPP6 Hard Start Capacitor. Replace for Appliance produces noise during startup; System takes a while to startup; Want to reduce energy consumption

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$17.99

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ATMA SUPPLY

ATMA SUPPLY CSR-U1 Hard Start Device Compressor Saver for 1- to 3-Ton AC Units

8.8

ChoiceComparer.com Score

8.8

/ 10

Great

Main highlights

•This hard start kit works on 1-2-3 tons AC units, Package includes 1 x CSR-U1 Hard Start Capacitor Kit, 1 x Cable Ties, 2 x Screws
•The compression savor uses a powerful multi-layer starting capacitor and a smart switch to give your compressor the boost it needs to start up quickly, more reliably, draw less power and save you money
•The compressor saver significantly reduces the amount of time your compressor is on high amp start-up. Using a powerful multi-layer starting capacitor and a smart switch to give your compressor the boost it needs to start up quickly, more reliably, draw less power and save your money
•Easy to install-There are only 3 color coded wires which need to be connected, the black wire will be connected to the common side if the compressor, the stripped wire will be connected to the start winding of the compressor, and the red wire will be connected to the run winding of the compressor. Or you can look up for a YouTube video how to change the parts, it's not hard at all
•For any reason you are not completely satisfied, please feel free to contact with us

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$18.99

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Supco

Supco SPP6 Hard Start Kit

8.6

ChoiceComparer.com Score

8.6

/ 10

Good

Main highlights

•Supco Brand item
•Manufacturer model SPP6
•This is a genuine replacement part
•Model number: SPP6

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$16.40

$17.38

-6%

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MIFLUS

MIFLUS SPP6 Hard Start Capacitor/SPP6 Hard Start Kit for Air Conditioner,Increases Starting Torque 500% from 4,000 BTU Window Units to 120,000 BTU Commercial Units(1/2 Thru 10 H.P.)

8.5

ChoiceComparer.com Score

8.5

/ 10

Good

Main highlights

•【Hard Start Kit For Air Conditioner Installation Instructions】Connect the two wires from the hard start kit for air conditioner SPP6/ac hard start capacitor kit in parallel with the run capacitor(one wire each side)without removing any original wires.Use special"piggy back"terminal of the SPP6 if all the run capacitor terminals are being used.Install only on PSC units equipped with run capacitor⚠Be sure to disconnect the power supply before starting maintenance
•【AC Hard Start Capacitor Kit Parts Number】SPP6 compressor hard start boost capacitor/ac hard start capacitor kit can save compressor aging by increasing compressor starting torque by 500%.Designed for use on permanent split capacitor single phase A/C and heat pump systems.Widely used in air conditioner start capacitor,Air conditioner soft start,AC hard start kit,AC capacitor, hvac capacitor, hvac hard start kit etc
•【Superiority of HVAC Hard Start Kit】The solid-state relay/hard start capacitor/ac hard start kit and the PTC thermistor are connected in series has no loose parts and no complicated wiring.Only need to be connected in parallel with the running capacitor.Easy to install hard start kit for air conditioner,saves time and effort and use our hvac hard start kit can save you a large amount of maintenance costs
•【AC Hard Start Capacitor Kit Fix Symptoms】SPP6 relay start capacitor/spp6 hard start capacitor--1.Appliance produces noise during startup 2.System takes a while to startup3⃣You want to reduce energy consumption.Compatible for All PSC Single Phase AC115V-288V
•【After Service】MIFLUS takes customer satisfaction very seriously.If you have any questions about the SPP6 hard start kit for air conditioner,please contact us through our Amazon homepage.⚠Please check whether the package is damaged due to transportation problems as soon as you receive ac hard start kit

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$13.77

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