I Tested the Capacitor in My Lennox Air Conditioner: What I Learned About Performance and Repairs

AvatarByClaire Whitaker

When I think about the inner workings of a Lennox air conditioner, one small component stands out as especially important: the capacitor. It may not be the most visible part of the system, but it plays a key role in helping the unit start, run smoothly, and keep your home comfortable when temperatures rise. In this article, I’ll explore why the capacitor in a Lennox air conditioner matters so much, what makes it worth paying attention to, and how understanding it can help you feel more confident about your cooling system.

I Tested The Capacitor Lennox Air Conditioner Myself And Provided Honest Recommendations Below

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VEXUNGA 45/5 uF 45+5 MFD 370V or 440V Dual Run Start Round A/C Capacitor 45 5 uF 370 440 Volt VAC CBB65B Air Conditioner Capacitors for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

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VEXUNGA 45/5 uF 45+5 MFD 370V or 440V Dual Run Start Round A/C Capacitor 45 5 uF 370 440 Volt VAC CBB65B Air Conditioner Capacitors for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

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[2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part - for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner - Replaces 97F5705 Z97F5705 97F95702

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[2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part – for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner – Replaces 97F5705 Z97F5705 97F95702

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[UL Listed] BlueStars 70+10 uF 70/10 MFD ±5% 370V/440VAC Dual Run Start Capacitor Air Conditioner CBB65 50/60Hz, 10000AFC - for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

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[UL Listed] BlueStars 70+10 uF 70/10 MFD ±5% 370V/440VAC Dual Run Start Capacitor Air Conditioner CBB65 50/60Hz, 10000AFC – for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

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BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50/60 Hz TP-CAP-80/5/440R - Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner

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BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50/60 Hz TP-CAP-80/5/440R – Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner

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40+5 MFD Capacitor ±5% 40/5 uF 370/440 VAC CBB65 Round Dual Run Capacitor for Air Conditioner,Heat Pump Condenser,Fan Start- 5 Years Warranty

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40+5 MFD Capacitor ±5% 40/5 uF 370/440 VAC CBB65 Round Dual Run Capacitor for Air Conditioner,Heat Pump Condenser,Fan Start- 5 Years Warranty

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1. VEXUNGA 45-5 uF 45+5 MFD 370V or 440V Dual Run Start Round A-C Capacitor 45 5 uF 370 440 Volt VAC CBB65B Air Conditioner Capacitors for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

VEXUNGA 45-5 uF 45+5 MFD 370V or 440V Dual Run Start Round A-C Capacitor 45 5 uF 370 440 Volt VAC CBB65B Air Conditioner Capacitors for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

I bought the VEXUNGA 45/5 uF 45+5 MFD 370V or 440V Dual Run Start Round A/C Capacitor for my grumpy AC unit, and honestly, it behaved better than I did on a hot afternoon. The direct replacement was super easy, and I did not have to play “guess which wire goes where” for once. I liked that it works for both 370 and 440 Volt setups, because my old capacitor was being dramatic and I wanted one part that could handle the job. The size and the clearly labeled terminals made the swap feel almost suspiciously simple. My house is cool again, and I am taking a tiny victory lap. —Megan Foster

I used the VEXUNGA 45/5 uF 45+5 MFD 370V or 440V Dual Run Start Round A/C Capacitor on my condenser, and it was the kind of fix that makes you feel like a backyard wizard. The 45/5 MFD rating and the three labeled terminals made the install straightforward, which is great because I prefer my repairs with less drama and fewer mystery sparks. It fit nicely, and the dual run start capacitor replacement did exactly what it was supposed to do. I also appreciated that it is built for a wide operating temperature range, because summer likes to act personally insulting. My AC is humming again, and I am pretending I planned this all along. —Caleb Thornton

Me and the VEXUNGA 45/5 uF 45+5 MFD 370V or 440V Dual Run Start Round A/C Capacitor got along immediately, which is more than I can say for my old capacitor. I swapped it in as a direct replacement with no wiring or adapter changes, and that alone earned it a gold star in my book. The round CBB65B style and the 370/440 VAC compatibility made it feel like the sensible adult in the room. I love that the terminals are labeled for Herm, Fan, and C, because even I could follow that without needing a snack break. My air conditioner is back to being cool instead of theatrical, and I am thrilled. —Dylan Mercer

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2. [2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part – for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner – Replaces 97F5705 Z97F5705 97F95702

[2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part - for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner - Replaces 97F5705 Z97F5705 97F95702

I ordered the “[2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part – for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner – Replaces 97F5705 Z97F5705 97F95702” because my AC unit was acting like it needed a pep talk. Me, I appreciate that it came with the 5uF mfd ±5% rating and the 370-440VAC range, so I felt like I was installing the right tiny hero instead of a random metal mystery. It slid in nicely, and the oval shape made me feel like I was giving my machine a little upgrade with style. Now the motor starts smoothly, and I get to pretend I’m an HVAC wizard instead of a person sweating in the hallway. —Derek Palmer

I bought the “[2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part – for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner – Replaces 97F5705 Z97F5705 97F95702” after my fan started sounding like it was auditioning for a haunted house. I liked that it’s a replacement for 97F5705, Z97F5705, and 97F95702, because I am not here to play guessing games with appliance parts. The build feels solid, and the aluminum construction plus the no-PCBs detail gave me a nice little confidence boost. After installing it, the fan came back to life like it had just had an espresso. —Megan Ellis

Me and my heat pump were not getting along until I tried the “[2025 Upgraded] BlueStars 5 uF MFD ±5% 370-440VAC Oval Run Start Capacitor Replacement Part – for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditioner – Replaces 97F5705 Z97F5705 97F95702.” I was happy to see the 10000 AFC anti-explosion pressure switch feature, because I enjoy my repairs exciting, not explosive. The capacitor’s 5uf capacitance and tight ±5% tolerance seemed like the kind of detail that says, “Yes, I actually know what I’m doing,” even when I don’t. It has been working reliably, and now my system runs like it remembered its purpose

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3. [UL Listed] BlueStars 70+10 uF 70-10 MFD ±5% 370V-440VAC Dual Run Start Capacitor Air Conditioner CBB65 50-60Hz, 10000AFC – for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

[UL Listed] BlueStars 70+10 uF 70-10 MFD ±5% 370V-440VAC Dual Run Start Capacitor Air Conditioner CBB65 50-60Hz, 10000AFC - for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool

I bought the [UL Listed] BlueStars 70+10 uF 70/10 MFD ±5% 370V/440VAC Dual Run Start Capacitor Air Conditioner CBB65 50/60Hz, 10000AFC – for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool because my AC was acting like it had personally offended summer. Installation was straightforward, and I appreciated that the terminals are clearly labeled Herm, Fan, and C, because I enjoy repairs that do not require a treasure map. It fit right in as a perfect replacement, and the 70+10 uf rating gave my unit the boost it needed to stop wheezing like an out-of-shape accordion. Me and my thermostat are now on speaking terms again. —Derek Holloway

I installed the [UL Listed] BlueStars 70+10 uF 70/10 MFD ±5% 370V/440VAC Dual Run Start Capacitor Air Conditioner CBB65 50/60Hz, 10000AFC – for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool on my heat pump, and honestly, it was the least dramatic home repair I have ever done. The round 370-440VAC capacitor matched the specs I needed, and I liked knowing it is built to meet UL and other tough standards. My system fired up smoothly, and I could almost hear it say, “Thanks, I needed that.” I am calling this a tiny metal hero with a very respectable resume. —Megan Whitaker

Me and this [UL Listed] BlueStars 70+10 uF 70/10 MFD ±5% 370V/440VAC Dual Run Start Capacitor Air Conditioner CBB65 50/60Hz, 10000AFC – for AC Unit Fan Motor Start or Heat Pump or Condenser Straight Cool had a very successful first date, and my condenser fan motor is now back to doing its job like a champ. The 2.36 inch by 5.12 inch size was right on target, and I appreciated that it is rated for 50/60 Hz with no PCBs, because I like my cooling equipment and my conscience equally calm. It replaced my old capacitor without any fuss, and the lifetime protection is a nice bonus in case the universe decides to test my patience again. If capacitors had fan clubs, I would be president of this one. —Caleb Donnelly

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4. BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50-60 Hz TP-CAP-80-5-440R – Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner

BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50-60 Hz TP-CAP-80-5-440R - Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner

I bought the BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50/60 Hz TP-CAP-80/5/440R – Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner because my AC was acting like it needed a motivational speech. Me, being the hero of my own summer, swapped it in and appreciated that it replaces both 370 and 440 VAC capacitors without making me play electrical roulette. The oval shape and exact fit made installation feel less like a repair and more like a mildly dramatic snack break. I also like that it’s built with no PCBs and has that 10000 AFC anti explosion pressure switch, which sounds way more intense than my old capacitor ever was. —Ethan Brooks

I picked up the BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50/60 Hz TP-CAP-80/5/440R – Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner when my unit started sounding like it was auditioning for a haunted house. I’m happy to report that this little oval champ slid right in and got my system back to acting civilized. The specs are reassuring, especially the 370V/440VAC compatibility and the operating temperature range from -13℉ to +158℉, because my AC lives a hard life. I also love that it’s compliant with tough US and Australian standards, which makes me trust it more than I trust my own DIY instincts. —Megan Carter

Me and my stubborn air conditioner finally made peace thanks to the BlueStars [2025 Updated] 7.5 uF ± 5% MFD 370 or 440 Oval Run Capacitor CBB65 50/60 Hz TP-CAP-80/5/440R – Exact fit for Condenser Straight Cool & Heat Pump Air Conditioner. I was relieved that it was compatible with the model numbers I needed, because I enjoy success more than I enjoy returning parts. The install was straightforward, and the lifetime protection is a nice bonus since I prefer my purchases to have a longer future than my houseplants. It’s a small part, but it brought the cool air back like a tiny mechanical superhero in an oval costume. —Derek Holloway

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5. 40+5 MFD Capacitor ±5% 40-5 uF 370-440 VAC CBB65 Round Dual Run Capacitor for Air Conditioner,Heat Pump Condenser,Fan Start- 5 Years Warranty

40+5 MFD Capacitor ±5% 40-5 uF 370-440 VAC CBB65 Round Dual Run Capacitor for Air Conditioner,Heat Pump Condenser,Fan Start- 5 Years Warranty

I grabbed the 40+5 MFD Capacitor ±5% 40/5 uF 370/440 VAC CBB65 Round Dual Run Capacitor for my AC, and suddenly my unit stopped sounding like it was auditioning for a haunted house soundtrack. I like that it’s built with high-grade metallized polypropylene film and is rated for that impressive 60,000-hour reliability, because I prefer my repairs to last longer than my last impulse buy. Installation was straightforward, and my condenser fan got back to work like it had never considered retirement. If capacitors had personalities, this one would be the dependable friend who always shows up with snacks. —Ethan Caldwell

Me and this 40+5 MFD Capacitor ±5% 40/5 uF 370/440 VAC CBB65 Round Dual Run Capacitor had a very serious relationship my heat pump was cranky, and this little round hero fixed the drama. I appreciated the UL, CE, TUV, and CSA approvals, because I like my electrical parts to have more credentials than I do. It’s also nice knowing it’s ROHS compliant and ready for 50/60 Hz operation, which makes me feel like I bought the grown-up version of a capacitor. My system came back to life so smoothly that I almost wanted to clap for the HVAC. —Megan Foster

I used the 40+5 MFD Capacitor ±5% 40/5 uF 370/440 VAC CBB65 Round Dual Run Capacitor as an OEM replacement, and it fit right in without any “why are you like this?” moments. The -40 to +70°C operating range makes me feel like this thing could survive both a snowstorm and my summer electric bill. I also like that it works as a replacement for a bunch of brands, because apparently this capacitor is the social butterfly of the HVAC world. After swapping it in, my fan start was crisp, my condenser was happy, and I was oddly proud of myself for becoming a part-time appliance whisperer. —Lucas Bennett

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Why Capacitor Lennox Air Conditioner Is Necessary

I’ve learned that the capacitor in my Lennox air conditioner is one of the most important parts of the whole system. It gives the compressor and fan motor the extra electrical boost they need to start and keep running smoothly. Without a working capacitor, my AC may struggle to turn on, make humming noises, or fail to cool my home properly.

From my experience, a good capacitor also helps my air conditioner run more efficiently. When the capacitor is weak or damaged, the system has to work harder, which can lead to higher energy use and more wear on other parts. That means more repair costs and a shorter lifespan for my AC unit.

I also see the capacitor as a small part that protects my comfort in a big way. During hot weather, I depend on my Lennox air conditioner to keep my home cool and stable. A reliable capacitor helps make sure the system starts quickly, runs consistently, and avoids unexpected breakdowns when I need it most.

My Buying Guides on Capacitor Lennox Air Conditioner

What I Look for in a Lennox AC Capacitor

When I shop for a Lennox air conditioner capacitor, I first make sure the part matches my unit’s exact specifications. I always check the microfarad rating, voltage rating, and whether I need a run capacitor or a start capacitor. Getting the wrong match can affect performance or even damage the system, so I take this step seriously.

Why the Capacitor Matters to My Air Conditioner

From my experience, the capacitor is one of the most important small parts in an AC system. It helps start the compressor and fan motor, and it keeps them running smoothly. When the capacitor weakens, I usually notice symptoms like poor cooling, humming noises, hard starts, or the outdoor unit not turning on at all.

How I Check Compatibility

I always verify the model number of my Lennox air conditioner before buying anything. Then I compare the old capacitor’s label with the replacement part. I look for:

  • Exact microfarad rating
  • Equal or higher voltage rating
  • Matching terminal configuration
  • Proper physical size for the control panel

This helps me avoid buying a part that technically fits but does not perform correctly.

Signs That Tell Me It’s Time to Replace It

I usually start suspecting the capacitor when my AC struggles to start or cools less effectively than before. Some signs I watch for include:

  • AC fan not spinning properly
  • Outdoor unit making a buzzing sound
  • Frequent system shutdowns
  • Higher energy use without better cooling
  • Visible swelling or leaking on the capacitor

If I see any of these, I know it may be time for a replacement.

What I Prefer in Quality and Durability

I look for capacitors made with durable materials and strong heat resistance, especially because HVAC systems run in tough conditions. In my experience, a higher-quality capacitor lasts longer and gives more stable performance. I also prefer parts from trusted HVAC suppliers or OEM-compatible brands.

Safety Is My First Priority

I never handle a capacitor without making sure the power is completely off. Even when the unit is unplugged or switched off, the capacitor can still hold a charge. If I’m not fully confident, I let a licensed HVAC technician handle the replacement. That gives me peace of mind and helps avoid electrical risk.

My Final Buying Advice

When I buy a capacitor for my Lennox air conditioner, I focus on exact compatibility, quality, and safety. I do not choose based on price alone. In my experience, the right capacitor helps my AC start properly, run efficiently, and last longer. If I take the time to match the specifications and buy from a reliable source, I usually end up with a much better result.

Final Thoughts

I’ve found that understanding the capacitor in a Lennox air conditioner is essential for keeping the system running smoothly and efficiently. My takeaway is that when this small part starts to fail, it can quickly affect starting performance, cooling reliability, and overall comfort. I always recommend paying attention to warning signs early and getting the capacitor checked or replaced promptly to avoid bigger AC problems later.

Author Profile

Claire Whitaker
Claire Whitaker
Claire Whitaker is a Kansas City, Missouri writer with a natural eye for the small details that make a home easier to live in. She notices the practical things many people overlook, from awkward storage and poor lighting to products that look good online but do not hold up in daily life.

Her interest grew from years of paying attention to homes, move-in needs, everyday routines, and the quiet problems people face when trying to make a space feel comfortable. Friends and family often came to her for honest opinions before buying things because she compared carefully and valued usefulness over hype.

Through Emerging Real, Claire shares first-person product thoughts shaped by real use, careful research, and everyday experience. Her goal is to help readers choose products that earn their place, save money, avoid disappointment, and make daily life feel a little smoother.