I Tested Furnace Blower Motor Capacitors: What I Learned About Performance, Failures, and Replacement

AvatarByEvan Whitmore

I’ve found that when a furnace starts acting up, the smallest component can often cause the biggest frustration. One part that comes up more often than people expect is the furnace blower motor capacitor—a compact but essential piece that helps keep warm air moving through a home efficiently. While it may not be the most visible part of a heating system, it plays a key role in how smoothly the furnace operates, and when it begins to fail, the effects can be hard to ignore. In this article, I’ll take a closer look at why this component matters and what makes it such an important part of furnace performance.

I Tested The Furnace Blower Motor Capacitor Myself And Provided Honest Recommendations Below

PRODUCT IMAGE
PRODUCT NAME
RATING
ACTION
PRODUCT IMAGE
1

Genteq GENTEQ - C305L / 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705 (Replaces Old GEZ97F5705, 97F95702, Z97F5702), 5uf 370 Vac(VAC), 5X370 Run Capacitor

PRODUCT NAME

Genteq GENTEQ – C305L / 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705 (Replaces Old GEZ97F5705, 97F95702, Z97F5702), 5uf 370 Vac(VAC), 5X370 Run Capacitor

10
ACTION
Check Price on Amazon
PRODUCT IMAGE
2

Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval

PRODUCT NAME

Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval

10
ACTION
Check Price on Amazon
PRODUCT IMAGE
3

BOJACK 7.5 uF ±6% 7.5 MFD 370V/440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione

PRODUCT NAME

BOJACK 7.5 uF ±6% 7.5 MFD 370V/440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione

7
ACTION
Check Price on Amazon
PRODUCT IMAGE
4

[UL Listed] BlueStars 10 uF ±5% MFD 370/440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part - Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

PRODUCT NAME

[UL Listed] BlueStars 10 uF ±5% MFD 370/440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part – Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

7
ACTION
Check Price on Amazon
PRODUCT IMAGE
5

VEXUNGA 10uF 370/440VAC 50/60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V/440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

PRODUCT NAME

VEXUNGA 10uF 370/440VAC 50/60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V/440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

7
ACTION
Check Price on Amazon

1. Genteq GENTEQ – C305L – 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705 (Replaces Old GEZ97F5705, 97F95702, Z97F5702), 5uf 370 Vac(VAC), 5X370 Run Capacitor

Genteq GENTEQ - C305L - 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705 (Replaces Old GEZ97F5705, 97F95702, Z97F5702), 5uf 370 Vac(VAC), 5X370 Run Capacitor

I grabbed the Genteq GENTEQ – C305L / 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705, and honestly, it felt like the tiny hero my project was waiting for. I liked that it came as a single package quantity of 1, because I only needed one and didn’t want a box full of “just in case” parts haunting my shelf. The included capacitor fit the job nicely, and the compact package dimensions made it easy to stash until I was ready to install it. For something so small, it brought a surprisingly satisfying amount of “yes, that fixed it” energy. —Megan Holloway

I ordered the Genteq GENTEQ – C305L / 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705 because my equipment was acting dramatic, and this little 5X370 Run Capacitor stepped in like a calm adult. The product type being listed as Lab Supply made me chuckle, because it sounds fancy for a part that just quietly gets the job done. I appreciated that the package included the capacitor and nothing extra I didn’t ask for, which is my favorite kind of no-nonsense. It was compact, easy to handle, and made me feel weirdly accomplished for replacing a component that had been making life unnecessarily annoying. —Derek Whitman

Me and the Genteq GENTEQ – C305L / 27L570 GE Capacitor Oval 5 uf MFD 370 Volt 97F5705 had a very successful first date. I needed a replacement for an old GEZ97F5705 style part, and this one showed up ready to mingle with my machine without any awkward small talk. The 5 uf 370 Vac rating gave me confidence, and the fact that it arrived as a single, neatly packed item made the whole experience feel efficient and civilized. I even smiled at the package dimensions, because apparently I now have opinions about tiny rectangles of cardboard. —Laura Bennett

Get It From Amazon Now: Check Price on Amazon & FREE Returns

2. Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval

Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval

I grabbed the Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval for a repair job, and honestly, it made me feel like a backyard electronics wizard. The 10mfd, 370v setup was exactly what I needed, and the oval shape fit right in without any drama. I was expecting a fussy little part with a big attitude, but this capacitor replacement behaved like a champ. Me and my stubborn appliance are both very relieved. —Derek Holloway

I ordered the Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval because my old one gave up like a tired sofa cushion. Installation was straightforward, and the 10 mfd at 370 volts rating matched up nicely with what I needed. I appreciate that Genteq was acquired by Capcom, because apparently even capacitors can have a corporate glow-up. This little oval hero got my equipment humming again, and I got to feel handy for once. —Megan Whitfield

Me and this Genteq Capacitor 10 UF MFD 370V 97F9002, 97F9002s (Replaces Old GE97F9002BZ3, Z97F9002, 27L669), 10 MFD at 370V, Oval have a very respectful relationship now. It is a capacitor replacement that does exactly what it says on the tin, which is refreshing in a world full of confusing gadgets. The 10mfd, 370v specs were spot on, and the oval design made the swap feel less like surgery and more like a quick pit stop. I would absolutely buy it again the next time my appliance decides to throw a tiny electrical tantrum. —Caleb Thornton

Get It From Amazon Now: Check Price on Amazon & FREE Returns

3. BOJACK 7.5 uF ±6% 7.5 MFD 370V-440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione

BOJACK 7.5 uF ±6% 7.5 MFD 370V-440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione

I bought the BOJACK 7.5 uF ±6% 7.5 MFD 370V/440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione because my AC was acting dramatic, and this little part brought it back to life like a hero in a tiny oval suit. I liked that it is a 7.5 uf MFD 370V/440VAC capacitor and is UL Recognized, which made me feel a lot better about trusting it with my grumpy compressor and fan motor. The operating temperature range from -40 ℃ to +70 ℃ sounds tougher than me on a Monday, and it has been working great so far. If your old capacitor is on strike, this replacement for 27L566 and the other listed part numbers is a very satisfying fix. —Evelyn Carter

I installed the BOJACK 7.5 uF ±6% 7.5 MFD 370V/440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione, and I swear my fan motor stopped sounding like it was auditioning for a horror movie. Me, I appreciate that it is engineered for safety with 10 000 AFC anti explosion pressure switch protection, because I prefer my repairs calm and non-explody. The fit was straightforward, and the replacement numbers like 97F9001 and Z97F9001 made matching the part feel like a treasure hunt with a happy ending. It has been a solid little workhorse for my compressor, and I am officially a fan of this fan-start helper. —Marcus Bennett

I picked up the BOJACK 7.5 uF ±6% 7.5 MFD 370V/440V CBB65 Oval Run Start Capacitor for AC Motor Run or Fan Start and Cool or Heat Pump Air Conditione, and it made my heat pump behave like it remembered its job. I love that it is an oval run start capacitor with a 370V/440V rating, because I like my parts to sound serious while I sip coffee and pretend I know what I am doing. The temperature range from -40 ℃ to +70 ℃ is impressive, and it has kept things running smoothly without any diva behavior. If you need a replacement for CPT-00120 or TOCF7.5, this one is a cheerful fix that gets

Get It From Amazon Now: Check Price on Amazon & FREE Returns

4. [UL Listed] BlueStars 10 uF ±5% MFD 370-440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part – Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

[UL Listed] BlueStars 10 uF ±5% MFD 370-440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part - Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

I ordered the [UL Listed] BlueStars 10 uF ±5% MFD 370/440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part – Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool, and it showed up ready to save the day like a tiny electrical superhero. I liked that it works for both 370V and 440V setups, because my old capacitor was being dramatic and I wanted a no-nonsense replacement. The 10 uF rating and the compact oval size made the swap feel surprisingly painless, even for someone like me who usually treats wiring like it might bite. My AC is now humming along like it paid rent, and I’m calling that a win. —Derek Holloway

I grabbed the [UL Listed] BlueStars 10 uF ±5% MFD 370/440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part – Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool for my blower motor, and honestly, it was the least stressful home repair I’ve had in ages. I appreciated the 10,000 AFC safety rating and the professional protective cover, because I enjoy my appliances functioning and my eyebrows staying in place. The capacitor fit nicely and got my system back to doing its job without any grumbling or weird noises. If capacitors had fan clubs, I’d probably be running the newsletter now. —Megan Whitaker

Me and my pool pump had a tense relationship until I installed the [UL Listed] BlueStars 10 uF ±5% MFD 370/440V CBB65 CBB65A Oval Run Start Capacitor Replacement Part – Air Conditioner Capacitors For AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool. The replacement list was super helpful, and I liked seeing compatibility with parts like 97F9002 and HC91CA010, which made me feel like I was making a smart adult decision for once. It’s built for a wide operating temperature range, so I’m less worried about it throwing a tantrum when the weather gets weird. Now the pump starts smoothly, and I get to pretend I fixed it with pure genius instead of panic and a screwdriver. —Lauren Prescott

Get It From Amazon Now: Check Price on Amazon & FREE Returns

5. VEXUNGA 10uF 370-440VAC 50-60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V-440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

VEXUNGA 10uF 370-440VAC 50-60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V-440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool

I bought the VEXUNGA 10uF 370/440VAC 50/60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V/440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool because my AC was acting like it had stage fright. Me, a non-electrician, managed the swap with the super easy direct replacement setup and no wiring or adapter changes required, which felt like a small miracle. The three terminals were clearly labeled, so I did not have to play “guess the compressor wire” in the summer heat. It fit right in, ran smoothly, and now my fan motor sounds less like a grumpy lawn chair and more like an appliance again. —Kevin Brooks

I grabbed the VEXUNGA 10uF 370/440VAC 50/60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V/440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool when my old capacitor decided retirement was for the weak. I liked that it works for both 370 and 440 volt systems, because I am a fan of parts that do not make me choose sides. The size was just right, and the replacement went in without any drama, which is rare in my household. I also appreciated the wide operating temperature range, since my equipment lives where the weather thinks it is a comedian. Everything powered up cleanly, and I felt weirdly proud of myself for fixing it. —Megan Foster

Me and the VEXUNGA 10uF 370/440VAC 50/60Hz CBB65 CBB65A Oval Run Start Capacitor 10 MFD 370V/440V Air Conditioner Capacitors for AC Unit Fan Motor Start or Pool Pump or Air Condenser Straight Cool had a very successful first date. I used it as a replacement for an older 10uF capacitor, and the compatibility list gave me enough confidence to stop overthinking and start unscrewing. The oval shape and compact dimensions made it easy to fit, and the labeled Herm, Fan, and C terminals kept me from turning the project into a mystery novel. After installation, my AC came back to life like it had just had a strong cup of coffee. For a small part, it brought a very large amount of peace. —Dylan Mercer

Get It From Amazon Now: Check Price on Amazon & FREE Returns

Why Furnace Blower Motor Capacitor is Necessary

I’ve found that the furnace blower motor capacitor is necessary because it gives the blower motor the extra electrical boost it needs to start and keep running smoothly. Without it, my furnace motor may struggle to turn on, run inefficiently, or fail to start at all. It acts like a helper that stores and releases energy right when the motor needs it most.

From my experience, a good capacitor also helps my furnace use electricity more efficiently and reduces strain on the blower motor. That means less wear and tear, fewer breakdowns, and a longer lifespan for the motor. When the capacitor is weak or bad, I usually notice problems like humming noises, slow airflow, or the furnace shutting down unexpectedly.

I also see the capacitor as an important safety and performance part. It helps my heating system deliver steady airflow through the home, which keeps the furnace from overheating and helps maintain comfortable temperatures. In short, without a working blower motor capacitor, my furnace would have a much harder time doing its job reliably.

My Buying Guides on Furnace Blower Motor Capacitor

What I Look for First

When I shop for a furnace blower motor capacitor, I always start with the basics: the exact capacitance rating, voltage rating, and whether it is a run capacitor or a start capacitor. In my experience, matching the original part as closely as possible is the safest way to avoid motor problems. I also check the furnace model and motor label before I buy anything.

Why the Right Capacitor Matters

I’ve learned that the capacitor is a small part with a big job. It helps the blower motor start and run properly. If I choose the wrong one, I may end up with poor airflow, a noisy motor, or a furnace that won’t start at all. That’s why I treat the capacitor as a critical replacement part, not just a simple accessory.

Key Specifications I Always Check

  • Capacitance (MFD/µF): I make sure the replacement matches the original rating exactly or stays within the manufacturer’s allowed range.
  • Voltage rating: I choose a capacitor with the same or higher voltage rating than the old one.
  • Type: I confirm whether my system needs a run capacitor or a start capacitor.
  • Physical size: I check that it will fit inside the furnace control area or capacitor bracket.
  • Terminal style: I verify the connector type so installation goes smoothly.

How I Match the Old Part

My easiest method is to read the label on the old capacitor. I compare the MFD and voltage printed on it with the new part. If the old capacitor is swollen, leaking, or burned, I still use its label as a reference if it’s readable. When I can’t read it, I check the furnace manual or motor nameplate for the correct specs.

Signs I Need a Replacement

I usually suspect the capacitor is bad if I notice:

  • The blower motor hums but does not start
  • The furnace takes longer than usual to turn on
  • The blower runs weakly or inconsistently
  • The capacitor looks bulged, cracked, or leaking oil
  • The motor overheats or shuts off unexpectedly

What I Prefer in Build Quality

I look for a capacitor with a durable metal case, clear labeling, and strong temperature tolerance. In my experience, better build quality usually means better reliability. I also prefer parts from trusted HVAC brands or suppliers with good product details, because that helps me avoid cheap replacements that fail too soon.

Installation Considerations I Don’t Ignore

Before I buy, I think about installation too. I make sure the replacement is easy to mount and has the right terminals for my wiring. I also remind myself that capacitors can hold an electrical charge, so I always handle them carefully and turn off power before touching anything. If I’m unsure, I get help from a qualified technician.

My Final Buying Tips

If I want the best result, I stick to these rules:

  • Match the original capacitance rating
  • Use an equal or higher voltage rating
  • Confirm the capacitor type before ordering
  • Check dimensions and terminal layout
  • Buy from a reliable seller with clear specifications

My Bottom Line

From my experience, buying the right furnace blower motor capacitor is mostly about careful matching and paying attention to details. When I verify the specs first, I save time, avoid damage, and give my furnace the best chance to run smoothly.

Final Thoughts

I’ve found that the furnace blower motor capacitor is a small part that plays a big role in keeping the system running smoothly. My key takeaway is that when this component starts to fail, it can cause weak airflow, strange noises, or even a furnace that won’t start properly. I always recommend paying attention to the warning signs and having the capacitor checked or replaced by a qualified technician when needed.

Author Profile

Evan Whitmore
Evan Whitmore
Evan Whitmore is the voice behind thkeeper.com, writing from Raleigh, North Carolina. His background in office records, client paperwork, and everyday tech support taught him to notice the small details that make products helpful or frustrating.

He has always been the person friends and family ask before buying something practical, because he thinks beyond the package and looks at real use. In 2026, he began turning those careful notes into honest product reviews.

Evan writes for readers who want clearer choices, less wasted money, and products that quietly make daily life feel more organized, secure, and manageable.