I Thought I Had This Generator Thing Figured Out
I manage purchasing for a mid-sized company—about 150 employees across two locations. When I took over in 2020, one of my first big tasks was standardizing our backup power setup. The previous guy had left a mess: three different generator brands, no central maintenance schedule, and a stack of hand-written invoices that gave our finance team headaches.
I figured I'd just pick one brand, standardize, and be done with it. Generac seemed like the obvious choice—everyone knows the name, and the 18kW and 24kW models I was looking at had decent specs on paper. Easy, right?
Not quite. I'm not an electrician, so I can't speak to the technical intricacies of load balancing or transfer switch wiring. What I can tell you from a procurement perspective is that the 'simple' decision to go with Generac (or any brand) has layers of hidden costs that don't show up on the initial quote. This is my story about how I learned to look beyond the sticker price.
What I Thought Was the Problem: Choosing the Right Model
At first, I thought the hard part was picking the right wattage. We have an 18kW unit at our main office and I was considering a 24kW for a newer facility. I spent weeks comparing specs online—Honeywell vs. Generac, air-cooled vs. liquid-cooled. I even called a few dealers to get quotes. All the numbers looked fine.
Then I saw the price for a 24kW Generac generator battery replacement. A simple battery? That's when I started to realize the real problem wasn't the generator itself.
The Battery Surprise
We have a 24kW Generac at our secondary site. During a routine inspection in 2023, the tech said the battery was weak. I figured—how much could a battery cost? Maybe $50, $60? The quote came in at over $200 for the replacement. That's a specific Generac battery, mind you—not a standard automotive one you can grab at AutoZone. It's a "maintenance-free" AGM battery with specific terminals and a vent kit. If you just throw in a cheap battery from the auto parts store, you risk voiding the warranty or, worse, the battery doesn't fit and causes connection issues.
I know, I know—some of you are thinking, "Just get a generic one and make it work." I've seen people do that. I've seen the results, too: corroded terminals, failed starts during a real outage, and a voided warranty that cost way more to fix than the OEM battery would have.
The Deeper Problem: We're Not Buying a Generator; We're Buying a System
That battery experience made me rethink everything. It's not just a battery—it's the whole ecosystem. This is where the 'total cost of ownership' thing really hits home. The generator itself might be competitively priced, but the consumables and maintenance items have a markup that adds up over the 20+ year life of the unit.
Here are a few things I wish someone had told me upfront:
- Air filters: I had to learn which way to put in the air filter on our 18kW unit. Sounds stupid, right? But if you put it in backward (yes, there's an airflow direction arrow), the engine sucks unfiltered air. We had a tech catch it during a tune-up, and a new filter is only $15, but the labor to diagnose the issue was the expensive part.
- Fuel filters: The universal fuel pump removal tool and 1/2 inline fuel filter sounds like basic stuff. But Generac uses specific fittings. Don't assume a generic inline filter will work. The OEM filter is like $12, but the time you waste with the wrong one... not worth it.
- The battery (again): The 24kw Generac generator battery isn't the only one. The 18kW uses a different part. And they're all more expensive than car batteries.
The Real Cost of Getting It Wrong
Let me give you a real example. In 2022, we had a minor outage—maybe 45 minutes. The 18kW fired up fine. The 24kW? Dead. Failed to start because the battery was weak (the same one I later replaced with the OEM part). The outage wasn't the problem—the loss of confidence was. My VP asked why a brand-new-ish system failed. I had to explain that the battery had been sitting for a few years and probably wasn't maintained properly by the previous facilities manager.
I saved maybe $60 by delaying the battery replacement that first time. The cost of lost trust from my leadership? Priceless. Plus, I had to pay for an emergency service call to get it running again. That call alone was $300.
Another example: A colleague at a different company bought a cheap 1/2 inline fuel filter from Amazon. It didn't seal properly. The generator ran rough, threw a code, and the dealer had to come out and replace the filter and the fuel line (which got contaminated). Total cost: about $500 in parts and labor. The OEM fuel filter? $15.
So, What's the Solution? (It's Not What You Think)
I'm not gonna tell you to only buy OEM parts. Sometimes a generic is fine—if you know what you're doing. But for a business, you need reliability. The solution I've found is to think in terms of total cost of ownership (TCO) from the start.
When I spec out a new Generac generator now, I include a 5-year maintenance budget in the decision. That means factoring in the cost of the specific battery, the air filters (and knowing which way they go!), the fuel filters, and the dealer's labor rates. I also factor in the value of having a dealer who stocks these parts. The cheap online dealer might save you $50 on a battery, but if the part is backordered when you need it, you've lost the game.
The way I see it, the generator is just the start. The real investment is in the system of parts, service, and trust. And honestly, since I've started calculating TCO, I've seen that Generac's pricing on those consumables... well, it's not cheap. But having a system that works when you need it? That's worth a lot.
So, my advice: Don't just compare generator prices. Ask your dealer for a list of all the recommended replacement parts and their prices. Calculate what a 5-year maintenance plan looks like. And for heaven's sake, make sure you know which way that air filter goes. Trust me on that one.
