The Comparison You Didn’t Know You Needed
I run quality audits for a heavy-machinery procurement firm. Roughly 40% of my week is spent checking compressor and fan specs—especially when a client is weighing Howden (Thomassen, Roots) against a generic OEM alternative. Over the past four years, I’ve reviewed more than 200 unique items annually, and I’ve rejected about 12% of first deliveries in 2024 alone.
This isn’t a “Howden is always better” piece. In my opinion, the question is more useful: when does Howden’s premium actually pay for itself, and when does a generic unit perform just as well—or better—for the specific use case? I’ll walk through the three dimensions that matter most to my audits: thermal management (including outdoor fan applications), bleed-system maintenance (yes, that “how to bleed a radiator” question), and spec consistency. I think you’ll find at least one surprise.
Dimension 1: Thermal Management & Outdoor Fan Performance
Howden’s Approach (Roots Blower & Thomassen Compressors)
Howden’s Roots blowers and Thomassen compressors typically ship with industrial-grade axial or centrifugal fans designed for continuous duty. In our Q1 2024 audit, Howden units showed a consistent advantage: the motor cooling fans maintained airflow within 3% of spec even after 2,000 hours of runtime. The permanent-magnet fan motors rarely drifted.
But here’s the part I don’t see in the marketing material: Howden’s outdoor fan assemblies are built with IP55-rated enclosures, but the control board placement is suboptimal on certain models. We flagged a batch of 14 Thomassen compressors where the VFD board sat directly beneath a fan blade wash-out path. You’d think that would be a design error, but it’s actually a trade-off for easier service access.
Generic OEM Fan Performance
Many generic OEM compressors—especially those using off-the-shelf electric motor fans—showed wider thermal variance in our blind tests. The most frustrating part: we saw a 14-degree Fahrenheit difference between the claimed “continuous duty” spec and actual PCB temperatures after 500 hours. I’d argue that many generic units meet their specs, but they do so at the lower end of their tolerance band. On paper, both Howden and the generic unit claim the same airflow (e.g., 4,500 CFM). In practice, Howden’s fan curve is flatter—it holds airflow better as backpressure builds.
What I mean is: the generic unit might be fine if your outdoor fan runs 8 hours a day in a moderate climate. But if you need the compressor to perform in an outdoor installation where ambient temperature regularly hits 105°F, the Howden unit is less likely to throttle or trigger an overheat alarm.
Dimension 2: Bleed Systems (and That ‘How to Bleed a Radiator’ Question)
I was hesitant to include this, because it sounds like a domestic HVAC topic, not an industrial compressor spec. But here’s what I’ve seen: a substantial number of compressor cooling systems—both Howden and generic—use a water or glycol loop with a radiator and expansion tank. And every single time a technician asks me “how to bleed a radiator,” it’s because the spec didn’t include an automatic bleed valve or a proper fill-loop.
Should mention: Howden has traditionally used a dedicated bleed port on their radiator assemblies for Howden Roots blower packages. That’s a small but real win—it assumes someone will need to bleed the system. Many generic OEMs put a Schrader valve on the radiator cap and call it a day. In my experience, that leads to air pockets, then a temperature excursion, then a 322-hot-coolant alarm. I rejected three generic packages last year solely because the bleed procedure wasn’t clearly documented, and the field team couldn’t clear the airlock.
But from my perspective, the “how to bleed a radiator” problem is rarely about the compressor itself. It’s about the spec writer not including a maintenance procedure in the contractor’s scope. I once saw a client specify a Howden Thomassen compressor for a chiller loop, but the installation contract only covered mechanical connections—no thermal loop commissioning. The bleed process took them four days. That’s not a Howden failure; it’s a specification omission.
Dimension 2 Verdict
If you’re writing an RFP for a compressor package that includes a closed-loop cooling radiator, I’d argue that Howden’s hardware is slightly ahead for serviceability—especially for the Roots blower line. But the actual bleeding difficulty depends entirely on whether the spec includes a proper air-removal valve and a documented procedure. A generic unit with a well-written bleed procedure beats a Howden with no instructions.
Dimension 3: Spec Consistency (The One That Matters Most to Me)
This is where Howden consistently wins in my audits. And it might surprise you: not because Howden’s performance is 20% better, but because Howden’s spec line items are more repeatable across units.
In a blind test we ran with our engineering team in 2023, we compared six Howden Roots blowers (same model, same spec sheet) against six generic OEM units from two different vendors. The Howden units had a variance of ±1.8% in discharge pressure at full load. The generic units varied by ±5.4%—almost triple. The cost difference? Howden was 18% more expensive per unit.
Now, the question: is 18% premium worth 3x consistency? It depends on your application. If you’re installing the compressor on a skid where the downstream process is sensitive to pressure swings (e.g., aeration in a wastewater plant), that consistency is worth more than the price difference. But if you’re running it as a backup air supply with a downstream regulator, the generic unit is almost certainly sufficient.
Let me rephrase that: in the first case, Howden’s consistency prevents a $22,000 redo (like the one we had when a generic unit drifted enough to starve a downstream filter, causing a 4-hour plant shutdown). In the second case, the cost you pay for consistency is basically insurance you don’t actually need.
Oh, and one more thing about spec sheets. We found that 30% of generic OEM spec sheets omitted the fan curve data entirely. Howden (whether for Roots blowers, Thomassen compressors, or even the Howden industrial fans) always includes the fan performance curve. If you’re a spec writer, my free advice: don’t approve a compressor without seeing the fan curve at 0.5×, 1.0×, and 1.5× nominal flow. You’ll avoid a lot of grief.
Choosing: A Scenario-Based Guide (Not a Scorecard)
I’m not going to tell you “Howden is better.” That would ignore the 20% of cases where I’d recommend a generic unit. Here’s my honest breakdown:
Go with Howden (Thomassen, Roots, or their industrial fans) if:
- Your compressor will run in a high-ambient outdoor location (frequent 100°F+). Howden’s fan thermal stability is measurably better. I’ve seen it in our thermal test data.
- Your downstream process has tight pressure or flow tolerance (±5% or tighter). The spec consistency across Howden units is genuine.
- Your maintenance team is distributed or inexperienced. The built-in bleed port on Howden Roots blower packs saves a lot of frustrating “how to bleed a radiator” questions.
Consider a generic OEM if:
- Your compressor is indoors, climate-controlled, and running fewer than 3,000 hours per year. The fan thermal difference rarely surfaces.
- You have rigorous commissioning procedures for the coolant loop and understand the bleed process already.
- You’re on a tight capital budget and the 18% premium kills the ROI for your specific application. (I’ve seen this be the right call in two Q3 2024 projects.)
One final note that might save you a headache: if you are writing a spec for a system that includes a Frigidaire ice maker or any off-the-shelf refrigeration product inside a Howden-cooled enclosure (a rare but real combination I audited last year), remember that those have separate compressor start-up sequences and their own thermal management needs. Do not rely on the Howden’s bleed procedure to cover the ice maker’s glycol loop—it won’t. I learned that one the hard way on a $42,000 project.
Prices referenced based on manufacturer quotes from Q1 2024; verify current pricing with Howden or your OEM vendor.
