If you're searching for "Howden roots blower specification sheets," you're probably trying to figure out whether a particular blower will work for your application—and what it'll really cost you. I've been there. As a procurement manager, I've spent the last six years buying industrial rotating equipment, and I've made my share of mistakes. This checklist is the process I now use every time I evaluate a Howden rotary lobe blower (or any comparable blower, for that matter).
Let me start with a confession: when I first started buying this type of equipment, I assumed the cheapest quote was the best quote. I couldn't have been more wrong. I also thought that reading a spec sheet was mostly about checking the flow and pressure numbers—something an intern could do. It turns out that a blower spec sheet is more like a contract, and the fine print is where the money goes.
Before we dive in, I want to be clear: this is not a sales pitch. I don't work for Howden. I'm a buyer who has used their equipment in chemical and food processing plants, and I'm sharing what actually matters when you're evaluating their spec sheets. If you're here because you've been comparing residential options like a Dyson fan or figuring out how to set a Honeywell thermostat, this guide will be a bit of a shift—industrial blowers are a different beast entirely.
Who This Checklist Is For
Use this if you're involved in purchasing, engineering, or maintenance and need to compare quotes, verify a vendor's proposal, or specify a blower for a new project. It's written for standard industrial applications—dry bulk conveying, wastewater aeration, pneumatic conveying, and similar duties. If you need a blower for an exotic specialty gas application, this list still gives you a starting point, but you'll need additional engineering reviews.
The 6-Step Checklist for Reading Howden Blower Specs
Here's the high-level list. I'll explain each step below.
- Confirm the operating conditions.
- Read the performance curve, not just the rated point.
- Check the mechanical design and materials.
- Add up the auxiliary equipment costs.
- Calculate total cost of ownership (TCO).
- Verify support, warranty, and service history.
Step 1: Confirm the Operating Conditions
The most common mistake I see—and I've made it myself—is skipping the operating conditions at the top of the spec sheet. A Howden rotary lobe blower is rated at specific inlet pressure, inlet temperature, and gas composition. Change any one of these, and the actual volume flow changes significantly.
For example, a blower rated at sea level might deliver 20% less mass flow at 5,000 feet altitude without any change in speed. If your application is at altitude and you don't derate, the blower will be undersized. Your process will struggle, and your energy bill will reflect an inefficient operating point.
Checklist items:
- Inlet pressure (absolute, not gauge)
- Inlet temperature range
- Gas molecular weight and composition
- Site altitude
- Required discharge pressure
- Ambient temperature for cooling
One thing I always tell our engineers: treat the spec sheet like a legal document. Those numbers in the header aren't suggestions. I've seen purchase orders written with the wrong pressure rating because someone skimmed the “maximum allowable pressure” box—that's a $15,000 mistake waiting to happen.
Step 2: Read the Performance Curve, Not Just the Rated Point
If you only look at the “rated flow” and “rated pressure” boxes, you'll miss the story. The performance curve shows how the blower behaves across its operating envelope. In the Howden spec sheets I've seen, there are curves for flow vs. pressure at different speeds, power consumption, and efficiency. The sweet spot is usually between 70% and 100% of the maximum speed, but it depends on the design.
I used to think a blower either worked or it didn't. Then I saw a compressor installation where the operating point was far from the peak efficiency island. The unit ran fine, but it consumed 15% more power than a properly sized alternative. Over 8,000 hours per year, that's real money. You wouldn't buy a water heater without checking its recovery rate and energy factor; a blower is no different—the curve tells you where it spends its whole life.
Ask yourself: What's the efficiency at my actual duty point, not at the design point on the brochure? If the vendor can't give you a curve for your conditions, that's a red flag. Even a small deviation can turn a "budget" blower into an energy hog.
Step 3: Check the Mechanical Design and Materials
The next area is the bill of materials and mechanical details. You don't need to be a metallurgist, but you should know if the rotor, shaft, casing, and seals are made of materials that suit your process. For example, a standard blower with cast iron casing and carbon steel shafts may be fine for air, but it will corrode quickly in a humid or mildly acidic environment.
A cost controller's trick: look at the spare parts list in the manual. The material grade and the recommended replacement interval tell you a lot about the design philosophy. If the bearing oil seals are listed as needing replacement every 2,000 hours and they're expensive, that's an operating cost you should capture.
Also check the manufacturing standard. Howden's rotary lobe blowers are generally designed to recognized API or ISO standards. In the spec sheet, the code should tell you what standard was used. If it says "in accordance with API 619" (the standard for rotary type positive displacement compressors), you know the safety and reliability expectations are high—and so is the price. That's fine, as long as you budget for it. The same logic applies to checking whether the motor included is suitable for a variable frequency drive—an important detail that many buyers miss.
Step 4: Add Up the Auxiliary Equipment Costs
This is where most initial cost comparisons go wrong. The blower itself might be $20,000, but the complete package with inlet filter, silencer, pressure relief valve, check valve, flexible connections, and a motor might be $35,000. I've seen vendors quote a bare shaft unit and leave out all the accessories, making their price look 25% lower than a competitor who included everything.
Even worse, sometimes installation materials like anchor bolts, gaskets, and V-belts are extra. When you're comparing quotes, make a checklist of every component on the datasheet and verify each one is included in the price. Mark the ones that are "not included" and get a quote for them from the same vendor. That's the only way to compare apples to apples.
I remember a project where we selected a package based on base price, thinking we'd buy the pulsation dampener separately. It ended up costing us more in freight and engineering time than if we'd just bought the full package. Don't fall into that trap. And if the vendor says "you probably won't need a check valve," get it in writing—because if the system surges, you'll need it.
Step 5: Calculate Total Cost of Ownership (TCO)
Here's where I earn my keep. Once you have the complete initial pricing, run a simple TCO model. The formula I use is:
TCO = initial price + installation cost + (power consumption × hours × electricity rate) + planned maintenance + expected downtime cost + spare parts inventory.
Let's work through a quick example. Suppose a Howden rotary lobe blower draws 50 kW at your operating point, and a competing unit draws 55 kW for the same duty. At $0.08/kWh and 8,000 hours/year, the difference is 5 kW × 8,000 h × $0.08 = $3,200 per year. Over a 10-year life, that's $32,000—more than the initial price difference would likely be. And that's just the energy cost. (Should mention: these are illustrative numbers; verify current electricity rates and operating hours for your plant.)
When I compare options, I always calculate the power draw at the actual operating point, not the motor nameplate. Another nuance: some spec sheets list absorbed power at the blower shaft; you need to add gearbox and motor losses if they're not already included. If the sheet doesn't specify, ask. This is the same mindset as comparing water heaters—the cheap unit with low efficiency can burn through your savings in two winters.
Step 6: Verify Support, Warranty, and Service History
This is the step most buyers skip until it's too late. A blower specification sheet won't tell you whether the local service engineer actually shows up, or whether the spare parts warehouse has stock. But you can research it. Ask the vendor for references from companies with similar applications. Call the maintenance superintendents. Ask about response times and warranty claim handling.
I can't stress this enough: as a smaller customer, you deserve the same level of support as a large account. When I was starting out, the vendors who treated my $200 orders seriously are the ones I still use for $20,000 orders. If a Howden sales rep doesn't return your call because your order quantity seems small, that's a warning sign. The same principle applies to spec sheets: a vendor who can't provide clear documentation on a small project probably won't provide great service during a crisis.
Also, read the warranty section very carefully. Some warranties are based on operating hours and require proof of proper maintenance. Others exclude parts like seals and gaskets. Know before you buy.
Common Mistakes I've Made (So You Don't Have To)
Here are the errors that cost my company real money:
- Assuming pressures are absolute when they're gauge (or vice versa).
- Ignoring the effect of temperature swings on capacity.
- Not checking if the motor included is suitable for a variable frequency drive.
- Overlooking the noise limitations at the site and having to retrofit a silencer later.
- Forgetting to leave a 10% capacity cushion for future process changes.
One more thing: the spec sheet you're reading might be an older revision. Always ask for the latest version. I've seen specification sheets where the vendor updated the curve but the old PDF still floated around on a third-party website. It's your job to verify you're working from the current document.
Final Thoughts
Reading a Howden roots blower specification sheet doesn't have to be intimidating, but it does have to be systematic. Whether you're buying a single unit or a whole fleet, the same checklist works. Start with the operating conditions, read the curves, dig into the materials, add up the accessories, model the total cost, and verify the support. That's what separates a good procurement decision from a costly mistake.
And remember: the goal isn't to be an expert in blower engineering. It's to be an expert in asking the right questions. If you can ask the vendor why a particular curve looks the way it does, you're already ahead of most buyers. In my experience, the cost savings come not from squeezing the purchase price, but from avoiding surprises down the road.
If you're also juggling household decisions like comparing a Dyson fan to a cheaper model, or figuring out how to set your Honeywell thermostat, I get it—procurement is a mindset. But for your plant, the biggest risks are usually in the big rotating machines, and the specification sheet is your first line of defense. Prices and standards change, so always verify the current data with the manufacturer. According to Howden's published information (howden.com), the company has been engineering air and gas handling solutions for over 160 years—you'd think that history would make their documents perfect, but you still need to read them carefully. This checklist is based on my personal purchasing experience and not an official Howden endorsement—but it's how I've kept our plant running without a budget overrun.
