There's no single "best" Howden roots blower package. It depends on your budget timeline, your maintenance crew, and how long you plan to own the thing. I've been in procurement for a six-person engineering firm (we manage about $180k/year in rotating equipment), and I've learned this the hard way.
Here's the framework I use. It's split into three common scenarios you'll actually encounter on the plant floor.
Scenario A: Your Budget Is Fixed (You're Replacing Like-for-Like)
- Goal: Lowest TCO for a direct replacement with a known duty cycle.
- Tools: Standard lobe profile, cast iron casing, standard shaft seals.
A vendor once quoted me a "premium" package with ceramic rotor coatings. Sounded great on paper. But the unit was going into a standard pneumatic conveying line running at 8 psi. The coating added $4,200—totally unnecessary for that application.
What I learned: Stick with the standard Howden package. The base Roots Universal RGS series (or legacy HRB models) already comes with hardened rotors and heavy-duty bearings. For most industrial blower duties (10 psig or less, clean air), the baseline spec is over-spec'd already.
The dirty secret here: Vendors love adding "upgrades" (special coatings, exotic seals) because they carry huge margins. Most of them won't improve your blower's life by even a year in a standard air-moving job.
Scenario B: You Need Maximum Reliability (The Critical Process)
- Goal: Minimum downtime over 10 years.
- Tools: Mechanical seals (over lip seals), cartridge bearings, stainless steel rotors (if gas is corrosive).
Now, this is where spending more actually saves you money. I had a client running a Howden RGS blower on a digester gas boost application. The standard lip seals failed every 18 months. Each failure cost $1,500 in parts and about $8,000 in lost production.
We swapped to a unit with double mechanical seals and a buffer gas system. Up front, it was $3,200 more expensive. Over five years, we didn't have a single seal failure. Saved $28,000 in downtime alone.
Insider move: If you're specifying for a critical process, ask for a quote with the exact bearing and seal options you need. Don't accept a standard catalog price. Most Howden rep offices can configure a package with specific internals. The lead time might be longer (10-12 weeks vs. 2-4 weeks), but the reliability gain is massive.
Scenario C: You're Retrofitting an Older System (The "Hybrid" Approach)
- Goal: Better performance without scrapping existing piping.
- Tools: High-efficiency lobe profiles, adjustable discharge ports, acoustic enclosures.
This is the trickiest scenario. Most people say, "Just buy a new blower and bolt it on." But the old motor, old baseplate, and old piping all have constraints. If you mismatched the new blower's flow coefficient (Cv), you'll actually get worse performance than the 20-year-old unit you replaced.
Here's what I do now: get the rep out to measure the actual piping length, number of elbows, and discharge pressure at the point of use. Then we model the new blower's operating point on that specific system curve. Don't trust catalog performance curves—they're measured on ideal test stands.
Real-world example: We replaced a 1997 HRB with a new Howden RGS package. Same duty, same speed. The vendor said we'd see 12% energy savings. We actually saw 8%—decent, but not 12%. Why? The old piping had a higher pressure drop than we estimated. The new blower's operating point drifted left on the curve. We should have upsized the blower by one frame rating.
How to Know Which Scenario You're In
Ask yourself these three questions:
- Is this a planned replacement or emergency? If it's emergency, you're almost always in Scenario A (fastest path). Don't try to over-spec. Get a stock unit running.
- How long do you plan to own the asset? Less than 3 years? Stick with standard spec. More than 5 years? Start looking at Scenario B upgrades. The payback math changes dramatically after year 4.
- Can you document your existing system's actual operating conditions? If not, you're in Scenario C, and you need a site survey before spec'ing anything. Blindly matching nameplate data is a recipe for disappointment.
I've been doing this for about 7 years now. The biggest mistake I see procurement managers make is treating a blower like a commodity. A Howden roots blower is a precision piece of process equipment. Treat it like one, and the total cost of ownership will surprise you—on the low side.
Oh, and one more thing: do not skip the lubrication system spec. That's a story for another time, but it's the number one cause of premature blower failure I've seen. (Should mention: the standard splash-lube system is fine for intermittent duty. For continuous 24/7 operation, insist on a forced-feed oil pump. That upgrade alone costs maybe $600, but it'll double your bearing life.)
