Winter in the Office: From a Smoke Alarm Slow Red Flash to an iRobot Roomba 675 vs 891 Decision

It was the second week of January 2025, and our office at the architecture firm was cold. The thermostat insisted it was 62°F. The people in the studio insisted that was unacceptable.

At 9:40 a.m., someone brought in a portable gas space heater from home and slid it under their desk. I told myself I'd handle it after the budget call. At 2:13 p.m., I looked up from my screen. The smoke alarm on the ceiling was doing a slow red flash. No beeping. Just a red LED pulsing. The phrase I'd later Google was 'smoke alarm slow red flash,' and this was exactly that.

It wasn't a fire. The heater hadn't even been turned on yet. But the sight of that red light made me realize I had no idea how old our smoke detectors or carbon monoxide detectors were. I've been the office administrator for this firm since 2017. I manage roughly $45,000 in annual purchasing across 10 vendors. I can tell you the difference between two paper suppliers in my sleep, but detector replacements? Not even on my list.

The Slow Red Flash

After the alarm chyron moment, I did what any responsible facilities person does: I got a ladder and looked at the detector. There was a date sticker on the side: August 2013. Twelve years, almost, of quiet service. The detector wasn't beeping, wasn't chirping, and didn't look old. It just was old.

So I Googled 'how often change carbon monoxide detector' while standing on a ladder. The answer on the replacement unit's packaging was clear: every 5 to 7 years, depending on the model, and backup batteries every 6 months. Our combination smoke/CO detector was eleven and a half years old. It needed to be replaced before we even thought about using that portable gas space heater again.

We ended up banning portable gas space heaters entirely. Not because one caused the alarm—it didn't. But because the alarm made us pay attention, and a gas heater in a small office is a risk I'm not willing to take. We bought an electric space heater with tip-over protection, locked it in the supply closet, and set a rule: no personal heaters unless operations approves them.

The Robot Vacuum Decision

The heater situation wasn't the only thing on my list. Our old robot vacuum had died the week before, and with February budgets due, I needed a replacement. I started with the newest iRobot vacuum, because that's what I'd want in my own house. As of late January 2025, the newest iRobot vacuum I found was a Roomba Combo with an AutoEmpty dock and a mop setting. It had smart mapping, could learn room layouts, and basically seemed like a tiny robot butler. Honest reaction: I wanted it. Practical reaction: our office didn't need it.

So I compared two older, more affordable models: the iRobot Roomba 675 vs 891. Both connect to Wi-Fi, both work with the iRobot Home app, and both use the standard 3-Stage Cleaning System. The main difference I cared about was carpet pickup. The 891 is stronger and does a noticeably better job on rugs. The 675 is lighter, simpler, and easier on the budget. Our studio is mostly hard floors with two area rugs in the conference room. The 675 made sense.

Why not the newest iRobot vacuum? Because our office doesn't need a mop, and the self-emptying dock is a nice-to-have, not a need. Maybe that's the facilities buyer in me talking. I'd rather spend budget on things like detectors that haven't expired.

I ordered the Roomba 675 on February 3, 2025. Setup took 15 minutes. It doesn't use smart mapping—it uses random navigation—but it covered the open studio well enough. It picked up dust under desks, crumbs in the break room, and a surprising amount of drywall dust from a small ceiling repair. It also got stuck on a phone cord once. I'm not going to oversell it.

Here's the thing: a robot vacuum can keep your office cleaner, but it won't tell you if a carbon monoxide detector is expired. The safety stuff is just as much a part of facilities management as the cleaning stuff.

The surprise wasn't that a basic robot vacuum couldn't handle a 20-person office on its own. The surprise was that the same month I bought a robot vacuum, I also learned our carbon monoxide detector was past retirement age. The two things felt unrelated until I realized they were both facilities tasks I'd let slide.

What I'd Do Differently

If I'm being honest, I only take the detector expiration rule seriously now because I got caught. I read about CO detector lifespans years ago, but I didn't act on it until I saw a 2013 date sticker in my own hallway. The lesson stuck in the dumb way: after the fact. I don't recommend that method.

I still have mixed feelings about buying the 675 instead of the newest iRobot vacuum. Part of me wants the big one with the mop and the self-emptying dock. Another part knows I'd be paying for features we don't need. Maybe in 2026, if the 675 gives up, I'll revisit. For now, it does what we need.

This combination—a basic Roomba, a no-gas-heater rule, a detector replacement schedule—works for our office. But our situation is specific: one floor, mostly hard floors, no gas appliances in the suite, and a landlord who handles HVAC. If you have wall-to-wall carpet, you might genuinely need the 891. If you have gas appliances, check your CO detector more often. The calculus changes with context.

One more thing. I bought a single Roomba from iRobot's online store, not a fleet. I asked a support question over chat, and they answered in under 10 minutes. I've been the small customer that vendors ignore, and those vendors don't get my business now that our budget is bigger. Small orders aren't worthless. Treating a small order with respect is how you get a bigger one later.

So, what did I learn from a cold office, a slow red flash, and a Roomba? Cleaning is about maintenance, not magic. And the question 'how often change carbon monoxide detector' has an answer you should look up before you need it, not after.