At 3:17 p.m. on a Thursday in January, I picked up a call that started with the words I never like to hear: “We have an event this Saturday, and the heat is completely dead.”

The caller was a facilities manager for a 3,200-square-foot event space in a converted Hudson Valley mill. The space was booked for Saturday evening, which gave us roughly 48 hours. The overnight forecast was 9°F. If the building couldn’t hold heat, the event wasn’t going to be uncomfortable—it was going to be cancelled. Pipes could freeze. Guests could back out. The venue was looking at five figures in potential damage on top of lost revenue.

In my role coordinating emergency heating and equipment for commercial clients, I’ve handled dozens of these calls—this one was the third emergency of January alone. The first thing I do is triage: How much time do we have? What’s the actual system? What’s the worst case?

I asked the facilities manager what kind of system he had. “It’s a water heater,” he said. “It’s big, it’s in the basement, and it’s leaking.”

The Boiler vs Water Heater Mix-Up

I assumed that when a facilities manager says “water heater,” he knows exactly which box sits in his mechanical room. Didn’t verify. Turned out he was calling the boiler a water heater. That’s not harmless slang—it’s a costly distinction.

Let me be clear: a boiler and a water heater are different machines. A water heater heats potable water for sinks, showers, and dishwashers. A boiler heats water and sends it through radiators, baseboard, or in-floor loops to warm the building. Some boilers also provide domestic hot water through an indirect coil or tank, but their primary job is space heating. According to the U.S. Department of Energy, water heating accounts for about 18% of a typical home’s energy use. Space heating is a much larger load, especially in a drafty old mill. When you’re talking about boiler vs water heater, the real question is: Are you heating people, or heating rooms?

This client needed to heat a room. The answer to that one question changed the entire plan.

The Options at Hour 42

Now came the part I usually get called in for: choosing a temporary heat source with almost no time left.

The first option we looked at was Dimplex storage heaters. I like them for permanent installs—they’re a smart way to shift electric demand to off-peak rates, and they do a great job in apartments and small commercial spaces. But this was an emergency, not a retrofit. Dimplex storage heaters need a full overnight charging cycle to build up heat, and most models are designed as fixed wall units. We didn’t have 12 hours to charge a thermal mass, and we couldn’t do a permanent mount in a rented event space. So I ruled them out for this job, even though they might be the right long-term answer for another building.

The better fit, in this case, was the Dimplex fan forced wall heater. We had six high-capacity units in stock, each with a programmable thermostat. They’re not portable by design, but with a simple mounting bracket and temporary circuits, we could make them work in about 20 minutes per unit. They also had one major advantage over combustion heaters: no fumes, no open flame, and no exhaust to vent. In an event space where about 180 guests would be moving around, that mattered.

Why does the difference matter? Because an event venue’s heat source has to be invisible. A flame you can smell or a heater that sets off a carbon monoxide detector is a dealbreaker, no matter how fast it puts out heat. To me, the clean heat was worth the extra installation work.

Why Not a Kerosene Heater?

Now, the question people always ask: why not use a kerosene heater? They’re powerful, they don’t need electrical circuits, and you can rent them anywhere.

Honestly, I considered it. The upside was fast, intense heat. The risk, though, was a different kind of problem. Most kerosene heaters designed for temporary construction heat produce combustion gases and need to operate in spaces with serious ventilation. An event space with high ceilings and old windows might have some air leakage, but controlling carbon monoxide in a room with 180 people is not something I want to gamble on. I kept asking myself: is avoiding a few hours of electrical work worth potentially shutting the place down? The worst case wasn’t just a cold room. It was an insurance claim, a cancelled event, and a client who never calls me back. The expected value said no.

That’s the kind of risk weighing that happens in the middle of an emergency. It’s not always about the equipment—it’s about the consequences if the equipment fails.

The Milwaukee Fan and the Last Hour

Electric heat is clean, but it has a weakness: hot air rises. In an 18-foot ceiling space, the heat would collect near the timber beams and leave the guests shivering on the floor. The solution was air movement.

We set up a Milwaukee fan on a tripod stand, angled it up slightly, and used it to push the warm ceiling air back down to the floor. The Milwaukee fan isn’t a replacement for a heater. But in an emergency setup, it turned six heat sources into something that actually heated the whole room. It was the difference between “there are warm patches near the walls” and “the space is comfortable all the way across.”

By 4:10 a.m. on Friday—36 hours before doors opened—we had eight Dimplex fan forced wall heaters running, the Milwaukee fan circulating air, and the temperature holding at 64°F while the outside temp dropped into the teens.

Even after choosing this route, I kept second-guessing. What if one of the temporary circuits tripped at 2 a.m.? What if the thermostat on unit four wasn’t reading right? I didn’t relax until we checked the space again at 6 a.m. and it was still warm. That’s the part of the job nobody sees: the doubt after the decision.

What I’d Do Differently

Here’s the thing: none of this needed to be an emergency. The client’s boiler hadn’t failed overnight—it had been leaking for two weeks, and nobody called a service tech because they thought it was “just a water heater” that could wait. That little delay turned a routine repair into a high-cost, high-stress race.

So here’s my honest advice, from the perspective of someone who gets called at 3 p.m. on a Thursday:

  • Know which box is which. If the unit heats your building, it’s a boiler or a furnace, not a water heater. Label it if you have to.
  • Never ignore a small leak. A slow drip from a heat exchanger or pressure relief valve is almost always a warning, and it only gets worse.
  • Have a temporary heat plan before you need one. That means knowing your electrical capacity and at least one option for emergency heat.
  • Do the pre-season check. In my opinion, a boiler inspection in October is the cheapest insurance an event space can buy.
5 minutes of verification beats 5 days of correction.

The event went off without a hitch on Saturday. The client walked in at 9 a.m., felt the warmth, and said it was the most comfortable that space had been in a month. No pipes froze. No alarms went off. The Dimplex heaters did the job, and the Milwaukee fan made the whole room feel like it was supposed to.

But the real lesson was about prevention, not equipment. The boiler could have been repaired weeks earlier for a fraction of the cost. The temporary heaters were the right emergency tool, but the better solution would have been catching the problem before I got the 3:17 p.m. call.