There isn't one best heater. If someone tells you to buy the same heating unit for every cold room, they're either selling something or they haven't looked at your energy bills. Over the past seven years, I've managed HVAC-related purchasing for a 40-person facility services company. I have a spreadsheet with about $180,000 in equipment and repair costs, and the clearest pattern I see is this: the right purchase depends on how the room is used, how long the heat needs to run, and whether the space is actually dry.

So here's a decision framework I use before ordering anything. It's not glamorous, but it has prevented a lot of expensive returns.

One framework, four common scenarios

If you're here because the office is cold, stop and sort the problem into one of these four categories.

  1. Steady heat needed: The room is occupied for four or more hours, and you need quiet, stable warmth.
  2. Quick spot heat needed: The room is used for twenty minutes, then empty.
  3. Cold that feels damp: The temperature is okay, but the space feels clammy.
  4. Control problem: The equipment is fine, but the thermostat or filter is making the system do the wrong thing.

Most buyers focus on wattage and BTU. They miss the controls, the humidity, and the duty cycle. Those are the factors that determine whether your next purchase is actually going to fix the problem.

Scenario 1: Long occupancy and steady heat — Dimplex oil filled heater

If you need to heat a front desk, a workshop bay where someone sits all day, or a bedroom overnight, you want steady heat without a noisy fan cycling on and off. This is where a Dimplex oil filled heater makes sense—or, actually, any good oil-filled radiator with a decent thermostat. I keep coming back to Dimplex because their controls have been reliable in our orders.

An oil-filled radiator heats the oil inside the fins, and that heat radiates and convects into the room. It takes longer to warm up than a fan heater. But once it's up to temperature, it holds heat longer. The thermostat can cycle the element on and off instead of running it flat out all day.

Why I'll pay more for the oil-filled style

The lowest quote I ever approved was for a batch of cheap fan heaters. They were less than half the price. They also sounded like a jet engine, blew dust into the electronics, and the elements kept burning out. Within a year we were back to buying oil-filled units. That "cheap" option cost us more in labor and replacements than the difference would have covered for several good heaters.

I'm not saying every oil-filled heater is bulletproof. But there are fewer moving parts: no fan, no exposed element, no grille to clean. For long-cycle heating, the total cost of ownership tends to favor the unit that doesn't need to be replaced next year. That's why I've standardized, at least partly, on Dimplex oil filled heaters for our steady-heat rooms.

Dimplex's oil-filled heaters usually include thermostats and programmable controls. That matters. You don't want the heating element working all night. You want it to hit setpoint, shut off, and use residual heat. That's the energy-efficient way to run one.

Scenario 2: Quick spot heat — sometimes a Lasko heater is the right tool

Now for the opposite case. If you need to warm a mechanic's bay for half an hour, a garage while you're working, or a loading area during a delivery, you don't need a radiator that takes time to heat its own oil. You need hot air, now.

A fan heater like a Lasko heater can do that. These are simple forced-air units: a heating element and a fan that pushes air past it. They're loud, and they dry out the air, but they are fast.

The mistake is buying one for a room that's occupied all day. That pattern shows up in our maintenance requests every winter: a small fan heater installed as the primary heat, a high electric bill, and an employee who still says the room is cold when the fan cycles off.

If your usage is genuinely short, a budget-priced fan heater isn't a bad decision. It's a bad decision when it's the only heater in a space that needs steady, controlled heat. The upside is speed and low upfront cost. The risk is that it runs all day and creates a monthly energy spike that makes your "cheap" purchase very expensive.

Scenario 3: Humidity makes it feel colder — Dimplex 20L smart dehumidifier

Sometimes the issue isn't warmth. It's moisture. A basement or laundry room at 65°F and 80% humidity feels colder than the same room at 65°F and 50% humidity. Your body can't evaporate sweat when the air is already full of water, so you feel clammy and chilled.

A dehumidifier doesn't replace a heater, but it can take the edge off so the heater doesn't have to work as hard. This is where the Dimplex 20L smart dehumidifier fits.

"20L" means extraction capacity: 20 liters per day in ideal conditions. The smart part matters more than the capacity number. It has a humidity sensor and can cycle itself based on a target RH level. You set it for 55%, and it runs when needed, not all day.

I don't have hard data on how much a dehumidifier changes perceived temperature. I wish I had tracked that metric. What I can say anecdotally is that our field managers reported fewer "cold and drafty" complaints at the same thermostat setting after we put a unit in the damp areas.

Compared with another portable heater, a smart dehumidifier costs more upfront. But if it prevents a mold remediation call in two years, the ROI is obvious. That's the "value over price" argument I keep making to my own team.

Scenario 4: The cheapest fix is usually thermostat replacement or filter direction

Before you buy any heater, look at the existing controls. This sounds boring, but it's the most cost-effective step I know.

Thermostat replacement: the unglamorous fix

If the room is cold but the thermostat says it's 72°F, you have a sensing problem, not a heating problem. A thermostat that reads 4°F high means the room stays around 68°F while the heater keeps running longer than it should—or, worse, shuts off before the room is warm.

Thermostat replacement is a relatively small project. For a procurement person, it's a purchase order that doesn't get a marketing photo. Based on what we've paid through 2024, a basic programmable thermostat runs $25–60 in parts, plus labor if you hire an electrician. That's less than a new heater that doesn't fix the actual issue.

Which way to put air filter in furnace: up or down?

The question I see in facility notes is: "Which way to put air filter in furnace, up or down?" The answer is neither, exactly. The arrow needs to point in the direction of airflow. On most furnaces, that's toward the blower/furnace, not toward the ceiling.

If the arrow points back toward the return duct, the filter can collapse under suction. Air then bypasses the filter, dust gets into the system, and the furnace works harder. That's a $20 filter causing a potential repair bill that costs more than any heater you were thinking about buying.

So before you order another heater, check the thermostat and the filter. I've had more than one facility manager request a new heater when the actual fix was a thermostat replacement and a correctly oriented filter.

How to figure out which one you're dealing with

Use the same questions I put on our purchase request form.

  1. How long will someone actually be in the space? If it's less than an hour, lean toward spot heating. If it's more than four, lean toward steady, thermostatically controlled heat.
  2. Does the cold space feel damp? If yes, address humidity first or in parallel. A heater fighting a damp room is wasting energy.
  3. Have you checked the thermostat and the filter direction? If not, do that before comparing models.
  4. What's the three-year total cost? Unit price + shipping + expected energy use + likely replacement cost, not just the sticker.

There is no single brand that wins every scenario. When someone asks whether to buy a Dimplex oil filled heater, a Lasko heater, or a Dimplex 20L smart dehumidifier, I ask how they plan to use it. That usually answers the question before I do.

One caveat: I'm a procurement guy, not an HVAC engineer. For electrical or ductwork changes, bring in someone licensed. For selecting equipment, this framework has saved us money more often than any vendor discount.