What this checklist is for

I'm the office administrator for a 137-person engineering services company—or rather, 142 now that the field team grew. I manage all facilities equipment ordering: roughly $300,000 a year across 9 vendors. I report to both operations and finance, and I've learned the hard way that the cheapest first quote rarely survives contact with reality.

This checklist is for anyone who needs to buy heating, cooling, fan, or dehumidification equipment without being an HVAC engineer. It has six steps. I use them before every equipment order, especially when the request comes in as 'just get a heater.'

Step 1: Write Down the Problem, Not the Product

The most common mistake is starting with a product name. 'We need a diesel heater' or 'we need a fan.' Fine, but why? What I mean is: what exactly is the pain?

Take a maintenance shed with pipes that freeze every January. That's not a 'heater' problem. That's a frost-protection problem. For a small enclosed space, a Dimplex tube heater with its built-in thermostat is often enough. It just keeps the temperature above freezing. If you instead order a big diesel heater because someone heard it's powerful, you're paying for output you don't need and adding venting, fuel, and noise headaches.

Write this down before you start:

  • Room dimensions and approximate insulation level
  • Minimum temperature needed, not 'as warm as possible'
  • Hours per day it needs to run
  • Who will operate it and how
  • What happens if it fails

That last one matters more than people expect. If failure means pipe burst, the right answer is a simple mechanical unit with a reliable thermostat. If failure just means a cold lunchroom, you have more flexibility.

Step 2: Size It for the Space, Not for the 'Bigger Is Better' Instinct

It's tempting to think more heat is better. But an oversized electric heater cycles on and off, creates hot pockets, and wastes energy. The goal is to match the load.

For basic electric heating, a rough way to translate is 3.41 BTU per watt. If you're comparing a 1.5 kW Dimplex panel heater and a 3 kW alternative, you're comparing roughly 5,100 BTU/hr vs. 10,200 BTU/hr. Which one fits the space? Start with a load calculation or your supplier's sizing chart, not with the biggest number.

If the request mentions diesel heater, I slow down. A diesel heater can heat an uninsulated warehouse more efficiently than electric resistance heat in many cases. But you have to account for installation, exhaust venting, fuel storage, and carbon monoxide safety. That's a project, not a purchase. If the actual need is spot heating or frost protection, a small electric tube heater may be the better total-cost answer. If the actual need is whole-shop heat, then yes, the conversation changes.

Step 3: Check the Thermostat and Controls Before You Order

This is the step I skipped in 2022. I ordered 12 wall heaters in a hurry. Everything I'd read said heating equipment is heating equipment. It isn't. Some heaters come with a basic thermostat, some require a separate controller, and some don't have a timer option at all.

So now I ask: Does the heater include a thermostat? Is it a mechanical dial or programmable? If you need the heat to drop overnight, can a Dimplex thermostat handle that schedule? And when I'm not sure, I search the manual for 'thermostat Dimplex' to confirm which controller is compatible. If the unit is mounted high on a wall, do you really want people reaching for a manual dial?

For a Dimplex product, this varies by model. Some panel and storage heaters have built-in controls; others are designed to work with an external thermostat. The trick is to verify before you order, not after. The wrong thermostat can turn a good heater into a manual chore.

One more thing: if you rely on a schedule, make sure the thermostat actually supports a program. I've seen 'adjustable thermostat' on a spec sheet and assumed it meant programmable. It didn't. So glad I checked before buying 20 units. Almost learned that after installation.

Step 4: How Does a Dehumidifier Work—and What That Means for Your Purchase

This is probably the most-searched question in this space, and it's worth answering before you spend money. A refrigerant dehumidifier pulls moist air over a set of cold coils. The air cools, water condenses on the coils, and drips into a tray or drains away. Then the air passes over a warm coil and goes back into the room. No, it doesn't 'add' heat exactly; it just re-heats the air after taking moisture out.

That mechanism tells you what to compare:

  • Capacity, usually pints per 24 hours. This is the big number. Match it to the room and the dampness level.
  • Operating range. Some dehumidifiers don't work well if the space gets below about 40°F / 5°C. If you're buying for a basement that gets cold, the manual matters.
  • Drainage. Does it have a built-in pump? If not, can you gravity drain it? If neither, someone has to empty the tank. That someone is often me when I don't check.

The same value-over-price logic applies here. A dehumidifier that is $150 cheaper but needs daily emptying will cost you in labor within a season. An Energy Star certified unit can cut the electricity draw, which for a unit running for months is meaningful.

Step 5: Use the Right Outdoor Fan for the Location

Outdoor fan is not a single product category. A portable floor fan from the supply closet is not an outdoor fan, even if it runs for a couple of days. The first time we put one on a covered loading dock, it rusted before the season ended. The replacement had a weather-rated motor and blade coating, and it's still going.

When you see 'outdoor fan' on a request, check:

  • Is the fan rated for damp or wet locations? Damp-rated can handle humidity; wet-rated can handle direct water exposure.
  • Is it going to be fixed or moved around? A mounted wall or pedestal fan might be safer than a free-standing one in a busy area.
  • What's the airflow need? CFM matters, but so does placement. I've seen powerful fans useless because they were blowing over a wall.
  • Does it have a UL/ETL listing and an IP rating? If not, it's a problem waiting for a rainy day.

Also consider whether you actually need a fan for cooling or for ventilation. If heat is the problem, sometimes moving air is enough. If fume or dust is the problem, you need something with the right motor and possibly an explosion-rated option. That's not a place to save money.

Step 6: Compare Total Cost of Ownership, Not Unit Price

Now you can look at price. Do it after you've defined the problem, sized the load, checked controls, and understood the environment. That's the order that works.

Let me give you an example. In our 2024 vendor consolidation project, we compared two electric heaters that had similar specs. One was $80 cheaper per unit. It looked like an easy win. But the cheaper model didn't have a programmable thermostat option, and the space wasn't on a decent controller. That meant somebody had to walk over twice a day to turn it on and off. At the rate we pay maintenance technicians, that $80 saving cost us a lot more before spring. We installed the controls after the first month. If I'd priced the whole system first, I would have chosen differently.

Total cost includes:

  • Unit price
  • Thermostat or controller cost
  • Installation labor and electrical work
  • Shipping and lead time
  • Expected energy use
  • Maintenance and repair likelihood
  • Invoicing and support quality

The last one sounds non-technical, but it's not. A supplier who can't provide proper specs or invoices creates hidden work. I've eaten that cost. It's real.

And as I said earlier, a diesel heater quote needs to be evaluated the same way. Fuel cost, delivery, exhaust routing, and safety certification all belong in the total. If you're comparing a diesel heater to an electric Dimplex option, you're not comparing heaters. You're comparing two different infrastructure projects. Pick the one that fits the site.

Common Mistakes I See in Equipment PO Reviews

Use this as a final check:

  • Don't skip electrical capacity. Add up the current draw. A 2 kW heater at 230V draws about 8.7 amps. If the circuit already has lights and a panel, it can trip. Verify with a qualified electrician before ordering a fleet of heaters.
  • Don't ignore lead time. If a part is backordered and you need it before winter, it doesn't matter how good the unit is. I built in a 3-day buffer on a critical order and still barely made the deadline.
  • Don't bury the spec sheets. Save the model, thermostat instructions, and warranty page. When the facility team calls me, I can answer the question in one search instead of three emails.

Oh, and one more: don't assume 'compatible thermostat' means it's included. Verify. The most expensive words in procurement are 'I assumed.'

This checklist isn't glamorous. But it turns 'just get a heater' into a decision you can defend to finance and operations. The best part is seeing a unit come in, get installed, and run without someone needing to babysit it. After managing this stuff for years, I'll take boring reliability over a low price every time.