I've been handling heating equipment orders for about 8 years now. If I remember correctly, my first big Dimplex project was in 2017—a 40-unit apartment building retrofit. I made mistakes on that one. Honestly, a few of them. By the time we wrapped, I had personally documented 6 significant errors that cost us roughly $3,200 in wasted budget and rework.

Since then, I've created a checklist for our team. We've caught 47 potential problems using it in the last 18 months alone. This article is basically that checklist—tailored for anyone working with Dimplex electric heaters, infrared panels, or storage heaters in a commercial setting. It's a 5-step framework for getting the specification right the first time.

I can only speak to medium-scale commercial work. If you're dealing with residential single-unit installs, the scale changes, but the principles hold up.

Step 1: Match the Heating Load, Not the Floor Plan

This is the one that got me early on. I assumed a 1,000 sq ft open plan needed the same heating as 1,000 sq ft of partitioned offices. Dead wrong.

We didn't have a formal load calculation process in my first year. Cost us when we installed 3 kW panel heaters in a conference room that had seven external walls and massive windows. The units ran non-stop and still couldn't hit 68°F. The tenant complained for four months before we swapped them for 5 kW units.

Here's the rule I use now:

  • Perimeter rooms with exterior walls: Calculate at 15–20 watts per sq ft
  • Interior spaces (no exterior exposure): 8–12 watts per sq ft
  • Rooms with high ceilings or large windows: Add 25% to the base figure

This is a ballpark approach, not a substitute for a Manual J calculation. But as a sanity check, it's caught me three times already this year.

Saved $75 once by skipping the load calc on a small office. Ended up spending $450 on a replacement heater plus labor when the undersized unit failed in December. Net loss: $375 plus a pissed-off client.

Step 2: Zone by Use Case, Not by Floor

The second mistake I made—and see other teams make all the time—is zoning heating by physical location rather than how the space is actually used.

On that 40-unit job, we put every living room on one zone and every bedroom on another. Sounded logical. But the east-facing units heated up way faster in the morning than the west-facing ones. Residents in west units were cold until noon; east units were overheating by 10 AM.

The better approach:

  • Group rooms with similar solar exposure on the same circuit
  • Separate spaces with different occupancy patterns (a conference room vs. a quiet office)
  • Put bathrooms and hallways on their own low-wattage circuits or thermostats

Honestly, this sounds basic. But when you're staring at 50 blueprints and a deadline, it's easy to grab the easy zoning. Don't. Take the extra hour to think through how people actually live in the space.

Seeing our Q1 and Q2 complaint logs side by side—same building, different zoning strategies—made me realize zoning by use case cut service calls by 40%.

Step 3: Account for the Control Logic Gap

This is the one most people miss. Dimplex makes some excellent smart baseboard heaters and panel heaters with programmable thermostats. They work great—when the end user understands them.

Here's the problem: we installed smart convector heaters in a 12-unit assisted living facility. The units had scheduling, eco modes, and adaptive start. Sounds great. But the residents were in their 70s and 80s. Nobody knew how to set a schedule. Half of them just pressed the 'up' button until the heat came on and left it there.

The result? Energy bills 30% higher than projected, and the facility manager blamed our equipment. It wasn't the equipment. It was the assumption that 'smart' means 'intuitive to everyone.'

What I do now:

  • For senior living or rental properties: Specify basic manual thermostats or lock out the scheduling features
  • For owner-occupied commercial: Program the schedule during commissioning and leave a quick-start card
  • For mixed-use spaces: Install Dimplex units with a simple 'up/down' control and remote management for facility staff

I'd rather spend 15 minutes explaining thermostat options than deal with mismatched expectations two months later. An informed customer asks better questions and makes faster decisions.

Step 4: Size the Supplementary Heating Correctly

Dimplex makes a wide range—from low-wattage panel heaters to high-output infrared units. The temptation is to oversize, 'just to be safe.' That's a mistake, just not the one you think.

Oversizing an electric heater doesn't mean it runs less. It means it cycles on and off more frequently, which creates temperature swings and can actually feel less comfortable. I've seen this with infrared heaters in particular—put a massive unit in a small room and you get blast furnace, then ice box, then blast furnace again.

The calculation I use for supplementary heating (heat pumps with electric backup, or hybrid systems):

  • Supplemental heat should cover 60–70% of the design load at most
  • If the primary system covers the base load, electric heaters are for recovery and cold snaps
  • Low-wattage units (500–750W) are often better for continuous background heat than one big 3 kW unit

This worked for us, but our situation was temperate climate (zone 5). If you're in a zone 7 deep freeze, the calculus is different.

Step 5: Don't Forget the Maintenance Profile

This is the step I used to skip entirely. I'd specify the heaters, get them installed, and move on. Then the calls would start: 'The unit isn't heating.' 'There's a strange noise.' 'The display is flashing.'

Dimplex storage heaters, for example, require some user awareness. They charge overnight and discharge during the day. If a tenant sets the discharge control to max first thing in the morning, the heat dumps in two hours and they're cold by 4 PM. That's not a product problem—it's an education gap.

My pre-install checklist now includes:

  • Does the client have someone on-site who can reset thermostats and check error codes?
  • Are air filters or intake grilles accessible for cleaning? (Dust on a panel heater cuts output noticeably)
  • For dehumidifiers or cooling fans specified alongside heating: is there a shared maintenance schedule?

The third time we got a service call for 'broken heater' that was actually a dirty filter, I created a one-page maintenance guide. Should have done it after the first time.

Common Mistakes I Keep Seeing

I'm not 100% sure why these happen, but they crop up on almost every project review:

  • Ignoring the voltage drop on long runs to electric heaters. We had a Dimplex air heater (chauffe air) that performed at 75% capacity because the voltage drop was 8% at the unit. Check wire gauge.
  • Mixing storage heaters and direct-acting heaters on the same thermostat. Different charge/discharge profiles create chaos.
  • Assuming 'energy-efficient' means 'cheapest to run.' High efficiency units are great, but they're most effective when the building envelope is tight. If the windows are drafty, no heater will perform well.

Take this with a grain of salt: these observations come from maybe 50+ installations across the Northeast. Your context—different climate, different building stock, different client sophistication—might make some of these irrelevant.

But if you take one thing from this: match the equipment to the user, not just the room. That lesson cost me $890 in my first year. If this checklist saves you even one mistake, it's worth the read.