I've been handling custom door orders for contractors since 2019. And for the first two years, I made a lot of expensive mistakes. I'm talking about a $350 error on a single order, total, across about 20 significant blunders. I now maintain our team's pre-order checklist to prevent others from repeating my errors.
There's one piece of advice I keep seeing online that drives me nuts: "You should buy an exterior door based on its core thickness." I think that's misleading at best, and at worst, it'll cost you more money in the long run. I believe the real decision factor is the total cost of ownership (TCO)—the price tag is just the beginning.
The Problem with the "Thicker is Better" Advice
The logic sounds solid: a thicker door (say, 1.75 inches instead of the standard 1.375) has more insulation, is stronger, and feels more solid. So, it should be better, right? Not always. (I learned this the hard way.)
Back in Q1 2022, I ordered a dozen "heavy-duty" 1.75-inch fiberglass doors for a multi-unit project. The quote was $750 each. I compared that to a standard 1.375-inch door from a different supplier at $620. On paper, the thicker door was only 20% more. I approved the $750 door without hesitation.
But the TCO told a different story. The $620 door came with a magnetic weatherstripping system pre-installed. The $750 door did not. Adding that weatherstripping cost another $45 per door. Also, the $750 door had a specific jamb requirement that the contractor didn't know about—it needed a reinforced frame to support the extra weight. That added $80 per opening. Suddenly, the price delta looked like this:
- Door A (Standard 1.375"): $620 (including pre-installed seal and standard jamb compatibility)
- Door B (Heavy Duty 1.75"): $750 + $45 (seal) + $80 (reinforced jamb) = $875
That's a 41% cost increase for a door that was supposedly only 20% more expensive. The worst part? The contractor called me furious. The extra weight made the hinges bind, and we had to re-hang all 12 doors, costing an extra $120 in labor per door. (ugh, I still remember that call.) That was my $350 mistake on that single order, but multipled by 12 doors... I don't want to do the math.
What TCO Really Includes for Exterior Doors
Most people just look at the "sticker price." But in my experience, the real cost of a door includes four hidden factors:
1. The "Inflation" Factor (Installation Complexity)
This is the big one. A door that's not standard can require custom framing, special jambs, and heavy-duty hinges. I learned this the hard way. The price of the door is only half the battle; the installation cost is the other half. If a thicker door requires a reinforced frame, that's not a door cost, it's a construction cost. (note to self: always ask about jamb requirements before ordering).
2. The "Whack-a-Mole" Factor (Performance Trade-offs)
Thicker isn't always better for energy performance. A door with a superior thermal break and quality weatherstripping (even if it's thinner) often outperforms a thicker door with a poor seal. The extra thickness adds mass, which helps with sound, but if the seal leaks, you lose all benefit. So, unless you live next to a highway, the R-value (insulation value) matters more than the door's thickness.
3. The "Upsell" Factor (Required Accessories)
The $620 door was all-inclusive. The $750 door was a "base" model that required you to buy the weatherstripping, the hinges (which were a different gauge), and sometimes even the threshold separately. This is a classic trick. The cheap base price lures you in, but the TCO balloons when you add the mandatory parts.
4. The "Time is Money" Factor (Delivery and Scheduling)
This is less concrete but very real. If you order a non-standard door (like the 1.75" thick one), it might have a 4-week lead time instead of 2 weeks. If you're on a deadline, that delay costs you. In my experience, the scheduling hassle alone can justify sticking with standard sizes. The market rate for standard doors (circa 2023, things may have changed) was fast turnaround. Non-standard meant waiting.
When Should You Actually Buy the Thicker Door?
Okay, so I'm not saying never buy a thicker door. I'm saying don't buy it because of the thickness alone. If you're dealing with extreme climates (northern Minnesota) or need to meet specific hurricane impact codes, the thicker door is often necessary. In that case, the TCO for a standard door would be higher because it wouldn't meet code.
But for 80% of residential and commercial projects in temperate climates, a high-quality standard-thickness door (1.375") with a good thermal break and a proper magnetic seal will outperform a cheap 1.75" door that's poorly sealed and requires expensive installation modifications.
I know some contractors will disagree. They'll say a thicker door just "feels" better to customers. And they're right—it does feel more substantial (circa 2024, that is a legitimate selling point). But if your goal is to save money and avoid callbacks, then the TCO calculation is the one to use. If you're selling a luxury home over $2 million, then yes, spend the extra $200 for the thicker door that feels solid. But for standard rentals or mid-tier builds, thick cores are just a waste of money.
The Bottom Line
I now calculate TCO before comparing any vendor quotes for doors. I add up the door price, shipping, required accessories, estimated installation labor, and potential delays. I also compare the energy rating (U-factor and SHGC) rather than just core thickness.
Stop asking "How thick is the core?" and start asking "What is the total installed cost for a functional, properly sealed exterior door?" That's the question that separates a smart purchase from a $875 mistake. This worked for us, but our situation was a mid-size B2B operation with predictable ordering. Your mileage may vary if you're a custom home builder dealing with unique architectural specifications.
