Over the past six years of tracking every HVAC invoice in our cost tracking system, I've watched our cumulative spending pass $180,000. That's not a boast—it's an uncomfortable number that taught me a simple lesson: the lowest upfront cost rarely is.
This article compares three decisions I've had to make with McQuay equipment, using the same framework I use for vendor bids: total cost of ownership, hidden fees, and long-term reliability. I'm writing from the perspective of a procurement manager who has compared 8+ vendors in a single cycle and learned to ask "what's NOT included" before "what's the price."
The Three Comparisons
These are the questions that come up most often when managing McQuay chillers, heat pumps, and fan coil units:
- Air filter replacement: DIY or hire a professional?
- Old McQuay water source heat pump: repair or replace?
- Heating system choice: baseboard heaters or boiler/water heater combos?
Prices reflect quotes we received in April-May 2025. Verify current rates before you budget—HVAC pricing moves faster than you'd think.
1. Air Filter Replacement: DIY vs. Professional Service
When we first took over an office building with McQuay fan coil units, the maintenance plan called for monthly filter checks. I figured this was the easiest corner to cut. A 20x20x2 MERV 8 filter costs about $25 at a local supply house (based on our last order of 48 units in March 2025). Our facilities guy could swap it in five minutes. Why would we pay a professional $150 to do something that simple?
So we went DIY for about eight months. At first, it worked fine—or rather, it seemed to work fine until the energy bill jumped 12% in a single month and the units started cycling more often. The technician who came out, after a $95 service call fee, found the filter was seated wrong. Not dirty. Not clogged. Seated wrong. It had pulled away from the frame just enough to let unfiltered air bypass the media, coating the coil in a layer of fine dust.
That coil cleaning cost us $420. Total cost of that DIY "savings": $445 plus the $95 fee, against the $150 a professional visit would have charged (which, honestly, felt excessive until that moment).
To be fair, DIY filter replacement works well when the person doing it knows the equipment. At least, that's been my experience with facilities teams that have worked with these units for years. But there's a hidden cost most DIY calculations miss: the cost of your own mistakes. I've come to believe that for simple tasks, the difference isn't labor—it's training.
One more data point: when I audited our 2023 spending, I found we'd paid for 14 professional filter changes across three properties. That seemed like waste—until I did the math on what those visits included. They checked the coil, inspected the drain pan, and tightened the electrical connections. The $150 wasn't for the filter. It was for the checklist. That's a lesson I wish I'd learned sooner.
2. Old McQuay Water Source Heat Pump: Repair or Replace?
Here's where the comparison gets genuinely interesting. We have a McQuay water source heat pump from 1998 in one of our satellite offices (I want to say it's a horizontal console model, but don't quote me on the exact series). It still runs, but it's loud, and the refrigerant lines have needed two top-ups in the past three years.
When the compressor started making noise last winter, I did what procurement managers do: I looked for the manual first. If you've ever searched for an old McQuay water source heat pump manual, you know it's a treasure hunt. I eventually found a scanned PDF buried on a parts distributor's site, dated 1999. The wiring diagram was almost illegible, but the spec table was readable.
One number in that manual arrested my attention: the COP—coefficient of performance. This old unit was rated at 3.2 COP under ideal conditions. A current mid-range water source heat pump is rated around 5.0 COP. That's not a small improvement. That's a 56% efficiency gap, and it shows up directly on the electric bill.
So we built the TCO comparison:
- Repair: $800 for a new starting relay and refrigerant top-up. The unit keeps running at 3.2 COP, with the same risk of another breakdown next season.
- Replace: $12,500 for a new unit and installation (based on quotes from two vendors in April 2025; verify current pricing). Estimated energy savings: roughly $950/year.
The payback period on replacement is about 11 years. That's not compelling on paper. But the risk profile changed the math: another $800 repair, or a worst-case $3,000 compressor failure, could happen in any given year. I kept asking myself: is saving $950 a year worth spending $12,500 now? The expected value said no, but the downside felt worse than the spreadsheet suggested.
Looking back, I should have recommended replacement two years ago, when the first refrigerant leak appeared. At the time, the $600 repair seemed obviously smarter than a $12,000 capital expense. Given what I knew then—nothing about how old heat pumps fail after their first leak—my choice was rational. It was also exactly the kind of decision that looks wrong in hindsight.
If you're in a similar situation, ask your service provider for a COP test. It's a simple measurement—inlet and outlet water temperatures plus flow rate—and it takes about 15 minutes. The number will tell you more about your old McQuay's health than any visual inspection.
3. Baseboard Heaters vs. Boilers/Water Heaters
Now for a comparison that isn't about McQuay equipment directly, but it affects the same maintenance budget. When we renovated a small retail space in 2024, we had to choose between electric baseboard heaters and a combined boiler/water heater setup.
Baseboard heaters were dramatically cheaper upfront: about $1,200 for materials and labor across three zones. They're simple, silent, and need almost no maintenance. The downside? Electric resistance heating costs more per BTU than almost any other option. We estimated the annual operating cost at $1,100 for a space that's only occupied 30 hours per week.
The boiler/water heater combo would have cost $5,800 installed. It's more efficient, especially with a modern condensing design, and it provides better temperature control. But it's also more complex. More components mean more failure points, and more failure points mean more invoices. In our cost tracking system, boiler-related service calls on our older units average $230 per visit, and they happen about once a year per unit.
Here's the conclusion that surprised me: for the part-time retail space, the baseboard heaters were the right call. The boiler's efficiency advantage would take more than a decade to pay back at that usage level. But for a full-time occupied building, I'd choose the boiler every time—not because it's "greener," but because the operating cost difference is real and compounding. There's no universal winner. Only the comparison that fits your usage pattern.
How to Make These Decisions Yourself
After tracking our HVAC spending this way, I've come to believe that the "best" choice is highly context-dependent. That said, a few rules have held up across every comparison I've done:
- For simple maintenance like filter replacement, train someone properly before going DIY. One bad filter seating cost us more than three years of professional service would have.
- Before repairing an old McQuay heat pump, calculate the COP difference. If the efficiency gap is more than 50%—as it was for our 1998 unit—start a replacement fund even if you repair for now.
- Choose baseboard heaters only for intermittent-use spaces. For consistent occupancy, a boiler/water heater combo is worth the higher upfront cost.
One more thing about transparency: when a vendor lists all fees upfront, even if the total looks higher than a competitor's base quote, that vendor usually costs less in the end. Per FTC advertising guidelines, claims like "energy savings guaranteed" must be substantiated (ftc.gov/business-guidance/advertising-marketing). I've been burned by a "cheap" quote that added a $250 "commissioning fee" and a $180 "paperwork charge" after the fact. That's not pricing. That's a bait-and-switch—and it's exactly what the FTC's truth-in-advertising rules are designed to prevent.
Prices quoted here are from our actual orders and vendor quotes between March and May 2025. They're meant for comparison, not as a price list. Verify current rates before you commit.
