Called an Audible

06:46 Tuesday, 29 September 2026
Current Wx: Temp: 54.86°F Pressure: 1017hPa Humidity: 98% Wind: 3mph
Words: 470

I've been frustrated by the fact that we can't install rigid ducting in the floor trusses, because you have to do that as you're setting the trusses, and we didn't know that at the time. I also didn't have an HVAC contractor at that time either.

I was chatting with Mom on Sunday and expressing my frustration, because it turns out that the only solution is to build a chase down the top of the south wall of the basement to enclose the main duct trunk. More work, plus it's just an unwelcome intrusion in the space.

I told Mom, "I kind of wish I'd just gone with mini-splits and been done with it."

Well, that seemed to have tripped a switch somewhere.

Mini-splits are ductless, which is part of their appeal. The air is heated or cooled at the point of delivery in a cassette, and it's the refrigerant that conveys the heat to or from the compressor, so you have these long exterior (some are interior) refrigerant line-sets running around the house.

Well, hydronic heating and cooling is usually ductless too. They have fan-coil units that are essentially the same as the mini-split cassettes. So the light bulb went on and I decided to see if we could forego the central air-handler in favor of a few fan-coil units.

We'd planned to have a meeting yesterday with the contractor and Energy Vanguard to discuss some elements of the design, but as the meeting began I announced that I was calling an audible and wanted to change the design. I acknowledged it'd be an additional cost at their hourly rate, but I thought it might be a better solution overall.

There are a couple of downsides, one is that you don't distribute the conditioned air as evenly, so location is pretty important. They can probably handle the latent load (dehumidification), but you also have to pipe a condensate drain as well as the supply and return lines. Neither seems to pose an insurmountable obstacle.

So Energy Vanguard is performing a redesign, and my rigid ducting frustration is over. I don't know if there's an overall energy penalty. It takes less energy to convey heat with water, but I still need to move air to do the heat exchange at the point of delivery. But those fans won't be dealing with the same volume of air or static pressure. We're looking at about three, relatively small, fan-coil units, so hopefully it's a net overall energy savings.

So I'm glad that we didn't pull the trigger on ordering the equipment. I'd intended to order it last week, but we were preoccupied with a lot of things and it didn't happen, somewhat to my annoyance. But in hindsight, it feels like a happy accident.

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