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A GreenBuildingAdvisor forum poster building a small North Texas granny flat argues that four single-zone mini-splits may suit the home better than a central ducted system. The post describes the builder’s estimated heating load and equipment prices, but does not report an installation or measured performance; the comparison remains a proposal and set of opinions.
A builder planning a 1,120-square-foot North Texas granny flat says they are leaning toward four single-zone mini-splits rather than central ducted heating and cooling, challenging advice from other commenters that a central system would be better. The GreenBuildingAdvisor post describes the equipment plan and the builder’s estimated heating load, but supplies no installation results or measured comparison between the options.
The planned home has two bedrooms and an 800-square-foot conditioned attic, according to the post. The builder puts the heating load at about 21,000 Btu on the worst day. Their proposed layout uses one mini-split in each bedroom, one in the living room and kitchen, and one in the attic. They say they would likely consider four 9,000-Btu single-zone units.
The post gives approximate prices of $500 per 9,000-Btu unit for purchase and installation, while saying 6,000-Btu models start at $1,400. Those figures are the poster’s estimates; the source does not specify the brands, scope of installation, date of pricing, or whether costs are directly comparable. The builder says a central system was recommended by people in another group, but the post does not identify those commenters or provide their detailed reasoning.
In support of the mini-split plan, the writer argues that separate indoor units could let occupants cool bedrooms without conditioning the whole home, provide some backup if one unit fails, and avoid losses and upkeep associated with ducts. They also question whether central equipment would solve humidity or temperature differences in this particular design. These are the poster’s arguments, not findings from a test or an independent HVAC assessment.
Choosing HVAC for a Small, Zoned Home
The discussion matters to homeowners weighing HVAC for a compact, high-performance house because equipment layout can affect comfort, operating costs, maintenance and resilience. A central system distributes conditioned air through ducts, while separate mini-splits can serve different rooms or zones. Which approach works better depends on the building, equipment sizing, installation, controls and occupants’ needs; the post does not establish a general winner.
The writer highlights a practical trade-off: room-by-room control may help avoid cooling unused spaces, but multiple indoor units also mean more equipment and controls to select, install and maintain. The post’s price estimates could shape a reader’s expectations, yet they are not a verified quote or a complete cost comparison. Readers considering either option would need project-specific load calculations and installation estimates rather than relying on the post’s figures alone.
The post also raises questions about humidity management, filtration, solar heat gain and equipment failure. Those concerns are relevant to the proposed home, but the source offers no measurements of humidity, energy use, indoor air quality, or comfort. Its value is as a record of a homeowner’s reasoning and the questions they want answered—not evidence that ducted HVAC performs poorly across similar homes.
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The Proposed Four-Unit Layout
The builder says the home is in North Texas and describes it as a high-performance, small house. The living room and kitchen face south and are expected to receive passive solar heat through windows, while the north-side bedrooms may remain cooler. The writer asks where a central system’s thermostat should go if sunny winter conditions heat the common area more than the bedrooms.
The post also refers to an ERV, or energy-recovery ventilator, planned to exchange air at a stated rate of 0.35 air changes per hour. The writer suggests its filtration could be as good as or better than filtration through a ducted HVAC system. The source does not provide the ERV model, filter specification, ventilation design, or evidence comparing its filtration with a particular HVAC filter.
For humidity, the poster asks why high-performance homes in the same climate zone that use central ducted systems sometimes also install whole-house dehumidifiers. That question is not accompanied by examples or data, and does not establish that a ducted system cannot control humidity. The post presents it as a challenge to the claim that ducted equipment necessarily offers an advantage.
“I’m more convinced than ever that DUCTED hvac is not the way.”
— The builder, in the GreenBuildingAdvisor forum post
Costs and Performance Still Unverified
The source does not say whether the granny flat has been completed, whether the mini-splits were installed, or what system the builder ultimately chose. There are no measured results for energy use, humidity, temperature balance, filtration or reliability, and no independent evaluation of the stated load or equipment sizing.
The listed prices also lack details needed for a fair comparison, including equipment models, labor, electrical work, refrigerant-line routing, controls and any duct or ventilation costs. It is unclear whether the four proposed units can operate as expected across the home’s heating and cooling conditions, or how the design would handle ventilation and humidity. The post does not include a response from an HVAC contractor or a manufacturer.
The writer’s references to duct cleaning and eventual duct replacement are concerns, not established outcomes for this specific house. Likewise, the claim that other mini-splits could provide relief if one unit fails has not been tested in the proposed layout. Both systems’ real-world results would depend on design and installation details absent from the post.
A Project-Specific System Decision
The next development is whether the builder proceeds with the proposed four-unit layout or selects central ducted equipment; the forum post does not report a decision or installation date. A useful comparison would require a documented load calculation, equipment performance data, written bids and plans for ventilation, filtration and humidity control.
If the home is built and the system installed, measured operating results could show how well the chosen design handles the poster’s concerns, including uneven temperatures between the south-facing living space and north-side bedrooms. Until such information is available, the post remains a homeowner’s argument for one approach, rather than evidence of the outcome.
Key Questions
What HVAC setup is the builder considering?
The builder proposes four single-zone mini-splits: one for each bedroom, one for the living room and kitchen, and one for the conditioned attic. The post does not confirm that the units were purchased or installed.
What heating load does the post give?
The writer estimates a heating load of about 21,000 Btu on the worst day. The source does not include the calculation or an independent assessment.
Does the post prove mini-splits are better than ducted HVAC?
No. It presents the builder’s reasoning and concerns, but reports no completed installation, measured performance, or independent comparison. The claim applies to the writer’s planned home, not all houses.
Are the equipment prices verified?
No. The post says 9,000-Btu units could be bought and installed for about $500 each and that 6,000-Btu units start at $1,400. It does not identify models, explain what installation includes, or provide comparable bids.
Source: rss
