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A homeowner planning an 1,120-square-foot granny flat in North Texas says they are reconsidering a central ducted HVAC system in favor of four single-zone mini-splits. The proposal and its cost estimates are the poster’s, not a reported installation or independently verified performance result; the thread does not resolve which system would work better.
A homeowner planning an 1,120-square-foot granny flat in North Texas says they are more persuaded that four single-zone mini-splits may fit the project better than one central ducted HVAC system. The post describes a proposed equipment layout and the owner’s reasoning, but does not report a completed installation or measured results, leaving the system’s eventual performance unknown.
The poster says the building will have two bedrooms and an 800-square-foot conditioned attic, with a stated heating load of about 21,000 BTU on the coldest design day. They propose one mini-split for each bedroom, one for the living room and kitchen, and one for the attic. The poster estimates that four 9,000-BTU single-zone units could each be bought and installed for about $500, while 6,000-BTU units start at $1,400. Those are the poster’s cost figures; the discussion does not document quotes or verify what is included in the prices.
The homeowner says other people in a separate group favored a central system. Their objections to ducted HVAC include possible duct losses, the challenge of choosing a thermostat location in a home with south-facing windows and passive solar gain, and the difficulty of cooling only a bedroom at night. They also raise concerns about duct cleaning and a single point of failure if a central unit breaks down.
The proposed alternative would let occupants condition individual rooms, according to the poster. They argue that if one zone risks short cycling in mild conditions, one or two units could serve more of the home. The poster also plans to use an energy recovery ventilator, or ERV, for ventilation and filtration. These are design expectations and arguments, not results from a tested system.
Room-by-Room Comfort and Control
The choice affects how occupants control temperatures, what equipment and distribution work the project needs, and how the system behaves when only part of the home needs heating or cooling. A multi-zone approach can offer independent room settings, while a central system generally distributes conditioned air through ducts from shared equipment. Which arrangement performs better depends on the building, equipment selection, installation, and how occupants use it.
The poster’s concerns also touch on the relationship between passive solar gain and thermostat placement. If south-facing common rooms warm in winter sun while bedrooms stay cooler, a single thermostat may not represent conditions throughout the house. But the post does not provide a detailed mechanical design, airflow plan, or equipment performance data to show how either option would address that difference.
For readers weighing similar choices, the thread is a case-specific set of questions rather than evidence that ductless or ducted HVAC is broadly superior. The proposed $500-per-unit estimate may also shape the comparison, but the source does not establish whether it includes all required equipment, electrical work, installation details, or other project costs.
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A Small Home With Distinct Zones
The discussion began with a design for a small North Texas dwelling that includes bedrooms, a shared living and kitchen area, and a conditioned attic. The owner says the design heating load is about 21,000 BTU on the worst day. That figure describes the poster’s estimate; the source does not include the load calculation or explain the assumptions behind it.
The poster lists several arguments commonly raised in comparisons of ducted and ductless systems. A central system can distribute air throughout a home and may support filtration through its air handler, while individual mini-splits give occupants separate zone controls. Duct placement and air leakage are relevant design questions, but the source provides no measured duct losses, filtration test, or maintenance history for this particular project.
Humidity is another point of disagreement. The homeowner asks why some high-performance homes they have seen in the climate zone use whole-house dehumidifiers alongside central ducted systems. That observation does not establish that ducted systems cannot control humidity, or that the same equipment would be needed in this granny flat. The post contains no indoor humidity measurements or proposed dehumidification calculations.
“I’m more convinced than ever that DUCTED hvac is not the way.”
— The homeowner who posted on GreenBuildingAdvisor
System Performance Has Not Been Tested
The source does not say whether the granny flat has been built, whether the owner has selected or purchased equipment, or whether the four-unit plan will be installed. It also does not supply the design documents needed to check equipment sizing, minimum operating capacity, room-by-room heating and cooling loads, or how the attic zone would connect to the rest of the home.
There are no operating data comparing the proposed mini-splits with a central system. The poster’s statements about short cycling, humidity control, filtration, efficiency, cleaning, and backup capacity remain arguments or expectations. The source also does not clarify whether the quoted equipment costs include all installation requirements or whether a central system was priced on the same basis.
The Design Choice Still Lies Ahead
The next concrete development would be a final mechanical design or an update from the owner confirming which system is installed. Until then, the comparison remains a proposal rather than a documented outcome. A later account could clarify equipment models, installed costs, commissioning, and performance during North Texas heating and cooling conditions.
The discussion could also be informed by the project’s load calculations, room-by-room design, humidity targets, and ventilation plan. The available post does not say whether those details or a final decision will be shared.
Key Questions
Has the homeowner installed the four mini-splits?
The source does not confirm an installation. It describes a planned granny flat and a proposed four-unit layout.
What is the proposed mini-split arrangement?
The poster proposes one single-zone unit for each bedroom, one for the living room and kitchen, and one for the conditioned attic.
What heating load does the poster report?
The homeowner gives a figure of about 21,000 BTU on the worst day. The source does not provide the calculation or its assumptions.
Does the discussion prove ductless HVAC works better?
No. It reports the homeowner’s reasoning and proposed design, but gives no installation results or measured comparison between ductless and ducted systems.
Source: rss
