A new detached ADU needs heating and cooling planned as part of a new dwelling, including separate required ventilation. We assess the layout, loads, electrical supply and installation routes with the project documents. A compact floor plan does not automatically make one head sufficient or turn the project into a simple bedroom retrofit.
Establish the construction category first
A new detached ADU, a conversion and an addition can follow different project conditions. Tell us which work is proposed and what plans or compliance documents already exist. We use those documents rather than infer the scope from a rear building’s appearance.
This matters to equipment selection and coordination. If walls are not yet closed, routes may be planned alongside framing and utilities. If construction is complete, access and finish repairs can change the installation work. We discuss the stage before settling the equipment positions.
Room boundaries matter even in a small dwelling
An open studio and a one-bedroom ADU can have similar floor areas while needing different distribution. A head in the main room may not cool an enclosed bedroom reliably with its door closed. We review how occupants will actually use the space.
Dedicated units or an appropriate concealed-duct arrangement may be options. A ducted solution needs supplies, a return-air path and sufficient equipment access. We compare those construction requirements alongside the visible appearance of wall heads or grilles.
Ventilation is independent of recirculated cooling air
A typical ductless head moves indoor air across its coil and back into the room. That is not outdoor-air ventilation. New detached dwellings need their required ventilation even when a small mini-split meets the heating and cooling load.
We coordinate the scope discussion so ventilation equipment and responsibilities are identified. Bathroom and kitchen moisture need their appropriate provisions as well. A cooling or dry setting should not be presented as the entire dwelling’s ventilation design.
Match the load and the equipment range
Windows, orientation, insulation and air leakage influence demand. We use the intended construction conditions and suitable local design inputs. Heating requirements deserve review if the mini-split will provide the dwelling’s heat as well as cooling.
Minimum output matters for small spaces. A variable-speed system still has an operating minimum. We compare that with the periods when only one small room needs conditioning, rather than choose extra capacity as a precaution. Shared outdoor equipment needs a system-level check as well as indoor labels.
Routes need coordination before finishes close
We review the outdoor location for airflow, support and service space. We also consider its effect at nearby occupied areas, including the main home. Refrigerant length and elevation limits follow the selected system.
The indoor drain needs a suitable gravity route or pump arrangement. Piping that can rise does not make condensate rise without pumping. Where pumping is needed, we discuss access and sound. A concealed installation still needs maintainable components after construction finishes.
Compliance and electrical responsibilities need definition
The CEC’s ADU guidance distinguishes the relevant project categories and requirements. Required ECC verification follows the applicable code and compliance documents; older-code work may follow a different path. We identify who handles documentation, inspections and closeout rather than assume one universal test package.
Electrical supply needs the actual equipment requirements and available property capacity. A new branch circuit differs from panel or service changes. Those wider electrical responsibilities should be coordinated with the ADU project rather than left outside the equipment conversation.
Keep the ADU budget complete
A single-zone price example is configuration-level context, not a complete dwelling budget. We define equipment, routes, access, electrical work and finish responsibilities for the actual scope. LADWP’s current rebate program excludes ADUs and new construction, so we do not subtract a retrofit incentive from that budget.
Let’s work out the installation for your space
Tell us what is happening in your rooms. We’ll help you plan the system and the work needed to install it.
Get an Installation EstimateYour project questions
Does a very small ADU need ventilation?
New detached dwellings need their required ventilation regardless of the mini-split’s room size. Recirculated cooling air does not replace that function.
Is one indoor head always enough?
No. Loads and normal room boundaries determine distribution. An enclosed bedroom may need direct service or a designed air path.
Can you coordinate while construction is underway?
We review the project stage and available plans so equipment routes and access can be coordinated with the construction scope.
Further guidance: CEC 2025 ADU guidance.