Start with the converted attic
Show the provider roof slopes, available mounting space, insulation information, windows, and room use. Ask for the attic's heating and cooling calculation and a comparison with the proposed equipment's output.
If insulation, air leakage, or the conversion's construction needs assessment, involve a qualified building professional. Coordinate any proposed building work with the equipment design rather than sizing from assumptions.
Identify what must stay comfortable when the attic door is closed. A downstairs unit is not a documented plan for an upstairs room.
Plan the rest of the house
A DOE-hosted handout describes mini splits as retrofit options for homes without distribution ducts and for individual-room conditioning. It does not establish the number of heads your home needs. DOE-hosted air-source heat-pump handout.
Request a marked floor plan showing each served room, indoor units, controls, and any spaces relying on existing heat.
Discuss closed bedrooms, airflow near beds, sound, and maintenance access. Ask whether different approved unit styles or a combination of approaches fits the small rooms and attic better.
Make the installation scope visible
Have the provider show refrigerant-line routes, cooling-drain routes, outdoor placement, and necessary wall or roof penetrations. Ask how the plan protects finishes and maintains access for future service.
A licensed electrician should assess the proposed electrical work. The responsible providers should identify current Denver permit requirements and any building work included or excluded.
Request exact models and approved combinations. Do not choose equipment from a floor-area rule alone.
Decide from a coordinated plan
We would resolve the attic's building condition and equipment fit before ordering. An unexplained hot attic can leave a homeowner paying for equipment that does not address the whole problem.
Your next step is a site assessment with room calculations and an installation drawing. Get one coordinated scope for equipment and related trades, with a clear owner for each part.