Overview
Code requirements and best practices for installing mini-split outdoor condensing units in Michigan climate. This information will be critical during Stage 6 (After Build / MEP & Finish) when installing the HVAC system.
Related: HVAC Strategy
Mounting Height & Pad Requirements
Michigan Residential Code (IRC)
- Minimum elevation: At least 3 inches above ground to permit free drainage of defrost water
- Compliance: Must conform to manufacturer’s installation instructions
Michigan Climate Recommendations
- Concrete pad: Required for stability and proper drainage
- Must be level
- Should extend slightly beyond unit footprint
- Snow/flood protection: Stand or platform highly recommended
- Elevate 12-24 inches above ground level
- Height should exceed typical snowfall accumulation
- Platform must be rated for snow loads
- Protective hood/awning: Install 40 inches above unit to protect from heavy snow and ice accumulation
Clearance Requirements
From Building Walls
- Code approach: IRC defers to manufacturer’s installation instructions (no fixed distance specified)
- Typical manufacturer requirements:
- 12 inches minimum from wall or other obstructions
- 28 inches minimum from front (service access side)
- 12 inches minimum from rear
- 40 inches minimum overhead clearance
Service Access (IMC Section 306.1)
- 30” x 30” level working space required on control side for servicing
- Additional clearances per manufacturer’s specifications
Why Clearances Matter
- Insufficient clearance increases operating costs
- Reduces system efficiency
- Shortens equipment lifespan
- May cause airflow restrictions and performance issues
Property Line Setbacks
General Information
- Not uniform: Requirements vary significantly by municipality in Michigan
- Typical range: 3-5 feet from property line (common standard)
- Fire safety minimum: 3 feet is a common fire safety standard across jurisdictions
- Some jurisdictions: May extend to 5-6 feet depending on zoning
Michigan Residential Code (MRC 2015)
- No specific setback for HVAC condensing units in state code
- Exhaust openings: Must be 3 feet from property lines (MRC M1506.3)
- Defers to: Manufacturer clearances and local zoning ordinances
- Note: 2021 MRC adoption delayed by court order (July 2025); 2015 codes remain in effect
Clare County Setback Research
Jurisdiction: Clare County Community Development handles all building/mechanical permits for City of Clare (as of July 25, 2016).
Contact Information:
- Clare County Community Development
- 225 W Main St, Harrison, MI 48625
- Phone: 989-539-2761
- Hours: 7:30 a.m. - 4:00 p.m. (closed noon-1 p.m.)
- Website: clareco-buildingdev.net
City of Clare Contacts:
- Zoning/Code Enforcement Officer: Terry Acton
- Building Official: Mark Fitzpatrick
Our Situation:
- Garage rear wall is 6 feet from rear property line
- Typical 3-foot setback requirement would leave 3 feet for unit placement
- Unit width (~3 ft) + wall clearance (1 ft) = 4 ft total depth needed
- Assessment: 6 feet is likely sufficient, but must verify with county
Questions to Ask Clare County:
- What is the required setback for mechanical equipment from rear property line?
- Are there noise restrictions for HVAC equipment near property lines?
- Does the township have additional zoning requirements beyond county code?
Common Requirements from Other Jurisdictions (Reference)
Based on research of various municipalities:
- 3 feet: Common fire safety minimum (Bay Area cities, many others)
- 5 feet: Seattle, Albany CA, some Michigan townships
- Enclosures: Cannot extend more than 4 ft into setbacks; must be 3 ft from lot line
- Noise limits: 50 dBA at property line (when within 10 ft of neighbor’s living areas)
Noise Considerations
- Keep at least 10 feet from:
- Neighbors’ patios
- Bedroom windows (yours and neighbors’)
- Property lines where noise could be an issue
- Typical noise limits: 45-50 dBA at property line
- Hyper-Heat units may be slightly louder during defrost cycles
Required Action
⚠️ Critical: Contact Clare County Community Development (989-539-2761) to confirm specific setback requirements before finalizing placement.
Electrical Requirements (NEC)
Service Receptacle (NEC 210.63)
- Requirement: 125V, single-phase, 15A or 20A receptacle
- Location: Within 25 feet of outdoor unit, on same level as equipment
- Accessible: Must be in an accessible location
- GFCI protection: Required (effective January 1, 2023 for mini-splits)
- ⚠️ Important: Receptacle must NOT be connected to load side of equipment disconnect
Dedicated Power Supply
- Provide exterior electrical box for outdoor unit
- Install dedicated circuit breakers per equipment nameplate specifications
- Follow manufacturer’s electrical requirements
Condensate Drain Requirements
Piping Standards (Michigan Plumbing/Mechanical Code)
- Trap/check valve: Required in drain line
- Pipe size: Minimum ¾ inch internal diameter
- Cannot decrease in size from drain pan to disposal point
- Material: Approved corrosion-resistant material
- Slope: Minimum 1% slope (⅛ inch per foot) toward disposal point
- Disposal: Must convey to approved place of disposal
Freeze Protection (Critical for Michigan)
- Exterior drain lines: Require insulation and/or heat trace
- Preferred solution: Route condensate drain to heated/protected location
- Winter operation: Ensure drain system functions during heating mode (defrost cycles produce condensate)
Auxiliary Protection
Required where overflow could damage building components:
- Auxiliary drain pan, OR
- Water-level detection device
Michigan Climate-Specific Considerations
Snow Management
- Unit placement: Avoid locations where snow drifts accumulate
- Roof eaves: Don’t place where snow/ice can slide/fall onto unit
- Access paths: Ensure year-round access for service/maintenance
- Prevailing winds: Consider wind direction for snow accumulation patterns
Cold Weather Performance
- Hyper-heat models: Recommended for Michigan (rated to -13°F or lower)
- Defrost cycle: Ensure proper drainage during defrost operations
- Base pan heater: Some units include this feature for freezing conditions
Seasonal Maintenance Access
- Plan for snow removal around unit
- Consider lighting for winter service access
- Maintain clear path from service entrance
Installation Sequence & Coordination
Pre-Installation (Stage 3 - Framing)
- Determine exact outdoor unit location
- Verify property line setbacks with local building department
- Plan lineset and condensate routing through wall
- Install wall sleeve/penetration during framing
During Exterior Finish (Stage 5 - Siding)
- Install exterior electrical box for outdoor unit
- Complete lineset and condensate penetrations
- Coordinate with siding for proper flashing
Installation Phase (Stage 6 - After Build)
- Pour concrete pad (outside main contract scope - see Open coordination items)
- Install mounting stand/platform (if using)
- Set outdoor unit on pad
- Complete electrical connections
- Route and connect lineset
- Install condensate drain with freeze protection
- Install protective hood/awning if applicable
- Commission system per manufacturer specifications
Open Items & Decisions
Outdoor Unit Location Decision
Under Consideration: Center-back placement vs. side wall placement
| Factor | Side Wall (24’) | Center-Back (40’) |
|---|---|---|
| Lineset length | Longer (40+ ft to far units) | Shorter (~20-25 ft max) |
| Electrical run | Shorter (near panel) | Longer (across building) |
| Cost impact | Higher (copper lineset expensive) | Lower (wire is cheap) |
| Efficiency | Lower (longer refrigerant lines) | Higher (shorter lines) |
| Service access | Wall-mounted or ground | Ground level (easier) |
| Property setback | Side yard | 6 ft to rear property line |
Current Preference: Center-back placement for shorter lineset runs and better efficiency.
Blocker: Must confirm rear property line setback with Clare County before finalizing. See Clare County Setback Research.
From Initial Build Coordination
- Ask about pouring small slab for mini-split heat pump (currently outside contract scope)
- Coordinate timing with other exterior work
- If center-back placement confirmed, adjust slab location accordingly
To Be Determined
- Confirm setback with Clare County (call 989-539-2761) — stage:: 3
- Finalize placement location based on setback confirmation — stage:: 3
- Stand/platform height based on typical snow accumulation (12-24” recommended)
- Condensate drain routing (ground-level simplifies this if center-back)
- Protective hood style and mounting method
- Service access pathway design (year-round access to back of building)
- Check for roof overhang/snow shedding hazard at center-back location
Permit & Inspection Requirements
Typical Requirements
- Building permit for HVAC installation
- Electrical permit for outdoor unit circuit
- Mechanical inspection after installation
- Final inspection before commissioning
Pre-Installation Checklist
- Confirm local property line setback requirements
- Obtain necessary permits
- Schedule required inspections
- Review manufacturer’s installation manual
- Verify all clearances meet code and manufacturer specs
References & Resources
Related Project Documents
- HVAC Strategy - Overall HVAC system design
- Initial Build - Contract scope and coordination items
- Insulation Strategy - Envelope performance (affects sizing)
Code References
- Michigan Residential Code (MRC) Chapter 14 - Heating and Cooling Equipment
- International Mechanical Code (IMC) Sections 304.1, 306.1
- National Electrical Code (NEC) Section 210.63
- Michigan Plumbing/Mechanical Code - Condensate drain requirements
Manufacturer Resources
- Consult specific equipment installation manual for exact clearances
- Follow manufacturer’s specifications for electrical, refrigerant, and condensate requirements
- Mitsubishi Hyper-Heat installation guidelines (when unit selected)
Notes
- Initial code research conducted October 2025
- Clare County setback research conducted January 2026
- Center-back placement option added January 2026
- Always verify current code requirements with local building department before installation, as requirements may change and vary by jurisdiction
- Michigan Residential Code 2015 remains in effect (2021 adoption delayed by court order July 2025)