Install New HVAC System
A whole home remodel demands properly sized HVAC equipment for your updated home. Right-size equipment based on new insulation and air sealing levels, and consider zoned systems or mini-splits for optimal comfort and efficiency.
Quick Summary
Typical Cost
$12,000 - $40,000
Complete system with ductwork
Time Required
3 - 7 days
Equipment and ductwork
Difficulty Level
Professional Required
Licensed HVAC contractor
Why This Matters
Your HVAC system is the largest energy consumer in your home, typically accounting for 40-60% of energy costs. During a whole home remodel, you have a unique opportunity to install an optimized system that matches your updated home's actual heating and cooling needs rather than relying on outdated equipment sized for a leaky, poorly insulated house.
A remodeled home with new insulation, air sealing, and high-performance windows requires far less heating and cooling capacity than the original structure. Installing new equipment sized for the old load wastes money and provides poor comfort. Properly sized equipment runs longer cycles, maintains more consistent temperatures, and controls humidity better than oversized units that blast on and off.
Modern HVAC technology has advanced dramatically. Variable-speed equipment adjusts output to match conditions, providing whisper- quiet operation and excellent efficiency. Heat pumps now work effectively in cold climates. Zoning systems and ductless mini-splits provide individual room control. This is your chance to install a system that provides exceptional comfort for decades to come.
Step-by-Step Guide
Step 1: Perform Manual J Load Calculation
Proper equipment sizing starts with an accurate load calculation based on your remodeled home's characteristics.
- Hire an HVAC contractor who performs proper load calculations
- Provide details on new insulation levels and window specifications
- Account for new air sealing and building envelope improvements
- Consider room-by-room loads for zoning decisions
- Factor in internal gains from occupants, appliances, and lighting
- Verify calculations match your climate zone and design temperatures
Step 2: Select System Type
Choose the HVAC system type that best matches your home's needs, climate, and efficiency goals.
- Heat pump: Best overall efficiency, both heating and cooling, ideal for most climates
- Dual-fuel: Heat pump with gas furnace backup for extreme cold
- Gas furnace with AC: Traditional choice where gas is inexpensive
- Ductless mini-splits: Excellent for zoning, no ductwork needed
- Ducted mini-splits: Combines ductless efficiency with hidden installation
- Geothermal: Highest efficiency but significant installation cost
Step 3: Plan Zoning Strategy
Decide how to zone your home for optimal comfort and efficiency in different areas.
- Separate zones for each floor in multi-story homes
- Zone additions or master suites independently
- Consider room orientation (sunny rooms need different treatment)
- Plan for variable occupancy (guest rooms, home office)
- Damper-based zoning works with single systems
- Multi-head mini-splits provide individual room control
Step 4: Design Ductwork Layout
Proper duct design using Manual D ensures adequate airflow and system efficiency.
- Calculate CFM requirements for each room
- Size ducts for proper velocity and low static pressure
- Plan duct routing within conditioned space when possible
- Include adequate return air paths for each zone
- Specify duct material: sheet metal, insulated flex, or hybrid
- Plan register locations for optimal air distribution
Step 5: Install Equipment
Install the main HVAC equipment in appropriate locations with proper support and access.
- Position furnace/air handler in accessible location with service clearance
- Install outdoor unit on level pad with proper clearances
- Run refrigerant lines between indoor and outdoor units
- Install condensate drain with proper slope and trap
- Connect gas line if applicable with proper shutoff
- Wire electrical connections per code requirements
Step 6: Install Ductwork
Install supply and return ductwork throughout the home, focusing on air-tight connections and proper support.
- Install main trunk lines from equipment
- Run branch ducts to each room per design
- Seal all joints with mastic and/or approved tape
- Support ducts properly without sagging or kinks
- Insulate ducts in unconditioned spaces (R-6 or R-8)
- Install return air ducts or panned returns
Step 7: Install Registers and Grilles
Install supply registers and return grilles in planned locations for optimal air distribution.
- Position supply registers near exterior walls under windows (heating mode)
- Or ceiling location for cooling-dominated climates
- Install return grilles away from supplies for good air circulation
- Size registers appropriately for CFM and throw distance
- Use adjustable registers for balancing airflow
- Ensure proper installation flush with finished surfaces
Step 8: Install Controls and Thermostat
Install thermostat(s) and any zoning controls for system operation.
- Position thermostat on interior wall away from drafts and heat sources
- Install at 5 feet height in frequently occupied area
- Wire for power and communication per equipment requirements
- Install zone dampers and zone control board if zoning
- Connect smart thermostat to WiFi if applicable
- Program settings for occupancy patterns
Step 9: Charge Refrigerant and Test
Complete refrigerant charging and initial system testing to verify proper operation.
- Evacuate refrigerant lines to remove moisture
- Charge system with correct refrigerant type and amount
- Verify subcooling and superheat are within specifications
- Test heating and cooling modes
- Check safety controls and error codes
- Verify condensate drainage
Step 10: Balance and Commission System
Fine-tune the system for optimal performance and comfort throughout the home.
- Measure airflow at each register with anemometer
- Adjust dampers and registers to balance airflow
- Verify static pressure is within equipment limits
- Test temperature differential across equipment
- Document all measurements for future reference
- Schedule inspection if required by local jurisdiction
HVAC System Comparison
Air Source Heat Pump
All-electric heating and cooling with excellent efficiency for most climates.
- Cost: $8,000-$15,000 installed
- Efficiency: SEER 16-26, HSPF 9-13
- Pros: One system, high efficiency, tax credits
- Cons: Efficiency drops in extreme cold
- Best for: Moderate to warm climates
Dual-Fuel System
Heat pump with gas furnace backup provides year-round efficiency.
- Cost: $10,000-$18,000 installed
- Efficiency: Heat pump primary, furnace backup
- Pros: Best of both technologies
- Cons: Higher cost, two fuel sources
- Best for: Cold climates with gas available
Ductless Mini-Split
Individual room units connected to outdoor compressor, no ductwork needed.
- Cost: $3,000-$7,000 per zone installed
- Efficiency: SEER 20-33, excellent part-load
- Pros: Zoning, no ducts, quiet operation
- Cons: Visible indoor units, multiple heads
- Best for: Zoning, additions, homes without ducts
Gas Furnace with AC
Traditional split system with gas heating and electric air conditioning.
- Cost: $6,000-$12,000 installed
- Efficiency: 80-98% AFUE, SEER 14-20
- Pros: Low operating cost where gas is cheap
- Cons: Two systems, combustion concerns
- Best for: Cold climates, low gas prices
Cost Breakdown
Pro Tips
Do Not Oversize
Bigger is not better with HVAC. Oversized equipment short-cycles, wasting energy and failing to control humidity. Remodeled homes with good insulation and air sealing often need 30-50% less capacity than the old system. Insist on a proper Manual J calculation.
Consider Variable Speed
Variable-speed equipment costs more but provides significantly better comfort, humidity control, and efficiency. Instead of blasting on at full power and shutting off, it runs longer at lower speeds, maintaining consistent temperatures with less noise.
Seal Ducts Aggressively
Duct leakage is one of the biggest energy wasters in homes. Use mastic sealant at all joints, not just tape. Test duct leakage after installation. Target less than 4% leakage to outside. Well-sealed ducts can be worth 20% or more in energy savings.
Keep Ducts Inside
Ducts in unconditioned attics or crawlspaces lose efficiency and can cause condensation problems. During a remodel, plan duct routing within conditioned space: in dropped ceilings, framed chases, or within floor cavities. This eliminates losses and simplifies insulation.
Claim Available Incentives
Heat pumps and high-efficiency equipment qualify for significant federal tax credits (up to $2,000) and often state or utility rebates. The Inflation Reduction Act provides generous incentives through 2032. Factor these into your equipment decision.
Plan for Commissioning
Too many HVAC systems are never properly commissioned. Budget for proper startup, refrigerant charge verification, airflow measurement, and balancing. A properly commissioned system performs better and lasts longer. Get documentation of all measurements.
Common Mistakes to Avoid
Matching Old System Size
Just replacing with the same size equipment ignores the improvements you have made to the building. A remodeled home with new insulation, windows, and air sealing has dramatically lower heating and cooling loads. Size for the house you have now, not what it was before.
Ignoring Return Air
Many systems have inadequate return air paths. Every room with a supply register needs a way for air to return to the system. This may be through return ducts, transfer grilles, or undercut doors. Closed rooms with no return build pressure and reduce airflow throughout the house.
Poor Equipment Location
Installing equipment in locations without adequate service access causes maintenance problems forever. Furnaces need clearance for filter changes and repairs. Outdoor units need space for airflow and service. Think ahead to the life of the equipment, not just initial installation convenience.
Reusing Undersized Ductwork
Older ductwork is often undersized by modern standards, creating high static pressure, noise, and reduced airflow. While walls are open during a remodel, evaluate whether existing ducts can handle the new system. Adding ducts or upsizing during construction is far cheaper than retrofit.
Forgetting Ventilation
Tight, well-insulated homes need mechanical ventilation. Without it, indoor air quality suffers and moisture problems develop. Plan for an ERV (energy recovery ventilator) or HRV (heat recovery ventilator) as part of your HVAC system. This provides fresh air while recovering energy from exhaust air.
Frequently Asked Questions
Should I install a heat pump or traditional furnace and AC?
Heat pumps are increasingly the preferred choice for whole home remodels. Modern heat pumps work efficiently in temperatures down to -15F or below, provide both heating and cooling from one unit, and qualify for significant tax credits and rebates. In very cold climates, a dual-fuel system (heat pump with gas furnace backup) provides the best of both worlds. Traditional furnace/AC systems still make sense where natural gas is inexpensive and winters are severe.
How do I know what size HVAC system I need?
Proper sizing requires a Manual J load calculation performed by an HVAC professional. This calculation considers your home's square footage, insulation levels, window area and orientation, air infiltration, climate zone, and occupancy. Never size based on square footage alone or match the old system size - remodeled homes typically have much lower loads due to improved insulation and air sealing. Oversized systems short-cycle, waste energy, and fail to control humidity.
What SEER rating should my air conditioner have?
As of 2023, minimum SEER ratings are 14-15 depending on region. For a whole home remodel, we recommend SEER 16-18 or higher for optimal efficiency and comfort. Higher SEER systems cost more upfront but provide lower operating costs, better humidity control, and quieter operation. Variable-speed systems (SEER 18-26) provide the best comfort by adjusting output to match conditions rather than cycling on and off.
Do I need zoned HVAC for my remodel?
Zoning is highly recommended for most whole home remodels, especially for two-story homes, homes with additions, or those with varying sun exposure. Zoning allows different areas to maintain different temperatures, improving comfort and efficiency. Options include damper-based zoning with a single system, multiple systems, or ductless mini-splits for individual room control. The added cost typically pays back through energy savings and improved comfort.
Should I keep my existing ductwork?
Evaluate existing ductwork carefully. If it is in good condition, properly sized, well-sealed, and located within conditioned space, it may be reusable. However, most older ductwork has significant issues: undersized, poorly sealed, located in unconditioned attics or crawlspaces, or made of failing materials. During a whole home remodel, replacing ductwork costs relatively little since walls and ceilings are open. New ductwork ensures proper sizing, sealing, and location within the building envelope.