How to Vet Specialty Contractors for Your Whole-Home Remodel
Your home's electrical, plumbing, and HVAC systems determine comfort, safety, and operating costs for decades. While your GC typically manages these subcontractors, you should understand who's doing the work and ensure they're making the right decisions for your home.
Quick Summary
Time needed
4-6 hours of meetings
Difficulty
Moderate (technical topics)
Cost
Free (included in GC scope)
Why Specialty Contractor Quality Matters
You might never think about your plumbing until it leaks, your electrical until something fails, or your HVAC until you're sweating or freezing. These are the hidden systems that determine whether your home works well— and they're expensive or impossible to change after construction.
A whole-home remodel is your one chance to get these systems right. The decisions made now affect your utility bills, comfort, safety, and repair costs for the next 20-40 years.
Working with Your GC's Subs
Your general contractor typically hires the electrical, plumbing, and HVAC subcontractors. This is usually fine—they have established relationships and accountability. But you should still meet these subs, understand their recommendations, and feel confident in their expertise.
- Long-term cost impact: An inefficient HVAC system costs $500-$1,500 extra per year—every year for 15-20 years.
- Safety implications: Electrical and gas systems done wrong can cause fires, shocks, or carbon monoxide poisoning.
- Hidden nature of work: Most MEP (mechanical, electrical, plumbing) work is hidden in walls—problems are hard to fix later.
- Code compliance: These trades require permits and inspections. Poor work fails inspections and delays projects.
- Warranty protection: Quality contractors provide meaningful warranties and stand behind their work.
Electrical: Questions and Considerations
Electrical work is the backbone of modern living. A whole-home remodel is your opportunity to upgrade service, add circuits, and plan for future needs.
Key Electrical Interview Questions
- • Service upgrade: Do we need to upgrade to 200-amp or 400-amp service? What's the current capacity?
- • Panel location: Can we relocate the main panel? Should we add a sub-panel?
- • Future planning: Can we accommodate EV charging (50-amp 240V)? Solar readiness? Battery backup?
- • Code requirements: What current code requirements will trigger updates? (AFCI, GFCI, etc.)
- • Low-voltage: Do you handle data cabling, security pre-wire, and smart home infrastructure?
- • Brands: What panel and breaker brands do you install? Why?
- • Lighting layout: Do you work from our designer's lighting plan, or do you provide design input?
Green Flags
- • Asks about your future needs
- • Recommends quality panel brands
- • Familiar with smart home wiring
- • Discusses energy efficiency
- • Has experience with similar projects
- • Clear on code requirements
Red Flags
- • "We'll just match what's there"
- • No interest in future needs
- • Uses off-brand or discontinued equipment
- • Can't explain code requirements
- • Dismissive of low-voltage needs
- • No experience with remodels
Typical Electrical Scope in Whole-Home Remodel:
- • Panel upgrade to 200A (possibly 400A for large homes)
- • Complete rewiring with new circuits throughout
- • AFCI protection on all bedroom circuits
- • GFCI protection in kitchens, baths, garage, exterior
- • Dedicated circuits for major appliances
- • EV charging prep (conduit and breaker space)
- • Low-voltage wiring for data, security, speakers
- • Whole-house surge protection
Typical cost: $15,000-$40,000+ depending on home size and scope
Plumbing: Questions and Considerations
Plumbing affects every bathroom, kitchen, and utility area. Old pipes, poor layout, and inadequate water heating are common problems in older homes.
Key Plumbing Interview Questions
- • Pipe replacement: Should we replace all supply lines? What material (copper vs. PEX)?
- • Water heater: Tankless or tank? Single or multiple units? Sizing for our needs?
- • Water quality: Should we add a whole-house water filter or softener?
- • Drain lines: What's the condition of our drain lines? Do they need replacement or repair?
- • Fixture compatibility: Are there any limitations on the fixtures we've selected?
- • Shower valves: What valves do you recommend? (Pressure-balance, thermostatic, etc.)
- • Future needs: What should we rough-in now for potential future use?
Green Flags
- • Recommends PEX for supply lines
- • Discusses water heater sizing properly
- • Asks about water pressure and quality
- • Familiar with high-end fixtures
- • Suggests shut-off valve locations
- • Mentions proper venting
Red Flags
- • Wants to keep old galvanized pipes
- • One-size-fits-all water heater recommendation
- • Unfamiliar with your fixture brands
- • Dismissive of water quality concerns
- • Doesn't ask about usage patterns
- • No discussion of maintenance access
Replace Now or Regret Later
If your home has galvanized steel pipes, polybutylene (gray plastic), or copper pipes over 40-50 years old, replace them during your remodel. The cost while walls are open is a fraction of what it costs later. You'll also get proper shut-off valves, modern materials, and peace of mind.
Typical Plumbing Scope in Whole-Home Remodel:
- • Complete re-pipe with PEX supply lines
- • New shut-off valves at every fixture
- • Water heater upgrade (tankless or high-efficiency tank)
- • New drain lines if needed (PVC/ABS)
- • Proper venting for all fixtures
- • Kitchen and bathroom fixture rough-in
- • Washer/dryer hookups
- • Exterior hose bibs with freeze protection
Typical cost: $12,000-$35,000+ depending on scope and fixture count
HVAC: Questions and Considerations
Heating and cooling account for 40-50% of home energy costs. Proper sizing, efficient equipment, and good ductwork design make a dramatic difference in comfort and operating costs.
Key HVAC Interview Questions
- • Load calculation: Will you perform a Manual J load calculation? (Not just rules of thumb)
- • System type: Central forced air, mini-splits, or hybrid? What do you recommend and why?
- • Efficiency: What SEER rating do you recommend? Variable speed vs. single stage?
- • Zoning: Should we zone the system? How many zones make sense?
- • Ductwork: Do existing ducts need replacement? Sealing? Insulation?
- • Air quality: Should we add air filtration, UV purification, or humidity control?
- • Equipment brands: What brands do you install and service? Why?
- • Warranty: What's covered by manufacturer vs. labor warranty?
Green Flags
- • Performs Manual J calculations
- • Discusses your home's specific needs
- • Recommends high-efficiency equipment
- • Asks about insulation improvements
- • Stocks parts for brands they install
- • Offers service agreements
Red Flags
- • "One ton per 500 square feet" only
- • Pushes biggest equipment
- • Won't discuss alternatives
- • Installs only one brand
- • Unclear about warranty terms
- • Doesn't ask about existing ductwork
Sizing Matters—A Lot
Bigger is not better with HVAC. An oversized system short-cycles (turns on and off frequently), never properly dehumidifies, wears out faster, and wastes energy. After a remodel with improved insulation, your old 4-ton system might need to be replaced with a 3-ton. Insist on a proper Manual J load calculation.
Typical HVAC Scope in Whole-Home Remodel:
- • New high-efficiency furnace/heat pump (16+ SEER, variable speed ideal)
- • New A/C or heat pump condenser
- • Complete ductwork replacement or sealing/insulation
- • Zoning system (2-4 zones typical)
- • Smart thermostat(s)
- • Upgraded filtration (MERV 13+ or HEPA)
- • Optional: Whole-house humidifier/dehumidifier
- • Optional: Fresh air ventilation (ERV/HRV)
Typical cost: $15,000-$40,000+ depending on system type and complexity
General Vetting Process for All Trades
Regardless of the specialty, follow this process to evaluate any subcontractor.
1. Verify Licenses and Insurance
Each trade requires specific licenses. Verify through your state's licensing board. Check that they carry liability insurance and workers' compensation. Your GC should have these on file, but verify independently.
2. Ask About Experience
How long have they been in business? How many whole-home remodels have they done? Experience with your home's era or style? Remodels are different from new construction—verify remodel-specific experience.
3. Understand Their Recommendations
Good contractors explain why they recommend certain products or approaches. They should be able to answer your questions clearly. Be wary of contractors who dismiss questions or can't explain their reasoning.
4. Clarify Warranty Coverage
Understand what's covered by manufacturer warranties vs. labor warranties. Who do you call if something fails in year 2? Year 5? Get warranty terms in writing before work begins.
5. Ask About Code Compliance
Good contractors know current codes and can explain what updates your project will require. They should be comfortable with inspections and have good relationships with local inspectors.
Common Mistakes to Avoid
Assuming the GC vetted subcontractors thoroughly
Why it's a problem: GCs may use subs based on price or availability, not quality
What to do instead: Meet each major sub yourself. Ask questions. Verify you're comfortable with their expertise.
Accepting the cheapest equipment
Why it's a problem: Budget equipment has shorter lifespans, lower efficiency, and poor warranties
What to do instead: Calculate total cost of ownership over 15-20 years, not just upfront cost.
Not planning for future needs
Why it's a problem: It's 10x more expensive to add capacity later when walls are closed
What to do instead: Discuss EV charging, solar, ADUs, and other potential future needs now.
Skipping proper sizing
Why it's a problem: Oversized or undersized systems waste energy and money for decades
What to do instead: Insist on Manual J calculations for HVAC. Proper sizing for electrical panels.
Not understanding warranty terms
Why it's a problem: You may think you're covered when you're not
What to do instead: Get warranty details in writing before work begins. Know who to call for service.
Frequently Asked Questions
Should I hire my own specialty contractors or use my GC's subs?
For most homeowners, using your GC's established subcontractors makes sense—they have working relationships and accountability structures. However, you should still meet and interview these subs. For major systems upgrades, you can request specific subs or get independent opinions.
What should I ask an electrician before a whole-home remodel?
Key questions: Do we need 200-amp service? Experience with whole-home rewiring? Future needs (EV charging, solar)? Panel and breaker brand preferences? Low-voltage handling (data, security)? Code compliance process?
How do I know if my HVAC system is sized correctly?
Proper sizing requires a Manual J load calculation—not rules of thumb. Ask if contractors perform Manual J. After remodeling with improved insulation, your needs may actually decrease from your old system size.
Should I replace all plumbing during a whole-home remodel?
If you have galvanized or polybutylene pipes, yes. Even copper over 40-50 years should be evaluated. The cost while walls are open is far less than doing it later, and you get modern materials and proper shut-offs.
What questions should I ask about HVAC equipment brands?
Ask: What brands do you install and service? Why that brand? Warranty coverage? Do you stock parts? Who handles warranty service? Expected lifespan? Established brands with good warranty networks make sense.
Ready for the Next Step?
With your professional team in place—architect, designer, general contractor, project manager (if applicable), and specialty contractors—you're ready to move forward. The next phase focuses on contracts and insurance to protect your investment.