Hiring a Furnace Installer: What to Check Before You Sign
A well-installed Goodman outperforms a poorly installed Lennox. The installer matters more than the brand. Here is how to find a good one and what to watch for.
Get at Least 3 Quotes
This is the single most effective thing you can do. Homeowners who get 3+ quotes save an average of $500 to $1,500.
What to Tell Each Contractor
- Current furnace type, age, and any known issues
- Fuel type preference (or ask them to recommend)
- Approximate efficiency range you are considering
- Any brand preferences (or none, let them recommend)
- Whether you also need AC replacement or ductwork
- Any access challenges (tight crawl space, narrow stairway)
Ask each contractor to visit your home before quoting. Phone/email quotes without an inspection are unreliable and often lead to surprise charges on installation day.
What to Check
State Contractor License
Required in most states. Verify the license number with your state contractor board. An unlicensed installer leaves you with no recourse if something goes wrong.
NATE Certification
North American Technician Excellence certification. The industry standard for HVAC competence. Not legally required but a strong signal of professionalism.
EPA 608 Certification
Required for handling refrigerants (relevant if your system includes AC). All legitimate HVAC technicians have this.
Insurance: Liability + Workers Comp
Ask to see certificates of insurance. General liability ($1M+) and workers compensation. Without these, you are liable if a worker is injured on your property.
Years in Business
Look for 5+ years. Warranty service 10 years from now requires a company that will still exist. Check BBB complaints and Better Business Bureau rating.
Google Reviews
Look for 4+ stars with at least 50 reviews. Read the 1-star and 2-star reviews to see how the company handles problems.
What the Quote Should Include
A professional quote is detailed and itemized. If a contractor gives you a single lump sum with no breakdown, ask for line items.
7 Red Flags
Pressure to decide today
Any contractor who says 'this price is only good today' is using a high-pressure sales tactic. Legitimate quotes are good for at least 30 days.
Cash-only payment
Reputable contractors accept credit cards and checks. Cash-only suggests they are avoiding a paper trail, which complicates warranty claims.
Suggesting you skip the permit
This is illegal in most jurisdictions and voids your warranty. A contractor who suggests this is cutting corners elsewhere too.
No written contract
Everything should be in writing: scope, price, timeline, warranty. Verbal agreements are unenforceable.
Sizing by square footage alone
A contractor who sizes your furnace without inspecting your home, ductwork, insulation, and windows is guessing. Proper sizing requires a Manual J calculation.
No home inspection before quoting
Phone quotes without visiting the home lead to surprise charges on installation day. Insist on an in-home assessment.
Price dramatically below competitors
If one quote is 30%+ below the others, investigate. It may indicate cheap equipment, cutting corners on installation, or a bait-and-switch.
What to Expect on Installation Day
Standard replacements take 6 to 8 hours. Complex installations (new gas line, ductwork mods) take 10 to 14 hours and may span two days.
Post-Installation Checklist
Register your warranty
Most manufacturers require registration within 60 to 90 days of installation. Without registration, your warranty may be limited to 5 years instead of 10.
Schedule annual maintenance
Have the furnace inspected and tuned annually. Fall is the ideal timing. Cost: $100 to $200 per visit. Prevents most common failures.
Change filters regularly
Every 1 to 3 months depending on filter type and household conditions (pets, allergies). A clogged filter reduces efficiency and can damage the blower motor.
Keep inspection records
Save all receipts, warranty cards, and maintenance records. These are important for warranty claims, home insurance, and resale.