HVAC Quotes: How to Compare Them and Tell If One Is Fair

A fair HVAC quote names exact model numbers backed by an AHRI certificate and sizes the system with a Manual J load calculation. It also lists ductwork, permit, removal, labor and warranty terms. Compare quotes on those lines, not on the total. If one quote skips the load calculation, the permit or the model numbers, it is not the cheaper quote. It is an incomplete one.

What should an HVAC installation quote include?

ENERGY STAR tells homeowners to sign a written proposal before work starts that lists costs, model numbers, the job schedule and warranty terms. Its bid comparison checklist goes further. It asks each contractor to size the system with Manual J, install a matched indoor coil and outdoor unit, test duct leakage, and leave you the Manual J report and AHRI certificate after the job.

Model numbers and the AHRI certificate

A split system's efficiency rating belongs to the combination, not to the outdoor unit alone. AHRI, the industry body that certifies ratings, says that for split systems it certifies the performance of the system and not the individual units. Each matched combination gets a certified reference number. AHRI adds that its certificate may be required for rebates and incentives.

Ask every contractor for the AHRI reference number of the exact equipment in their quote. Carrier says homeowners can search the AHRI Directory at ahridirectory.org by reference number or model number. If the models on the certificate differ from the quote, the efficiency printed on the quote may not apply to what you are buying.

SEER2, HSPF2 and AFUE

Cooling and heat pump ratings changed in 2023. The Department of Energy says SEER2, HSPF2 and EER2 are not directly comparable to the old SEER and HSPF numbers. If one quote shows SEER and another shows SEER2, ask both for the SEER2 figure from the AHRI certificate.

The federal minimums make a quick sanity check. DOE sets split air conditioners under 45,000 Btu per hour at 13.4 SEER2 in the North and 14.3 SEER2 in the Southeast and Southwest. Split heat pumps must reach 14.3 SEER2 and 7.5 HSPF2 everywhere. DOE says it is illegal for a contractor to install an air conditioner that misses the regional standard in the Southeast or Southwest.

For furnaces, AFUE measures the heat delivered to your house compared with the fuel supplied, per DOE's consumer guide to heating and cooling. An 80 percent AFUE furnace turns 80 cents of each fuel dollar into heat. ENERGY STAR currently lists gas furnaces at 97 percent AFUE or higher in the North and 95 percent in the South.

The Manual J load calculation

Manual J is the load calculation method published by ACCA, the contractors' association. It works from your insulation, windows, air leakage and climate. DOE's consumer guide says the rule of one ton of cooling per 400 to 500 square feet ignores climate and how efficient the house is. It says contractors should use Manual J, and warns that oversized cooling systems can cost too much, give poor comfort and lead to mold.

The rule of thumb is often far off. Reviewing 40 Manual J calculations on ACCA's blog, building scientist Allison Bailes found an average of 1,431 square feet per ton, with a range of 624 to 3,325. Local codes often require the math too. Pima County, Arizona, cites International Residential Code section M1401.3, which calls for sizing per ACCA Manual S based on Manual J loads.

Copying the old unit's size is not a load calculation. CBS News makes the same point: size the system by calculation, not by matching the old unit's capacity. If the old system was oversized, a copy of it will be too.

Ductwork

ENERGY STAR estimates that about 20 to 30 percent of the air moving through a typical duct system is lost. Its bid checklist recommends total duct leakage of no more than 20 percent in most cases. It also asks whether the contractor will test the largest system your existing ducts can carry. A quote that puts new equipment on old ducts without checking them is guessing.

Permit and inspection

Many cities require a mechanical permit for this work. Maplewood, Minnesota, for example, requires one to replace a furnace or air conditioner, or to extend or replace ductwork. Rules vary, so check with your city or county building department. The FTC lists a contractor who asks you to get the required building permits as a sign of a scam.

Warranty: parts and labor

Manufacturer warranties often depend on registration. Carrier says you must register eligible equipment within 90 days of installation to choose a 10-year parts-only limited warranty or a 5-year parts plus 3-year labor warranty. Skip registration and the standard 5-year parts-only warranty applies. The labor option exists only if your installer joined Carrier's program. Other brands set their own terms, so ask who registers the equipment and get proof.

The installer's own labor warranty is separate. Get its length and coverage written on the quote.

Refrigerant

Lennox describes R-454B as the refrigerant much of the industry is transitioning to, and says existing systems can't be retrofitted to work with it. In May 2026 the EPA removed the installation deadline for equipment with older, higher-impact refrigerants made before January 1, 2025. That stock can be installed until supply runs out. Ask which refrigerant each quote uses. If a quote replaces only the outdoor unit, ask how it will work with your existing indoor coil.

How to compare HVAC quotes apples to apples

1. Get at least three itemized quotes. Carrier's cost guide suggests itemized quotes from at least three dealers. The FTC says not to automatically pick the lowest bid, and to ask for an explanation when estimates differ widely.
2. Build one comparison table. List models, AHRI number, SEER2, HSPF2 or AFUE, tonnage, refrigerant, duct scope, permit, warranty and total. The ENERGY STAR bid checklist has columns for three contractors and prints on one page.
3. Look up every AHRI number. Confirm the ratings on each quote match its certificate.
4. Compare sizes. If one quote says 3 tons and another says 4, ask both to show their load calculation. Bigger is not safer.
5. Price the scope gaps. If quote A replaces ducts and quote B reuses them, the totals are not comparable. Ask B to price duct testing and sealing, or ask A to price the job without new ducts.
6. Match efficiency tiers. A single-stage heat pump and a variable-speed one are different products. Ask each contractor to price the same tier.
7. Read the payment terms. The FTC says not to pay the full amount up front, notes that some states limit down payments, and says never to make the final payment until the work is done and you are satisfied.
8. Check license and insurance. The FTC says to confirm the license with your state or county and ask for proof of insurance.

How much should a new HVAC system cost?

No single fair price exists, and published figures disagree. Use them to spot a quote far outside the norm.

The spread comes from size, efficiency tier, ductwork, electrical work and local labor. Even one source can wobble: This Old House gives a heat pump average of $8,007 in its table and $10,575 in its summary.

Red flags in an HVAC quote

• Sizing by square feet, or by copying the old unit, with no load calculation.
• No model numbers, only a brand and a rating like "16 SEER system." You cannot verify a rating you cannot look up.
• Old SEER ratings on a new quote, or a SEER2 number that does not match the AHRI certificate.
• No permit, or a request that you pull it yourself.
• Pressure to decide on the spot. The FTC lists pressure for an immediate decision as a scam sign.
• Full payment up front, or cash only, which the FTC also flags.
• Blank spaces in the contract, or verbal promises that never made it into writing. The FTC says to fill every blank before you sign.
• A federal tax credit subtracted for a 2026 install. That credit has ended (see below).
• A full replacement quote for a fault with no written diagnosis, test readings or photos.

If you signed in your home, the FTC's Cooling-Off Rule generally gives you until midnight of the third business day to cancel certain sales made there for a full refund. Exceptions include sales needed to meet an emergency and repair visits you asked the seller to make. Read the cancellation notice in your contract.

Are HVAC quotes negotiable?

You can always ask. The useful levers are scope and timing, not the bottom line.

• Make the high bidder explain the gap. Go line by line. The difference may be a duct job, a higher tier or an add-on the other quote left out.
• Drop what you did not ask for. Every add-on should be its own line so you can remove it.
• Ask about rebates. ENERGY STAR says contractors should be able to show you savings calculations, and its checklist asks them to point you to local rebate programs.
• Use time if you have it. CBS News notes that emergency replacements cost more and a planned replacement gives you more negotiating power. If you have no heat right now, start with our no-heat checklist. A repair may buy you weeks to compare quotes.

HVAC tax credits and rebates in 2026

The federal Energy Efficient Home Improvement Credit is over for new installs. The IRS says it covers improvements made through December 31, 2025. Through 2025 it allowed up to $2,000 a year for qualifying heat pumps and up to $600 per item for central air conditioners and furnaces. A system installed in 2026 does not qualify.

What remains is local. Enter your ZIP code in the ENERGY STAR Rebate Finder to see utility and partner offers near you. DOE's Home Energy Rebates are run by states. DOE says its electrification rebate can save households up to $14,000, that rebates are available in select states, and that you should contact your state energy office. Get the rebate terms in writing before you sign, and ask who files the paperwork.

Was I overcharged for a repair or a refrigerant recharge?

Refrigerant runs in a sealed loop. Lennox links low refrigerant to a hole or crack in the coils and says only licensed professionals should test and repair leaks. If you paid for a recharge, ask where the leak is, whether it was fixed, and how much refrigerant went in. A recharge with no leak repair can mean paying again next season. The EPA requires technicians who maintain, service or repair equipment that could release refrigerant to hold Section 608 certification.

If a contractor quotes a new furnace, ask for the diagnosis in writing: the failed part, the test readings and photos. A bad pressure switch or inducer motor is usually a repair, not a replacement (see furnace inducer and pressure switch problems). A cracked heat exchanger is a real reason to stop using a furnace. You can still ask for photos and a second opinion; our cracked heat exchanger guide covers what proof to request.

Bought a house where the AC never cooled right? Ask the building department for the permit and inspection record. Compare the model numbers on the outdoor unit and indoor coil labels with the AHRI Directory. Then ask the installer for the Manual J report and test records the ENERGY STAR checklist describes.

Call a pro now, or get a second opinion, if

• A technician shut off or red-tagged your furnace. Do not restart it until a second licensed tech checks it.
• A tech says the heat exchanger is cracked and the fix is a new furnace. Ask for proof first.
• The system needs refrigerant. Only an EPA 608 certified technician should handle it.
• A breaker trips repeatedly, or you smell burning from the unit. Stop resetting it, turn the system off and call.
• Two quotes differ in size by a ton or more and neither shows a load calculation.
• A contractor wants you to pull the permit or pay in full before work starts.

Questions people ask