How to Compare HVAC Replacement Quotes

Why two quotes can look alike and still be different jobs

A quote is a description of work. Say one quote lists a new indoor coil and a new refrigerant line set, and the other says nothing about them. The two are not for the same job, so putting them side by side tells you little. Our reading: the fix is to turn every quote into the same list of items, then ask each company to fill any gap in writing.

ENERGY STAR publishes a one-page bid comparison checklist built for this. It has a column for each contractor and the same questions down the side. The checklist is undated, so treat it as a list of good questions, not as current program rules. This page walks through the items that decide whether quotes match, and it leaves out price on purpose.

The load calculation: is the size based on your house?

A load calculation estimates how much heat your house gains and loses, so the equipment can be chosen to fit. The industry method is ACCA Manual J for the load and Manual S for choosing equipment. Florida's residential code, in section M1401.3 of the 2023 edition, says heating and cooling equipment must be sized by Manual S or another approved method, based on loads from Manual J or another approved method.

The same code section has exceptions. One covers multistage or variable refrigerant flow equipment when the calculated loads fall within the maker's published capacities. Our reading: a different size from your old unit can therefore be correct, and so can the same size, if the calculation says so. The Department of Energy's Building Science Education site warns that rule-of-thumb sizing is common and produces badly oversized equipment.

A Building America guide on air conditioner replacement says the size of the system and the size of the indoor coil should both be re-evaluated at replacement. A U.S. government agency sponsored it, but its authors say the views are theirs, so we credit the authors, not the government. Our reading: a quote that simply repeats the old unit's size has not shown its work.

What to look for: a line saying a Manual J calculation will be done or was done, and a promise to hand you the result. The ENERGY STAR checklist asks whether the contractor will provide documentation including the Manual J calculation. Pinellas County's guide for permit applicants also names HVAC sizing calculations and energy forms as paperwork that may be required with a submittal. For why sizing matters in a humid climate, see why oversizing hurts and what a ton of cooling means.

A matched system and the AHRI certificate

A matched system is an outdoor unit and an indoor coil or air handler that the maker has rated to work together. AHRI, the Air-Conditioning, Heating and Refrigeration Institute, says a certified matched system lists the indoor and outdoor unit combination together, and each system gets a unique Certified Reference Number. The directory can then generate an AHRI Certificate of Product Ratings with the system's certified ratings.

ENERGY STAR's checklist says the contractor should provide an AHRI certificate to document that your system was properly matched. The Building America guide adds that codes in some locations require evaporators and condensing units to be matched, with their ratings in the AHRI database. It also notes that the indoor coil and expansion valve are typically replaced along with the condenser.

Our reading: compare the model numbers in each quote with each other, and later with the certificate and the equipment label. If a quote names only the outdoor unit, ask which indoor coil or air handler it pairs with, and ask for the certificate for that pair.

The permit: is it in the written scope?

A permit is the local building department's record that the work was approved and inspected. The reasons behind it are on the permit page, so this page covers only how it affects a comparison. Tampa Bay offices describe the process differently, so read the one that covers your address.

Largo's permit page describes a like-for-like, size-for-size changeout as usually handled at the counter, with no plans reviewed. The City of Tampa says many projects do not need plan review, and it names A/C change-out as one, with permits for those projects available through its Express Permits service. Pinellas County publishes inspection instructions for an A/C equal changeout with no gas, oil or electric.

Our reading: no plan review does not mean no permit. Ask each company who applies for the permit, whether it is in the written scope, and whether the final inspection is part of the job. A quote that is silent on the permit leaves a gap to close before you compare.

What is replaced and what is reused

This is where quotes differ most, and where a short question saves confusion. ENERGY STAR's checklist asks, as separate items, whether the contractor will install new refrigerant lines rather than reusing existing lines, set up a thermostat, and check existing ductwork for damage. The line set is the pair of refrigerant tubes linking the two units; the detail is on the refrigerant line sets page.

The same checklist asks whether the contractor will test that duct leakage stays within recommended levels, and whether the system will be checked for proper refrigerant level and airflow across the coil. Those checks are done by the licensed technician, and they are listed here only so you can see whether each quote includes them.

Ask for a plain list with one of three answers per item: replaced, reused or not applicable.

1. Outdoor unit and indoor coil or air handler.
2. Refrigerant line set.
3. Thermostat.
4. Condensate drain line and the safety switch on it, which keeps a clogged drain from flooding.
5. The pad or stand under the outdoor unit.
6. Ductwork repairs and the return grille and filter.

The last three are our additions, not checklist items. They are common places where one quote includes work and another assumes the old part stays.

The written scope, the contract and the license

Under Florida law, a contract for repair, restoration, improvement or construction on residential property must contain a written statement of the consumer's rights under the Florida Homeowners' Construction Recovery Fund. A small-job exception applies. Section 489.1425 of the Florida Statutes sets this out and lets the licensing board fine a contractor who leaves it out. If a quote or contract lacks that statement, ask about it.

The Florida Department of Business and Professional Regulation runs a licensing portal where you can look up a licensee by name, license number, city or county, or license type. Check that each company's license matches its quote. Our reading: the written scope should name the equipment by model number, list what is replaced or reused, state who pulls the permit, and say what documents you receive at the end.

ENERGY STAR's checklist lists those end documents: manuals, the Manual J calculation, the AHRI certificate and records of any measurements or testing. For what correct commissioning readings look like, see what to expect from an AC replacement.

Warranty registration: who does it, and by when

Equipment warranties come from the manufacturer, and their terms differ by brand and by model. Goodman's learning-center page says its equipment can be registered by the homeowner or by the installing dealer, and it advises confirming with your dealer who will do it to avoid confusion. It says online registration should be completed within 60 days of installation to qualify for the longer terms it lists.

The same page adds a note for residents of California, Florida, Georgia and Quebec: registration is not needed to receive the same rights and remedies that registered owners have under the limited warranty. That is one maker's statement, and other makers' terms can differ. Our reading: put the registration question in writing for each quote, and read the warranty certificate for the exact model. Transfer to a later owner is covered in transferring a warranty to a new owner.

Questions to put to every company, in writing

Send the same list to each company and keep the answers together.

1. Will you do a Manual J load calculation for my house, and will I receive it?
2. What are the exact model numbers of the outdoor unit and the indoor coil or air handler, and will I receive the AHRI certificate for that pair?
3. Who applies for the permit, is it in the written scope, and does the job include the inspection?
4. Which of these are replaced, and which are reused: line set, thermostat, drain line and safety switch, pad, ductwork repairs?
5. What readings and documents will I receive when the job is done?
6. Who registers the equipment with the manufacturer, and by when?
7. Does the contract include the Florida recovery fund statement, and does the license number match the state's record?

If a company's answers leave out an item, ask again before you rank anything. For the decision to replace at all, see repair or replace: how to decide.