A replacement quote often has more than one total on it. Some lines add cost, and some lines take cost away. The lines that take cost away are the ones to read most slowly.
Find Every Credit Line Before You Add Them Up
Look for any line that reduces the total: a manufacturer rebate, a utility incentive, a dealer promotion, a membership discount, or an allowance for an old unit. Write each one on your sheet with its name, its issuer, and what it depends on. Do not subtract any of them yet.
Ask What Each Credit Depends On
Most conditional credits have a short list of requirements. Common ones include a model that must appear on a program list, an installer who must be enrolled, a registration that must be filed within a set window, an inspection or startup check that must be completed, or work that must happen in a particular season. Ask the seller to point to the written text for each requirement. A verbal assurance is not something you can check later.
Separate the Issuer From the Seller
Some credits come from the equipment maker. Others come from a utility, a government program, or the seller. Each issuer has its own form, its own deadline, and its own proof route. A seller may file one credit for you and leave the others to you. Ask who files each one, and whether you will receive a copy of what was submitted.
Check the Timing and the Proof
Ask when each credit is applied: at the point of sale, on a later bill, or through a mailed or online claim. If it is a claim, keep the purchase record, the model and serial information, the installation record, and the claim confirmation together. Missing proof is a frequent cause of a credit that never arrives. Put the claim deadline on your calendar the day you sign.
Compare Two Quotes on the Same Basis
Put both quotes side by side with the credits listed separately, not netted into the total. One quote may look lower only because it assumes a credit the other does not. Ask each seller to state whether every credit is included, conditional, or excluded. Compare the equipment and labor lines first, then compare the conditional credits.
Let the Equipment Age Set the Date, Not the Deadline
If a credit has a season or an enrollment window, that window can pull a replacement earlier or later than the equipment's age suggests. Check the planning point for your system before a deadline sets the date. The gas furnace guide and the heat pump guide show typical service life and planning points for each. Use them to decide whether the timing makes sense, not only whether the credit does.
What This Guide Does Not Cover
This is a general walk-through. It does not describe any particular program, manufacturer, utility, or contract. The published tables on this site hold the service life figures. Read the program's own terms for each credit, and read the quote for the work. Keep both documents in the same folder.