Two quotes can show similar totals and still describe very different deals. The difference is often in the fine print: how long the price holds, what it assumes about your house, and what it leaves out. Before you compare numbers, read these items in each quote.
Find the validity line
Look for a line stating how long the quote is valid, sometimes called an expiration or validity period. If the quote does not state one, ask in writing how long the price holds. A verbal answer is not enough, because the next person you talk to may give a different one.
Also ask what happens if you accept after the period ends. Some companies will re-quote at current prices, and others will treat the old figure as void. You need to know which applies before you wait to decide.
Ask what the price lock covers
A price lock may cover the equipment only, the installation only, or both. It may also hold for materials but not for labor, or the reverse. Ask the company to name each cost category the lock applies to.
Ask whether the price changes if the supplier raises the cost of the equipment or parts before installation. Get the answer in writing, along with any condition that would allow a revised price.
List the assumptions behind the quote
Most quotes assume certain things about your house without saying so clearly. Common assumptions include the distance from the supply line to the install spot, the condition of the existing drain, the availability of an electrical outlet, the access route for equipment, and whether any existing plumbing needs changing.
Write each assumption down and check it against your house. A wrong assumption is a common reason for a revised price, so each one should appear in writing on the quote. If an assumption is missing from the quote, ask the company to add it.
Check taxes, fees, and delivery
Ask whether sales tax is included in the total, shown separately, or left out. Ask whether delivery, disposal of old equipment, and any permit fees are included. A quote that omits these is not the same as a quote that includes them, even if the headline figure is lower.
Compare like with like
Ask each company for the exact model name and the rated capacity in the same units, so you are comparing the same equipment. If one quote lists a different model or a different rating, ask why, and do not assume the cheaper one is the same product.
If you are comparing companies that have been recognized in local programs, the process behind those honors is described on the award methodology page. That page explains how winners are selected, but it does not replace the written quote, and it does not tell you whether a particular price is fair for your house.
Keep every version
Quotes often change as the site is reviewed. Ask for each revision to be numbered, and keep every version you receive. When you sign, make sure the signed document matches the final version and that the assumptions and inclusions are listed in it. If a version is missing a line that another version had, ask which one is correct before you accept either.