What Should You Ask Before Signing an AC Installation Contract?
Ask whether a Manual J load calculation was performed, what SEER2 rating is recommended and what the payback analysis shows, what ductwork assessment and work is included, and who pulls the permit. Then confirm both warranties: manufacturer coverage is typically 5 to 10 years on parts with a 10-year compressor warranty on registration, and the contractor labor warranty is typically 1 year on installation workmanship.
Did You Perform a Manual J Load Calculation?
This is the most important question in AC installation. A Manual J load calculation is the professional standard for determining the correct system size for your home. Ask specifically: ‘Can I see the Manual J report that supports the system size you are recommending?’ A contractor who sized by square footage alone without accounting for insulation, windows, orientation, and local climate data may be recommending equipment that is too large (the most common error), resulting in short-cycling, poor dehumidification, and premature system wear.
What SEER2 Rating Are You Recommending and Why?
The SEER2 recommendation should reflect a payback analysis: how long does the premium for a higher-efficiency unit take to recover in energy savings at your local electricity rate? A contractor who recommends the highest-efficiency unit without discussing payback may be prioritizing margin; one who recommends the lowest-efficiency unit without discussing efficiency options may be prioritizing the lowest quote number. The right answer involves presenting options with payback analysis. ENERGY STAR publishes certified efficiency ratings for heating and cooling equipment, which is the cleanest way to compare models.
What Is the Warranty Coverage?
Confirm both the manufacturer warranty (typically 5 to 10 years on parts, 10-year compressor warranty with registration) and the contractor’s labor warranty (typically 1 year on installation workmanship). Ask: ‘If the system has a problem in the first year, do I pay for the service call?’ The answer tells you what the labor warranty actually covers. (For more on this, see How to Find the Best AC Installation Contractor.)
Are Permits Included and Who Pulls Them?
Permits should be pulled by the installing contractor and included in the quoted price. Ask specifically: ‘Do you pull the permit for this installation, and is the permit fee included in your quote?’ A contractor who suggests skipping permits or expects you to pull your own permit is creating a liability for you unpermitted HVAC work can cause problems at home sale and may void equipment warranties. (For more on this, see Questions to Ask an AC Installation Contractor.)
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
Making a Confident Decision
The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home.
Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.
When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.
AC Installation Cost at a Glance
Unit size and tonnage: Larger homes need larger systems, which cost more.
Efficiency rating (SEER2): Higher-efficiency units cost more upfront but lower bills over time.
Ductwork and installation complexity: New or modified ductwork raises the total significantly.
Overall range: $6,000 to $15,000, averaging $8,500 for a standard replacement in a home with usable ducts.
Cost figures on this page were checked against published pricing on August 23, 2026. How we source cost data.
