Check the summer comparison
Ask what current cooling equipment is being replaced, what actual cooling use is known, and what matched new equipment is being modeled. If the home has no AC, new summer cooling is a new expense and comfort benefit, not a reduction from a nonexistent cooling bill.
Request the cooling-load assessment, comfort setting, weather assumptions, and electricity tariff used. Ask whether the forecast assumes repairs or improvements to the home or air distribution, and whether those costs are included.
Check the winter comparison
Ask the estimator to separate space heating from other gas use. Request the heating load, temperature-specific equipment performance, backup strategy, and estimate of backup use. Ask what happens to fixed gas charges if other gas appliances remain.
Have the utility confirm the applicable current rate plan. Xcel's rate-book page provides official tariffs and dated summaries; it does not establish your individual future bill. Xcel rate books.
We would want a range rather than one precise savings number. Ask for a colder-weather scenario and a scenario with more backup heat. Those show how dependent the estimate is on favorable assumptions.
Keep incentives out of the operating claim
A rebate may lower purchase cost, but it does not make an equipment performance assumption more accurate. Request the gross project price, each proposed incentive, the conditions for receiving it, and your responsibility if it is not awarded.
If the proposal includes a long-term payback claim, ask which rates, maintenance costs, and equipment life were assumed. Treat it as an estimate to assess, not a promise. You may still value comfort, cooling, or replacing a failed system even if operating savings are modest.
Your next action is a revised quote that separates cooling cost, heating cost, and upfront cost. We would approve the equipment choice only after its comfort plan and financial assumptions are clear enough to compare.