Homeowner tools · heating & cooling
What size AC do I need?
Don’t pay for a bigger system just because it sounds safer. Start by checking how the size was chosen.
Know what to ask
Choose your project to get started.
A whole-home system needs a load calculation. A room air conditioner uses different sizing guidance.
Why square footage is not enough.
Two homes with the same floor area can have different heating and cooling needs. Windows, insulation, air leakage and local design conditions affect the load. Ductwork and airflow also need assessment when equipment is selected.
Ask your contractor to share the calculation and explain the equipment choice. Our whole-home tool prepares questions; it does not calculate a required tonnage or certify a design.
Compare the reasoning, then the price.
If two contractors recommend different sizes, ask each to explain the loads and assumptions. With Full Advocacy comparison support, we can help request those explanations and organize the answers. The qualified HVAC professional remains responsible for design and installation.
Understand HVAC replacement costs · Check an existing HVAC bid
Further reading: ENERGY STAR: room AC capacity chart and adjustments. Reviewed October 17, 2026.
Further reading: ENERGY STAR: Manual J guidance for home systems. Reviewed October 17, 2026.
A number is a starting point. Written bids are your next step.
Find out what your project could actually cost.
Bring your plans, questions or the bid you already have. We step in to organize the details and coordinate with contractors, so you spend less time repeating yourself. Optional $499 Full Advocacy adds comparison, negotiation and one local visit when needed. We’ll explain the help available before you commit.
Tell us what you’re planning on a free 5-minute call. We prepare the request, screen contractors as bids are requested and deliver written proposals. Three bids are our target, subject to availability and project fit.
Free delivery does not include a comparison or recommendation. Optional $499 Full Advocacy adds detailed comparison, clarification and one final negotiation round. The contractor assesses and performs the work.