Free HVAC Load & Sizing Calculator
Estimate a preliminary heating and cooling load range for Sacramento, Rocklin, Roseville and nearby homes. Free HVAC sizing tool with clear assumptions.
How to use this estimate
This simplified model combines assumed heat transfer through walls, windows, roof and floor with air exchange, sunlight, people and equipment. Your home's measured condition can produce a substantially different result.
See the method, assumptions and source references
Full calculation assumptions appear with your result.
Local weather references: CEC 2025 Joint Appendix JA2, Table 2-3. Cooling uses 1% dry-bulb; heating uses 0.6% dry-bulb. Nearby references are identified explicitly. These are planning weather values, not a property-specific climate-zone determination.
Final professional work: ACCA Manual J loads, equipment selection and Manual D duct design. This tool is not ACCA-approved software or a permit compliance calculation.
What size HVAC system do I need?
Start with the home's heating and cooling load: how much heat it loses in winter and gains in summer. Square footage helps describe the building, but windows, insulation, air leakage, ceiling height, sunlight and local outdoor temperatures also affect the answer. An existing three-ton unit does not establish that the replacement should be three tons.
This free HVAC load calculator provides a preliminary range for Sacramento, Rocklin, Roseville and surrounding communities. Enter the total conditioned floor area across all stories, rather than just the building footprint. Use the insulation and window preset that best describes the home's current condition, including upgrades.
How many square feet does one ton of AC cool?
There is no single reliable square-feet-per-ton value for every home. A ton represents 12,000 BTU/h of cooling capacity. Two homes of the same size can have different loads because their windows, insulation, exposure and local conditions differ. Use the range as a starting point for a measured assessment.
Is the heating result a furnace size?
No. The heating number is estimated heat output needed by the building, not furnace fuel input or a selected heat-pump model. Furnace efficiency and heat-pump capacity at the actual winter design temperature must be considered separately.
Does this replace a Manual J calculation?
No. This simplified model uses assumed geometry, insulation and air exchange. A professional room-by-room Manual J calculation evaluates the actual building. Equipment selection also requires manufacturer performance data and duct and installation checks.
Can I use the result for a replacement estimate?
You can include it in a request to Heco so the team understands your planning assumptions. The result is not an installation quote or confirmation of a specific equipment size. Choose “Request Assessment With These Results” after calculating to carry your details into the booking form.
Published by Heco Heating and Air Conditioning • California C-20 contractor license #1050351. Tools are for preliminary planning; contact Heco to verify property conditions and service availability.