Plan HVAC Systems for New Construction
ACCA-compliant calculations delivered in 2–3 days using Wrightsoft software for residential builds.
Manual J
The Manual J residential calculation is the proper way to size your HVAC unit. Designed by the Air Conditioning Contractors of America (ACCA), this calculation typically relies on complex computer programs to accurately depict the demands of a house as well as the heat loss or gain within the home. Accuracy matters when it comes to designing the proper HVAC unit, as a perfectly sized system will generate the correct temperature without wasting energy.
Manual S
ACCA Manual S provides specific procedures for selecting HVAC equipment against a set of Manual J loads and design conditions. Manual S uses OEM data and specifies how large or small the selected HVAC equipment capacity can be when compared to the Manual J load calculation. Manual S defers to the Authority Having Jurisdiction (local permit, Energy Star, LEED etc.) requirements for minimum rated efficiency values such as SEER, HSPF, EER. COP, etc.
Manual D
Manual D is for sizing home HVAC return and supply duct & registers. Manual D duct design distributes the correct amount of heating and cooling CFM to each room based on the Manual J load calculation results. The furnace and A/C selected during the ACCA (Air Conditioning Contractors of America) Manual S process will determine the duct CFM for your exact humidity and winter and summer design temperatures.
Design Residential HVAC Systems Built to Perform
Complete load calculations and duct layouts backed by software precision
Load Calc Designs is a family-owned and operated HVAC design company serving builders, contractors, and homeowners across Meridian and the Treasure Valley. We specialize in new construction residential HVAC system planning, delivering the technical foundation that keeps projects moving forward. Whether you're building a model home, framing a custom home in Boise, or coordinating a subdivision in Nampa, accurate equipment sizing and duct layouts are essential to align with building plans and energy goals. Furthermore, meeting local jurisdiction requirements is critical, as Manual J, S, and D calculations are required by local municipalities to successfully secure your building permits.
You'll receive detailed reports that outline heating and cooling loads, equipment specifications, and duct configurations tailored to your project's square footage and layout. Every calculation follows ACCA standards, and every design is formatted for straightforward handoff to your installation crew. You'll know what equipment to order, where ductwork should run, and how airflow will balance across the home before the first section of duct is hung.
Load Calc Designs combines over a decade of HVAC industry experience with hands-on ductwork installation knowledge and builder coordination. That real-world perspective shapes every design we produce, ensuring your plans translate smoothly from paper to the jobsite. Our approach supports residential growth throughout Eagle, Caldwell, and Kuna with the same attention to detail and accountability that defines a family-run operation.
Request a customized HVAC design consultation and move your project forward with confidence.
Our Services
Manual J Load Calculations
Accurate heating and cooling load assessments ensure proper equipment sizing for every residential project.
Manual S Equipment Selection
Precise matching of HVAC equipment to load requirements supports efficient system performance.
Manual D Duct Design
Detailed duct layout planning balances airflow and minimizes energy loss throughout the home.
HVAC Zoning Design
Custom zoning strategies allow independent temperature control across different areas of the residence.
Pricing is $0.12/sq ft, with a minimum of $180 for homes under 1,500 sq ft. We guarantee delivery in 2–3 days.
Trust Family-Owned Experience for Your Design
Over 10 years of industry knowledge paired with real-world ductwork installation insight.
Featured Resources
From Blueprint Review to Final Report
Understanding what happens between uploading your plans and receiving your design package helps you coordinate timelines and set expectations with your team. We begin with a full review of your architectural drawings, including site plan, foundation plan, floor plan, elevations, and roof plan. Those documents inform load calculations that account for insulation levels, window placement, ceiling heights, and orientation. Once loads are established, we select equipment that meets capacity requirements without oversizing, then design duct systems that deliver balanced airflow to every room.
Each step is documented in your final report, which includes Manual J load summaries, Manual S equipment recommendations, and Manual D duct layout drawings. You'll see CFM values for every register, duct sizes for every run, and static pressure calculations that confirm system performance. That level of detail supports smooth inspections, accurate bids, and confident installations.
Our process is built to give you the information you need when you need it:
- Wrightsoft software generates ACCA-compliant calculations that meet code requirements and energy program standards
- Turnaround is guaranteed within 2–3 days, keeping your construction schedule on track
- One revision is included in our standard pricing to accommodate minor layout adjustments
- Additional services include Energy Star Forms, REScheck documentation, zoning system design, and calculations for supplementary HVAC equipment
- Service coverage extends throughout the Treasure Valley, including Middleton, Payette, McCall, Coeur d'Alene, and Pocatello
Reach out to discuss your project and receive a proposal tailored to your scope.
Built on Field Knowledge and Family Standards
Load Calc Designs operates with the accountability that comes from a family-owned business and the technical grounding that comes from years spent installing ductwork onsite. We've worked directly with builders and contractors throughout the Treasure Valley, and that experience informs every load calculation and duct layout we produce. You're not receiving theoretical designs—you're getting plans shaped by an understanding of how systems actually get installed, what challenges arise in the field, and how design decisions impact long-term performance.
Our commitment to accuracy and follow-through reflects the way we run our business: with integrity, attention to detail, and respect for the professionals we serve. Every report is checked for completeness, every duct drawing is reviewed for constructability, and every design is delivered with the goal of making your job easier. When your name is on the work, quality and reliability aren't optional.
Connect with us to start planning your next residential HVAC system with a team that values precision and dependability.
Our Service Area
McCall, ID
Coeur d'Alene, ID
Pocatello, ID
