HVAC Load Calculations for Residential House

I am seeking an experienced residential HVAC engineer to evaluate two upstairs HVAC systems installed during a renovation in New Jersey. The work may be used in construction arbitration. We need an independent and objective assessment of: - Whether the upstairs HVAC equipment was properly sized - Whether the associated supply and return ductwork was properly designed and sized - Whether calculations later prepared by the contractor reasonably support the installed equipment - What corrective work is actually required Background Our contract specified four hydro-air systems totaling 9.5 tons, but the installed system totals 14 tons! The primary-bedroom area has had continuing problems maintaining appropriate temperature and humidity. Multiple HVAC contractors state that the sizing and ductwork are absurd, but we need an independent calculation and written professional opinion. The original contractor later produced load calculations that he contends justify the installed systems. We need those calculations reviewed against the actual architectural plans and construction. I can provide: Architectural plans, Equipment model numbers, The contractor’s load calculations, Photographs of equipment and accessible ductwork, Any additional measurements or information you need. Initial Scope of Work 1. Independent upstairs load calculations: Prepare room-by-room residential heating and cooling load calculations for the areas served by the two upstairs systems. The calculations should follow ACCA Manual J or another accepted residential methodology and identify: - Heating load - Total cooling load - Sensible cooling load - Latent cooling load - Room-by-room loads - Total load assigned to each upstairs system Please clearly disclose the principal assumptions used, including insulation, windows, orientation, infiltration, indoor design conditions, and outdoor design conditions. ** The house was built in 2023, so this should be based on New Jersey statutes prior to the updated HVAC code changes. ** 2. Equipment-sizing determination Using the independent load calculations, determine a reasonable equipment capacity for each upstairs system. Compare: - The equipment required by the independent calculations - The equipment specified in the contract - The equipment actually installed - The equipment supported by the contractor’s later calculations Please explain whether the installed upstairs systems are reasonably sized for the areas they serve and whether any oversizing is minor or materially excessive. 3. Review of the contractor’s calculations Review the load calculations prepared by the contractor and determine whether they reasonably justify the equipment installed. Identify any material problems, such as: - Incorrect square footage - Improper assignment of rooms to systems - Unsupported insulation or window assumptions - Excessive infiltration assumptions - Improper indoor or outdoor design temperatures - Incorrect sensible or latent loads - Mathematical errors - Assumptions that do not match the plans or actual house - Use of inputs that appear designed to support equipment already selected The report should explain the important deficiencies in understandable language rather than merely stating that the calculations are wrong. 4. Targeted ductwork evaluation. The contractor used excessive amounts of flex tubing rather than duct work. Review the available plans, photographs and equipment to determine whether the main floor and upstairs flex tubes / ductwork appears capable of properly serving the installed systems. Please address: - Approximate required airflow for each installed unit - Whether the visible or documented supply and return ducts appear appropriately sized - Whether the ductwork is likely to create excessive static pressure or inadequate airflow - Whether the room-by-room distribution is consistent with the calculated loads - Whether the ductwork could reasonably support the installed equipment capacities - Whether flex duct sizing or layout likely contributes to the temperature and humidity problems A complete redesign of every duct run is not required during the initial phase unless necessary to support the conclusions. 5. Corrective recommendations State what work is reasonably necessary to correct the upstairs HVAC problems. Please address: - Appropriate replacement capacity for each upstairs system - Whether one or both upstairs units should be replaced - Whether the existing ductwork must be substantially modified or replaced - Whether equipment replacement without duct correction would be adequate - Whether any reasonable lesser repair could correct the problems - Whether additional field testing is necessary before reaching a final conclusion We need an objective opinion. Please do not assume in advance that replacement is required; however, if the calculations and duct analysis show that replacement or substantial reconstruction is necessary, explain why lesser measures would not adequately correct the system. Deliverables The initial deliverables should include: - Room-by-room load calculations for the upstairs areas - Recommended equipment capacity for each upstairs system - A table comparing contracted, installed, contractor-calculated, and independently calculated capacities - Review of the contractor’s load calculations - Targeted analysis of the upstairs supply and return ductwork - Recommended corrective scope - A concise signed PDF report suitable for submission in arbitration - Identification of the documents, assumptions, standards, and software relied upon The report does not need to be unnecessarily long. It should clearly explain the calculations, important deficiencies, conclusions, and basis for each conclusion so that a nontechnical arbitrator can understand it. Preferred Qualifications - Familiarity with residential construction in New Jersey, prior to HVAC code changes in 2023 - Mechanical Professional Engineer licensure - Experience with ACCA Manuals J, S, and D - Experience evaluating oversized residential equipment and deficient duct systems - Experience preparing reports for construction disputes, litigation, or arbitration - Familiarity with hydro-air systems Proposal Requirements Please provide: - Your professional license and HVAC qualifications - Whether you have prepared reports for arbitration or litigation - Your fixed price or estimated hours for the initial scope - Any information you would need before beginning - Whether you can sign and defend your written conclusions Thanks! I appreciate your help with this project!