Multi-room BTU planner

What the planner does

The planner accepts up to four room areas, an average ceiling height, and the same insulation and climate multipliers used in the main calculator. It outputs a combined BTU recommendation, a tonnage conversion, and a reminder to cross-check design temperatures. Because the calculations mirror the single-room workflow, you can compare the combined results back to the sizing summary without worrying about inconsistent math.

When to use it

• You are planning a single ductless condenser with two to four heads and need a quick way to total the cooling load before selecting equipment.
• A retrofit requires verifying that an existing supply branch can deliver airflow to several bedrooms after insulation upgrades.
• You are preparing homeowner documentation alongside the room-by-room worksheet and want to summarize each zone on one line.
• A contractor proposal lists only total tonnage and you want to confirm that the grouped rooms in question justify the number.

Input checklist

Before you open the tool, gather the following information:

1. Square footage for every room sharing the system. Capture these using the printable worksheet or directly in your notes app.
2. Average ceiling height. If one room includes a vaulted or tray ceiling, use the highest value and note the difference for your contractor.
3. Envelope performance. Match insulation quality and solar exposure to the options provided so the planner uses the correct multipliers.
4. Occupancy and equipment notes. While the planner focuses on sensible load, the main calculator handles occupants and appliances. Pair both results to create a complete picture.

Step-by-step workflow

1. Enter the area for each room. Empty fields default to zero, so you can analyze two, three, or four spaces without editing the form.
2. Select the average ceiling height. The tool scales the square footage by this value, just as the primary calculator does.
3. Choose insulation and climate exposure levels. These multipliers align with the logic discussed in the methodology section.
4. Submit the form to reveal the combined BTU recommendation and the rounded tonnage. Copy the results into the heat pump sizing checklist or your project brief.
5. Follow the callout to the BTU and tonnage converter and climate load adjuster to finish the workflow.

Example scenario

Imagine a one-story renovation with three bedrooms sharing a central air handler. Bedroom A is 180 square feet, Bedroom B is 210 square feet, and Bedroom C is 140 square feet. The ceilings average nine feet, insulation rates as average, and the rooms face a warm climate exposure. After entering the data, the planner outputs roughly 11,000 BTU, or just under one ton. You can now confirm that the original 1.5 ton branch was oversized and plan duct resizing or balancing. You can also check each bedroom individually in the main calculator to determine whether window upgrades in Bedroom B would further reduce the combined load.

How it complements other ACCalculator tools

The multi-room planner anchors the middle of the HVAC decision tree. Start with the core calculator for detailed occupant and appliance inputs. Use the planner to group rooms. Convert the final BTU recommendation to tonnage with the converter, then simulate hotter or cooler design days with the climate adjuster. Each page cross-links to the BTU myths article so you can explain to stakeholders why right-sizing beats over-sizing.

Documentation tips

When you share planner outputs, include a screenshot of the results and attach the worksheet used to gather inputs. Contractors appreciate seeing the math, and homeowners value transparency. Add notes about supply register sizes, return placement, or insulation upgrades so the numbers remain meaningful months later.

Frequently asked questions