MRCOOL Heat Pump Sizing Guide for DIY'ers

Choosing the right heat pump size is crucial to ensure optimal comfort and efficiency in your space. Follow this step-by-step sizing guide to find the perfect MR COOL heat pump for your needs:

Step 1: Measure Your Space

• Measure the length, width, and height of the room or area you want to heat/cool. If you have multiple rooms, measure each one separately.

Step 2: Calculate the Square Footage

• For each room, multiply the length by the width to get the square footage. If you have irregularly shaped rooms, break them down into smaller rectangles and calculate their square footage individually. Add up the square footage of all the rooms to get the total.

Step 3: Determine the Heat Load

• Ceiling Height: High ceilings may require larger units for heating and cooling.
• Insulation Quality: Well-insulated spaces may require smaller units for heating and cooling.
• Window Type: Evaluate the number and type of windows in the area to be conditioned.
  • Single Pane: In spaces with single-pane windows, consider a slightly larger heat pump to compensate for potential heat loss or gain.
  • Double Pane: For double-pane windows, a standard heat pump size may suffice.
  • Large Windows: If you have expansive windows, opt for a slightly larger heat pump to manage temperature fluctuations.
  • Shaded Areas: Rooms with ample shade might require a smaller heat pump due to reduced direct sunlight impact.
  • Sun-Exposed Rooms: Sunny spaces may need a larger heat pump to counter increased solar heat gain.

• Heating Seasonal Performance Factor- HSPF can range from 6.8 to 13.5. The lowest HSPF rating for a heat pump to be considered ENERGY STAR rated is 8.2 for single package units and 8.5 for split systems.
• Seasonal Energy Efficiency Ratio – SEER. It is a measurement used to indicate the efficiency of an air conditioner or heat pump in cooling mode. The minimum SEER rating for new air conditioners and heat pumps varies based on regional energy efficiency standards and climate zones. Higher efficiency units typically have SEER ratings ranging from 14 to 25 or more.

Step 5: Understand Your Climate Zone Requirements

• Determine your climate zone to assess heating and cooling demands.
• Cold Zones: In colder areas, choose a larger capacity heat pump for efficient heating.
• Hot Zones: In hotter regions, focus on cooling capacity when sizing your heat pump.
• Consider Humidity Levels:  Factor in humidity to achieve maximum comfort and efficiency. In areas with high humidity, opt for a Heat Pump equipped with Dry or Humidity control mode. All MRCOOL Mini Split units feature a Dry Mode accessible via the remote control, while Centralized Units offer a Comfy (Humidity Mode) option via the Mini Thermostat. In ‘dry mode’, the fan operates at a low speed, drawing air through the unit to extract moisture from the room. This mode is perfect for humid days when the temperature is too cool for the cooling mode. Dry mode is highly energy-efficient and can significantly reduce electricity costs.

Step 6: Match the Heat Pump Size

• Once you have realistic understanding of the heat load requirements, refer to the MRCOOL heat pump sizing chart below and match your calculated heat load with the appropriate heat pump model: