New Load Calculation Tools for Ductless Heat Pumps
Dec 02, 2020
The first step in choosing the right-sized HVAC system is knowing how much heating and cooling the home requires. Every home has a unique design that affects its heating and cooling needs. Oversized equipment can overheat the space on mild days and lead to larger heating bills, and it is difficult for service technicians to diagnose oversized equipment once installed. The NW Ductless Heat Pump Project recommends all installers perform a load calculation before selecting a unit.
Installers can use the following two free options to accurately calculate the heating and cooling load of a home.
Option 1: HVAC Sizing Tool
The first option is a free and easy-to-use online load calculator called the HVAC Sizing Tool. NEEA created the tool to help homebuilders and the HVAC community design installations that reduce energy use at peak demand times.
Sizing Tool users can complete a room-by-room load calculation of a typical home in under 15 minutes. The Project recommends new users start with tutorial videos to get familiar with the tool.
The Sizing Tool requires an internet connection and can operate on any web browser. It does not require a software subscription or regular updates. All data remains confidential and is stored in the software’s cloud-based servers.
To start using the tool, create an account on HVAC.BetterBuiltNW.com.
The results view of a whole-home load calculation performed in HVAC Sizing Tool
Option 2: Quick and Easy Load Calculation Method
The second option is a quick and easy load calculation method designed for displacement applications and single room installations. It includes an easy-to-use look-up table. Users select the column that best matches the winter design temperature and the row that most closely describes the construction type. The corresponding cell offers the BTUs of heating needed per square foot of floor space. To calculate the heating load, multiply the floor area of the space by the BTU value.
This straightforward load calculation method produces more accurate results than guesswork and will help limit the over-sizing issues seen in ductless heat pump installations.
A table for a quick and easy heating load calculation
The Project will upload an additional video on sizing and selecting ductless heat pumps using the above methods to the GoingDuctless YouTube page by January 2021.