Unmet Load Hours (ULHs) are a critical metric in building energy simulations, indicating periods when HVAC systems cannot maintain the desired indoor temperature setpoints. High ULHs can indicate issues with system sizing, control strategies, or model configuration, and are often a key factor in compliance with standards like ASHRAE 90.1 and LEED.
DesignBuilder have published a Modelling Guide for Unmet Load Hours which offers in-depth explanations, checklists, and troubleshooting workflows that you can apply directly to your projects. It’s an invaluable resource for anyone committed to accurate, reliable, and compliant building energy modeling.
The Guide is designed specifically for DesignBuilder and EnergyPlus users who want to understand, diagnose, and resolve ULHs in their building energy models. Whether you’re a beginner or an experienced energy modeler, this guide provides a step-by-step approach to:
- Identifying when and where unmet load hours occur in your simulation results
- Understanding the most common causes, from equipment sizing to airflow distribution and control settings
- Troubleshooting issues using practical, real-world examples
- Implementing solutions that optimize HVAC performance and ensure compliance with industry standards
By reading the guide, you will:
- Gain a clear understanding of what unmet load hours are and why they matter
- Learn how to interpret simulation outputs and pinpoint problem areas
- Discover best-practice strategies for resolving ULHs in your models
- Develop the skills to optimize HVAC systems for both comfort and compliance
Download or read the Modelling Guide for Unmet Load Hours here.
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