If your cooling or heating system is too big or too small for your home, you won’t enjoy the energy efficiency and performance you’d get with a system that’s correctly sized. When sizing an HVAC system for a home, the installation technicians first should calculate the three types of heating and cooling loads (requirements) for the home.
Design Load
This is how much cooling or heating your home requires to be comfortable (perhaps 24 degrees in summer and 21 in winter) under designated typical outdoor temperatures for that season. These usually approximate the average highs and lows (summer and winter) for a particular area. In a cold-winter climate, that might be 22-23 degrees in the summer, and minus-12 in the winter. Calculating the design load takes into consideration various factors, including the home’s energy efficiency, size and layout. Then it determines how much cooling or heating is needed to bring that home to the indoor design (comfort) temperature when the outside is at the design temperature.
Extreme Load
These heating and cooling requirements occur on the hottest and coldest days of the year. Your home’s HVAC system should not be designed to accommodate these loads, however, since that would mean it would be oversized for the rest of the day/year. An oversized system will waste energy, among other problems.
Partial Load
The majority of the time, your home will experience partial heating and cooling loads. Most of any day or season, your HVAC system won’t be struggling to heat or cool during either extreme or design conditions outside. Any given day experiences the average high/low for only a small part of the time. Consequently, even properly sized heating and cooling systems may cycle on and off frequently. The good news is that increasingly, modern HVAC systems come with variable-speed and level components that allow the equipment to adapt its running speed or level to current conditions.
For more information on how heating and cooling loads relate to performance and energy efficiency in your Calgary area home, contact us at Arpi’s Industries.
Our goal is to help educate our customers in Calgary, Alberta about energy and home comfort issues (specific to HVAC systems). For more information, download our free Home Comfort Resource guide.
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