It’s tempting to think that purchasing the largest central air conditioner or heat pump will ensure your house is comfortable. In fact, the opposite may be true.

If the unit is too large for your home, you will be less comfortable and might actually have higher utility bills. Oversized equipment operates in short run cycles (your equipment will turn on and off more frequently), not allowing the unit to reach efficient operation and remove humidity from the air – resulting in an uncomfortable home.

Idaho Power's Heating and Cooling Efficiency Program requires all participating companies be trained in best practices to size HVAC equipment for your home.  

Sizing

Units are sized by conducting a thorough cooling load analysis that includes taking several measurements of the home and assessing the needs of each particular home.

Manual J (a handbook for contractors) procedures determine the design heating and cooling loads based on:

• The amount of wall, ceiling, window, and floor area
• Their insulation value
• Building envelope and duct air leakage
• Building orientation
• Roof surface color
• Occupancy

These factors go above and beyond conventional sizing methods that many contractors use today and help ensure your unit will be the most efficient for your type of home.

Installation

The same is true for installation. If your heat pump or central air conditioner isn’t installed to best practices, the equipment won’t work as designed and you may end up with higher energy bills and a less comfortable home.

Two requirements of best practice installation under the Idaho Power Heating and Cooling Efficiency Program are:

• Refrigerant charge – Refrigerant is the working fluid in your air conditioner that removes the heat from your home. To operate properly, air conditioners must have the appropriate amount of refrigerant. That amount is dictated by the installation of your system and is unique to your home.
• Air flow – To effectively remove heat and cool your home, air conditioners require the proper amount of air flow through your ducts. Too much or too little air flow can reduce the efficiency of your system and affect your comfort levels.