The right-size furnace for your home assures you that it will heat your home efficiently and durably. Sizing concerns with HVAC equipment make a big difference because a system that’s too big won’t run nearly as efficiently. It will turn off and on frequently, also called short cycling. Short cycling wears out the parts faster, doesn’t heat your home thoroughly, and drives up your energy bills. In the summer, the HVAC system doesn’t remove as much humidity, leaving you uncomfortably warm.
When you start the process of sizing your new heating system, start by determining the size of your existing furnace. Find the Btus (British thermal units) of the furnace inside the blower cabinet or in the owner’s manual. You’ve probably noticed if your furnace short-cycles, and if it does, your current system is likely too large, especially if you’ve increased the energy efficiency of your home.
The best approach to finding the right-size furnace is to ask a contractor to size your system using Manual J, which takes into account many features and factors about your home that go into the conditioning load, including:
- Cubic footage you need to condition;
- Insulation levels;
- Windows, their energy efficiency and orientation to the sun;
- Layout of your home;
- Preferred indoor temperatures;
- Number and ages of home occupants;
- Heat-producing appliances in the home; and
- Lifestyle factors.
After the contractor completes these steps, he or she will know the proper size for your home. The second step is using Manual D to see if your current ductwork is adequate for the new system, or to tell the HVAC contractor if changes to your ducts need to be made. The ductwork is as important to the system’s efficiency as the appliance. When it’s inadequate, increased air pressure in the ducts may loosen the connections and increase noise.
If you would like more information about the right-size furnace for your home, please contact us at Marsh Heating & Air Conditioning. We’ve provided quality HVAC services for the Twin Cities area since 1974 and can help you with this critical task.
Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems). For more information about sizing HVAC equipment and other HVAC topics, download our free Home Comfort Resource guide.
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