Before buying a new system or contracting for the repair of an existing air conditioner/furnace and ventilation system from a licensed California HVAC contractor, there are a few important questions to ask. Consumer protection agencies usually suggest interviewing at least 3 contractors before making a purchasing decision. A new HVAC system will effect your energy costs for decades.
First, ask which method the contractor uses to calculate the size of the air conditioner and furnace. There are four code-approved methods. These use volume, insulation levels, glass type and size, air tightness and orientation of the shell of the house to calculate the correct unit size and “room by room” air flow. If the contractor uses a simplistic square footage “rule of thumb” from the 1970s, ask the next contractor on your list. The ACCA, the Air Conditioner Contractors of America, have published paper calculation forms for a long time, probably since before your contractor was born.
“Please tell me about your duct design process....” If you are met with a blank stare or surprise, ask the next contractor on your list. These days, software, such as Wrightsoft, is commonly used to guarantee correct system sizing and CFM of air-flow to each room in your home.
Ask them about total airflow. “How many cubic feet of air will this system move?” New California A/C systems are code-required to move 350 cubic feet of air per ton of cooling (12,000 BTUs). Top notch contractors are delivering up to 550 CFM per ton, providing more comfort and efficiency for our dry climate where we don’t need to remove much, if any, humidity.
Ask about the duct leakage rate they will be providing to you. Code requires 6% or less leakage, existing systems must have less than 15% leakage. Experienced contractors routinely hit the 3% level while hot-rod-high-efficiency contractors sometimes beat 1% leakage.
How much will my heating and cooling bills be after you install a new system? “There is no way to tell…” is not the response that you are looking for. More advanced contractors will be able to model your house and new HVAC system in a software program such as EnergyPro and be able to give you a good idea what your future costs will be.
Ask what type of motor will be in the new equipment. Air conditioners depend on the fan motor of the furnace, to move system air. The two types of motors are standard and ECM, electronically commutated motors. Standard motors are either on or off. ECM units are more efficient and often able to vary their speed according to the need for cooling.
One of the required tests performed by California HERS Raters is called Fan/Watt Draw. The test measures how many Watts (power) of electricity it takes to move one (1) cubic foot of air. A system must use less than 0.58 watt per cubic foot of airflow. The difference between passing and failing the test could be an ECM motor and a well-designed duct system.
For extra credit, here is a good question to pose. “This high performance, properly calculated and designed, energy efficient heating and cooling system, guaranteed to pass California’s strict energy code and provide us decades of energy savings... costs more than I have lying around in my checking account at the moment… Is there an affordable financing instrument that requires a ‘less than stellar’ credit rating? Is there be some sort of low interest, government loan for this type of thing?”
Your in-the-know HVAC contractor should be able to point you to a PACE, Property Assessed Clean Energy loan provider. PACE loans require no credit check as long as you own your own home with no taxes owed or liens against the property. Our application process took about 5 minutes before approval!
California has at least 10 PACE energy independence loan providers as of this writing. California First in Sacramento is one such provider. The Sonoma County Energy Independence program is the type of service that every California county should proudly aspire to. To learn more about PACE loans check out http://www.pacenow.org/resources/all-programs/
If your contractor can answer the above questions to your satisfaction, your next question might be, “When can you start?”.
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Building Energy Compliance Testing
HERS Duct and A/C testing for Compliance with the 2013 California energy code
San Francisco to Silicon Valley
