Post War California Tract House Energy Audit Reveals Room for Improvement

Postwar, 1947 tract house on 1/3^rd acre lot is inundated with sun since the old trees died. The owners are doing a remodel. West facing single pane windows let in ample sun and warmth on a February 1^st afternoon. By April or May it will surely feel like a furnace. New, California Energy Code level windows formulated for western orientation will make the dining/living room more comfortable year-round.

The house has no insulation in the floor or walls. The ceiling has about 3 ½ inches of old, disturbed, blown in insulation. Building a dam around the fold-down access stairs and furnace and insulate it to R40 (about 14 inches of blown-in cellulose) would make the place far more comfortable and cause the furnace/AC to run less often.

The attic access is an area where warm conditioned air escapes to the attic, causing drafts and wasted energy dollars. Those fold-down access stairs to the attic are really hard to air seal or weatherstip properly. I suggest adding on one of the zip-up “tents” that go on top of the access area.  I’d never seen one until last fall. They are air tight and really work.  Check out one site selling such “tents”, http://www.energyefficientsolutions.com/attic-tent.asp

That same attic, under a brown roof must surely bake in the summer sun. I suggest adding radiant barrier under the roof deck. You really have to feel the difference to believe how much energy this material stops from radiating into the attic. It works! Check out http://energy.gov/energysaver/radiant-barriers  to learn more. For a low tech way to go, here just paint the roof white. They do it from the Bahamas to India to the Greek Islands. Put on your sunglasses and check out Santorina, Greece, cool…
 

The crawlspace is open and ventilated to the outside with no insulation in the floor. Many would suggest adding R19 fiberglass  insulation to the bottom of the floor. That is an imperfect way to go. A more interesting and healthy option is to encapsulate the crawlspace. This action can not only keep the floor warmer in the winter but keep the nasty air from the crawlspace out of the house. I’ve read articles stating that over 40% of the air in a house comes up from the crawlspace. Below is a before and after pic that shows the visual improvement. The lower pic shows how a crawlspace can become a semi-conditioned sub-first floor that seems more like an operating room than a crawlspace.

il. Above Left: Thick plastic separates house from soil
Right: Americover.com materials encapsulate crawlspace

The water heater is a standard .62 tank water heater that takes up a significant amount of space in the garage. The owner mentioned how an expanse of pipes makes the cold water hot in the summer months.  An upgrade to an instantaneous gas water heater could both free up space and provide energy savings.  The pipes could be insulated to reduce heat gain.
Takagi Instantaneous gas water heater saves space and energy

The house has a newer large furnace/air conditioner system that appears to be well sealed except for a small leak on the right hand side of the furnace. Place UL 181 aluminum tape on the corner of the plenum to seal it.  The flex ducts appear thoughtfully sealed however they all leak unless there is mastic on the joint of duct to the plenum. Twelve dollars worth of air duct mastic and an hour spreading it around every duct connection would surely keep more air inside the system and the house rather than in the attic.

Doing the above items would render the house more comfortable and lower the energy bills. How much? To learn that, computer energy modeling is necessary. Your energy consultant could easily model them and assign dollar values.  The nice thing about the upgrades is that they offer non-energy dollar benefits of  improved air quality, added space and improved thermal comfort.

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What homeowners need to know about the new California Energy code before hiring an HVAC contractor

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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