by Southface Home Performance with Energy Star staff

When making home improvements, we all want to get the most bang for the buck. Consumer advocate Clark Howard is certainly no exception. Those who know Clark Howard from radio, television, or the newspaper know that he is always searching for the best value. So when Clark wanted advice on the most cost effective improvements for lowering his energy bills this winter, he called Southface.

Clark, wife Lane, and their children live in a comfortable and well-maintained 18-year-old home in Atlanta. They have invested in home improvements and maintenance to increase the comfort, health and energy efficiency of their home during their eight years in the house. Specifically, Clark and Lane have installed high efficiency air conditioners and high efficiency air filters for their heating and cooling systems, which are regularly serviced. Despite these efforts, their energy bills were quite high, and some family members experience asthma and allergy symptoms in the home.
Southface developed and administers a program called Home Performance with ENERGY STAR®. Under the program, Southface trains contractors to use the whole-house approach to inspect homes, diagnose problems and offer solutions. The homeowner receives a list of recommended improvements prioritized by cost effectiveness that the contractor can perform, with Southface monitoring for quality control on a percentage of projects. Southface’s Howard Katzman and Sydney Roberts performed an inspection of the Howard residence using the Home Performance with ENERGY STAR protocol.

The home was visually inspected from the basement to the attic, inside and out. In the attic, insulation over flat ceilings was fairly level but vertical or sloped walls (kneewalls) did not look as good (Figure 1). Insulation should be continuous and even to function most effectively.

Several open cavities connecting the attic to interior walls and the floors below were located. Dirty insulation was the telltale sign. These chases allow warm or cold air from the unconditioned attic to circulate throughout the house making rooms and floors uncomfortable. All chases should be sealed properly so that air can not pass.

Exhausts for two bathroom fans were emptying into the attic instead of being ducted to the outside. This situation had caused visible moisture damage and mold growth on the underside of the roof deck. Bath fans, as well as kitchen fans and laundry dryer vents, should be ducted to the outside. Controlling moisture at the source reduces the work that the air conditioner must do to decrease humidity.

Outside the house some downspouts terminate only a foot from the building. This tends to soak the foundation walls, increasing the likelihood of high humidity or water penetration into the basement. Downspouts should be connected to piping that carries the water to a spot that is downhill and at least 5 feet from the house.

Clark has been diligent in replacing incandescent light bulbs with more efficient compact florescent lights (CFLs). Not only do CFLs use only 25 percent of the energy of incandescent bulbs, but they also last 10 times longer. For an average bulb, this will save $50 over the life of the CFL.

In all homes with combustion equipment (e.g., gas appliances and fireplaces), carbon monoxide detectors should be installed outside of each sleeping area and in each room with a fireplace or other combustion equipment.

The heating and cooling systems were relatively new and were well maintained. Both systems in the home are equipped with a high efficiency pleated air filter. These filters are 3-4 inches thick and are designed to capture dust and other small particles without restricting air flow.

A blower door test was performed to measure total air leakage into and out of the home. For the Howard’s, the results indicated that 50 percent of the conditioned air is escaping every hour through leaks and holes in the building envelope. Common areas of leakage are through attic access doors, unsealed recessed lights, whole-house fan louvers, plumbing and electrical penetrations and chimneys. These leaks equal energy and money lost.

A duct blaster test was performed to measure leakage into and out of the ducts of two HVAC systems. In this test, the ducts are pressurized with a calibrated fan and air leakage out of the ducts is measured. The systems showed leakage of 29 percent and 27 percent. In addition to lost energy, duct system leakage causes comfort and air quality problems.

	Figure 1. Missing insulation on sloped ceilings. Note that some is discolored, indicating air movement through the batt.

Clark and Lane were surprised to learn that their home and duct systems have significant air leakage. The good news is that many of these leaks can be sealed, leading to improved energy efficiency, comfort and indoor air quality. The Howards are in the process of making improvements, following the prioritized list generated by the Home Performance with ENERGY STAR assessment. Stay turned for a report on their progress, success and savings.

Clark Howard’s Homework

A	Priority
	Improve air tightness of ductwork
B	Priority
	Improve air tightness of house Improve kneewall insulation
C	Priority
	Improve attic insulation
*	Highly Recommended
	Install carbon monoxide detectors Duct exhaust fans to exterior of house Insulate water heater and first few feet of pipe Replace toilets with 1.6 gal per flush or better      Replace showerheads with 2.5 gal per minute or better

Duct Sealing is the Low Hanging Fruit

In the Howard home, duct system sealing was identified as the priority improvement. Studies show that ductwork leaks are the biggest source of energy loss in most Southern homes, accounting for up to 30 percent of total heating and cooling costs. For the average home, this amounts to hundreds of dollars each year. Additionally, comfort and indoor air quality are significantly compromised by leaky ducts.

Ductwork can be sealed from either the outside or the inside. The choice of approach depends on the home. If the ductwork is all accessible, for instance in an attic or unfinished basement, it is often possible to seal the ducts from the outside. Whether the ducts are constructed of hard metal or flexible runs, the insulation layer should be peeled back and all joints and seams should be sealed. They can be sealed with mastic, putty that dries hard and airtight, or with spray foam. Professionally applied spray foam both air seals the ducts and insulates them. In all cases, it is important that the seal be made at the actual connection and not on the insulation. Ducts must be reinsulated once sealing is complete. A duct system fact sheet is available at www.southface.org.

The other option is to air seal ductwork from the inside with a system such as AeroSeal®. This procedure involves computer controlled pumping of an aerosol sealant into the duct system to seal holes up to ½ inch in size. Sealing from the inside may be the best option if ducts are inaccessible or if hard metal ducts are already insulated. Additional information on AeroSeal is available at www.aeroseal.com.

Sealing flex duct with mastic - Rule one: never use duct tape.
Mastic is the proper sealant for making a solid seal between duct system components - this is true with flex-duct too. By combining good mechanical fastened compenents, such as duct collar take-offs from trunk lines, plenums and lots of mastic and strapping — you can improve the efficiency of your heating and cooling system. Now, be prepared to get dirty.	Seal the collar to the plenum or trunk with lots of goopy mastic.	Apply mastic to the duct collar take-offs.
Slide flex duct over the collar and cinch a strap around it to hold it in place.	Apply more mastic over the outside of the flex duct to ensure complete sealing.	Pull the insulation covering from the flex duct to complete the job and strap this.