Here's Michael testing for leakage with a duct blaster.

           I was in the lead. Wyrick was my backup when suddenly he called out, "Wow, this is refreshing! " I backtracked to Wyrick’s position. There in the midst of the 105º attic was an oasis, a breeze of cool air wafting up through the floorboards. This cold-air fountain was obviously the result of a break in the ductwork buried somewhere inside the framing of the building.

           I’ll spare you the details. Suffice to say, we advised our client of the bad news and the good news. The bad news was there’d be hammers flying to get past the sheetrock to where the break could be repaired. The good news was, once repaired, the ducts would be delivering conditioned air where it was needed and not into an empty attic.

Another season, fall 2006. I was working a job with Cheryl Pomeroy. Cheryl is one sharp cookie and the only PhD we have on our staff. {That's Cheryl checking out a skylight.) Not only is she smart, she really knows her way around a construction site. You see, Dr. Pomeroy left a promising career as a college professor and spent 13 years working as a union carpenter. She also has her own home inspection business. Somehow she finds the time to moonlight with us as an Energy Detective. You guessed it: she, too, must be motivated by the glamour and the high pay.            The weather was a dreary 35º outside and we were in an attic with a ridge vent and two gable vents. Logically you would expect this attic to be cold, right? Well, this attic was 85º. The homeowner had called us in because she felt like someone was stealing her heat.  And she was right.

The house had also been through a renovation in the last few years and the contractor had placed a furnace and a/c unit in the attic, installed the ridge vent, and positioned rigid ductwork across the attic floor. At first sight it looked pretty good.  But under careful observation we found a very leaky setup. Whenever the furnace cycled on, 130º air spewed out of poor joints in the ductwork at several locations. The hot air ballooned right through the insulation that wraps the ducts. No other spot in the house even came close to the temperature in that attic.

           Our client was in luck. We’re not only good at detecting the problem, but we come up with pretty good solutions. So we advised our client to get the duct joints in the unconditioned attic sealed up tight. She was relieved—-could have been worse.

            Not all attics suffer from too much heat. Just this past week, Pomeroy and I were diagnosing a single family home in Chicago's Gold Coast and came across quite the opposite. This fine home, built in the 1880s, had been retrofit with a high-pressure air-conditioning system located in the attic crawl space. When we entered through a hatchway in the ceiling of a closet, the space felt strangely cool to us. A quick check with the digital infrared thermometer confirmed that the unvented attic was between 68 and 70 degrees Fahrenheit. I'll let you be the detective on this one. What do you think was going on?

           Yep. We found more than a dozen major leaks in the high-pressure duct work. Whoever installed the ducts had put them together with duct tape. Everybody knows there are a thousand and one ways to use duct tape but sealing ducts is not one of them. Duct tape dries out and easily comes loose.

           It's no mystery that out of hundreds of buildings we test every year, the majority has some kind of problem with ductwork. In fact, studies by the Florida Solar Energy Group show that the average home loses between 10% and 30% of conditioned air through leaks in the ductwork.

           These losses are most critical when the ducts are running though unconditioned spaces like attics and crawl spaces. Supply-duct leaks can cause expensive conditioned air to be lost to the outside rather than being delivered to the building. Return-side-duct openings can draw in air at sharply higher or lower temperatures, increasing the load on the central equipment. The Minneapolis Blower Door Company, makers of building diagnostic equipment, estimates that the addition of 10% of the return air from a hot attic will reduce the efficiency of an air conditioning system by as much as 30%.

           In humid locations, moisture-laden air drawn into the ducts from basements and crawl spaces can overwhelm the dehumidification capacity of an air conditioning system. If the source is a basement, garage or crawlspace, this air could contain household chemicals, poisons, gasoline, carbon monoxide, mold spores, dust, paints and other contaminants you don’t want to be caught dead with. 

           ‘Course, these days you might think with cities and states across the country adopting “energy codes” that call for ductwork to be sealed with aluminized tape or duct mastic, we’d have an end to this travesty. But our experience shows many builders pay little attention to energy codes, or, for that matter, to best practice procedures. A case in point: Chicago has had an energy code since September 2003 but when I recently checked the shelves in the showroom of a major HVAC supplier I found only 5 one-gallon cans of duct mastic and they were covered in dust.

           If the ducts aren't sealed at the time of construction, it is very difficult to get at them later. After all, they are usually hidden in attics or crawlspaces, or buried inside of wall and floor cavities.

           While getting an airtight seal on ductwork is very important, it is by no means the only problem we encounter with ductwork:

[Left] At the center of image, an open break in the ductwork. [Center] Supply and return registers are in close proximity. [Right] No space at all between supply and return registers.

[Left] Well-sealed ducts are nonetheless tortured and twisted. [Right] Ductwork was used as a dustpan during construction sweep up.

           Just when we thought things couldn’t get any worse; things got worse.

            It was the dead of winter. Dr. Pomeroy, Porterfield and yours truly converged on the crime scene of a regular Saturday night massacre. We had seen ducts run through unconditioned spaces before but this house took the cake. There before our very eyes someone had run leaky barely insulated ductwork across a roof --- in Chicago!!! Could this have something to do with our client’s $700-800 heating bills!

           Not long after, Porterfield and Michael reported another unbelievable case. This time the contractor made no attempt to insulate major sections of the ducts.

Ducts across rooftop are exposed to temperature extremes. In the last photo, the installer hasn't even attempted to insulate the ductwork.

           We're swapping stories at a conclave of the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) when Shawn Mansfield, another fine energy detective, tells one that beats all. He's in a house with a mysteriously high 62% relative humidity. You might expect this on a houseboat, but there was no sign of standing water anywhere. He was stumped until he sent a mini camera into the underground ducts where it almost drowned in ground water. Talk about leaky ducts!

           By now, you may have figured we’re not just after the energy waste. Like a lot of other folks in the industry, we believe the goal of homebuilding and rehab should be to build a quality product that is safe, healthy, durable and, of course, energy efficient. Poorly designed and installed ductwork cuts across all of this. It doesn’t have to happen.

           As energy consultants and “green building” advisors, the Energy Detectives™ at Informed Energy Decisions are proud to train and identify a growing list of developers and contractors who build better buildings.

           Until it's time to post our next case, catch us by the car with the sign that says, "Energy Detectives – we’re on the case to make buildings more energy efficient."