In last month’s column, I introduced readers to the Jetson House, the iconic home that has been around since the early 1960s and has been seen by pretty much anyone who has driven the corridor of Interstate 70 between Denver and the western side of the Continental Divide. Other than a high-efficiency window replacement program done during the first remodel in 1999, not much attention has been paid to energy conservation until now.
During the addition, started in 1999, the building and the addition were retrofitted with a panel style of hydronic based radiator, two fan coil units, and four zones of in floor hydronic radiant heat. I am told that there were two boilers used to power the system. These boilers were extremely problematic. The person in charge of installing the home’s security/energy management system set up a remote telephone reset system that would allow the mechanical contractor the ability to call the home up and reset the boilers remotely to keep the system running.
Eventually, the homeowner became so disgruntled with the two boiler system that he had the two near condensing boilers replaced with one undersized modulating condensing boiler. This boiler is still operational to date, however, whoever installed it did not hook up the outdoor air temperature sensor. So every time there is a call for heat, the boiler runs the water temperatures up to the 180°F limit. It has a whole host of other related issues, and was in need of emergency replacement in order to maintain the integrity of the historically designated property.
This is where I make my entrance. The new owners originally approached my master plumber brother who had a little experience with hydronic heating to do the work on the new system. He has been doing plumbing on numerous projects of the owners for many years and had become good friends with them in the process. My brother took one look at the complexity of the system, heard the horror stories attached to the home and told the new owner that he needed to speak to me. I met with the new owners, and got the insiders tour of the building, and was also introduced to the new owners’ plans as it pertained to the building. He basically wanted to make this icon as energy efficient as possible, within reason, and within the confines of the historic designation.
I began by doing a thorough heat loss calculation of the existing structure, as well as the new addition. I also had to take into consideration the fact that there was an extremely large soaking tub in the master suite, plus four showers, and a snowmelt system serving the area directly in front of the garage.
The decision was made that a home of this class had a zero diversity factor in energy loading, meaning that the system was going to have to have the capacity to reasonably provide all of the thermal loads that would be imparted upon it. The hardest part of the heat loss calculation was in determining what the overall resistance values in the walls and ceilings of the space ship were because the depth of the walls and ceilings were not consistent. I had to drill numerous representative holes on the shell, which is made of old school metal lathe and plaster. Once the available insulation cavities were determined, oddly enough, there were no blue prints for the stem or the top floor, only drawings for the new construction begun in 1999, hence the need for extra specialized insulation cavity sleuthing. I used a small remote snake camera to look inside of the cavities to determine the possibility of adding insulation to these cavities as a part of the effort to make this icon greener. The owners had possession of it in January of 2011, and he said the utility bills were nothing short of outrageous for a house of that size.
The home had numerous areas of comfort concern, and based on reviews with an infrared camera, it had a lot of energy leaks as well around commercial grade glass doors, of which there were three. Replacement of these leaky glass energy hogs are a part of the greening process.
We also had the students from Red Rocks Community Colleges advanced energy conservation program perform a blower door test to see exactly how leaky the home was. This is essential when sizing the heating system for an existing dwelling of this size and stature, and it not only shows how much energy is being lost to infiltration, but also shows exactly where those leaks are located at using either smoke sticks or infrared cameras. The infiltration rates were higher than would be considered normal, due mostly to the poor fitting commercial grade doors that were slated for replacement.
In addition to the thermal energy equipment, I took on the task of making the other energy consuming physical plant as efficient as possible, including the cooling system serving the top floor, the potable water delivery/distribution system, and the homes ventilation systems. One critical detail was that the existing physical plant had to be kept intact while the new system was built and brought on line in stages. Much of the existing physical plant was spread out all over the home, with zone valves remotely located. The new owner wanted as much of these components to be located in one room as was physically possible. The utility room was a new addition to the existing building, and allowed me to completely install the replacement system and leave the troublesome existing system on line until it was safe to switch everything over.
Tune in next month as we continue our journey through this iconic homes energy retrofit. Until then, happy hidden efficiency hydronicing!
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