Plug Loads...An Ever Increasing Demand
As excited as we are about Passive House and its impact on our utility numbers for heating and cooling, the elephant that is still sitting in the room (and getting larger by the day) is the energy used for what we plug into our houses. Refrigerators, washers, dryers, cupcake makers, hot dog cookers, hair dryers, set top boxes, computers, and cell-phone chargers are just some of the culprits. The list is constantly increasing without a growing awareness of the energy cost of these items...many of which draw energy when not in use, but are simply plugged in. If a building is built to Passive House standards, it is safe to say that the amount of energy used for heating and cooling is minimal and now plug loads represent the lion's share of energy usage...three steps forward, two steps back. An excellent synopsis can be found in the Green Building Advisor.
Unlike the design of the building and envelope, the electrical items that get plugged into a building by the occupants are not in the architect's control. One of the hot topics in our office is how to increase the homeowner's awareness of energy usage...and more importantly, how do we get them to care about it?
A friend, who recently lived in Africa, relayed to us that there energy is paid for upfront and credited to a card; homeowners then return home, plug the card into the meter, and spend the energy they have prepaid. In his estimation this shifts the focus and creates a constant understanding of how much energy is left to be used. The user who is paying attention can get a feel for how energy intensive certain activities are. For a society that is uniformly concerned about the cost of energy, this is a great solution. We are obviously not a culture who has reached that point yet.
There is a cool net-zero project in Maine, created by Kaplan-Thompson Architects: the house has a band of lights at the building skirt that glow red when the building is using more energy than it is producing, and glow green when it is producing more energy than it is using. It creates a visual message to the homeowners - and the neighbors - about energy use.
Another approach is the whole-house power switch in another project, by Ziger-Snead. There is one button that all miscellaneous non-essential plug loads are wired into so that the homeowner can turn these off by pressing that one button when leaving the house.
There is still another alternative for monitoring plug loads: Current Cost and Enerati both offer a simple set of wireless devices that monitor the plug loads in your project. They have many types of devices that monitor energy use, and different levels of price and complexity.
The real issue here is not the ability to monitor plug loads; the real issue is to get the occupants of any project to care. In a nation of cheap and abundant energy this is particularly challenging. Nevertheless, it must be the next step.