In big cities, older buildings with outdated wiring schemes tend to cost a lot more to heat, cool, and illuminate than more modern multi-family dwellings. Last year, a New York Times article titled “Air-Conditioners That Run When Nobody’s Home” highlighted how tenants tend to behave when they’re not responsible for their energy costs. It said, essentially, when utilities are included in the rent price, leaving the heat on from September to March doesn’t seem like such a bad idea to most people.
Master-metered buildings, according to findings by the New York State Energy Research and Development Authority (NYSERDA), can use up to 26 percent more energy than those where residents are billed individually for their energy use. And in New York City alone, there are some 250,000 apartments whose residents’ energy use is completely disconnected from how much it costs.
This touches on two topics that we’ve discussed somewhat frequently on this blog: (1.) how to get people to change their energy consumption habits and (2.) how wireless networking technologies like Zigbee and Z-Wave are bringing down the cost of energy efficient retrofits.
In this case, the relationship of behavior to cost is quite obvious. If residents aren’t charged for their energy use, they will do things like leave their air conditioner on for hours on end while they’re out enjoying the fresh air.
It’s also clear that there are tangible savings to be had, on an individual and aggregate basis, should we convert to a system, also known as submetering, that holds individual tenants responsible for their energy use.
Of course, there are big obstacles to changing over, the least of which is not whether building owners or their tenants will bear the cost of converting. But regardless of who pays the upfront costs, it’s fairly well-established that both stand to gain. In the current environment, building owners are confronted with strong incentives and disincentives to comply with state, federal, and local energy standards. For residents, all but the heaviest energy users are likely to see their total costs go down. In most buildings, energy use is fairly consistent, with 10 percent of the occupants consuming upwards of 25 percent of the electricity. Where submeters are available, those users will also bear a disproportionate share of the cost instead of distributing among their neighbors.
Today, wireless technologies are further lowering the impediments to retrofitting commercial buildings with submeters. According to the Schneider Electric White Paper titled “Lowering the Total Cost of Ownership of a Sub-metering System,” the expense associated with upgrading a master-metered building primarily owes to labor and installation fees. Wireless systems, the paper argues, can reduce total costs by up to 70 percent for the following reasons:
● Automatic node discovery minimizes need to access residents’ apartments
● Wireless systems avoid grounding problems and have built-in diagnostics
● Many wireless systems are smaller and reduce materials handling costs
● Pre-configured systems eliminate need for on-site customizations
In addition to lower upfront costs, there’s the potential for longer term savings by extending smart energy management inside the home. This is where, as the Zigbee Alliance puts it, HAN meets NAN. The NAN, or neighborhood access network, is the centrally located unit for each individual dwelling that carries usage data back to the master meter and eventually the utility company. The HAN is the home area network comprising things like smart appliances, light switches, and sockets aimed at making everyday tasks consume and cost less.
Because of their low cost and future-proof configuration, wireless submetering solutions have the potential for energy savings in both the short and long terms. These factors also seem to show promise for lowering resistance to their adoption, either because building managers won’t need to put up as much cash or tenants won’t need to pay such high premiums. Most importantly, however, the energy savings to be had can only be called massive.