Submetering Installation

Cheverly Crossing is a six-floor building with 60 apartment units, each containing a breaker panel and a gas furnace with an air conditioner. The property’s water system is riserpiped with a central gas boiler generating domestic hot water energy. With the installation of H2O Degree’s measurement and control system, NOVO began monitoring the apartment building’s electric, water, sewer, domestic hot water energy – as well as the gas used for heating.

In each apartment unit, H2O Degree’s battery-power wireless water meters (Figure 2) were mounted at the tub, shower, toilet and kitchen hot water feed, using four meters per apartment. The device provides a radio interface to remotely monitor and collect water consumption data from the H2O Degree flow sensor. The meter monitors water usage in gallons and records the number of events, the duration of events, water temperature and heat.

H2O Degree’s battery-powered water meters communicate with a transceiver (Figure 3).  At Cheverly Crossing, the thermostat and electric meter act as transceivers. This is a unique feature of H2O Degree’s wireless network, resulting in substantial savings over traditional wireless repeater networks.

The diagram in Figure 4 shows how H2O Degree’s comprehensive metering system is installed throughout the building.

Changing Tenant Behavior

Once the submeters were installed, Cheverly Crossing began receiving daily email reports based on the utility data collected at each tenant location. In addition to electricity, water/sewer and gas, the property owner was able to monitor – and bill for – domestic hot water energy (DHW). An essential calculation shown on the report is the average daily consumption, or ADC, which is typically 70 gallons of water per day for a typical one bedroom apartment. However, Cheverly Crossing’s ADC was a staggering 200 gallons!

H2O Degree was able to share the metering data with the billing company, who then passed on the water bills to the tenants based on their individual usage. With the submetering results, which were clearly shown on the bills of the building’s individual residents, the tenants immediately changed their behavior based on a financial incentive to conserve. They reduced their heating and cooling demands when their apartments were unoccupied, in addition to turning off lights, shutting windows and making sure that toilets weren’t running. 

Changing Landlord Behavior

An extremely useful side benefit of the remote monitoring system was that the landlord could use data – which reports and compares demand for heat to average set-points and temperatures every hour – to proactively fix problems. For example, the property manager previously had to rely on complaints from the tenants to be aware of a problem with the HVAC systems. But after submetering was installed, the manager had visibility into HVAC malfunctions that surfaced from monitoring data and could repair the units before they became an issue with the tenants.

In addition to monitoring and recording water consumption for tenant billing, the H2O Degree wireless water meter also detects leaks. Once the submeters were installed, submetering data collected at each tenant location was used to create Leak Detection Reports. H2O Degree delivered daily reports via e-mail to the Cheverly Crossing landlord so that maintenance staff could respond and make repairs before the leaks could generate significant waste. And by pinpointing water leakage in exact locations, building maintenance was able to replace specific parts – flapper valves, stuck chains, cracked flow values, etc.

The behavioral change by the maintenance team, based on the Leak-Detection Reports, combined with the tenants’ water conservation, resulting from targeted billing, enabled Cheverly to bring its Water ADC from 200 to 80 gallons in the first year – and lowered it even more in subsequent years.

Hurd, the NOVO property partner, noted the importance of having H2O Degree’s Leak Detection Report identify what was leaking, and why, so that the right parts could be in hand when maintenance knocked on the door. “The results,” he said, “are far better than even we forecast.”

Monitoring Results: Water and Sewer

The Cheverly Crossing apartment building installed its water submetering system in July 2009. The water/sewer rates provided by Cheverly’s water utility WSSB (Washington suburban sanitary commission) are graduated, so that high consumption is penalized with a much higher rate per thousand gallons. 

While Cheverly Crossing reduced water use by 66% in the last 12 months compared to the baseline, they reduced their water/sewer expense by over 80%. The building’s water/ sewer averaged $115 per apartment per month in the first nine months of 2008 – in the first half of 2010 dropped to an impressively lower $13.25 average. In the first year after the submetering installation, Cheverly’s total water sewer expense was went from $73,320 in 2008 down to a significantly lower $13,565 over the last 12 months of 2009. And since 2010, the results have been maintained at this low level (Figure 5).

As mentioned, the significant reduction in water use was mainly thanks to leak mitigation. In this case, the on-site manager was aggressive in repairing leaks as they were reported. Soon the property began reporting “0” leaks and maintaining water use in the range of 65-75 gallons per apartment, per day, for the total property (this figure includes water used in common area laundries).

When comparing total consumption in the first half of 2010 to the four-month period prior to submetering, the drop is 51%. Comparing the last 12 months to all of 2008, the drop is 66%. The conclusion: every property in H2O Degree’s meter reading portfolio now operates below 105 gallons per apartment per day, with an average of around 80. Savings projections to these levels are reasonable, but the amount saved depends on the baseline, which generally includes many undetected toilet leaks. 

Current water consumption of less than 80 gallons per apartment per day is consistent with other H2O Degree submetered properties, and serves as a benchmark goal that has been achieved at other properties. Since then, Cheverly has been able to maintain the number of gallons used since 2012 at the same low rate thanks to ongoing reporting and proactive repairs. 

Monitoring Results: Electricity

The submetering system for monitoring electricity at Cheverly Crossing was installed in February 2009. While leak detection prompts the property owner to take action themselves by fixing problems causing wasted water, tracking electricity throughout the building enables the owner to collect the data they need to bill tenants according to the tenants’ specific electricity usage.

Tracking electric usage at Cheverly immediately resulted in a 33% decline in use. The three critical summer months in the first year of metering, consumption was down by 49% compared to the same three months of the prior year. Savings was $24,126 per year, of which $16,500 accrued in the summer months alone. 

These H2O Degree thermostats were purchased by Cheverly to track heating energy of the gas furnaces, but they also allow residents to control air conditioner use, but just as importantly, they were able to use H2O’s Green Thermostats to control utility use.

Green Thermostats are easy to program with a simple menu function in one of three user-determined languages (English, Spanish and French). Residents who want to conserve can view a thermostat dashboard on the H2O Degree website (Figure 6) to show them results, or they can use a mobile app. To save energy, residents can aggressively schedule temperatures to rise when they are not home and to return to more comfortable levels for when they return.

H2O Degree also reports average indoor and outdoor temperatures, set-points, thermostats status (scheduled, hold or over-ride), along with demand (in minutes) for cooling. Diagnostics are developed from this data. For example, the data shows when the system capacity is compromised (dirty filters, broken fan motor) and when windows are open. NOVO can also use the data to correlate high electric bills with thermostat settings and A/C operating time. This information is especially helpful when a resident experiences a high bill – the owner can see why, and do something about it.

Of course, residents had a large incentive to behave differently once they were metered, although it is impossible to know how other resident behaviors may have changed, such as closing open windows while the A/C was on. However, the impact of submetering along with the use of Green Thermostats had a significant impact.

Monitoring Results: Natural Gas

At the Cheverly Crossing apartments gas is used for heat burned in furnaces, located in each unit and at the central boiler, to generate domestic hot water energy. Green Thermostats were installed to track the time of operation on heat; the time that the gas valve is open. Each furnace has a nameplate rating (BTU input per hour), which is multiplied by the run time recorded at the thermostat to determine the BTU’s of gas consumed in each apartment.

Tracking set-points, thermostat status and actual temperatures has been helpful in explaining why some gas-heat bills are higher and others are lower. This data also reveals the exaggerated benefit frugal residents enjoy, thanks to thermal sharing. When winter set-points are kept low, energy is transferred from warmer neighbors, reducing their furnace run time more than what one would expect. The opposite is also true: those who raise their set-point relative to their neighbors’ give up energy through their shared walls, floor and ceiling. The greater incentive to control set-points has inspired more aggressive set-point control, saving energy and lowering utility expense for everyone at the property.

Submeters used for tracking natural gas at Cheverly Crossing were installed in 2010. The last 12 months in monitoring in 2010 showed a 36% drop in total gas usage compared to 2008. However, gas rates also declined; so the drop in gas expense was 61%. Since historical rates were much higher in the winter months, dollar denominated savings attributable to reductions in water use were 35%, while savings in heat related consumption was a staggering 71%. Figure 7 shows the more objective decline in gas heating use.

It is difficult to draw conclusions regarding the drop in gas used for heating without also comparing the “degree-day” demand for heat in the periods used for comparison. (NOAA publishes this data.) Data through January of 2010 showed that degree days for the most recent winter were 5% below the prior year. Cheverly Crossing also installed a more efficient domestic hot water system that is better controlled, which contributed significantly to the drop in domestic hot water energy use.

This result has been influenced by weather (5%), by a more efficient domestic hot water system, and by using Green Thermostats (even though billing was not in force), and by residents keeping their windows shut, knowing that they would be billed at some point in time.

Ongoing Savings

When the first year of submetering results from Cheverly Crossing were analyzed, NOVO Properties showed a $70,000-plus per year cash flow improvement and a $1.32 million boost in property valuation ($22,000 a unit). Based on these initial energy savings, NOVO Properties was able to implement a rent reduction for existing residents of around $170, which was most of the projected $223 average monthly cost of utilities.

Table 1 compares projections made at the time of the submetering proposal, to actual results from utility data provided through the first quarter of 2010.

Today, Cheverly Crossing Apartments continues to enjoy the dramatic drop in utility consumption that was first tracked in 2010. The results have been so successful, NOVO Properties has installed H2O Degree submeters at three additional apartment NOVO buildings in Maryland: Canonbury Square (95-units) and Tudor Place (134 units) in Hyattsville property, and Finian’s Court (57 units) in Lanham.