Water and Energy Efficiency: Keeping Your Energy out of Hot Water

The previous four blogs in this series have dealt primarily with the purpose and benefits of developing custom utility allowances for Low Income Housing Tax Credit (LIHTC) properties. However, today’s blog will involve a shift from the macro level to the micro level, with specific emphasis on measures aimed at reducing water and energy consumption associated with hot water.

Whether you live in a single-family home, an apartment, or a townhome, it is very likely that water heating represents your second or third highest energy cost from month to month. In fact, nowhere else in your home is the water/energy nexus more prevalent than when it comes to hot water. The water/energy nexus refers not only to energy use associated with water production, transportation, storage, and treatment, but also to water use associated with the production of energy. In essence, every time you save water you save energy and vice versa.

The big question is: How much can I save and at what cost? We can all remember a specific television show or satirical comic strip making fun of low-flow showerheads or other low-flow fixtures at some point. While we all would like nothing more than lowering our utility bills, if doing so comes at the price of not being able to adequately rinse shampoo out of our hair, we would simply rather pass. So, what are the real options and benefits when it comes to “keeping your energy out of hot water”?

To answer that question, let’s start with the major end uses of hot water in your home. The single largest user of hot water in your home is the shower, which accounts for approximately 45% or more of all hot water. Chances are that more than 95% of all homes in the United States are equipped with showerheads that operate at 2.5 gallons per minute (gpm) or less.  In fact, any showerhead manufactured since 1994 is rated at no more than 2.5 gpm. Today, any showerhead with a “WaterSense” label is rated at 2.0 gpm or less, while most showerheads you will find in a hotel today are rated at 1.5 gpm or less. While one might think that the major differences in performance are related to flow rate, they really are not. The major differences actually have more to do with the design, spray pattern and system pressure within the building. For example, a showerhead rated at 1.5 gpm, with a more concentrated spray pattern and fewer spray nozzles, may actually provide sprays at a stronger force than a 2.5 gpm showerhead with a wider spray pattern and more nozzles. Finding the right showerhead for you simply takes time and a little bit of research.  

The following table (Table 1) illustrates the comparison between a residential unit with showerheads rated at 2.5 gpm versus a residential unit rated at 1.5 gpm. The energy rates for the purpose of this comparison include 11 cents per kilowatt hour (kWh) and $10.00 per 1,000 gallons for water and sewer.

The following table (Table 2) illustrates the financial savings and payback periods for individual residential homes and for an affordable multifamily housing development under a custom utility allowance.

The aforementioned numbers represent both a 39% reduction in hot water consumption and 40% reduction in shower water consumption. On a larger scale these same numbers represent a 24% reduction in total water consumption and a 10% annual reduction in total energy consumption. For a single-family home, the annual savings is $168 per year with a payback on investment of seven months. For a 250-unit affordable housing development under a custom utility allowance, the increased net operating income is $42,000 per year with a payback on investment of six months.

Now, if you want to go the rest of the way in getting your energy out of hot water, you can focus on faucet aerators. By federal law, the highest flow rate for any manufactured faucet aerator is 2.2 gpm. On average this is probably the most prevalent flow rate of all aerators currently installed in residential settings. Aerator flow rates can go as low as 0.5 gpm, with spray patterns that are needle-like. For a bathroom faucet, an aerator with a flow rate of one gpm will still give you that smooth aerated flow that you get from a higher flow aerator. For the kitchen faucet, a flow rate of 1.5 gpm will still meet all the needs of rinsing dishes, vegetables, etc. 

The following table (Table 3) illustrates the comparison between a residential unit with faucet aerators rated at 2.2 gpm versus a residential unit rated with faucet aerators rated at 1.5 gpm. The energy rates for the purpose of this comparison include 11 cents per kilowatt hour (kWh) and $10.00 per 1,000 gallons for water and sewer.

The following table (Table 4) illustrates the financial savings and payback periods for individual residential homes and for an affordable multifamily housing development under a custom utility allowance.

Concerned with filling the sink or a pot? Using a 1.5 gpm aerator, it will take approximately 13 seconds longer to fill a one-gallon container as compared to using a 2.2 gpm aerator. The additional financial savings of $122 per year for a single-family home and the additional net operating income for a 250-unit complex under a custom utility makes it well worth the wait!

Eddie Wilcut, Plummer’s Water and Energy Efficiency Practice Leader, has 6 years of experience conducting energy consumption modeling for Low Income Housing Tax Credit (LIHTC) properties and HUD regulated properties. Eddie also has 22 years of experience in Program Development, Project Management, Program Management, Contract Administration, Scheduling, Facility Assessment, Programming, Cost Estimating, Energy and Water Conservation and Sustainability. To date, the Plummer team has successfully provided energy consumption models for more than 200 properties across 28 states.

The Plummer team includes a group of highly skilled project managers, engineers and energy modelers. The significant expertise, experience and knowledge base of the team acquired by successfully conducting utility allowance modeling for a large number of properties across the United States will help them quickly determine the best and most cost-effective platform and methods required to achieve the best and most reliable results. A proven and collaborative process involving the modeling team and the developer will result in identification of the most important elements that will lead to decision making that will ultimately provide the greatest and most cost-effective results for both the tenants and the owner.