Cooperative Laundromat Water and Energy Recovery Calculator
Input your cooperative laundromat details
This calculator helps member-owned and community laundromats estimate the impact of installing greywater reuse and heat recovery systems. By combining your washer count, loads per day, water and electricity prices, and project costs, it estimates annual savings, simple payback, and longer-term economic performance.
It is intended for cooperative boards, facility managers, and sustainability committees who are comparing retrofit options, preparing a business case, or exploring grant or rebate opportunities.
How this water and energy recovery model works
The model starts by estimating your baseline water and energy use for washing, based on the number of washers, how many loads each washer runs on a typical day, and the number of operating days per year. It then applies your selected greywater reuse and heat recovery efficiencies to estimate how much water and energy can be offset.
At a high level, the baseline annual load count is:
Annual loads = washers × loads per washer per day × operating days per year
Annual fresh water use without any recovery is then:
Baseline annual water (gallons) = annual loads × fresh water per load
To convert water use into cost, the calculator uses your water and sewer rate per thousand gallons. In mathematical form:
where Cw is annual water/sewer cost, W is annual water use in gallons, and rw is your water and sewer cost per thousand gallons.
Electricity costs for washing are modelled similarly. Baseline annual electricity use is:
Baseline annual electricity (kWh) = annual loads × electricity per load
and annual electricity cost is:
Baseline electricity cost ($) = annual electricity (kWh) × electricity rate
Greywater reuse and heat recovery savings
The greywater reuse percentage represents how much of your fresh water demand is replaced with treated laundry water. For example, a value of 60% means the system is expected to offset 60% of the baseline fresh water volume.
The calculator estimates water savings as:
Water savings (gallons) = baseline annual water × greywater reuse % / 100
and corresponding water and sewer bill savings as:
Water cost savings ($) = water savings (gallons) ÷ 1000 × water/sewer rate
The heat recovery efficiency is the fraction of thermal energy recovered from warm wastewater and reused for incoming water. For example, a 45% efficiency suggests that 45% of the energy that would have been lost down the drain is recaptured.
The model approximates energy savings as:
Energy savings (kWh) = baseline annual electricity × heat recovery % / 100
and resulting bill savings as:
Energy cost savings ($) = energy savings (kWh) × electricity rate
Financial payback and lifecycle perspective
After estimating annual water and energy bill savings, the calculator nets out any additional annual maintenance cost for upgrades to arrive at your approximate annual net savings:
Net annual savings = (water cost savings + energy cost savings) − added maintenance cost
A simple payback period is then estimated as:
Simple payback (years) = capital investment cost ÷ net annual savings
The discount rate input allows you to evaluate the project from a time value of money perspective. A higher discount rate reflects a higher required return or more expensive capital. The calculator uses this rate in a standard discounted cash flow framework to show how attractive the investment may be over time, beyond simple payback.
In practice, many cooperatives consider simple payback of ≈ 3–7 years for equipment upgrades to be strong, while longer paybacks may still be acceptable when they deliver strategic benefits such as reduced exposure to rising utility prices, better service reliability, or improved environmental performance.
Worked example
Suppose your cooperative laundromat has 28 washers, each running 5.5 loads per day, 355 operating days per year. Fresh water use is 18 gallons per load, water and sewer costs are $13.50 per thousand gallons, electricity use is 1.7 kWh per load, and the electricity rate is $0.18/kWh.
- Annual loads ≈ 28 × 5.5 × 355 ≈ 54,670 loads
- Annual water use ≈ 54,670 × 18 ≈ 984,060 gallons
- Baseline water cost ≈ 984,060 ÷ 1000 × 13.50 ≈ $13,285
- Annual electricity use ≈ 54,670 × 1.7 ≈ 92,939 kWh
- Baseline electricity cost ≈ 92,939 × 0.18 ≈ $16,729
With a greywater reuse percentage of 60% and heat recovery efficiency of 45%, the model would estimate roughly 60% water savings and 45% energy savings on those baseline amounts. It then subtracts the additional maintenance cost and compares the resulting net savings to your capital investment (for example, $48,000) to estimate a simple payback.
Scenario comparison
The table below illustrates how conceptual scenarios differ. Use it as a reference while you explore different inputs in the calculator.
| Scenario | Greywater reuse % | Heat recovery % | Relative water use | Relative energy use |
|---|---|---|---|---|
| No recovery (baseline) | 0% | 0% | 100% (no savings) | 100% (no savings) |
| Greywater only | 50–60% | 0% | 40–50% of baseline | 100% of baseline |
| Heat recovery only | 0% | 30–50% | 100% of baseline | 50–70% of baseline |
| Greywater + heat recovery | 50–60% | 30–50% | 40–50% of baseline | 50–70% of baseline |
Your actual results will depend on local water quality, plumbing layout, washer technology, and how consistently the equipment is maintained.
How to interpret your results
- Annual savings: Large positive savings indicate that water and energy recovery are offsetting a meaningful portion of your utility bills. Compare these values to your current annual operating budget for context.
- Simple payback (years): Shorter payback periods suggest faster recovery of your capital investment. Many cooperatives consider 3–7 years attractive, but your board may set its own thresholds.
- Lifecycle view: When you include a discount rate, the model helps you view the project as a long-term infrastructure investment, not just a quick cost-cutting measure.
- Resilience benefits: Even where payback is modest, reduced dependence on municipal water and lower electricity use can improve resilience to price spikes, drought restrictions, or grid disruptions.
Assumptions and limitations
- Average conditions: The model assumes that the loads per washer and operating days per year you enter are typical for each year of the analysis, without extended downtime or major usage changes.
- Constant prices: Water, sewer, and electricity prices are treated as constant in real terms. In reality, they often rise over time, which would make savings more valuable than shown.
- Simplified energy relationship: Heat recovery savings are estimated as a percentage of total machine electricity per load. Actual performance may differ, especially if much of your water heating is gas-fired instead of electric.
- Regulatory variation: Rules for greywater reuse and heat recovery vary by jurisdiction. Always verify local plumbing codes, health regulations, and permitting requirements before investing.
- No financing structure: The calculator does not model specific loan terms, grants, or rebates. You can approximate their effect by adjusting capital cost and discount rate to match your situation.
- Illustrative benchmarks: Typical values such as 15–20 gallons per commercial load and 1.5–2.0 kWh per load are drawn from common industry ranges. Your actual equipment may sit above or below these benchmarks.
Use this tool as a planning aid and conversation starter, not a final engineering design or financial guarantee. For major investments, consider pairing these results with a site-specific engineering assessment and advice from your cooperative’s financial advisors.
Why Cooperative Laundromats Need a Recovery Calculator
Community-owned laundromats anchor neighborhoods with affordable cleaning services, job creation, and spaces to swap resources. However, they also consume enormous amounts of water and energy. Every load drained into the sewer takes dollars and heat with it. For cooperatives that reinvest profits into members rather than shareholders, trimming utility bills can unlock funds for child care, extended hours, or debt retirement. Yet many operators struggle to translate technical retrofit proposals into real-world savings numbers. Vendors might promise big returns for greywater reuse or heat recovery, but without transparent modeling it is hard to prioritize which upgrade comes first. This calculator helps members weigh options in plain language, centered on cooperative governance rather than corporate spreadsheets.
The inputs reflect questions board members and worker-owners debate at planning meetings: How many washers run daily? What is the utility tariff? How efficient are the machines? What portion of water can we safely recycle after proper filtration? What does the heat recovery loop capture from outgoing wastewater? What does installation cost, and what maintenance budget should we set aside? By plugging these assumptions into the form, cooperatives get an immediate read on annual savings, operating cost reductions per load, greenhouse gas benefits, and payback timelines. The tool also highlights when an upgrade remains financially out of reach without grants or subsidies, empowering members to advocate for public support.
How the Model Works
The calculator estimates baseline water use by multiplying the number of washers by loads per day, operating days per year, and gallons per load. It converts water costs from dollars per thousand gallons into dollars per gallon before multiplying by consumption. The greywater savings represent the portion of fresh water offset by reclaimed water, reducing both purchasing and sewer fees. On the energy side, the tool multiplies loads by electricity per load to get annual kilowatt-hours. Heat recovery efficiency describes the percentage of that energy recaptured to preheat incoming water. By multiplying the captured energy by the electricity rate, the tool calculates avoided costs.
Annual savings combine water and energy reductions, then subtract ongoing maintenance tied to the retrofit. Net savings feed into a discounted payback calculation that considers the time value of money. Rather than quoting a simple payback (capital cost divided by annual savings), the script computes the number of years required for cumulative discounted cash flows to offset the initial investment. If savings never catch up because the discount rate is too high or efficiencies are too low, the tool flags that reality so members are not surprised later.
Key Formula
The discounted payback calculation sums annual savings discounted by the rate entered. In MathML the cumulative value after years is:
where is annual net savings and is the discount rate expressed as a decimal. The calculator increments until meets or exceeds the initial capital cost. If it never does within a 25-year horizon, the result notes that the investment does not pay back under the current assumptions.
Worked Example: Member-Owned Retrofits
Picture a cooperative with 28 washers serving 5.5 loads each per day. Machines draw 18 gallons of fresh water per load and 1.7 kWh of electricity. Water and sewer fees cost $13.50 per thousand gallons, and electricity costs $0.18 per kilowatt-hour. Engineers estimate that a heat recovery loop can capture 45% of waste heat, while a greywater system can safely reuse 60% of water after filtration and disinfection. The upgrades cost $48,000 upfront with $3,200 in annual maintenance. The shop runs 355 days per year, and the co-op uses a 6% discount rate to reflect opportunity costs of capital and inflation.
Baseline water use equals 28 × 5.5 × 355 × 18 = 984,060 gallons annually. At $13.50 per thousand gallons, the co-op spends roughly $13,275 a year on water and sewer. Recovering 60% of that water offsets 590,436 gallons, saving about $7,966 each year. Electricity use totals 28 × 5.5 × 355 × 1.7 = 93,254 kWh. Recapturing 45% of that energy avoids buying 41,964 kWh, which saves $7,553 annually at the given rate. Combined savings reach $15,519. After subtracting the $3,200 maintenance budget, net savings equal $12,319 per year. Discounting those savings at 6% produces a payback just shy of 4.5 years. If members secure rebates, the payback accelerates; if they must finance the capital with loans at a higher rate, the payback lengthens.
Scenario Comparison Table
Use the table to compare retrofit strategies, assuming the same baseline facility described above.
| Scenario | Greywater Reuse | Heat Recovery | Net Savings | Discounted Payback | Notes |
|---|---|---|---|---|---|
| Baseline Retrofit | 60% | 45% | $12,319 | 4.5 years | Matches example |
| Water-Only | 70% | 0% | $6,486 | 7.9 years | Lower capital cost |
| Energy-Only | 0% | 55% | $5,721 | 8.5 years | High energy relief |
| Full Upgrade with Grant | 60% | 45% | $12,319 | 2.2 years | 50% grant support |
The water-only scenario stretches payback because energy waste remains untouched. The energy-only scenario slashes electricity costs but misses water savings, which can be a political goal if the city faces drought. When grants cover half the capital, the cooperative recoups costs in just over two years, strengthening the case for applying to green infrastructure funds.
Resilience and Equity Table
Beyond finances, member-owners care about community outcomes. This table ties technical metrics to resident impact.
| Outcome | Baseline | Retrofit | Change | Community Impact |
|---|---|---|---|---|
| Water Use per Load | 18 gal | 7.2 gal | -60% | Supports drought mandates |
| Energy Use per Load | 1.7 kWh | 0.94 kWh | -45% | Stabilizes rates for members |
| Annual Carbon Emissions* | ~41 metric tons | ~22 metric tons | -19 tons | Improves air quality |
| Emergency Operation Hours (with storage) | 4 | 10 | +6 | Greater disaster resilience |
*Assumes 0.44 kg CO2 per kWh from the grid. Lower emissions reduce strain on frontline neighborhoods already burdened by pollution. Longer emergency operation hours stem from the ability to store reclaimed hot water for hygiene during outages, especially when paired with the resilience hub backup power calculator and the community EV carshare reserve calculator, which together shape a holistic preparedness plan.
Limitations and Assumptions
The model assumes linear savings and uniform loads, yet actual laundromat traffic fluctuates by day of week and season. Some greywater systems may not legally reuse 60% of water depending on local health codes. Heat recovery efficiency can degrade if lint filters are not cleaned or if water temperatures drop. The tool ignores financing costs, taxes, depreciation, and membership dividends. It also does not calculate benefits from bundling upgrades with solar panels modeled in the community solar subscriber balancer. Always consult engineers, accountants, and code officials before making purchases.
Even with those caveats, the calculator arms cooperatives with evidence to negotiate rebates, union-scale labor bids, or community development grants. It reframes efficiency not as austerity but as solidarity—redirecting savings into member needs. Share the narrative in the explanation with lenders, municipal partners, or mutual aid allies to show the breadth of benefits beyond profit.