Historical cost illustration — reviewed September 9, 2026. This calculator uses October 2017 equipment prices and statewide average TDS assumptions. Its results are illustrative, not a current quote or a forecast for your water supply. Measure your source-water TDS and compare current equipment and replacement-filter prices before buying.
- DI Only Cost
Loading... - Multi-Filter Cost
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How Does This Calculator Work?
To make this calculator as simple as possible, we made a number of assumptions.
- For upfront cost, we compared the base prices of our most popular DI system (Unger HydroPower) and what we think of a an "average" Multi-Filter System (Triple Crown Twin Flow). Prices were as of October 2017.
- We also assumed that you'd restrict the flow on your DI system, which is what most of our customers tell us that they do. Though the Unger HydroPower is capable of a higher flow rate, we assumed it would be at 1.5 gpm, same as the Twin Flow. If you run the DI system at it's maximum flow, the cost per hour of DI Only will increase.
- We used a state-wide average for TDS (total dissolved solids) based on data from Zero Water. TDS can vary quite a bit from site to site, even in a small geographical area.
- We disregarded less significant factors such as the exact contents of the water. There are a lot of details that you can get into, but by far the biggest factor is TDS so we focused on that.
What if we got more specific?
The balance between DI-only and multistage equipment depends on source-water TDS, usage and current costs. Higher resin consumption can increase DI-only operating costs, while a multistage system generally requires a larger initial investment. A payback estimate needs inputs that match your water supply and workload.
Hopefully this calculator helps you in deciding what system is best for you. There's more to consider, and you can find out about it here. If you have any questions, feel free to reach out at 800-989-4003 or by clicking the live chat link at the bottom of your screen.
Use this calculator to compare costs
This tool illustrates how equipment cost, operating time and source-water TDS can affect the comparison between DI-only and multistage WaterFed systems. It does not calculate the exact water volume needed for a job, tank size, or guaranteed savings.
What to check before choosing a system
- Measure TDS at the water source you expect to use; a statewide average cannot represent every job site.
- Use current system, resin and replacement-filter prices when preparing a purchase budget.
- Check the manufacturer's flow and pressure requirements for your pole, hose length and working conditions.
- Estimate workload using actual operating hours, including seasonal changes.
For selection guidance, read how to choose a WaterFed cart. For help comparing equipment, contact abc Window Cleaning Supply at 800-989-4003.