//Quick answer
- No tank: hot water is made as it flows, so it does not run out at the rated flow.
- Sized by how many fixtures run at once, not by gallons stored.
- The install is gas, venting and condensate work, which is why it costs more than a tank swap.
- Navien, Noritz and Rinnai are the units Done-Rite installs.
01Definition
How does a tankless water heater work?
When a hot tap opens, a flow sensor fires the burner (or elements) and water is heated as it passes through the heat exchanger. Close the tap and the unit stops. There is no tank to keep hot, so standby loss is gone, and there is no tank to corrode, which is why tankless units are built for a longer service life than a storage tank when they are maintained.
What does the installation actually involve?
A gas line sized for a burner several times larger than a tank's, venting suited to the unit (condensing models use different materials and need a condensate drain), water connections with isolation valves for future flushing, and an electrical connection for the controls. That scope is why a tankless install usually involves a permit and why the installed price sits well above a tank replacement.
02When it applies
When is tankless the right choice?
A household that runs out of hot water, a home where the tank's floor space or closet is wanted back, a long-term owner who values lower standby loss and a longer equipment life, and anyone replacing a tank whose gas and venting are being reworked anyway.
When does a tank still make more sense?
A replacement on a tight budget where the existing gas and vent serve a tank fine, a home with modest hot water demand, or a situation where the step up in installed price does not pay back for the owner. The tank vs tankless comparison sets the two ranges side by side.
03What goes wrong
What goes wrong with tankless units?
Scale. Hard water leaves mineral deposits inside the heat exchanger, and a unit that is never descaled loses flow, throws error codes and fails early. The fix is a periodic flush through the isolation valves. The other failure is undersizing: a unit chosen for one shower will disappoint when two run.
What goes wrong with the install?
Undersized gas supply and improper venting are the two problems a tankless install can hide. Both are exactly what a permit inspection exists to catch, and both are why the work belongs to a licensed contractor.
04Proof
- Jason Shen, Google, September 16, 2026: "Daniel did an excellent job installing my whole house carbon filtration and water conditioning system. He also flushed out my tankless water heater."
- 1 year minimum warranty on labor. Manufacturer warranty handling varies by manufacturer.
- When a job needs a permit, Done-Rite pulls it and schedules the inspection.
- 4.9 stars across 1,720+ Google reviews on the Orange profile, checked September 17, 2026.
- California CSLB C-36 licence #998069. Licensed, bonded and insured, with workers compensation.
05Action
Price a tankless for your house
$4,000 to $6,000 installed with a Navien, Noritz or Rinnai unit, 1 year minimum labor warranty, no trip charge. Financing is available with terms up to 10 years.
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Where this applies
Done-Rite runs these calls across Orange County from its shop in Anaheim, CA, with no trip charge in any city it serves.
Common questions
$4,000 to $6,000 installed.
Navien, Noritz and Rinnai.
Yes. Periodic descaling keeps the heat exchanger clear, especially on harder water. Done-Rite flushes tankless units as part of its water heater service.
