Why homeowners switch to tankless
Hot water on demand — no waiting for a tank to recover
Frees up the space a 40- or 50-gallon tank takes
No energy spent keeping a full tank hot all day
The key is sizing. A tankless unit has a maximum flow, so we size yours around the showers and appliances you run at the same time — and the temperature of the water coming into your home.
Rinnai tankless, installed and maintained right
Rinnai is our go-to tankless brand. Before recommending a model, your plumber checks your hot-water demand, gas supply, venting and where the unit will be serviced. Tankless is a great fit for many homes — especially if you're replacing a direct-vent gas heater or short on space — and we'll tell you honestly if a tank is the better value for yours.
To keep it running efficiently, we generally recommend a yearly flush to remove scale.
What goes into a tankless installation
Sizing
We match the unit to how much hot water you use at once.
Gas, venting and drainage
Switching from a tank may need a larger gas line, new venting or a condensate drain — our licensed plumbers handle it.
One clear quote
Your quote spells out the equipment, removal of the old heater, any gas or venting changes and startup — one firm price before we begin.
Tankless repair
Losing hot water mid-shower, flashing an error code or struggling when two showers run? Note the code if you can see it, and your plumber will diagnose the real cause — often scale buildup, a flow sensor or an ignition issue — and give you a firm price for the fix.
How we can help
Your plumber diagnoses the problem or plans the installation on site, then gives you a firm price before any work begins. Our residential diagnostic fee is $89, waived when you go ahead with the repair. Pay by cash, check or card, or ask about financing.
Family-owned since 2011, licensed in South Carolina (Mechanical License CLM.111515 MC) and rated 4.9 stars from 298 Google reviews.
What our
customers say.
Google reviews“Just had a guy named Nate come out to my house to get my shower fixed. It was an unusual issue with my tankless water heater and to took a little bit to diagnose, but he was really patient and stayed at it until it got worked out. He was really nice and very professional. Fair price, good service, and easy to work with all around.”
“I have used OnCall for HAVC & plumbing services for over ten years. They have always been responsive and professional. If you need it done right and right now they are the people to call. Recently I needed a tankless...”
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“I have used OnCall for HAVC & plumbing services for over ten years. They have always been responsive and professional. If you need it done right and right now they are the people to call. Recently I needed a tankless water heater replaced. Jordan did a great job and took time to explain what he was doing so that I understood the whole process. Can't recommend them enough.”
A few common questions.
Will I ever run out of hot water with tankless?
It won't run out the way a tank does, as long as it's sized for how many showers and appliances you run at once. That's why your plumber sizes the unit to your household instead of just picking a model off the shelf.
Will hot water reach my shower faster?
Not by itself — water still has to travel through the pipes to the tap. If faster hot water is a priority, ask your plumber about a recirculation option.
How often should a tankless water heater be serviced?
We generally recommend flushing once a year to clear scale, adjusted to your water and Rinnai's instructions for your model. Flushing is quoted separately from our maintenance plans.
How much does it cost to switch to tankless?
It depends on your current setup — switching from a tank may need a larger gas line, new venting or a condensate drain. Your plumber gives you one firm installed price on site. Financing is available for qualifying installations, subject to credit approval.
