Why tankless installs are priced differently
A tank heater is a tank, a gas or electric supply and a flue. A tankless unit heats water on demand and needs far more energy for a short time. That often means a larger gas line, a new vent made of special material, a condensate drain and sometimes a new electrical circuit.
Because every house is set up differently, any price you see online is a starting point. The accurate number comes from a plumber who looks at the existing gas line, venting path and wall space.
The cost factors, side by side
Use this table to compare quotes line by line. A low quote that leaves out venting or the gas line is not really lower.
| Factor | What changes the price | Question to ask |
|---|---|---|
| The unit | Capacity, efficiency rating and brand. | How many gallons per minute at our incoming water temperature? |
| Gas line | A larger pipe or a longer run may be required. | Is the existing gas line big enough? |
| Venting | Tankless units often need new stainless or plastic vent pipe. | What type of vent and how long is the run? |
| Condensate drain | High-efficiency units produce acidic condensate that needs a drain. | Where will it drain and is a neutralizer included? |
| Electrical | Most tankless units need power for controls and fans. | Do I need a new outlet or circuit? |
| Water treatment | Hard water can scale the heat exchanger. | Do you recommend a softener or a service plan? |
| Permit and inspection | Fees and timing follow the job and the village. | Who pulls the permit? |
Tank or tankless: the honest comparison
Tankless units save space and never run out of hot water for a single use, and they can last longer than tanks. They cost more to install and need yearly maintenance. A tank is cheaper up front and simpler to replace.
If your gas line and venting already suit a tankless unit, the extra cost is lower. If the work involves opening walls, the price climbs. Our tankless water heater page explains when it makes sense, and our water heater replacement page covers a standard tank swap.
How to compare two quotes
Ask each contractor to put the same items in writing: unit model, gas line size, vent type and length, condensate drain, electrical work, permit, haul-away of the old tank and any water treatment. A quote that leaves any of these out may add them later as extras.
Ask about the warranty on the unit and the labor, and ask what maintenance is needed to keep the warranty valid. Ask whether the contractor is licensed, and check with IDPH if you want to verify it. Take time with the decision, because the installation is hard to change after the walls are closed.
We give a clear price before work starts, and we are glad to explain each line. If you would rather keep a tank, our water heater installation page explains that option.
Want a real number?
Call and describe your current heater, gas line and venting. We will explain what drives the price in your house.
Tankless and the village permit guide
The Village of Vernon Hills permit guide for water heaters lists the requirements for tank replacement, including an over-the-counter permit, a final inspection and a completion bond. The same guide describes tankless units as not needing a permit. That is helpful to know, but confirm the current rule at the building department, 847-367-3700, before you rely on it.
Water in the village comes from Lake Michigan through Lake County Public Works. The utility's report does not give a hardness number we would use, so test your tap before you decide how aggressively to treat scale.
Source type: Village of Vernon Hills permit guide and Lake County Public Works water quality reportWhen tankless is not the right call
Tankless is a poor fit when the gas line cannot be upgraded, when the venting path is blocked or when the household has several large simultaneous demands that exceed one unit's output. Two units or a hybrid system may solve it, at a higher cost.
It is also not ideal if the house has very hard water and no one will do the yearly flush. In those cases a tank or a heat pump heater may serve you better. We would rather tell you that before you buy than after the install.
Ongoing costs most buyers forget
Tankless heaters need to be flushed with a descaling solution on a schedule, more often with hard water. Skipping it shortens the life of the heat exchanger and may void the warranty. A service visit includes flushing, checking the inlet screen and testing combustion.
Our tankless water heater page describes the flush. Homes served from Mundelein and nearby towns should check their own water report, because hardness varies by supplier.
Rules and guidance note
The village permit guide says a tankless unit does not need a permit, but the guide is a few years old, so confirm with the Village of Vernon Hills building department at 847-367-3700. Gas and venting guidelines still apply.
Water quality matters too. Lake County Public Works publishes a report for the Lake Michigan supply.
Tankless water heater cost questions
It can be, if you value space, steady hot water and a longer lifespan, and if your gas line and vent suit it. Otherwise a tank may be the better value.
The village's published permit guide describes tankless units as not needing a permit. Confirm with the building department before work starts.
Not always. Test your water first. Scale is the main enemy, and a softener or regular flushing helps.
Often a day, longer if gas lines or venting need new routes.
Yes, but venting, gas supply and electrical work are the usual extras to plan for.