Combination boilers, or combi boilers for short, share a few key similarities with tankless water heaters but vary greatly in others. Since combi boilers also handle space heating on top of water heating, it’s probably no surprise that their prices reflect their greater utility.

After over 15 years of installing tankless water heaters and combi boilers across the Greater Los Angeles area, we’ve come to know these machines inside and out. This knowledge also extends to pricing, so we’re going to fill you in on how much a combi boiler costs so you can better explore your space and water heating options.

In this article, we’ll cover combi boiler cost per unit, the total cost with installation, and what factors can impact your final investment. Let’s jump right in with how much a combi boiler costs on its own.

How Much Does a Combi Boiler Cost?

Like any other major appliance, the cost of a combi boiler varies from brand to brand and model to model. Because of the wide variety of combi boilers on the market, addressing the cost of a combi boiler is slightly difficult.

On average, you can expect to invest somewhere between $2,200 to $6,000 on a combi boiler. Brands like Rinnai fall into the more value-driven category, while Noritz and Navien lean toward the mid to high range.

Not only does the make and model of the combi boiler have a bearing on the cost of your chosen combi boiler, but the heating load and water demand your home requires will also play a factor.

You’ll need a technician to properly size your combi boiler to get the full picture here. It’s possible to come up with ballpark figures on your own, but getting some assistance is a much safer bet. From here, you’ll have a much better idea of what you’ll need to invest in a combi boiler.

How Much Is a Combi Boiler with Installation?

While pricing out a combi boiler on its own in an article can be a bit tricky, installation is also best addressed with a wide range, given the variety of home types in Los Angeles County.

Typically, we’ve found that installing a combination boiler in Los Angeles County costs anywhere between $12,000 to $26,000. Again, this range considers a wide variety of home types and setups. For instance, in a smaller home, where there may be less demand for radiant space heating, a single combi boiler will do just fine and come in at the lower end of the range.

For more complex setups or larger homes with much more space and water heating demand, installation can become more complex. But what factors are we talking about here? Follow along as we break down what factors can influence installation costs.

Factors that Impact Installation Costs

Like with a standard tankless water heater, several factors can influence the cost of installing a combi boiler. Before we jump in, there’s no concrete way to tell you exactly how much these factors will impact your total investment without being on-site at your home. The following is meant to set the expectation of what may impact your installation cost so you can better navigate the process.

Home Size

Home size is the biggest aspect of a combi boiler installation that informs all other factors, including the number of hot water fixtures. Your home size will impact everything from the piping to communication boxes.

Typically, the smaller the home, the lower the installation cost due to reduced complexity and less material and time needed to complete the system.


One of a few major factors that can weigh on installation costs is piping. Depending on your home size, you will need more or fewer piping runs. Your home’s square footage and the layout of existing heating elements, like in-floor radiant heating runs, will be a large factor in the installation cost.

Factors like relocating your combi boiler will be a main driver in how much additional piping and fittings are required.


Some homeowners may choose to relocate their combi boiler when upgrading. Doing so can drive installation costs because the technician must run more piping and rework the venting.

Depending on the location, you can expect installation to be impacted somewhere between $1,200 and $3,500.

In some cases where a split system is being employed, like having a combi boiler and a tankless water heater in the same system, installation prices will reach the peak of the previously provided range due to the system’s complexity and having two different units in different locations.

Communication Boxes

Communication boxes are key for achieving control over your combi boiler system. These devices control zones within your home, much like a standard central heating system, and communicate with your thermostat.

Each communication box can handle up to three zones. If you have a larger home, you’ll likely need to install more communication boxes to ensure your home is adequately zoned for optimal comfort. The more communication boxes that are needed, the more you can expect to tack onto the installation cost.

Communication boxes can cause the installation to flex between $900 and $2,800.

Additional Equipment

Because combi boilers require a complex installation process, there are a lot of moving parts that can increase the overall cost of installation. Electronic valves, air separators, and expansion tanks are just a few of the usual suspects that may play a role in your final installation cost. Your technician will touch base with you and keep you informed of how they have to build out your system so you can stay in the loop.

Additional equipment costs typically land between $600 and $1,200.

Dialing in Combi Boiler Cost

We’ve touched on how much a combi boiler may cost on its own, the total cost with installation, and what informs your total investment with installation. While every home is different, the ranges provided reflect what we typically see in the field. Now, you can approach the installation process with set expectations and be able to avoid surprises like additional costs for piping or communication boxes.

We’ve spent over 15 years installing and servicing tankless water heaters and combi boilers in Los Angeles County and its surrounding areas. One thing we can say for sure is that every home is different.

If you’re not sure where to start regarding sizing a combi boiler for your home, get in touch using one of the buttons below, or book online with our convenient scheduler. We’re happy to help point you in the right direction for your home.

company icon