Are you looking for a heat and hot water solution that is efficient, cost-effective, and convenient? You may want to consider installing a combi-boiler in your home. 

How Do They Work?

Combi-boilers combine both a heating boiler and a tankless (on-demand) water heater in one small, wall-hung unit. They work by heating water as it passes through a heat exchanger, which is located inside the unit. When hot water is needed, the system heats the water on demand, providing a tankless, high efficiency solution.

What Are The Benefits?

Combi-boilers offer a number of benefits, including:

Energy Efficiency

Combi-boilers are very efficient, only running when heat and hot water are needed. Unlike traditional systems that store hot water in a tank, combi-boilers heat water on demand. This means you won’t run out of hot water, and you won’t be paying to heat water you’re not using as heat escapes a tank.

Space-Saving Design

Because combi-boilers combine two functions into one unit, they can save space in your home or property. If space is at a premium, this can be a significant advantage.


A combi-boiler is generally less expensive to install than a traditional boiler with a separate hot water tank.

Environmentally Friendly

Combi-boilers produce fewer emissions than traditional systems, making them more environmentally friendly.

Are There Any Disadvantages?

While they offer many benefits, there are a few disadvantages to consider before installing a combi-boiler, including:

Delayed Hot Water Delivery

Combi-boilers can take between 15-45 seconds to heat up water when you turn on the hot water tap. This delay can be frustrating if you’re used to instant hot water from a tank-based system.

Inconsistent Pressure and Temperature

Because combi-boilers heat water on demand, they occasionally need to go into recovery mode, allowing the system an opportunity to cool down. During periods of recovery (which occur more often during periods of high use), water temperature and pressure are reduced, which can be frustrating, especially while taking a shower.

Impact on Heat

A combi-boiler prioritizes domestic hot water, for your sinks, showers, etc. over heat. So, when using domestic hot water, the heat in your home can be impacted on cold days. When you have a separate boiler and water tank, the system can work on heating domestic hot water when the heat is not running.

Is a Combi-Boiler Right For My Home?

We recommend combi-boilers for properties that don’t need a lot of domestic hot water, such as homes with one bathroom. If you have a larger property with multiple bathrooms, you may want to consider a system with a tank style water heater, such as a boiler with an in-direct water heater to ensure you have domestic hot water ready when you need it. To learn more about this type of solution, keep a look out for future blog posts on this topic.

How Priority One Can Help?

At Priority One, we make a custom solution for each home. We can provide a free estimate to help determine if a combi-boiler is the right fit for you. Our team is highly experienced with all types of boilers and hot water heaters, so no matter the solution, we will ensure your system is installed properly and will serve your home well for many years to come.