How to Get Hot Water with a Boiler: A Homeowner’s Guide

Hot water is a necessity in every household, from showers to dishwashing to laundry. For many homeowners, boilers are the primary source of heating for both their home and their water. There are several different options to heat water with a boiler. If you’re new to using a boiler or looking to understand how this system works, this comprehensive guide will walk you through the essentials.

What is a Boiler?

Before diving into how boilers heat your water, it’s important to understand what a boiler is. A boiler is a system that heats water and distributes it throughout your home for heating and hot water purposes. Unlike a furnace, which heats air and distributes it through ducts, a boiler uses water to transfer heat, making it a highly efficient solution for home heating.

Types of Boilers

  1. Combination (Combi) Boilers: These are compact units that provide both home heating and domestic hot water on demand. They don’t require a separate hot water tank, making them ideal for smaller homes or apartments.
  2. System Boilers: These boilers have a separate hot water cylinder, but all other components are built into the unit. They’re suitable for homes with higher hot water demands.
  3. Conventional Boilers: Also known as regular or traditional boilers, these require both a hot water cylinder and a cold water storage tank. They’re ideal for larger homes with multiple bathrooms.

How Boilers Heat Your Home and Water

Boilers work by using a fuel source—natural gas, propane, oil, electricity, or even biomass—to heat water. This heated water is then distributed throughout your home for heating, or stored in a tank for immediate hot water use. Here’s a step-by-step breakdown of the process:

1. Fuel Ignition

The process begins with the boiler’s burner igniting the fuel source. In gas boilers, this is usually natural gas or propane. The burner is controlled by a thermostat, which ensures that the boiler only runs when necessary to maintain the desired temperature.

2. Heat Exchange

The burning fuel heats the water through a heat exchanger. This component transfers the heat from the fuel to the water without the two coming into direct contact. High-efficiency boilers often have multiple heat exchangers to maximize energy transfer and reduce waste.

3. Water Circulation

Once heated, the water is circulated through pipes to radiators, underfloor heating systems, or hot water cylinders, depending on your home’s setup. The circulation is usually managed by a pump, ensuring efficient distribution.

4. Hot Water Storage

In systems with a hot water cylinder, the heated water is stored until needed. This allows for a ready supply of hot water at all times, especially beneficial during high-demand periods like mornings or evenings.

5. On-Demand Hot Water (Combi Boilers)

With combi boilers, there is no need for a water storage tank. Instead, the boiler heats water on demand when a hot water tap is turned on. This ensures that you have a continuous supply of hot water without waiting for a tank to refill. It’s also highly efficient, since the boiler will only run to heat water when hot water is being used.

Using an Indirect Water Heater with a Conventional Boiler

If you have a conventional heat-only boiler, you can use an indirect water heater to store domestic hot water in your home. Rather than heating water directly like a conventional water heater, water is heated by your boiler through a heat exchanger. That water is then moved into the indirect water heater’s storage tank, where it’s kept until needed.

This setup is especially efficient in colder weather, since the boiler will already be running to heat the home. So you’re simply using that existing heat to heat your home’s water. In warmer months, a quality indirect water heater will keep the water hot for a long time, so the boiler will only need to run for relatively short periods.

Learn more about Bradford White’s Indirect Water Heaters here.

Benefits of Using a Boiler


Boilers are highly efficient, especially modern condensing models. They can achieve efficiency rates of up to 90% or more, translating to lower energy bills and reduced environmental impact.

Consistent Heating

Boilers provide a more consistent and even heat compared to forced-air systems. The radiant heat from radiators or underfloor systems offers a comfortable and steady warmth throughout your home.


Combi boilers, in particular, are space-saving units since they don’t require a separate hot water tank. This makes them an excellent choice for homes with limited space. For example, the Bradford White Brute FT® Combi boiler can be mounted on the wall so it doesn’t take up any floor space.


Boilers are known for their durability and long life spans. With proper maintenance, a well-made boiler can last 15-20 years or more, making them a reliable investment for your home.

Maintenance Tips for Optimal Performance

Regular maintenance is key to ensuring your boiler operates efficiently and lasts as long as possible. Here are some maintenance tips:

Annual Servicing

Schedule an annual service with a qualified technician to inspect and clean the boiler. This will help identify potential issues before they become major problems and ensure the system runs efficiently. If you need a plumbing professional, you can search here to find a Bradford White professional in your area.

Your plumbing professional can do the following:

  • Bleed Radiators – Bleeding radiators removes trapped air that can hinder the system’s performance. Plumbing professionals can use a bleed key to release any air pockets, ensuring your radiators heat up evenly.
  • Check Pressure – Regularly check the boiler’s pressure gauge. The optimal range is usually indicated on the gauge, and maintaining proper pressure ensures efficient operation.
  • Insulate Pipes – Insulating pipes reduces heat loss and prevents them from freezing during colder months, ensuring your boiler works efficiently year-round.
  • Monitor for Leaks – Keep an eye out for any signs of leaks around the boiler and associated pipes. Early detection by your plumbing professional can prevent costly repairs and water damage.


Understanding how your boiler works and maintaining it properly can ensure a steady supply of hot water and efficient home heating. Whether you’re using a combi, system, or conventional boiler, following these guidelines can help you get the most out of your system.

For those looking to upgrade or install a new boiler, consult with a heating professional who can provide tailored advice and ensure you choose the best system for your home’s unique needs. With the right boiler and maintenance routine, you can enjoy reliable, energy-efficient heating and hot water for years to come.

Learn more about the boilers available from Bradford White.