How to soundproof a combi boiler?

In this article, we will discuss different ways to soundproof a combi boiler. You will have a decent notion of how to soundproof a combi boiler for various budgets after reading this blog. Noise reduction is critical for occupants’ comfort, health, and interaction in a residential structure.

Because a boiler includes moving parts, it’s completely normal for it to generate some noise. If nothing else, the pump that circulates water throughout the heating system, especially in older boilers, can be rather loud. Most of us have become accustomed to the boiler’s typical noises to the point where we no longer notice them. As a result, if your boiler has started making unusual noises, it could be an indication of a larger problem.

Standard boiler noises, on the other hand, can irritate certain people. This is especially true if you have an older model, as the parts’ age and design might cause them to be significantly louder than modern models.

How to soundproof a combi boiler?

I’ll go through the most prevalent causes of boiler noise, as well as the best ways to soundproof a combi boiler. To keep boiler noises from entering your room, use the strategies listed below.

  • Identify the source of the noise and resolve any issues
  • Choose the best soundproofing material
  • Acoustic panels
  • Carpet tiles
  • Soundproof curtains
  • Fibreglass
  • Acoustic blankets
  • Soundproofing the Cupboard of the combi boiler

Identify the source of the noise and resolve any issues

Some boiler noises indicate a problem that requires attention rather than soundproofing. So, if you wish to quiet your boiler, you must first comprehend the noise it produces. When you notice weird noises coming from your boiler, figure out what they are and get them corrected. To begin, you might want to look into techniques to lessen the amount of noise your combi boiler makes.

Air is one of the main causes of a noisy boiler. Air can enter the system, causing the radiators and boiler to gurgle. To fix the problem, use a bleed key or a screwdriver to bleed the system. Open the valve and wait for the water to flow out before closing it again. You might also check the boiler’s pressure since this could be the source of the strange noises coming from your boiler.

If your boiler still makes a noise that you don’t think is normal after you’ve accomplished these steps, you should call qualified heating professional to inspect the pump and air intake/filter, as well as look for any loose or broken parts.

When you notice weird noises coming from your boiler, figure out what they are and get them corrected. Here are some common unusual noises that your boiler could make.

Tools Needed
bleed key

Banging Noises with No Heat

When your boiler is on but your radiators aren’t getting warm, the first thing that comes to mind is home heating oil. However, if the boiler is making a banging noise, the problem is most likely a malfunctioning pump. When there’s an issue with your pump, the boiler shuts down automatically. As a result, it makes a loud pounding noise and fails to supply hot water to the radiator. If this is the case with your boiler, you should hire a heating professional to replace the pump.

If you’ve confirmed that there isn’t any air in the system and have had an engineer inspect everything else, you should consider soundproofing the boiler cupboard. But first, you’ll need to figure out what things you’ll need.

Gurgling and Clunking

When an old boiler is turned on, it usually makes banging and popping noises. The build-up of corrosion or limescale obstructs the flow of water. As a result, the water in the boiler boils and expands, resulting in a loud crash.

This is the cause of gurgling or clunking noises from your boiler. To ensure a smooth flow of water into the system, have a specialist repair or replace the afflicted item.

Squeals and Squeaks 

If you hear these two sounds coming from your boiler, it signifies that something is loosely grinding against the boiler’s parts. Squeals and squeaks are usually the faults of the fan. The problem is solved once and for all by replacing the fan.

Noises from pipes and radiators

If your pipes are making a noise, there’s a good probability they have air pockets in them. The air is forced to go back and forth when hot water is flowing, forcing the pipes to vibrate. To eliminate these air pockets from your system, have it flushed.

Choose the best soundproofing material

Some materials may perform better than others in terms of soundproofing, but you must also examine what is safe while yet allowing simple access to the boiler. Cork and foam are well-known for their ability to absorb sound. Fibreglass, for example, is another material that could be useful. Below are some soundproofing products and materials that you may want to consider purchasing.

Acoustic panels

Your boiler cupboard would benefit from acoustic panels. They’re made up of 2 pieces of foam placed between a piece of fibreglass. Because they’re lightweight, you may use them to line cupboards or hang them on the backs of doors.

How to install Acoustic Panels?

Soundproof acoustic panels should be installed using the soundproof adhesive method, which I suggest.

  • Mark the place where you’ll be installing your panel with a straight-edge leveller and a pencil. This will ensure that your panels are straight after they’ve been hung.
  • The levelling brackets that come with the kit will then be screwed onto the top flange. This will ensure that your panels are installed correctly on the wall.
  • Apply adhesive to the acoustic panel’s back. Begin by applying a line of glue down the panel’s perimeter, about two inches from the edge. Now, using the adhesive, create an “X” to split the rectangle into 4 equal halves. In these parts, place a 2- to 4-inch circle of glue.
  • The final step is to hang the panel on the wall and wait for the adhesive to dry, which should take approximately a day.
Materials NeededTools Needed
soundproof foam panelAcoustic caulking adhesive straight-edge leveller

Carpet tiles

The majority of boiler cabinets are built of wood with bare flooring at the bottom. The boiler’s sound will ricochet throughout the flooring, and it may even travel downstairs.

Soundproof carpet tiles can be used to line your closet to help absorb some of the noise. Carpet absorbs sound Ten times better than wood flooring, so putting carpet on the floor of your cabinet could make a major difference. You could use a soundproof underlay below your carpet flooring to absorb even more noise.

Materials NeededTools Needed
carpetNon-slip area rug padCarpet tapeCarpet Cutter
Soundproof carpet tiles
soundproof underlay

Soundproof curtains

When attempting to lessen noise from your boiler cabinet, Soundproofing curtains may be a viable choice. You may soundproof inside the cabinet as well as the outside by putting curtains across the door. This is a low-cost and straightforward alternative.

To stop sound from passing through the material, the curtains should be thick and tightly woven. To establish a barrier, most soundproofing curtains will feature numerous layers of fabric.

Materials NeededTools Needed
Soundproofing curtainsA piece of cloth


Fibreglass is a material that is commonly utilised in the insulation industry. If you went into your loft, you’d probably discover fibreglass on the floor, which helps to keep your home warm in the winter and cool in the summer.

Fibreglass is molten glass that has been heated to a high temperature. Glass filaments are formed by forcing molten glass through very small holes. To make a material fire resistant, these threads are weaved into it, usually wool.

If the fibreglass is installed in a stud wall, it will operate better. Unless you plan to knock down walls, this may not be an option for you. Instead, the fibreglass can be put around the boiler cupboard’s perimeter.

Make certain to research the type of fibreglass you’re purchasing for your boiler cupboard. Some types of fibreglass are used for soundproofing, while others are used for heat insulation.

Materials Needed

Acoustic blankets

Soundproof curtains are similar to acoustic blankets. To assist dampen sound, the blankets can be draped from walls or doors. They’re usually composed of fibreglass or polyester, and they’re light enough to install quickly.

Materials Needed
Acoustic blanket

Soundproofing the Cupboard of the combi boiler

  • You can start installing your materials once you’ve picked them from the list above. You could use just one or a combo of materials to make your boiler so silent that you’ll forget it’s there.
  • Just keep in mind that you may wish to soundproof the door, as well as the floor and walls, which may need the use of additional materials.
  • Remember to provide enough space above and below the boiler to comply with rules. Check your boiler setup instructions to see what gap is appropriate. Typically, there is a 30 cm space above the boiler and a 10 cm gap below.
  • After you’ve silenced your boiler’s noise, you’ll want to check it regularly to make sure everything is still working properly. For instance, it might start making a weird noise that you aren’t aware of because you can’t hear it. Open the door now and again to make sure there aren’t any gurgling or whooshing noises coming from inside. If you hear anything unusual, call a Gas Safe registered engineer to investigate.


If your boiler is producing a lot of noise, the first thing you should do is make sure it’s working properly. If this is the case, there are a few soundproofing options available to you. However, I advise you to proceed with caution and to always follow any instructions in the boiler’s manual to avoid a fire.

Frequently Asked Questions (FAQs): How to soundproof a combi boiler?

Is a boiler’s loudness normal?

When your boiler makes a kettle-like noise, it’s due to kettling. Kettling is usually caused by a buildup of sludge or limescale on the heat exchanger, which can be resolved with a power flush. A leaking sound indicates that there is a leak in the system.

What is the noise level of a combi boiler?

Due to wear and tear, most older boilers feature noisy fans. The Grant Vortex Pro 26 combi boiler is currently one of the quietest on the market, while the Viessmann Vitodens 200 condensing boiler is one of the quietest.

How can you tell if your boiler is about to blow up?

Here are several warning indications that your water heater is about to burst. The pressure release valve is often found on the side of the heater, near the top. If the valve is leaking, it signifies the tank is overheated or under pressure. Either option is risky since it could result in an explosion.

What is the source of the noise coming from my circulator pump?

The circulating pump in your boiler is responsible for moving warm water from the boiler to your home’s radiators and back to the boiler. However, if your circulating pump is set too quickly for your home’s design, it can generate system vibrations that sound like a loud buzzing noise.

Which boiler is the quietest?

Vitodens 200 by Viessmann The Vitodens 200-W is a high-end gas-fired hot water boiler that is one of the most energy-efficient and quiet condensing boilers on the market. It is without a doubt one of the quietest boilers on the market, with noise outputs of 36 dB.

Is it a boiler that whistles unsafe?

Don’t be alarmed; your boiler may sound as if it’s about to blow up at any moment, but this is extremely unlikely, no matter how loud it is whistling or banging. Most boilers have safety features that cause them to shut down before they become dangerous.

What’s causing the pounding in my boiler pipes?

Water That Has Been Captured When water becomes caught in the boiler for any reason, it is exposed to too much heat and boils away, resulting in steam. When water boils, it expands to roughly 1700 times its original volume. The banging in your system could be caused by that abrupt and severe increase in pressure.

Is it bad to turn off your boiler?

Turning it on and off, or turning it off for an extended period, might cause your valves and pumps to lock up. We recommend that you have your boiler serviced once a year to avoid it breaking down.