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Best Quietest Boilers


A noisy boiler can be annoying, especially when installed near your bedroom. As such, you would want to replace it with an almost silent one that will guarantee you a warm and peaceful life. But how can you identify a quiet boiler amongst the many brands and models currently in the market?

Well, you need not worry about that as you have come to the right place. This guide will help you narrow down your options by listing some of the quietest combi, system, and regular boilers.

How to identify a quiet boiler

The easiest way to identify a quiet boiler is to look for the Quiet Mark logo usually stamped on the boiler. Quiet Mark is an independent body that assesses and tests everyday machines and appliances to identify the most silent ones.

However, Quiet Mark only tests and approves boilers made by Ideal, Vaillant, and Glow-Worm. This means you should extend your search for the quietest boilers beyond the Quite Mark accredited ones.

Luckily, most modern boiler manufacturers usually indicate the decibel rating of their boilers in their sales brochures and operating manuals.

How loud should a boiler be?

Sound intensity is usually measured in decibel (dB), with silence being allocated a value of 0dB. A sound that reaches or exceeds 85 dB is considered loud and harmful, and listening to them for a long can cause permanent hearing damage.

Modern boilers are built with silence in mind and have sound levels ranging between 30 to 60 decibels, making them as loud as most refrigerators or moderate rainfall.

Best quietest combi boilers

Combination boilers often abbreviated “combi boilers”, are single boiler units that provide instantaneous central heating and domestic hot water. They usually take water directly from the mains water supply and heat it when there is a hot water demand.

Here is a list of the five quietest combi boilers.

  1. Viessmann Vitodens 200

Viessmann Vitodens 200 is a highly efficient combi boiler that can perform at an efficiency level of 98%. It is also the quietest condensing combi boiler with a noise emission of 36dB, which is lower than that of most refrigerators. The boiler has a central heating output of 27.8 kW and a domestic hot water output of 30.5 kW.

Some of its top features include:

  • Up to 98% efficiency ratings
  • It is compact in design and can fit into a standard kitchen cupboard
  • It is extremely quiet in operation
  • Stainless steel heat exchangers
  • It has a wide modulation ratio of 1:17, meaning it can perform at 1/17 of its maximum power to reduce energy consumption.
  1. The Grant Vortex Pro Xs 26

This is a floor-standing compact oil-fired combi boiler suitable for kitchen installations. The boiler is designed with the engineer in mind, and its installation is straightforward as no complicated wiring or plumbing is involved. With a noise level of 41dB, the Grant Vortex Pro Xs 26 is the second quietest combi boiler and the quietest oil-fired combi boiler.

Some of the main features of this boiler include:

  • Large plate stainless steel heat exchanger
  • Extremely compact design as it is only 515 mm wide
  • Low system pressure cut-off switch that turns off the boiler when there is a system water loss
  • Built-in frost protection
  • Neon diagnostic indicators
  • A 24-litre expansion vessel
  1. Worcester Bosch Greenstar 2000

Worcester Bosch is a premium boiler brand whose products are famed for their reliability, high-quality standards, and impeccable energy efficiency ratings. However, these products are often overpriced, making them above the reach of most homeowners.

The manufacturer recently released the Greenstar 2000 boiler range, a premium, price competitive combi boiler. This gas boiler range is available in outputs of 25 and 30 kW and is fueled by gas or LPG.

Worcester Bosch Greenstar 2000 combi boilers have an ERP decibel rating of 43, making it Worcester’s quietest combi boiler.

Some of the main features of the Worcester Bosch Greenstar 2000 include:

  • 5-year standard guarantee, which can be extended to 6 years by fitting it with a Greenstar System Filter
  • LPG-fueled models are available for off-grid properties
  • Can modulate power to 4.8 kW to minimize energy consumption
  • C6 heat exchanger with a 10-year guarantee
  1. Ideal Logic Max C35

The Ideal Logic Max C35 combi is a Quiet Mark accredited boiler with an ERP dB rating of 44. Although the boiler is highly efficient, it is designed for large homes with up to 20 radiators and can be too powerful for a standard home.

The main features of this combi boiler include:

  • Compact design
  • Built-in frost protection
  • A standard 10-year warranty
  1. Vaillant ecoTEC Plus

This Quiet Mark accredited combi boiler range has a dB rating of 45 and is best suited for small to medium-sized homes. The boiler comes with a 24 kW central heating output and a 30 kW domestic hot water output.

Some of the top features of the Vaillant ecoTEC Plus combi boiler include:

  • It is designed to fit into a kitchen cupboard
  • Features removable side panels, making it easy to clean the heat exchanger
  • It has a modulation ratio of 1:6
  • It comes with a 5-year standard warranty with the option to extend it to 10 years.
  • Available in gas and LPG models

Best quietest system boilers

A system boiler is a sealed boiler system that takes water directly from the mains water supply, heats it, and stores it in a hot water cylinder. The hot water cylinder ensures a constant supply of hot water throughout your home.

Here is a list of the five quietest system boilers

  1. Worcester Bosch Greenstar 4000

The Greenstar 4000 is the latest boiler released by Worcester Bosch. It is available as a combi and a system boiler, with the system boiler featuring an ErP decibel rating of 42. The system boiler also comes in five different outputs, with the lowest being 12 kW and the highest being 24 kW.

Some of the top features of the Greenstar 4000 system boiler include:

  • Flue lengths of up to 12 m
  • Easy to use controls
  • Easy to read full-colour display
  • It can be modulated to operate at a central heating output of 1.9 kW
  1. Ideal Logic Max

The Ideal Logic Max is the second quietest system boiler in the market, with a noise level of 44dB. The boiler features a compact design and can be stowed away in a kitchen cupboard.

Some of the main features of this boiler include:

  • It is compatible with all Ideal controls
  • Lengthy 10-year warranty
  • Has a built-in service reminder with telephone number
  • Scratch-resistant body
  1. Glow-worm Energy 12S

The Glow-worm Energy System boiler comes with five kW outputs, each having a different ErP dB rating. All Glow-worm energy system boilers feature a light and compact design and fit into a standard kitchen cupboard. Of the five different outputs, the Glow-worm Energy 12S is the quietest, with a noise level of 45dB.

The top features of the Glow-worm Energy 12S system boiler include:

  • Top and rear flue installation options
  • Highly efficient automotive-grade heat exchanger
  • High efficiency modulating pump
  1. Vaillant ecoTEC Plus

Vaillant ecoTEC plus is a range of system boilers available in different kilowatt ratings. The boiler can serve all properties as it is available in 12 kW,15 kW, 18 kW, 24 kW, 30kW, and 37 kW output ratings. All the boilers in this range feature a sleek and compact design, meaning they can be installed in the smallest spaces. Vaillant ecoTEC Plus 630 is the quietest boiler in this range and has a noise level of 48dB.

Best quietest regular boilers

Regular or heat-only boilers have a cold water storage tank usually installed in the loft or attic of your home. The cold water in the storage tank is fed to the boiler via gravity, and once the boiler is ignited, it displaces the hot water, which then makes its way to the hot water storage tank.

Regular boilers are often large and unsuitable for small properties with limited space.

Here are some of the quietest regular boilers currently in the market.

  1. Ideal Logic Max Heat

The Ideal Logic Max Heat boiler range consists of some of the quietest regular boilers currently in the market. Ideal Logic Max Heat regular boilers are available in a wide range of outputs ranging from 12 kW to 30 kW. The 12 kW boiler is the quietest one in this range and has an ErP dB rating of 36 kW. However, the limited output of this boiler makes it unsuitable for properties having more than eight radiators.

If you live in a larger property, you should consider installing the Ideal Logic Max Heat 30 kW boiler, which has a noise level of 49dB.

  1. BAXI 600 Heat

The BAXI 600 Heat regular boiler is available in a wide range of outputs, making it suitable for properties having between 8 and 20 radiators. BAXI 600 Heat boilers are quiet in operation and have noise levels that range between 37dB 49dB.

  1. Viessmann Vitodens 100-W Open Vat

Like many Viessmann boilers, the Viessmann Vitodens 100-W Open Vat regular boiler is designed with few movable parts to reduce the noise it makes while in operation. The boiler is not only easy to install and use but is also highly efficient, clocking an ErP efficiency rating of 97%. It is also quieter than most fridges and has a noise level of 39dB.

  1. Ideal Mexico HE

The Ideal Mexico HE is a compact floor-standing regular boiler that features a built-in frost protection feature, an optional remote user kit, and a user-friendly display panel. This boiler comes in a wide range of outputs and has a maximum noise level of 40dB.

  1. Worcester Bosch Greenstar Ri

The Worcester Bosch Greenstar Ri regular boiler is a compact and highly reliable boiler suitable for all properties. This Worcester Bosch’s best-selling regular boiler range features noise levels ranging from 45dB to 52dB.

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