Baxi 630 combi boiler review

Company type: Manufacturer

HQ: Warwick, England

Founded: 1866

CEO: Karen Boswell

The Baxi 630 combi boiler is one of three boilers within the Baxi 600 combination boiler range. It comes with a number of useful features designed with homeowner comfortability in mind, and its modest size and reliability make it a popular choice with installers. Let’s find out what else this small yet powerful combi has to offer and if it is the right boiler for you.

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Is the Baxi 630 combi boiler the right size for my property?

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Power output

The Baxi 630 combination boiler has a power output of 30.9kW, making it a great choice for small to medium sized homes with 1 bathroom.

When referring to a boiler’s “size”, we mean its power output, which is measured in kilowatts (kW). A boiler's power output is how much power it uses to heat up your home.

There are four main factors to consider when determining what size boiler is suitable for your property:

  • Type of boiler (combination, regular or system)
  • The number of radiators
  • The number of bedrooms
  • The number of bathrooms

Combination boilers typically have higher power outputs when compared with regular or system boilers. Combination boilers need more power as they heat water on demand, whereas system and regular boilers slowly boil water and store it in a hot water cylinder for later use.

Below is a rough guide to what size combi boiler is recommended for different sized properties.

Property Type No. of Bedrooms No. of Bathrooms No. of Radiators Recommended Boiler Size
Apartment 1-2 1 Up to 5 24-26kW
Small house 1-2 1 Up to 7 24-26kW
Medium house 2-3 1 Up to 7 30-32kW

Baxi 630

Family house 3-4 1 & 1 ensuite Up to 10 35-40kW
Large family house 4-5 2 & 1 ensuite Up to 15 Heat only or system boiler

It is important to get the correct size boiler for your home. If your boiler’s output is too low, it may struggle to heat up your radiators fully and it might not be able to meet your household’s hot water demands, but if your boiler’s output is more powerful than needed, you may find yourself spending more money on your utility bills!

We recommend that you get your home surveyed by a Gas Safe registered engineer who will assess your property and heating demands in order to choose the right boiler for you.

Flow rate

The Baxi 630 has a flow rate of 12.2 litres per minute. The flow rate of a boiler refers to how much water it can deliver to your taps or shower in one minute.

The flow rate for a good shower is between 10 and 15l/min, so the Baxi 630’s flow rate sits comfortably within this range.

With a flow rate of 12.2l/min, the Baxi 630 is capable of delivering a good amount of water to one shower. It will be able to cope with the demands of two showers at the same time, although you might notice a slight drop in the rate of water flow to both showers.

Does your home have high hot water demands?

The Baxi 630 combi boiler is a great choice for medium sized homes with limited space, but if you live in a larger property with limited space, then a Baxi Duo tec or a Baxi Platinum combi boiler will a better choice. If you live in a large property and space isn't an issue, then a Baxi Heat only boiler will better suit your needs.

How big is the Baxi 630 combi boiler?

The Baxi 630 combi boiler measures up at 700mm high, 390mm wide, 285mm deep and has a low lift weight of only 29.5kg. Such dimensions mean the Baxi 630 combi boiler can easily be installed in all the usual places you would store a boiler, such as in the kitchen, loft, airing cupboard, and so on, but due to its compact size, it can easily be installed in a standard kitchen cupboard!

Being a compact boiler with all the piping needed within its footprint makes the Baxi 630 a great choice for households with limited space. Installing a compact boiler such as the Baxi 630 could save you space, time and money.

If you would like to have a new Baxi 630 combi boiler or any other boiler installed, click here for more information.

How energy efficient is the Baxi 630 combi boiler?


The Baxi 630 is a 93% efficient boiler. The energy efficiency of a boiler refers to how much of its fuel it is able to convert into the energy needed to run the boiler. For example, the Baxi 630 combi boiler will use 93% of its fuel to heat a home, while only 7% of the fuel will become waste products. To put this into perspective, many UK households are still using boilers that were manufactured in the 1990’s that are as low as 60% efficient, meaning they could be wasting up to 40% of the boiler’s energy usage!

As with all modern boilers, the Baxi 630 is a condensing boiler. This means it is able to recover heat that was previously lost via the flue to pre-heat the heating system in order to make it more efficient.

Being a 93% efficient boiler gives the Baxi 630 an ErP A rating. ErP (Energy-related Products) ratings are part of an EU directive that aims to reduce greenhouse gas emissions by improving the performance standards of all products that use energy, such as boilers.

Energy-related Products are graded from A-G, with A-rated products being at least 90% efficient and G-rated products being below 70% efficient.

The energy efficiency of your boiler has a major impact on how much you are paying for your energy bills. When compared to an older, less efficient boiler, a highly efficient boiler such as the Baxi 630 could lower your heating bills by a few hundred pounds every year.

Baxi 630 Key Features

Easy to repressurise your central heating system

The Baxi 630 combi boiler is equipped with an easyfill filling loop, making it easier for households to repressurise their central heating system without the need to call an engineer.

The filling loop on your boiler is a pipe that connects the central heating system to the mains water supply and is used to fill your heating system with the water it needs to top it up if the pressure has dropped.

Some boilers have detachable filling loops that can be quite tricky to attach and use, whereas the easyfill filling loop on the Baxi 630 is a permanently attached pipe that allows you to repressurise the system by simply pulling and releasing the lever once the correct pressure has been reached.

For a more in depth read about Baxi filling loops and Baxi boiler pressure problems, click here.

Can operate at a lower power to save fuel and money

The Baxi 630 has a fully modulating burner, which in simple terms means it has the ability to adjust its power output according to the heating demand.

Boilers that don't have the ability to modulate constantly run at full power then turn off once your home is heated to the desired temperature. But once the temperature drops, the boiler then has to fire itself back up to full power just to get the temperature back up, which is not a very efficient way of working!

Instead of constantly turning on and off, the Baxi 630 will run longer at a lower power to maintain the desired temperature. This intelligent use of power increases fuel efficiency, user comfort, and the longevity of your boiler!

Easy to use OpenTherm digital interface

The Baxi 630 is compatible with OpenTherm digital thermostats. OpenTherm is the language that thermostats use to communicate with boilers.

OpenTherm thermostats are easy-to-use and have an in-built programmer that allows you to control your central heating with the scroll of the dial.

A main feature of this programmable thermostat is its load compensation function. This function measures the difference between what the indoor temperature is and what the user wants, and thanks to the Baxi 630’s modulation feature, it will adjust the boiler’s power output so that it uses the minimum amount of fuel necessary to close the gap, resulting in you saving money!

How long is the warranty period for the Baxi 630

To give homeowners peace of mind, and to show the confidence they have in the reliability and performance of the Baxi 630 combi boiler, Baxi has included a 7 year extended warranty with this model.

Terms and conditions apply in order for you to be eligible for the extended 7 year warranty.

If you would like to find out more about the terms and conditions of Baxi warranties and what is covered and what isn’t, click here.

Give your boiler a service.

Make sure you don't invalidate your warranty. Call Smart Plan to get a boiler checkup to see if everything is in good working order.

OR 020 8146 3960

Baxi 630 Specifications

Width 390mm
Height 700mm
Depth 285mm
Weight 29.2kg
Fuel Type Gas
Display Type LCD
Energy Rating (Heating) A
Energy Rating (Water) A
Flow Rate 12.2 l/min
Central Heating Max. Output 21.2 kW
Hot Water Max. Output 30.9 kW
Sound Power Leve 48 dB

Still need help with your Baxi boiler?

Call Smart Plan and speak to our expert engineering team free of charge.

0333 772 6247