In the Baxi vs Vaillant debate, Baxi usually wins on price and Vaillant wins on refinement, particularly quieter running and stronger hot water flow on the bigger models. If you want a dependable boiler for the least money, Baxi is hard to beat. If you plan to stay put and want the more polished boiler, the extra spend on a Vaillant often pays its way.
We’re Clever Energy Boilers, a Gas Safe registered (no. 554138) installation company from Bingley. As well as being accredited Worcester Bosch installers, we’re experienced, professional and registered installers of both Baxi and Vaillant, fitting new boilers in homes across Yorkshire, the North West and the Midlands. Here’s how they compare once they’re on the wall.
Is Baxi or Vaillant better?
Vaillant is the better boiler overall, while Baxi is the better value. For a typical three-bed semi with one bathroom, both will heat the house and run the showers without any fuss, so the choice comes down to budget and how much you care about the extras.
How do Baxi and Vaillant compare at a glance?
Here’s a quick side-by-side of the two brands’ main combi boilers, using current manufacturer specs.
| Feature | Baxi | Vaillant |
| Main combi ranges | Baxi 600 Combi 2, Baxi 800 Combi 2 | ecoTEC pro, ecoTEC plus |
| Combi outputs | 24kW, 30kW and 36kW (600 Combi 2) | 24kW to 30kW (pro), 26kW to 40kW (plus) |
| Max hot water flow | Up to 15 l/min (636) | Up to 18 l/min at a 35°C rise (ecoTEC plus 940) |
| Heat exchanger | Stainless steel | Stainless steel (ecoTEC plus) |
| ErP rating | A | A, 93% to 94% on ecoTEC plus |
| Quiet Mark | Not listed for the 600 or 800 | ecoTEC plus combi range certified |
| Smart controls | Baxi uSense | myVAILLANT app and gateway |
| Typical installed price (combi) | £1,800 to £3,000 | £2,200 to £3,300 (ecoTEC plus) |
| Best for | Tighter budgets, smaller homes, landlords | Long-term owners, bigger homes, quieter running |
Is Vaillant worth the extra cost over Baxi?
For most owner-occupiers who plan to stay five or more winters, yes, the Vaillant premium is usually worth it. Like-for-like, a Vaillant combi tends to cost a few hundred pounds more than the Baxi equivalent, and the installation labour is the same for both.
Our guide to new boiler costs puts a typical fitted combi at £1,800 to £4,000, with around £2,500 being average. Supply prices for a Baxi combi run from roughly £700 to £1,900, against £900 to £2,200 for Vaillant. A fitted Vaillant ecoTEC plus typically comes in at £2,200 to £3,300.
What does the extra money get you? Mainly quieter running and a wider choice of outputs at the top end. The newest ecoTEC plus models also monitor combustion continuously and adjust themselves, which helps keep them efficient as the gas supply varies. Baxi covers the basics very well. Vaillant goes a bit further.
If you’re selling within a couple of winters, or fitting a boiler in a rental, the Baxi makes more financial sense. Either way, long, market-leading warranties are available when we install either brand.
How do the combi ranges compare?
The Baxi 600 lines up against the Vaillant ecoTEC pro, and the Baxi 800 against the ecoTEC plus. That’s the comparison most people mean when they search for Baxi 800 vs Vaillant ecoTEC plus.
Baxi 600 Combi 2 vs Vaillant ecoTEC pro
These are the entry points for each brand, and they’re closely matched. The Baxi 600 Combi 2 comes in 24, 30 and 36kW, with a stainless steel heat exchanger and up to 15 litres per minute from the 636. Our Baxi 630 combi review covers the most popular size in detail.
The ecoTEC pro stops at 30kW, delivering about 12.3 litres per minute from the largest model. It’s compact and simple to live with, and our Vaillant ecoTEC pro 30 review explains where it fits best. For a flat or small house, there’s very little between these two apart from price.
Baxi 800 Combi 2 vs Vaillant ecoTEC plus
This is where Vaillant pulls ahead. The Baxi 800 Combi 2 is a solid mid-range boiler with a stainless steel heat exchanger, an Adey filter in the box and compatibility with Baxi’s uSense smart control. The 830 gives around 12.2 litres per minute.
The latest ecoTEC plus range (826, 832, 836, 840 and 940) goes up to 40kW and 18 litres per minute at a 35°C rise. It’s hand-built in Derbyshire, has a semi-touch display and works with the myVAILLANT app through an internet gateway. Above that sits the ecoTEC exclusive, and our ecoTEC exclusive 832 review covers whether the top model justifies its price.
Which is quieter and more efficient?
Vaillant is the quieter of the two, and on efficiency they’re effectively level. The ecoTEC plus combi range holds Quiet Mark certification, and Vaillant quotes ErP sound levels of 45 to 49 dB(A) across the new models. Baxi describes the 800 as quiet, but we couldn’t find a Quiet Mark listing for the 600 or 800.
Both brands are ErP A-rated for heating and hot water. Vaillant lists seasonal efficiency of 93% to 94% for the ecoTEC plus, and Baxi quotes around 93% for the 800. On a real gas bill that gap is tiny. How the boiler is set up matters far more, so we fit weather or load compensating controls where they suit the home and set the flow temperature low enough for the boiler to condense properly.
Which is more reliable?
Both are reliable when fitted and serviced properly, though Vaillant has the stronger reputation with heating engineers. Each brand’s current combis use stainless steel heat exchangers, which cope well with a well-cleaned system and a magnetic filter.
Most faults we hear about from either brand come from the heating system rather than the boiler itself, with low pressure and sludge the usual culprits. Our Vaillant error codes guide and our page on the Baxi H.02.07 low pressure code show the common ones. Topping up pressure through the filling loop is fine to do yourself. Anything inside the casing needs a Gas Safe registered engineer.
For a wider look at each brand, read our full Baxi boilers review and Vaillant boilers review.
Which suits your home?
Smaller homes get great value from Baxi, while bigger homes with more than one bathroom tend to be better served by Vaillant’s larger outputs. These are the models we’d typically look at.
| Home | Baxi option | Vaillant option | Our pick |
| 1 to 2 bed flat or terrace, one bathroom | Baxi 624 Combi 2 | ecoTEC pro 24 | Baxi, for value |
| 3 bed semi, one bathroom | Baxi 630 or 800 Combi 2 (30kW) | ecoTEC pro 30 or ecoTEC plus 832 | Either; Vaillant if noise matters |
| 3 to 4 bed, bathroom plus en suite | Baxi 636 or 800 Combi 2 (36kW) | ecoTEC plus 836 or 840 | Vaillant, for stronger flow |
| 4+ bed, two or more bathrooms used at once | Baxi system boiler with Megaflo cylinder | ecoTEC plus system boiler with cylinder | System boiler from either brand |
In larger homes where two showers often run together, a system boiler with a cylinder is usually the better setup. Our Baxi Megaflo system boiler review explains how that pairing works, and we cover the bigger picture in our guide to the best boilers for a four-bedroom house.
Our verdict
Choose Baxi if you want a well-built boiler at a keen price, especially in a smaller home or a rental. Choose Vaillant if you’re staying long term, want the quietest running or need strong hot water flow for a busier household.
If your current boiler is over 8 years old, it’s likely to be less efficient than either of these and replacing it will usually save more than keeping it going. Ask us to quote for a Baxi boiler installation or a Vaillant boiler installation and we’ll price both so you can compare them directly.
Weighing up other brands? Our Ideal vs Baxi comparison came before this one, and next in the series we put Glow-worm against Vaillant.
Does boiler noise matter more in Leeds and Bradford terraces?
It often does, and it’s one of the main reasons people in our area choose Vaillant. In back-to-backs and through terraces across Leeds and Bradford, the boiler usually sits in the kitchen, right next to the living space, and sometimes on a shared wall with the neighbours. A Quiet Mark boiler like the ecoTEC plus makes a real difference there, especially if it fires up early in the morning.
In larger semis and detached homes around Harrogate, Huddersfield and Wakefield, where the boiler is tucked away in a utility room or garage, the noise gap matters less and Baxi’s lower price becomes harder to argue with. There’s a northern connection on the Baxi side too, as its boilers are made near Preston in Lancashire, while Vaillant builds its UK combis in Belper, Derbyshire.
Whichever way you lean, our boiler replacement service covers both brands with fixed prices, and we’ll tell you straight which one suits your house.
FAQs
Is Baxi as good as Vaillant?
Baxi is close, but not quite as refined. At entry level the Baxi 600 and ecoTEC pro are evenly matched. Higher up, the ecoTEC plus offers bigger outputs, quieter running and more advanced controls than the Baxi 800.
Which lasts longer, Baxi or Vaillant?
A Vaillant often lasts a little longer, though installation quality and annual servicing make a bigger difference than the badge. Both brands use stainless steel heat exchangers on their main combis. A clean system with a magnetic filter, serviced every twelve months, matters more for lifespan than the choice between the two.
Which is cheaper to run?
Running costs are almost identical, because both are ErP A-rated with seasonal efficiency of around 93% to 94%. Getting the size right and running a low flow temperature will affect your bills far more than the brand.
Which is better for a 4-bed home?
Vaillant usually suits a 4-bed home better, thanks to the ecoTEC plus 836 and 840 and their higher hot water flow. If you have two or more bathrooms in regular use, a system boiler and cylinder from either brand is often the smarter choice.
Get your Baxi or Vaillant quote
Still torn? Tell us about your home and we’ll recommend the right Baxi or Vaillant model, with a fixed price that includes fitting. Get your free online boiler quote in a couple of minutes, or request a callback if you’d rather talk it through.