A very popular boiler, from a very popular brand. Here's our in-depth take on the ecoTEC Pro 28 combi boiler from the heating giants, Vaillant.
Vaillant is one of those boiler brands that heating engineers tend to nod approvingly at.
Premium German engineering, a long history in heating and a reputation for making boilers that are built properly rather than merely built cheaply.
Which is reassuring when said boiler is responsible for stopping your house becoming an igloo for half the year.
Among Vaillant’s best-known combi boilers is the ecoTEC pro 28, a 28kW model designed primarily for small-to-medium-sized homes.
But is it actually any good?
And, more importantly, is it worth paying Vaillant money for when there are cheaper boilers available?
In this review, we’ll look at:
Reliability
Performance
Hot-water flow rate
Efficiency
Controls
Build quality
Guarantee
Dimensions
Price
Who should actually buy one
And then, because apparently we’re boiler Michelin inspectors now, we’ll give it an overall score.
Book before 3 pm and you could get your new Vaillaint ecoTec Pro boiler installed as quick as tomorrow. Check the latest boiler prices here.
Our Vaillant ecoTEC Pro 28 Scores
Here’s how we rate the ecoTEC pro 28:
Category | Heatable score |
Reliability | 5/5 |
Performance | 4.5/5 |
Controls & features | 4.5/5 |
Guarantee | 4.5/5 |
Price & value | 4/5 |
Overall | 4.5/5 |
In summary?
Very good boiler.
Not cheap.
Not particularly flashy.
But extremely competent.
Which, when we're talking about a machine full of gas, flames and hot water hanging on your kitchen wall, isn't necessarily a bad personality to have.
What Is the Vaillant ecoTEC Pro 28?
The ecoTEC pro is Vaillant's combi boiler range aimed primarily at small-to-medium-sized properties.
It's currently available in:
24kW
28kW
30kW
And, just to clear up something that gets muddled surprisingly often:
The ecoTEC pro 28 is the 28kW model.
Not the 30kW one.
Groundbreaking stuff, we know.
As a combi boiler, it heats your central heating and provides hot water directly from the mains without requiring a separate hot-water cylinder.
That makes it particularly suited to flats and smaller houses where space is at a premium.
Main Features of the Vaillant ecoTEC Pro 28
Before we start poking around inside it, here are the headline features:
Designed for small-to-medium homes
28kW combi boiler
Approx. 11.1 l/min hot-water flow rate
Stainless-steel heat exchanger
A-rated for heating and hot water under ErP
Modulating heating technology
Bright digital display
Compatible with Vaillant heating controls
Weather-compensation options available
Quiet Mark certified
Compact 720 × 440 × 338mm body
Up to a 10-year manufacturer guarantee
Strong recent Which? reliability results
Not bad for a white box you ideally want to forget exists.
🎥 Watch Our Vaillant ecoTEC Plus Video Review
In our video review, we take a closer look at the Vaillant ecoTEC Plus, including its construction, controls and key components.
You can watch the full review above or read our detailed breakdown here.
Reliability: 5/5
This is probably Vaillant's strongest selling point.
There are cheaper boilers.
There are smaller boilers.
There are boilers with more colourful screens and enough app functionality to make your fridge feel inadequate.
But Vaillant has built its reputation on engineering and reliability.
And the current evidence supports that reputation.
Latest Which? Reliability Results
Forget relying on a Which? award from 2016.
We have much more recent evidence now.
In the latest Which? boiler research, conducted in 2025, more than 10,000 members of the public were surveyed alongside 225 Trusted Trader heating engineers.
Vaillant says it achieved:
5 stars for reliability
5 stars for engineer recommendations
That's far more meaningful than simply saying a boiler once won an award a decade ago.
Why do we particularly care about engineers?
Because unlike your neighbour Dave, who has owned precisely one boiler and considers himself an expert because it hasn't exploded, heating engineers see hundreds of them.
They know which boilers:
Develop recurring faults
Are horrible to service
Have awkward components
Have readily available spare parts
Are sensibly engineered
Make them question their career choices
So strong engineer feedback matters.
Vaillant Trustpilot Reviews
Vaillant's wider customer feedback is also extremely strong.
As of September 2026, Vaillant UK has more than 23,000 Trustpilot reviews and an overall rating of around 4.6/5.
That's impressive for a heating manufacturer operating at this scale.
Recent reviews frequently praise Vaillant's engineers, servicing and support.
Of course, Trustpilot isn't a controlled reliability study.
Someone giving five stars because “Steve was lovely and wore shoe covers” doesn't tell us the failure rate of a diverter valve.
But it does tell us something about the wider ownership and aftercare experience.
Stainless-Steel Heat Exchanger
Another positive is the ecoTEC pro's stainless-steel heat exchanger.
Stainless steel offers excellent resistance to corrosion and acidic condensate and is commonly used in premium condensing boilers.
Does stainless steel automatically mean the boiler will last forever?
No.
Water quality, correct installation, servicing, system cleanliness and how the boiler is operated all matter.
But it's certainly a nice bit of kit to find inside.
Performance: 4.5/5
Here's where we need to separate heating output from hot-water performance.
Because boiler manufacturers really do enjoy giving consumers several different numbers called “output”.
ecoTEC Pro 28 Hot-Water Performance
The ecoTEC pro 28 delivers approximately:
11.1 litres of hot water per minute at a 35°C temperature rise.
That's a decent result for its size.
In practical terms, it should be perfectly capable for many:
Flats
Two-bedroom homes
Three-bedroom homes
Properties with one main bathroom
But we'd be more cautious if you have several bathrooms and expect to run multiple showers simultaneously.
A combi boiler can only heat the amount of water passing through it.
And no amount of premium German engineering can negotiate with the laws of thermodynamics.
What About the ecoTEC Pro 24 and 30?
The wider range includes:
ecoTEC pro 24
A lower-output option for properties with more modest hot-water requirements.
ecoTEC pro 28
The Goldilocks option for many smaller and medium-sized homes.
ecoTEC pro 30
Provides stronger hot-water performance, at approximately 12.3 l/min, for properties where demand is slightly higher.
So if you're choosing between them:
Don't automatically buy the biggest one because bigger numbers feel more powerful.
Your boiler should be sized around your actual heating and hot-water requirements.
Otherwise you're effectively buying a Range Rover to collect the milk.
Which ecoTEC Pro Is Right for Your Home?
As a rough rule:
24kW: smaller properties and relatively modest hot-water requirements.
28kW: small-to-medium homes with one bathroom.
30kW: medium homes where slightly stronger hot-water performance is useful.
But that's deliberately simplified.
Correct boiler sizing depends on things including:
Property heat loss
Number of radiators
Insulation
Number of bathrooms
Incoming mains flow rate
Hot-water usage
Existing heating system
Want to avoid doing boiler thermodynamics over breakfast?
Use Heatable's online tool and we'll work it out for you.
ecoTEC Pro 28 Efficiency
The ecoTEC pro is an A-rated condensing boiler for both heating and hot water under ErP.
That means it's operating in a completely different league from the elderly non-condensing boiler you might currently have trying to heat the garden via the flue.
However, there's an important point here.
Boiler Efficiency Isn't Just a Number on the Sticker
Modern condensing boilers achieve their best efficiency when they can actually condense.
That generally means operating with sufficiently low return-water temperatures.
In practice, the efficiency of your heating system therefore depends on more than which boiler you buy.
Things like:
Flow temperature
Weather compensation
Load compensation
Correct radiator sizing
Boiler modulation
Hydraulic balancing
System cleanliness
can all matter.
A £2,000 premium boiler set permanently to 80°C isn't necessarily a masterclass in energy efficiency.
Modulating Heating
The ecoTEC pro can modulate its output rather than simply operating at full blast whenever your thermostat asks for heat.
That's important.
Imagine cruise control rather than:
FULL THROTTLE.
BRAKE.
FULL THROTTLE.
BRAKE.
A modulating boiler can better match its output to the heat your home actually needs.
That can improve comfort while reducing unnecessary cycling.
Controls & Features: 4.5/5
The ecoTEC pro isn't the newest boiler platform in Vaillant's range, but it still supports a good selection of heating controls.
Digital Boiler Display
On the boiler itself, you get a bright digital display providing information such as:
Heating temperature
Hot-water settings
System status
Pressure information
Diagnostic information
Fault codes
Basic?
Yes.
Useful?
Also yes.
A boiler does not need an OLED cinema screen.
It needs to tell you what it's doing when something goes wrong.
Vaillant VRT 350
The VRT 350 remains one of the controls Vaillant lists as compatible with the ecoTEC pro.
It's available for controlling room temperature and heating schedules and allows greater communication with the boiler than a simple mechanical thermostat.
And thankfully, its intelligence is reserved entirely for your heating.
It still can't help the children with their homework.
sensoCOMFORT
Vaillant also lists sensoCOMFORT compatibility with the ecoTEC pro.
This opens the door to more sophisticated heating control, including weather-compensation functionality.
Weather compensation allows the heating system to adjust its flow temperature depending on conditions outside.
Instead of waiting until the house gets cold and shouting:
MORE FIRE!
the system can make smaller, more intelligent adjustments.
What About vSMART?
You'll see lots of older ecoTEC pro reviews heavily promoting Vaillant vSMART.
That's because vSMART was a major part of Vaillant's smart-control offering when many of those reviews were written.
Vaillant's current UK control ecosystem has evolved, with products including sensoCOMFORT, sensoHOME, sensoROOM pure, myVAILLANT connect and the myVAILLANT app now taking greater prominence across its range.
So we wouldn't choose this boiler specifically because an old review says “it has vSMART”.
Instead, choose the control package appropriate to the heating system you're actually installing today.
Controls & features score: 4.5/5
Quiet Mark: Is the ecoTEC Pro 28 Quiet?
Yes.
The ecoTEC pro 28 and 30 are Quiet Mark certified.
The 24kW model is the exception.
Quiet Mark independently identifies products with reduced noise output within their category, which is useful if your boiler is going somewhere like:
A kitchen
Utility room
Open-plan living space
Near a bedroom
Will you hear it occasionally?
Of course.
It contains a pump, fan, gas valve and combustion system.
It isn't a monk.
But the ecoTEC pro has a strong reputation for quiet operation.
Size: Is the Vaillant ecoTEC Pro 28 Compact?
The boiler measures:
720mm high × 440mm wide × 338mm deep
That's reasonably compact for a combi boiler.
It isn't the smallest boiler on the market, though.
For example, several competing compact models are narrower and/or shallower.
So we'd describe the ecoTEC pro as:
Compact-ish.
Not:
“Fits inside your sock drawer.”
Also remember that boiler dimensions don't represent the full installation space required.
Clearances need to be maintained so your installer can fit, inspect and service the appliance properly.
Guarantee: 4.5/5
Here's another section where the old article needed updating.
The ecoTEC pro currently comes with a 2-year standard Vaillant guarantee.
However, Vaillant advertises the ability to upgrade that protection to up to 10 years, depending on the installer and applicable scheme.
Charges may apply for the extended cover.
That distinction matters.
So we wouldn't simply advertise:
“10-year guarantee”
without explaining the conditions.
Why the Guarantee Matters
A long manufacturer's guarantee is reassuring because boilers aren't cheap things to repair.
However, don't make the mistake of treating it as maintenance-free cover for a decade.
Guarantees normally depend on requirements such as:
Correct installation
Registration
Annual servicing
Approved system treatment
Compliance with manufacturer conditions
Read the exact terms supplied with your installation.
Yes, we know.
Nobody enjoys reading terms and conditions.
Still preferable to discovering Clause 73(b) while standing in a freezing house wearing three jumpers.
Guarantee score: 4.5/5
The potential 10-year protection is excellent.
We deduct half a point because the standard cover is only two years and the extended guarantee isn't automatically included in every installation.
Price & Value: 4/5
Vaillant is a premium brand.
And premium brands have a curious habit of charging premium-brand money.
The ecoTEC pro therefore isn't usually the cheapest route to obtaining a new A-rated combi boiler.
But that's not necessarily a criticism.
You're paying for things including:
Strong brand reliability
Stainless-steel heat exchanger
Established UK support
Good parts availability
Installer familiarity
Quiet operation
Long guarantee potential
Proven platform
We would not fix this review to a boiler-only price such as “£1,500”, because boiler retail prices fluctuate and that figure tells you surprisingly little about what replacing your boiler will actually cost.
Your total installed price depends on:
Boiler location
Flue requirements
Controls
System filter
Gas pipework
Condensate route
System cleaning
Boiler relocation
Additional installation work
That £100 bargain you found on a random boiler website suddenly becomes rather less exciting when the installation costs another £700.
Compare complete installed prices, not just boxes.
Get an instant fixed-price boiler quote here.
Price & value score: 4/5
What We Like About the ecoTEC Pro 28
There is plenty to like:
Excellent Vaillant reliability record
28kW output suits many UK homes
Good 11.1 l/min hot-water performance
Stainless-steel heat exchanger
Quiet Mark certification
A-rated heating and hot water
Good choice of controls
Straightforward digital interface
Strong installer familiarity
Up to a 10-year guarantee
Most importantly:
There isn't an obvious major weakness.
It's a very sensible boiler.
What Could Be Better?
Nothing is perfect.
Even German engineering.
Our main criticisms are:
It's relatively expensive
You're paying a premium for the Vaillant badge and engineering.
There are perfectly respectable boilers available for less.
The standard guarantee is only two years
The headline “up to 10 years” is excellent, but we'd prefer the longer cover to be standard.
There are newer Vaillant platforms
The current remastered ecoTEC plus is Vaillant's newer, more sophisticated platform.
If you're already spending premium-boiler money, it's worth comparing the price difference between the pro and current ecoTEC plus before buying.
11.1 l/min isn't designed for huge hot-water demand
It's perfectly respectable for its intended market.
But this isn't the combi we'd pick for a house containing three bathrooms and six teenagers.
Frankly, no boiler deserves that.
ecoTEC Pro 28 vs ecoTEC Plus: What's the Difference?
This is worth considering before buying.
The ecoTEC pro sits below the ecoTEC plus in Vaillant's hierarchy.
Think:
ecoTEC pro: solid premium workhorse.
ecoTEC plus: newer, more sophisticated premium model.
The remastered ecoTEC plus offers Vaillant's newer control platform and a broader selection of outputs and hot-water options.
That doesn't make the pro bad.
Far from it.
But if quotes for the two boilers are relatively close, we'd seriously consider stepping up to the ecoTEC plus.
If the ecoTEC pro is meaningfully cheaper?
The pro starts looking considerably more attractive.
You can read our full Vaillant ecoTEC Plus review.
Is your Vaillant boiler experiencing some of the brand's most common fault codes? We have you covered in our F29 fault code and F62 fault code guides.
Vaillant ecoTEC Pro 28 Verdict
So...
Should you buy one?
For the right property, absolutely.
The Vaillant ecoTEC pro 28 is a well-built, efficient and proven premium combi boiler with excellent brand-level reliability evidence behind it.
The 28kW model is particularly well suited to small and medium-sized homes with one main bathroom, offering a useful balance between compact dimensions and approximately 11.1 l/min hot-water performance.
We particularly like:
The stainless-steel heat exchanger
Strong recent reliability evidence
Quiet operation
Good control compatibility
Established UK service network
Potential 10-year manufacturer guarantee
Its biggest weakness?
Price.
Vaillant isn't trying to compete at the bargain end of the market.
And if the newer ecoTEC plus is available for only slightly more money, we'd compare the two carefully before committing.
But if you can get the ecoTEC pro 28 at a good installed price?
It's still an extremely solid choice.
Heatable Score: 4.5/5
Best for: small-to-medium homes wanting a premium, proven combi boiler.
Skip it if: you have very high simultaneous hot-water demand or the newer ecoTEC plus costs virtually the same.
Our verdict:
Not the cheapest boiler. Not the newest boiler. Still a very good boiler.
And sometimes boringly reliable is precisely what you want from something responsible for your heating.
Is the Vaillant ecoTEC Pro 28 Better Than a Worcester Bosch Greenstar 4000?
Both are excellent boilers.
The Worcester Bosch Greenstar 4000 is more compact and uses a newer design platform.
The Vaillant ecoTEC pro counters with:
Stainless-steel heat exchanger
Excellent reliability evidence
Quiet Mark certification
Strong engineer reputation
We'd typically compare the total installed price and guarantee package before choosing.
If both were identically priced?
The newer Greenstar 4000 probably has the edge over the ecoTEC pro.
Against Vaillant's newer ecoTEC plus, however, the contest becomes much tighter.
Read our full Worcester Bosch vs Vaillant comparison for the detailed head-to-head.
Vaillant EcoTec Pro 28 Combi Boiler Conclusion
Simply put, this is an award-winning German boiler from an esteemed brand.
If so, get your new boiler installed with Heatable, here’s why:
Gas Safe installation within 24 hours
Thousands of happy customers – an average score of 4.9 on Trustpilot (that’s better than the market leader).
Price match guarantee – if you find a cheaper quote, we will match (must be like for like)
Multiple payment options - interest-free available
12 year warranty on selected boilers.
Fixed price guarantee – no hidden costs
Save your quote until later
Heat Happy.
