On this page
- Vaillant ecoTEC plus vs pro at a glance
- Hot water flow: which range keeps up with your household?
- Minimum output: the difference most comparisons miss
- Controls, monitoring and smart features
- Guarantee and servicing
- Which Vaillant combi is right for your home?
- Get the right Vaillant for your home
- Frequently asked questions
Key takeaways
- Hot water: ecoTEC pro gives 9.6 to 12.3 litres per minute; the current ecoTEC plus combis give 10.6 to 16.3 litres per minute at a 35°C rise, according to Vaillant.
- Minimum output: the ecoTEC plus 826 can turn down to 2.5kW on heating, against 5.9kW for the pro 24 and 28. That matters in well-insulated homes and at low flow temperatures.
- Guarantee: up to 10 years on the ecoTEC plus and up to 7 years on the ecoTEC pro, both conditional on an approved installer and registration.
- The ecoTEC plus adds IoniDETECT combustion monitoring and myVAILLANT connect smart-home compatibility.
- Mains flow still caps any combi. Get your supply measured before paying for the higher-output model.
In the Vaillant ecoTEC plus vs pro choice, the ecoTEC pro is the simpler, lower-output combi for smaller homes with one bathroom, while the current ecoTEC plus range offers higher hot water flow, a much lower minimum heating output, smart-home connectivity and a longer available guarantee. If you have more than one bathroom, a low heat loss home, or want to run low flow temperatures efficiently, the plus usually justifies its extra cost. For a small flat with modest hot water use, the pro is often enough.
Below we compare the two using Vaillant’s published figures for the current ecoTEC plus combis (826, 832, 836 and 840) and the ecoTEC pro (24, 28 and 30), so you can see where the differences really lie.
Vaillant ecoTEC plus vs pro at a glance
| Feature | ecoTEC pro | ecoTEC plus (826 to 840) |
|---|---|---|
| Combi models | 24, 28, 30kW | 26, 32, 36, 40kW (plus 940 storage combi) |
| Hot water flow at 35°C rise | 9.6 / 11.1 / 12.3 l/min | 10.6 / 13.0 / 14.6 / 16.3 l/min |
| Lowest heating output (50/30°C) | 5.9kW (24 and 28), 6.9kW (30) | 2.5kW (826), 3.5kW (832), 4.5kW (840) |
| Height x width | 720 x 440mm | 720 x 440mm |
| Depth | 338mm | 352mm (840: 386mm) |
| Combustion control | Fully modulating low NOx burner | IoniDETECT, modulation up to 1:10 |
| Smart controls | Works with Vaillant controls | Smart home ready with myVAILLANT connect |
| Guarantee | Up to 7 years | Up to 10 years |
| LPG option | 28 LPG model | 826, 832 and 836 are LPG adaptable |
Sources: Vaillant installer pages for the ecoTEC plus 826 to 940 and the ecoTEC pro 24, 28 and 30. Vaillant notes its combis are fitted with a flow regulator, so real-world flow also depends on your mains supply.
Hot water flow: which range keeps up with your household?
For most buyers, hot water is where the two ranges feel different day to day. The ecoTEC pro 24 manages 9.6 litres per minute at a 35°C rise, enough for one shower at a time. The pro 30 lifts that to 12.3 litres per minute.
The ecoTEC plus starts at 10.6 litres per minute on the 826 and reaches 16.3 on the 840. If you have a bathroom and an en-suite, or a busy family who shower back to back in the morning, the higher plus models give a noticeably better experience when two outlets run together.
Your mains water decides what you actually get
A combi heats water from the cold mains as it passes through. If your mains only supplies 12 litres per minute, a boiler rated for 16 cannot give you 16. Paying for a higher-flow model only makes sense if your supply can feed it. A good installer will measure your mains flow and pressure during the survey. Our guide on combi boiler low hot water pressure explains how mains supply and boiler output interact.
Minimum output: the difference most comparisons miss
Combi kW ratings are mainly about hot water. On the heating side, what often matters more is how low the boiler can turn down. A boiler that cannot modulate low enough for a small or well-insulated home switches on and off repeatedly in mild weather. That short cycling wastes gas and adds wear.
Vaillant’s figures show a real gap. At condensing temperatures, the ecoTEC plus 826 modulates down to 2.5kW and the 832 to 3.5kW. The ecoTEC pro 24 and 28 bottom out at 5.9kW, and the pro 30 at 6.9kW. In a modern flat, a new-build or a home with good insulation, the plus is far better matched to the low heat demand of spring and autumn days.
This also matters if you want to run the boiler at lower flow temperatures with weather compensation to keep it in condensing mode. Our explainers on weather compensation and boiler flow temperature settings cover how that works.
Controls, monitoring and smart features
The ecoTEC pro is a straightforward boiler with a fully modulating low NOx burner and fan, removable side panels and a push-fit flue that make servicing simpler. It works with Vaillant’s room controls.
The current ecoTEC plus adds:
- IoniDETECT combustion monitoring, which Vaillant says helps it modulate across a range of up to 1:10 for better efficiency.
- Smart home readiness through the myVAILLANT connect gateway, for app control and boiler data.
- A semi-touch interface, stainless steel heat exchanger and a supplied filling loop.
If you already have, or plan to add, smart heating controls, check compatibility with your installer. Our guide to smart thermostats and boiler compatibility explains the options.
Guarantee and servicing
Vaillant’s consumer page for the ecoTEC plus lists a 5-year standard guarantee, extendable to 10 years when fitted by a registered installer with Vaillant’s boiler protection kit and registered. The ecoTEC pro is listed with a guarantee of up to 7 years when installed by an approved Vaillant installer.
In both cases the extended cover depends on registration, using the right system filter, and an annual service by a Gas Safe registered engineer. Missing services can void it. Our Vaillant boiler service guide explains what is involved each year.
Which Vaillant combi is right for your home?
| Your home | Likely fit | Why |
|---|---|---|
| Flat or small house, one bathroom, one or two people | ecoTEC pro 24 or 28, or plus 826 | Pro is cost-effective; 826 better if the home is well insulated |
| New-build or highly insulated home | ecoTEC plus 826 or 832 | Much lower minimum output reduces cycling |
| Family home, one bathroom, frequent back-to-back showers | ecoTEC pro 30 or plus 832 | More flow, if the mains supports it |
| Bathroom plus en-suite | ecoTEC plus 836 or 840 | Highest combi flow rates in either range |
| Large demand and limited mains flow | Storage combi or system boiler with cylinder | Stored hot water overcomes the mains limit |
Treat this as a starting point. The right size depends on a heat loss assessment, your mains supply and your household’s habits. We have not quoted prices, because they vary with model, flue, controls and installation; our guide to comparing boiler quotes like for like shows how to line quotes up fairly.
Get the right Vaillant for your home
Choose the ecoTEC pro for a straightforward, compact boiler in a smaller home. Choose the ecoTEC plus when you need more hot water, a boiler that can turn down low for a well-insulated home, smart connectivity or the longer guarantee. Either way, the survey matters more than the badge.
Gasmaster’s Gas Safe registered engineers survey and install Vaillant boilers across Stoke-on-Trent, Staffordshire, Cheshire and Derbyshire. Get a boiler quote and we will measure your mains flow and size the boiler properly, or contact us with any questions.
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Frequently asked questions
Is the Vaillant ecoTEC pro a good boiler?
For smaller homes with one bathroom, yes. It is compact, ErP A-rated, quiet on most models and easy to service, with a guarantee of up to 7 years through an approved installer. Its limits are lower hot water flow and a higher minimum heating output than the current ecoTEC plus, which matter more in larger or very well-insulated homes.
What is the difference between the ecoTEC plus 832 and the pro 30?
Vaillant lists the plus 832 at 13.0 litres per minute of hot water at a 35°C rise, against 12.3 for the pro 30. The bigger gap is minimum output: 3.5kW for the 832 against 6.9kW for the pro 30. The 832 also adds IoniDETECT, smart-home readiness and a longer available guarantee.
Is the ecoTEC plus worth the extra money?
It usually is if your home has more than one bathroom, is well insulated, or you want low flow temperature running and smart controls. In a small flat with modest hot water use and a basic thermostat, an ecoTEC pro does the job well. Ask your installer to justify the recommendation using your heat loss and mains flow.
Can both boilers run on LPG?
Vaillant lists an ecoTEC pro 28 LPG model, and says the ecoTEC plus 826, 832 and 836 are LPG adaptable. The 840 and the 940 storage combi are not. If your home is off the gas grid, tell your installer at the start so they quote a model that can be set up for LPG.
Related services
Abdul runs Gasmaster Plumbing & Heating and has worked on boilers, heating and gas appliances across Stoke-on-Trent since 2005. He is Gas Safe registered (reg. 220932), and these articles come from his day to day work in homes and businesses across Staffordshire, Cheshire and Derbyshire.
