Is the Vaillant ecoTEC pro 28 a good boiler for my home?
It is a sensible boiler for a small or mid-sized home with one bathroom. The ecoTEC pro 28 gives up to 24.0 kW of heating output and 27.2 kW for hot water, and Vaillant aims the ecoTEC pro range at homes with a smaller heating and hot water requirement. It is hand-built at Vaillant's Derbyshire plant and sold in 24, 28 and 30 kW versions.
Where it starts to struggle is a house that wants two hot outlets at once. It is a combi, so there is no cylinder and no stored hot water: everything is heated as it is drawn. Run a shower and fill a bath together and both slow down. If that is your house, a larger combi, or a system boiler and a cylinder, is the better answer.
Two other things to check before you commit. First, the size: 720 mm high, 440 mm wide and 338 mm deep, so it is wall-hung and deeper than many standard kitchen wall units. Measure the spot, and leave your installer room to service it. Second, the guarantee: Vaillant publishes 2 years as standard, and its own terms say it has to be registered within 30 days of installation or it reverts to 12 months (see the warranty section).
Explore the Vaillant combi boiler range
Vaillant ecoTEC pro 28 technical specifications
Every figure below is Vaillant's own, taken from the ecoTEC pro product data or the installation and maintenance instructions for the VUW 286/5-3, which is the model code printed on the data plate. Where the two documents give different numbers, the row says so.
| Model code | VUW 286/5-3 (H-GB), article number 0010021837 |
| Gas Council number | 47-044-89 |
| Boiler type | Gas combi, condensing, wall-hung |
| Dimensions (H x W x D) | 720 x 440 x 338 mm |
| Dry weight | 38 kg |
| Heating output (80/60 °C) | 5.2 to 24.0 kW |
| Heating output (50/30 °C, condensing) | 5.9 to 25.9 kW |
| Maximum hot water output | 27.2 kW (ecoTEC pro product data; the installation and maintenance instructions give a maximum heat output for hot water of 27.0 kW) |
| Hot water flow rate (35 °C rise) | 11.1 litres per minute |
| Lowest flow that starts the boiler | 2.0 litres per minute, at 0.8 bar or above |
| Hot water temperature range | 35 to 65 °C |
| Modulation | 1:5 |
| ErP efficiency | 93% |
| SAP 2009/2012 annual efficiency | up to 89.5% |
| Sound power | 49 dB(A), Quiet Mark certified |
| NOx | Class 6, 33 mg/kWh |
| Flue | 60/100 push-fit, up to 12 m horizontal or 16 m vertical |
| Standard guarantee | 2 years when registered within 30 days of installation, otherwise 12 months; option to upgrade to 10 years, charges may apply |
The full data set is in Vaillant's ecoTEC pro product specification and the installation and maintenance instructions (PDF).
Hot water: what 11.1 litres a minute really means
This is the number that decides whether you will be happy with the boiler, and it is the one most often quoted wrongly. The ecoTEC pro 28 delivers 11.1 litres a minute at a 35 °C temperature rise. The same boiler moves 13 litres a minute if you only ask for a 30 °C rise, and 9.3 litres a minute at 42 °C. Vaillant footnotes the 42 °C figure with a note that a flow restrictor is fitted to achieve that rise.
Why the spread? A combi heats mains-cold water as it passes through. In midwinter the mains is colder, so the boiler has to lift the temperature further and the flow drops to keep up. A shower that feels strong in August can feel thin in January on exactly the same boiler. That is normal behaviour, not a fault.
In practice, 11.1 litres a minute is comfortably enough for one shower or one running tap. It is not enough for two at once. The boiler also needs at least 2.0 litres a minute of flow, at 0.8 bar or more, before it will fire for hot water at all, so a weak cold mains is worth checking before you buy any combi.
Is the Vaillant ecoTEC pro 28 a high efficiency boiler?
Yes, though it is not the most efficient boiler you can buy. Vaillant lists 93% ErP efficiency and up to 89.5% SAP 2009/2012 annual efficiency, which is the figure UK energy assessments use. Set against a 1990s non-condensing boiler, that is a large gain. Set against the newest condensing combis, it is mid-table.
Two things move the real-world number more than the badge does. The first is return temperature. The boiler only condenses, and only reaches its best figures, when the water coming back from your radiators is cool enough. Vaillant quotes 107% net efficiency at 40/30 °C against 98% at 80/60 °C on this model, and that gap is the reward for running a lower flow temperature. The second is your controls, covered further down.
How much does a Vaillant ecoTEC pro 28 cost?
Vaillant does not publish a retail price for it. The boiler is sold through merchants and installers, and Vaillant's own product page simply points you at your local merchant. Anyone quoting a single national price for an ecoTEC pro 28 is quoting their price, not the manufacturer's.
What you can do is make sure you are comparing like with like. A fitted price should say which of these are inside it:
- The boiler itself, in the right model code for your gas supply, as there is a separate LPG version.
- The flue kit and any extension. Standard runs are 60/100, and length affects the cost.
- A magnetic system filter, and a chemical cleanse or flush of the existing system.
- Controls. Vaillant lists sensoHOME, sensoCOMFORT or the VRC 700 as the options that make the installation Boiler Plus compliant with weather compensation.
- Labour, any pipework or condensate changes, making good, and VAT.
Two further costs are worth budgeting for. Vaillant offers the option to upgrade the guarantee to 10 years and footnotes it "charges may apply to upgrade to 10 years guarantee. Please discuss upgrade options with your installer." Vaillant publishes no figure for that upgrade on its homeowner site, so get it in writing from your installer rather than working to a number you found online. The annual service the guarantee depends on is charged separately, because Vaillant's guarantee terms state that "the cost of annual servicing is not included in the guarantee". We have gathered the manufacturers' published service prices on our boiler service cost page.
Vaillant ecoTEC pro 28 warranty
Vaillant's current product page says the ecoTEC pro "comes with a 2-year standard guarantee, with the option to upgrade to 10 years", footnoted "charges may apply to upgrade to 10 years guarantee. Please discuss upgrade options with your installer." That 2 years is not automatic. Vaillant's guarantee terms say the guarantee must be registered within 30 days of installing the appliance, and that "failure to register within this time period will result in the guarantee reverting to 12 months from date of installation". So it is 2 years if it is registered in time and 12 months if it is not, and any extension beyond that is something to settle with your installer.
Older Vaillant material, including the installer page for this range, still describes a free 7-year extension through a scheme called Vaillant Advance. That wording is not on Vaillant's current homeowner pages, and Vaillant's current installer scheme is myREWARDS, so treat vaillant.co.uk as the live position and confirm the extension length and any charge before you buy.
The rules that catch people out are all in Vaillant's domestic boiler guarantee terms and conditions, wording checked 21 August 2026:
- Register within 30 days of installation. Miss it and the guarantee reverts to 12 months from the installation date.
- You need the full 28-digit serial number. Vaillant lists it on the boiler packaging, the appliance data plate, the removable stickers on top of the boiler, and the back of the control box.
- It must be serviced every year by a Gas Safe registered engineer, with the service recorded in the Benchmark logbook. The cost of that service is not included in the guarantee.
- It covers the boiler only. Parts of the heating system outside the boiler, such as room thermostats, time controls and motorised valves, are excluded.
- Dirty system water makes the visit chargeable. Vaillant says that where a failure is caused by contaminated water, such as sludge, limescale, flux residue or iron oxides, the engineer's visit is charged at the prevailing rate.
If you have inherited the boiler and do not know where you stand, our guide to a Vaillant boiler warranty check walks through the ways to confirm it. You can also register or check directly with Vaillant guarantee registration.
Register your Vaillant guarantee
How old is my ecoTEC pro 28, and where is the serial number?
The age is printed on the boiler. Vaillant's identification plate carries the date of manufacture as week and year, in the form ww/yyyy. The plate is fitted to the underside of the boiler at the factory, and the serial number also appears on a plastic label at the bottom of the front casing.
That date is the date of manufacture, not of installation, so a boiler can sit in a warehouse or a merchant's stock before it goes on a wall. Vaillant's guarantee terms require installation and commissioning within 6 months of the boiler leaving their warehouse, which gives you a sense of the gap.
The age matters for more than curiosity. It sets whether you are still inside the manufacturer's guarantee, it changes what a service plan will pay towards a repair, and it is the first thing an engineer asks. If yours is past 7 years old, our page on boiler cover for older boilers sets out what changes.
Key characteristics
aquaCOMFORT hot water
Vaillant's aquaCOMFORT system is fitted to this range. Vaillant describes it as providing "quick delivery of hot water at a constant temperature, which reduces unnecessary water wastage". In plain terms: less time at the tap waiting for it to run hot, and less swing in temperature once it does.
Built for the engineer, not only the buyer
Every component can be replaced from the front of the boiler, and the side panels come off for further access. That reads like a detail until you are paying labour by the hour for a repair in a tight cupboard. It is also why the boiler services more easily in a confined space than its depth suggests.
Two-stage frost protection
The boiler protects itself in cold weather with the gas and electricity on, whatever the room thermostat is doing. Vaillant's instructions set out the sequence: the pump starts when the boiler water falls below 12 °C; the burner fires if the temperature has still not reached 10 °C after 30 minutes, or at any point if it drops to 5 °C; and the burner stops again at 35 °C. It protects the boiler, not your pipework, so lagging outside pipes is still on you.
Controls and Boiler Plus
Vaillant lists sensoHOME, sensoCOMFORT or the VRC 700 as the controls to pair with it for a weather-compensated, Boiler Plus compliant installation. Weather compensation is the setting that quietly saves money, because it trims the flow temperature when it is mild outside and keeps the boiler condensing for more of the year.
Hybrid ready
Vaillant lists the ecoTEC pro as compatible with its aroTHERM plus air-to-water heat pump as a hybrid system. If a heat pump is a maybe rather than a now, that keeps the door open without changing the boiler again later.
Vaillant ecoTEC pro 28 alternatives
Worth putting side by side before you commit, on the facts rather than the sales patter:
Longer guarantee, same maker: Vaillant ecoFIT pure. Vaillant's ecoFIT pure page states a 2-year standard guarantee "which can be extended up to 10-years" when the boiler is fitted by a myREWARDS installer, footnoted "eligibility applies when registered with either the Boiler Protection Kit or the Advanced Boiler Protection Kit (filter)". The ecoTEC plus and ecoTEC exclusive pages carry the same myREWARDS wording, so the longer guarantee turns on who fits the boiler and what is registered with it, not on the model alone.
Different maker: Worcester Bosch Greenstar 4000, alongside the Worcester Bosch guarantee terms.
More hot water, same range: the ecoTEC pro 30, which Vaillant rates at 12.3 litres a minute at a 35 °C rise against this model's 11.1.
Not sure a combi is right at all? Our guide to combi versus system boilers is the place to settle that first, because it changes which models are even on your list.
One safety note before any of it. Installation, commissioning and servicing on a gas boiler are jobs for a Gas Safe registered engineer only. If you ever smell gas, call the National Gas Emergency Service on 0800 111 999, open the doors and windows, and leave the boiler alone.
Cover for when the Vaillant guarantee runs out
Seven years goes quickly.
Smart Plan is a service plan, not insurance. The boiler and central heating module covers parts and labour up to £500 in a 12-month period if your boiler is under 7 years old, or up to £200 if it is over 7, which is one more reason the date on your data plate matters. Cover is for future breakdowns, so if something is wrong today, book a one-off repair for that fault and use cover for the next one. We work with a national network of thousands of Gas Safe registered engineers, and within our call-out hours of Monday to Friday, 08:00 to 18:00, we aim to get an engineer out to you within two working days. A £95 call-out fee, paid in advance, applies in your first 30 days on the plan, and to faults the plan does not cover, no-access visits and early annual-service requests; cover itself still applies right through those first 30 days. That window is Smart Plan's own, and is nothing to do with Vaillant's 30-day guarantee registration rule higher up this page. Using a service starts a 12-month agreement period, and leaving early costs the remaining months or 75% of the outstanding balance. There is a 14-day cooling-off period, which ends as soon as a service is carried out. From UK Boiler Company Ltd, trading since 2014. See what the boiler and central heating module includes.
