Are you in the market for a compact Vaillant boiler for your small Edinburgh house or flat?

In that case, you’ve probably already got your eye on the EcoTEC Plus range – which I’m going to be reviewing individually.

Today, we’re going to take a closer look at the EcoTEC Plus 825 combi boiler. So sit back, relax, and read on…


Vaillant boilers are one step ahead of the game (or, as the company itself likes to put it; ‘Vaillant thinks ahead’). They’re incredibly reliable (in my eyes, the only direct competitor to Worcester Bosch), and Quiet Mark accredited – so they’re actually one of the quietest boilers on the market (another huge plus point).

The EcoTEC Plus range delivers great performance – almost instant hot water – with a compact size, and no need to worry about extra storage tanks or cylinders taking up space!

Let’s find out more about the 825, shall we?

Output and flow rate

For a small house or flat, the EcoTEC Plus 825 is one of the best boilers on the market right now because it delivers brilliant value for money.

It has a hot water output of 25.4kW, delivering 10.5 litres of hot water per minute to your taps, which is absolutely ideal if you regularly use the shower in your small house or flat.

The 825 can also handle a bath, although it can be slower to fill. If you have a deep cast iron bath or two showers, I’d steer clear of this model, as it’s not equipped to deal with higher hot water usage.

The 19.6kW heating output means it’s ideal to heat a 1-2 bedroom, one-bathroom flat, or a small house with a low hot water usage (so again, one bathroom).

Size and other features

The EcoTEC Plus range is ideal if you don’t have a lot of space, as they can easily fit in a kitchen cupboard or Edinburgh press cupboard.

Plus, the lack of hot water cylinder and storage tanks mean you can truly optimise the space in your small home – meaning you can keep that extra suitcase, after all!

These models are also quite stylish, with a contoured case and drop-down flap, so they don’t look out-of-place in your home.


You’ll be glad to know that the Vaillant EcoTEC Plus 825 used to come with Vaillant’s brilliant 10-year guarantee (when fitted by an accredited installer and serviced annually by a Gas Safe Registered engineer). Now, however, you’re looking at a 7-year guarantee, as Vaillant has scrapped its extended warranties – unless you want to pay extra.

And, much like Worcester Bosch, Vaillant also has its own dedicated engineers to attend call-outs if you ever need them.

Another reason I recommend Vaillant’s guarantees is that there’s no hidden small print or unexpected credit card charges to catch you out, unlike other similar boiler companies.

Tech Specs

Below, I’ve put together a brief summary of everything you need to know about the Vaillant EcoTEC Plus 825 at a glance:

  • Heating output: 19.6kW
  • Hot water output: 25.4kW 10.5 litres per minute
  • Ideal for: A small home with one shower room
  • ERP rating: A, 89.4% efficiency
  • Guarantee: 7 years


If you’re looking for a compact Vaillant boiler to heat your small Edinburgh property (house or flat), the 825 could be your ideal choice. It’s ideal if you mainly use the shower, although the 825 can handle a bath, despite being a bit slower to fill. I wouldn’t recommend this boiler if you own a deep cast iron bath, or have more than one bathroom in your home.

The compact size means it’s perfect for making the most of your available space, and the EcoTEC Plus range can easily fit in your kitchen cupboard or Edinburgh press – plus, they look stylish, too!

Finally, the EcoTEC Plus 825 also comes with Vaillant’s no-quibble 7-year guarantee (when fitted by an accredited installer and serviced annually by a Gas Safe Registered engineer), so you’ll be covered on the off-chance something does go wrong.

What do you think of the Vaillant EcoTEC Plus 825 combi boiler?