Understanding the Differences Between the Baxi 600 & 800 Range, the Mark 2 Models, and the Compact Variants
If you’ve been fitting Baxi boilers for a while, you’ve probably noticed how their range has changed over the years. The Baxi 600 and 800 series have always been some of the most popular compact boilers on the market — but then came the “Combi 2” and “System 2” versions, followed by the Platinum Compact and Duo-tec Compact models. To make things even more confusing, you’ll also find the Main Eco Compact, which is often mentioned in the same breath.
Here’s a simple breakdown of what’s what, how they all relate, and why many installers still prefer the original 600 range.
The Original Baxi 600 and 800 Range
The Baxi 600 and Baxi 800 were designed as compact, cupboard-fit boilers for small to medium homes.
They quickly became a favourite among installers because they were:
- Easy to work on and service
- Reliable and well-built
- Compact enough to fit in most kitchen cupboards
- Simple, with well-known components and parts easily available
The 800 was essentially the higher-spec version of the 600, offering longer warranties and slightly better flow rates, but both were built around the same solid platform.
The “Mark 2” Range — Baxi 600 2 and 800 2
The newer Baxi 600 Combi 2 and Baxi 800 Combi 2 models are the updated versions of the originals.
Baxi introduced these to modernise the range and bring in a few new features, including:
- An Easy-Fill system for topping up pressure without a filling loop
- Improved frost protection and condensate design for better winter reliability
- Updated compatibility with smart controls like the Baxi uSense
- Slightly different internal layouts and updated components
Although the new range has some good upgrades, many installers still prefer the original 600 and 800 models because they were simpler, easier to repair, and parts were more familiar and widely stocked.
The Baxi Platinum Compact and Duo-tec Compact
These two models are also part of Baxi’s compact boiler family and share a lot of similarities with the 600 and 800 range.
- Platinum Compact – A higher-end compact model with a longer warranty and strong hot water performance.
- Duo-tec Compact – A mid-range compact option that’s reliable, efficient, and excellent value for money.
Both of these sit alongside the 600 and 800 in Baxi’s line-up and are great options for installers who want something small, simple, and proven.
Why Baxi Renamed and Updated the Range
Baxi rebranded and updated these boilers mainly to:
- Modernise the look and feel of the range
- Add a few features customers now expect (like easy top-ups and smart control support)
- Refresh the product names to align with their newer branding and warranty structure
In short, it was more of a marketing and usability refresh than a complete redesign.
Why We Prefer the Original 600 & 800 Range
From an installer’s point of view, the original range still has a lot going for it:
- Tried and tested reliability
- Straightforward internal layout
- Easy to repair and source parts for
- Familiar to most engineers
While the Mark 2 versions are good boilers, the originals earned their reputation through simplicity and solid performance.
What Is the Main Eco Compact?
The Main Eco Compact isn’t a Baxi boiler — it’s made by Main Heating, another brand under the same parent group.
It’s a lightweight, compact combi boiler often compared with the Baxi 600 range. It’s designed for easy fitting in tight spaces and offers a good balance between price and performance, but it’s a more budget-friendly option.
In Summary
- Baxi 600 / 800 – The original compact range: simple, reliable, and loved by installers.
- Baxi 600 2 / 800 2 – Updated “Mark 2” models with modern features and new branding.
- Platinum & Duo-tec Compact – Other compact Baxi boilers that share much of the same DNA.
- Main Eco Compact – A separate compact model from Main Heating, not Baxi.
Many of us still prefer the original 600 and 800 models because of their proven reliability and ease of maintenance, but the newer versions do offer modern features and better warranty options for homeowners.
