Viessmann Vitodens 050-W vs 100-W: Which Viessmann Boiler, and What It Costs Fitted

Viessmann is a German boiler maker known for build quality, and with BoxHeat a Viessmann combi costs from £2,330 fully fitted. The choice comes down to two Vitodens models: the 050-W and the 100-W.

This guide explains how the two differ, whether you need a combi, system or regular boiler, which size to choose, what each costs fitted and how to keep the warranty valid. To browse the boilers themselves, see our Viessmann boilers page.

Yes. Johann Viessmann started the business in 1917, and it has been based in Allendorf in Germany since 1937. Its heating business became part of the US group Carrier in January 2024.

• Stainless steel heat exchanger: both models we fit use Viessmann's Inox-Radial heat exchanger with its MatriX-Plus burner and Lambda Pro combustion control.
• Long warranties: 10 or 12 years when we fit them, depending on the model.
• App control: the combi and system boilers have built-in WiFi for Viessmann's ViCare app.

The trade-off is price at the top end: the 100-W costs more than a Baxi 800 or Ideal Logic Max of the same size, so it suits people who value the longest warranty.

Both are A-rated condensing gas boilers with the same stainless steel heat exchanger. The main differences are the warranty, the sizes and types available, and the depth of the boiler.

• Vitodens 050-W: the most affordable Viessmann combi we fit, with a 10-year warranty. It's the shallower of the two, which helps in a tight kitchen cupboard. View the Vitodens 050-W
• Vitodens 100-W: the boiler we fit with the longest warranty, 12 years on the combi and system versions. It comes in more sizes and types. View the Vitodens 100-W

If you want a combi and a 10-year warranty is enough, the 050-W is the better value. If you want the longest warranty, a 35kW combi, or a system or regular boiler, choose the 100-W.

The type of boiler matters more than the model, and it's mostly decided by what you already have at home.

• Combi: no hot water cylinder or loft tanks. Best when hot water is mostly used in one place at a time. Vitodens 050-W and 100-W, from £2,330.
• System: a hot water cylinder but no loft tanks. Best when several showers or taps are often used together. Vitodens 100-W, from £2,800.
• Regular: a cylinder plus a cold water tank in the loft. Common in older homes. Vitodens 100-W, from £2,580.

Not sure which you have? Our guide to combi vs system boilers explains the difference.

For a combi, the size mostly decides how much hot water it can deliver at once:

• 25 or 26kW: hot water at up to 10.2 litres a minute (050-W) or 10 litres a minute (100-W).
• 30kW: up to 12.2 litres a minute on both models.
• 35kW: up to 14 litres a minute, 100-W only. Useful when a tap and a shower are often used at the same time.

For a system or regular boiler, the right output depends on how much heat your home needs, such as the number and size of radiators and how well the home holds its heat, as well as the hot water cylinder it heats.

These are our fixed prices for a like-for-like replacement, correct in November 2026.

Prices include the boiler, a magnetic system filter, removal of your old boiler, a chemical system flush, controls set-up and installation by a Gas Safe registered engineer. If your home needs extra work, such as moving the boiler or converting to a combi, it's included in your fixed quote. Get your fixed price online, or spread the cost with boiler finance (monthly finance available, subject to status).

Comparing brands? Our guides to Worcester Bosch, Baxi and Ideal boilers compare their ranges in the same way.

Viessmann's longer warranties need the boiler registering within 30 days of installation, and we register it with Viessmann for you. After that, have the boiler serviced every year by a Gas Safe registered engineer and keep your service records. The annual service isn't included in the warranty.