Oil heating systems remain among the most common heating systems. This is unsurprising, as the fuel is energy-rich and the system is considered safe. However, there are currently over two million heating systems in Germany that are over 25 years old. While they certainly still reliably provide heating and hot water, they typically rely on older heating technology and are therefore less efficient—to the detriment of the environment. Despite this, there’s no absolute need to abandon proven oil heating technology. By purchasing a Viessmann oil condensing boiler, homeowners are actively contributing to resource conservation and energy savings. This is because, thanks to its high efficiency, the fuel used is converted into heat more efficiently.
Furthermore, Viessmann oil condensing boilers are future-proof. They can be operated with renewable energy sources, meaning users of oil condensing boilers can make an additional contribution to climate and environmental protection. Viessmann has the right oil condensing boiler for every heating need. In addition to boilers for single-family homes and multi-family buildings, the product range also covers commercial and municipal buildings with higher heating requirements.
The operating principle of fuel oil heating using condensing technology
When fuel oil is burned, not only heat is generated, but hot flue gases are also produced. In older boilers, these gases are vented through the chimney into the open air. This waste heat remains unused. Viessmann oil condensing boilers utilize the so-called latent heat of condensation. This heat is released when the flue gases cool and the resulting hot water vapor condenses. Thus, up to 98 percent of the energy contained in the fuel oil is converted into heat. A detailed description of this process can be found in the section ” How Fuel Oil Condensation Technology Works ” and in the video below.
Viessmann’s Vitoladens series oil-fired condensing boilers feature impressively sophisticated technology, ensuring high efficiency and a long service life.
Inox-Radial heat exchanger provides high efficiency
As mentioned previously, condensing technology also utilizes the latent heat of flue gases. In this process, water vapor generated during combustion passes through a virtually indestructible Viessmann Inox-Radial heat exchanger made of high-alloy stainless steel. This causes the water vapor to condense, releasing thermal energy that is then fed into the heating system. The heat exchanger is directly connected to biferrous composite heating surfaces, allowing for virtually lossless energy recovery.
Vitoflame 300 blue flame oil burner with all Viessmann Vitoladens
The heart of any oil heating system is the burner. The Vitoladens 300-C and 300-T use a Vitoflame blue-flame burner. The blue-flame burner’s unique feature is that a portion of the flue gases is fed back into the burner’s flame root. Experts call this internal recirculation—the return of cooled hot gases. Essentially, the oil mist is gasified here before actual combustion. The result is particularly clean combustion, with very low levels of carbon monoxide and nitrogen oxide in the flue gases. This improves oil burnout and reduces soot formation and additional emissions.
The Vitoladens 300-C features a burner that not only operates in two stages but also modulate. This means it adapts its output to demand based on modulation. This minimizes frequent switching on and off of the burner (known as cycling), resulting in reduced wear on some boiler components.
Comparison of Vitoladens series products
The Vitoladens 300-C and Vitoladens 300-T offer flexible use. The following table summarizes the features of these models:
Criteria
Vitoladens 300-C
Vitoladens 300-T
Power range
10.3 - 28.9 kW (3 power levels)
35.4 - 53.7 kW
Scope of application
Modernization and new construction of detached and semi-detached houses
Modernization and new construction of detached houses and apartment buildings, as well as small commercial enterprises
Standard seasonal efficiency [according to DIN]
Up to 98%
Up to 97%
Energy savings of up to 35 percent and other benefits
By quickly replacing an outdated heating system with a highly efficient oil condensing heating system combined with solar technology, end consumers can reduce energy consumption by 35 percent. This would reduce Germany’s overall energy needs by 10 percent, while reducing annual CO₂ emissions by 54 million tons.
Oil condensing boilers are prepared for future standards
Beyond condensing technology, Viessmann Vitoladens products share many other common features. They are distinguished by high reliability and a long service life. Furthermore, all products in this series can operate on bio-oil (EL fuel oil with a low sulfur content and up to 10 percent bio-based components). This means Vitoladens oil-fired condensing boilers are ideally suited for future standards.
Combining a new condensing oil boiler with solar collectors and a heat pump
Viessmann warranty for Vitoladens products
Viessmann offers a 10-year warranty on heat exchangers in oil-fired condensing boilers. This warranty is subject to a maintenance contract with a Viessmann sales partner, which includes regular maintenance work and full certification of this work.
Viessmann also offers a free five-year warranty on all Vitoladens 300-C boilers purchased from April 1, 2019. This is provided that the heating contractor or system operator registers the new boiler online within the first six months of the invoice date.
Controlling a new oil condensing boiler with an app via the internet
With the free ViCare app, you can conveniently control your new oil condensing boiler online—even from your home or office. All you need for this digital control convenience is the Vitoconnect internet interface, which your heating contractor can configure upon request during installation of your new boiler.
Connect your new oil-fired condensing boiler to the internet via the Vitoconnect interface and receive an extended five-year warranty. In addition to improving operational reliability, the ViCare app also provides simple and convenient control of your oil-fired condensing boiler—wireless and securely via the internet.
Free energy from the environment is still underutilized for backup central heating and hot water heating. This technology is very advanced and has become cost-effective in recent years. The purchase of renewable heat generators is also supported by government subsidies. Today, every new condensing oil boiler must be combined with a hot water heat pump and solar collectors to utilize free solar energy. The hot water heat pump provides hot water heating. This significantly reduces resource consumption, and the building itself can generate electricity for the heat pump using a photovoltaic system. Viessmann condensing oil boilers are designed for combination with green and solar energy
There are two ways to finance a new heating system: through a bank or through Viessmann Wärme. With Viessmann’s service, you can lease a new oil-fired condensing boiler. This not only eliminates the need to invest in the purchase yourself, but also includes maintenance and repairs for the leased heating system.
The advantages of oil condensing boilers at a glance
Proven and safe technology ensures high supply reliability.
Up to 98 percent of the energy in fuel oil is converted into useful heat.
Optimal use of fuel reduces emissions.
The ecological footprint can be further reduced by using a bio-oil blend.
Combination with ecological heating systems such as heat pumps and solar thermal systems is possible.
When combined with heating systems based on renewable energy sources, they are eligible for funding.
App control provides a high level of ease of use.
Under certain conditions, warranty service may be extended.
No general obligation to replace
Modernizing an oil heating system running on outdated heating technology makes sense from both an economic and environmental perspective. Furthermore, the German Energy Act (GEG) requires the mandatory replacement of constant temperature boilers that are over 30 years old. On the other hand, modern oil-fired condensing boilers do not require replacement. Combining them with renewable energy sources for backup central heating is, however, recommended and, above all, promising.
Expert advice on oil heating
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Vitoset fuel oil tanks for your new condensing heating system
A complete condensing heating system also includes economical, compact, and trouble-free fuel oil storage. Whether you’re building new, expanding, or renovating, a fuel oil storage tank from the Vitoset range is always a reliable solution for your condensing boiler—whether in detached homes or apartment buildings, as well as in residential complexes, commercial buildings, or municipal projects.
A complete condensing heating system also includes economical, compact, and trouble-free fuel oil storage. Whether you're building new, expanding, or renovating, a fuel oil tank from the Vitoset range is always a reliable solution for your condensing boiler—whether in detached homes or apartment buildings, or in residential complexes, commercial buildings, or municipal projects.
Geothermal collectors for brine/water source heat pumps extract heat close to the surface and can be installed without a permit. You can read more about the differences here.
The heat pump provides heating in an environmentally responsible and efficient manner. Learn more about the types, incentives, and subsidies available, as well as the Viessmann product range, here.
Rated heating power: 10.3 - 28.9 kW
Standard seasonal efficiency [according to DIN]: up to 98% (Hs) [gross cv].
Energy efficiency class A
All commercially available low-sulfur EL fuel oils can be used. Environmentally friendly fuel.
