Oil Boiler – How to Choose one that’s Right for You

In today’s market there are many confusing technologies for heating private dwellings and flats. They use various kinds of fuel, ranging from gas boilers and electricity to wood and sawdust briquettes. But what to do and how to heat your house if natural gas grid is not available, electricity is too expensive, and biofuels are unavailable for different reasons? In this situation the alternative one is an oil boiler, also called oil-fired boiler.


Variety of boilers working with oil

So, because you can’t use other common energy sources you decided to choose an oil boiler for your home heating. It’s time to pick the boiler, here you should find out what are the different types of these heating products and select the most suitable option. Manufacturers offer oil boilers of the following types:

  • common oil boilers;
  • universal units, with the possibility of switching from oil to natural gas;
  • condensing oil boilers;
  • installations able to burn all kinds of used oils.


Some popular oil boiler models to look at are: Worcester Greenstar Danesmoor Oil Boiler or Warmflow U Series Utility Condensing Combi Oil Boiler.


If in the foreseeable future it is not expected to be able to change the situation with energy, then your option is heating of a private home with a boiler of the first type, with oil only.

Some homeowners, for a central heating boiler, consider that in oil boiler they can burn used engine oil or used cooking oil. This is mostly wrong and here’s why:

  1. not every burner works on contaminated oils.
  2. The calorific value of the liquid fuel is much higher than that of used oils. Accordingly, the area of heat exchange surfaces designed for liquid fuels, the combustion efficiency of used oil will be much lower.
  3. used oil when burning emits much more soot and generate build up around the flue. This can become a big problem for the maintenance and cleaning of pipe smoke.


The design of fuel oil boilers is very similar to commercial heat generators, powered by natural gas. Consequently, many manufacturers offer generic hot water installation with the alternate use of liquid and gaseous fuels. The transition from one fuel to another is done by replacing the burner. Universal boiler running on liquid fuel and gas lines will cost you a little more.

If the area of heated rooms or buildings is less than 1800 square feet, and soon you expect connection to the gas grid, you should not rush to acquire an oil boiler.

The fact of the matter is that the cost of the boiler unit and two burners can be higher than two separate units.

Domestic condensing boilers on oil are the most economical and effective representatives of this family of non-eco heat sources. Manufacturers declare their efficiency of condensing units at the level of 97%, the highest among all other heaters. As usual, their cost is quite high and not every homeowner can afford it.

Alternatives to Oil Boiler

Have we put you off already? If you feel like oil boiler is not the right choice for your home and you have free access to other sources of energy, have a look at:

Gas boilers – it’s the simplest and most common type of boiler for home heating. It’s cheap to install and cheap to maintain. The most popular examples in this category are the Worcester Bosch Greenstar 30 and Vaillant Ecotec Pro 28.

Electric boilers – although many properties are without gas grid coverage, electric boilers are not very popular. Nevertheless, if you’ve got a windmill or a decent size solar panel and you want to heat your home in the eco-mode, electric gas central heating boilers can help you do that. Have a look at Heatrae Sadia – they are amongst the most popular boilers in this category.


Construction of Oil Boiler and its principle of action

As mentioned above, oil-fired heating boilers are structurally similar to as two-pass and three-pass gas boilers. By virtue of its construction products are made to be installed on the floor (not wall-hung).

The similarity is in the design of heat exchanger of flame tubes enclosed in a water pipe, located in the heart of the combustion chamber, only the oil unit has a cylindrical shape burner. This is due to the design features of the burner that uses liquid fuel. The main elements and details are shown in the figure.

Oil Boiler

1- external thermal insulation shell;

2 – heat exchanger;

3 – combustion chamber;

4 – electronic control unit;

5 – burner.

In the products of leading manufacturers the burner is made of heat-resistant stainless steel, lower priced alternatives can be made from usual thick steel. Material of the heat exchanger is cast iron or steel, for heat insulation – basalt fibre is applied or dense polyurethane foam. Burner that runs on liquid fuels is of special interest – its construction is pictured below.

Oil Boiler Insides

1 – throttle for air adjusting;

2 – system of ignition with flame control sensor

3 – fuel line;

4 – fan motor;

5 – pump;

6 – supply and return fuel lines;

7 – solenoid valve;

8 – malfunction reset;

9 – automatic heat control;

10 – console;

11 – ignition cable;

12 – ignition system electrodes;

13 – cylindrical work surface;

14 – mixing device;

15 – oil nozzle;

16 -stem heater fuel;

17 – air manifold;

18 – burner;

19 – air duct;

20 – fan.


Advantages and disadvantages of oil boilers

The main advantage of oil boiler is that it can be used in the absence of other energy sources.

  1. high rate of effectiveness, efficiency within 90-97%.
  2. high automation level, so you can organize the temperature-regulation of heating system depending on the weather.
  3. possibility of switching to natural gas by replacing the burner.

Of course, oil boilers do not come without shortcomings. In this case, the main disadvantage is the high cost. It’s very expensive. Also fuel and maintenance is not cheap.

There is also the added cost of cleaning smoke pipes from soot, inevitably resulting in poor combustion of a heating oil.