Choosing a Gas Boiler

Gas boilers in residential, service or industry buildings are usually very old. They are usually poorly maintained, often oversized, have degraded efficiencies and sometimes 30% lower than new-generation boilers. Are you wondering about the energy you spend? Do you regret the rising price of gas? Is it time for you to renew your equipment? If you are thinking about these questions, it’s time to reflect on the gains promised to you by new technology.

Here are some answers to the most common questions regarding gas boilers: 

What should you consider when choosing a gas boiler?

A boiler is essentially composed of a heat exchanger and a burner. The combustion products (flue gas) transfer their energy to the coolant by convection, radiation and conduction. The goal is for a boiler to ensure complete combustion of the fuel and have a successful exchange surface to ensure the best possible performance.

What choice do you have?

There are now four types of operational boilers that you can choose from. Conventional boilers have been installed for over thirty years and provide a return (energy / heat production) between 80% and 90%, followed by high efficiency boilers with an efficiency rating between 90 and 95%. When it comes to Gross Calorific Value (SPC), it can even reach a rating of 110%! . This result can be further optimized if you opt for modulating burners that adapt the combustion to the actual demand for heat. These boilers, called "low temperature boilers", also receive a tax credit of 15%. Now you are free to choose from condensing boilers and double condensation boilers.

What is the principle of these condensing boilers?

The principle is to recover heat from the condensation of water contained in the fumes that are emitted by the products of gas combustion. To do this, the fumes need to have a temperature below the condensation temperature of the water.

This technology was introduced in the 80s and has improved greatly where you can now offer a yield of 10 to 15% higher than a conventional boiler. They can achieve an efficiency rating of around 110%. The measures are all incentives apart from these energy-saving condensing boilers because they emit less CO2 into the atmosphere. The Finance Act 2005 (revalued in 2006) allots a tax credit equal to 25% of the cost of the equipment and its installation in a residence older than 2 years. This credit increased to 40% for apartment installations or for houses built before January 1, 1977 and no later than December 31(of the second year following the acquisition).

How to choose a boiler

The purpose of the heating system is to compensate for any heat loss and to maintain a constant internal temperature. The type of boiler chosen can reduce energy consumption, optimize the investment and reduce the production of toxic and unburned substances such as nitrogen oxides (NOx).

Is usage a criterion?

When it comes to producing both hot water and heating, the ideal is to have two boilers to meet the exact needs in summer and winter. Indeed, performance is optimal when the boiler is operating at maximum. This is also the main problem in older buildings. Thirty years ago, boilers were installed to meet the needs of poorly insulated buildings. Since these buildings have been renovated to offset the heat loss, the boilers are not operating at full capacity anymore.

What to choose: condensation or high performance?

It’s preferable to opt for a condensing boiler in case of renovation or new constructions, the latter will have a higher cost (about 20%), but better performance. In addition to this, they reduce the gas bill by 20% and the recovery of the investment does not take longer than five years.

Alternatively, recent installation does not feature heat recovery and it’s preferable to add a fumes recovery generator depending on the size of the boiler. Some companies offer condensing boilers up to 9 MW, which largely covers the needs of all types of buildings (residential , commercial or industrial buildings alike).

How to optimize the operation of a boiler

A regular sweeping of the line (once per year) is required to remove any sludge or scale that degrades the heat exchange. Then, check whether the coat is well insulated or notso that you don’t lose 2-3% of the yield. It’s also advisable to set up a water softener (extra heating) and a magnetic sludge remover to increase the lifespan of the boiler.