Which Boiler Should I Choose Based on House Size?
Which Boiler Should I Choose Based on House Size?

Which Boiler Should I Choose Based on House Size?

A boiler of the same size is not needed for a small apartment and a house of 150 m2. If you want to benefit from economical and efficient heating, it is necessary to consider your living space. It would help if you chose neither too powerful nor insufficient boiler to have the best performance.

How to Choose the Right Boiler?

Above all, know that the power of a gas boiler is expressed in kilowatts (kW) and corresponds to the energy produced by your equipment. It should not be confused with your actual consumption, which is also expressed in kW. The different boiler models are distinguished by this data and make it easy to find the one that will suit your needs. Choosing an unpowered boiler for your home can result in high costs on the bill.


Moreover, as a result, the hot water taps will have a small flow, and the radiators will be almost lukewarm. To avoid these inconveniences, here is what you need to know before choosing your boiler.

Things to Consider When Choosing a Boiler

Before you rush to buy new boiler, do not forget to consider all these elements:


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Q: What kind of fuel does your boiler use?

The Importance of Gas Supply

When choosing a boiler, do not overlook the choice of your natural gas supplier either. If you are in the middle of a move, this may be an opportunity to change suppliers. You can save money much more efficiently while enjoying the comfort your boiler provides. As soon as you have chosen your boiler and your energy supplier, do not forget to open your electricity and gas meter.

Calculating the kW Required to Heat a House

You can always do the math yourself if you are comfortable with numbers. For this, you must use the following formula: Power = C x (TV + ITE) x V x DP.


Here are all the explanations:


Output in kW
















Gas Boiler for 50 m2 House

A house with an area of ​​approximately 50 square meters requires low heating power. A highly energy-efficient condensing boiler with a heat output of 24kW will be more than enough to meet the needs of a home of this size.

Gas Boiler for 100 m2 House

A 100-square meter house will necessarily have a higher heating requirement, but a high-efficiency condensing boiler with a power of 24kW will still be suitable and cost-effective.


However, in addition to the factors already considered, other aspects such as the number of rooms and heat points (radiators) must be considered.

Gas Boiler for 150 m2 House

To help you see more clearly, here is a concrete example for a 150 m² house. Imagine that it with good insulation, a standard ceiling height, and the desired temperature of 20°C: a 25 kW boiler would be needed.


This is a minimum. The boiler's power may vary if used to produce domestic hot water. In this case, it will be necessary to add 10 kW for a large family or 5 kW for a couple without children: a boiler between 30 to 35 kW will be ideal. However, do not forget that a one-storey house of 150 m² will not need the same power as a two-storey house.

Gas Boiler for 200/250 m2 House

Large-area houses, between 200 and 250 square meters, are characterized by requiring a considerably higher heating power, which can easily range between 27 and 34 kW.


It will be necessary to install a gas boiler with sufficient energy output to meet the needs of houses of this size. Choosing a boiler with a minimum power of 32 kW is recommended.


It is advisable to choose models with high energy efficiency to maintain adequate consumption, minimize polluting emissions and reduce costs.

Gas Boiler for Large Spaces

Large buildings, over 250 square meters, require boilers with a very high heat output, especially when the heating of interior spaces is combined with the need to produce domestic hot water for the kitchen and bathrooms.


Suppose you need to renew the heating system of a large building. In that case, the advice is to request the support of specialised technicians, who can provide you with the necessary help to analyze the construction and choose the most convenient solution.


As a general rule, a 120 kW gas boiler will be necessary for huge spaces. As an alternative, 280 kW boilers can be installed.

Contact Us For Any Help

To make sure you choose the right boiler, we recommend that you consult a specialized company. At Zara Heating we are experts in the installation and maintenance of heating systems. Contact Us to help you choose the right boiler for your home.