Boiler Size Calculator

Q: What combi boiler size for a 2 bathroom, 3 bedroom modern house?

For a 2 bathroom, 3 bedroom modern house, an 18-19 kW combi boiler is the bare minimum . This size might be just enough to provide heating and hot water supply for your household if it's well insulated. It's advisable to choose a bigger size than the minimum requirement.

Q: How do I choose a boiler size?

To choose the right boiler size: Determine your heating needs — Think about the size of your home and the number of bedrooms and bathrooms. Choose boiler type — Combi, heat-only, or system boiler based on what you need. Evaluate insulation level — Consider the age and insulation level of your property to determine the efficiency. Consult with information from boiler manufacturers or use an online calculator.

Q: How big is a standard boiler?

A standard boiler is typically around 24-30 kW , suitable for average-sized homes. However, they often use less than half of their power, as the actual power requirement is much lower.

Q: What's the best boiler type for a small apartment?

A combi boiler could be the best choice for a small apartment. It provides both heating and hot water without needing extra space for a separate hot water cylinder.

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Our boiler size calculator is here to help you answer your burning questions (or maybe we should say heating 😉). What boiler size do I need? How do I choose a boiler size? How big is a standard boiler? All of that and much more is covered in the article below!

What boiler size do I need?

Boiler size doesn't determine how big it is, but how much power it outputs in kilowatts (kW). The right boiler size for your home depends on how much heating and hot water you need. Getting the right size means your boiler will be efficient in both heat loss and water heating. You'd have to calculate your perfect boiler size based on the number of bathrooms and bedrooms and how well your home is insulated. You can pick a boiler that keeps your place warm and your energy bills down by figuring out your specific needs.

⚠️ The boiler size calculations in our calculator give you the minimum kW output. It's a good idea to pick a boiler that's a bit bigger than the result. This way, you'll be covered if you add an extra shower or someone new moves in, ensuring you always have enough heating and hot water.

Types of boilers

What boiler size do I need? Well, that depends on many factors, but first, let's establish what type of boiler is the perfect choice for your needs. There are different types of boilers because homes have different heating and hot water requirements. Our boiler size calculator focuses on the three most popular types:

Combi — Combines heating and hot water in one unit. It's great for smaller homes with limited space and no need for a separate hot water cylinder. Our calculator is here to help you choose the best combi boiler size for you.
Heat only — If you're wondering how big a standard boiler is, this type is usually the biggest. It needs a separate hot water cylinder and is ideal for larger homes with multiple bathrooms.
System — Similar to heat only but with built-in components, these require less space. They're a good choice for homes with higher hot water demands but less room for a big setup.

So, if you have a small apartment, the best choice would probably be a combi boiler. If you have a large house with multiple bathrooms and bedrooms, a heat-only boiler might be the most suitable. A system boiler could be perfect for homes with higher hot water demands but limited space.

How to use boiler size calculator

Use our boiler size calculator to find the minimum size that fits your needs!

Choose Boiler type — Combi, heat only, or system.
Enter Age of property — Based on the construction decade or renovation.
Input house information — Number of bedrooms and bathrooms for combi or number of bedrooms for heat only and system.

When you have selected the boiler type, the next step is to choose the age of your property. If your place hasn't been renovated since it was constructed, select the timeframe of construction. If it was renovated at some point, with more modern insulation, select the option that best represents its current insulation level.

And then, depending on your boiler type, input the number of bedrooms and bathrooms (for combi boilers) or just the number of bathrooms (for heat-only and system boilers). Combi boilers handle both heating and hot water, requiring more information, while heat-only and system boilers provide only hot water supply.

Our calculator will show you the minimum boiler size you need. Keep in mind that this is the minimum for your current situation. It's a good idea to choose a slightly bigger boiler so it's not running at maximum power all the time.

🔎 While you're here, check out our pool volume calculator and pool salt calculator. These tools make managing your pool as easy as picking the right boiler for your home!

FAQs

What combi boiler size for a 2 bathroom, 3 bedroom modern house?

For a 2 bathroom, 3 bedroom modern house, an 18-19 kW combi boiler is the bare minimum. This size might be just enough to provide heating and hot water supply for your household if it's well insulated. It's advisable to choose a bigger size than the minimum requirement.

How do I choose a boiler size?

To choose the right boiler size:

Determine your heating needs — Think about the size of your home and the number of bedrooms and bathrooms.
Choose boiler type — Combi, heat-only, or system boiler based on what you need.
Evaluate insulation level — Consider the age and insulation level of your property to determine the efficiency.
Consult with information from boiler manufacturers or use an online calculator.

How big is a standard boiler?

A standard boiler is typically around 24-30 kW, suitable for average-sized homes. However, they often use less than half of their power, as the actual power requirement is much lower.

What's the best boiler type for a small apartment?

A combi boiler could be the best choice for a small apartment. It provides both heating and hot water without needing extra space for a separate hot water cylinder.