If you're looking for the best boiler for a small house, the top pick is definitely a combi boiler. These little guys are like all-in-one powerhouses. They keep your place warm and provide hot water whenever you want it. Now, if you're a low-income family and can't afford expensive boiler replacements, the new boiler scheme might be the answer to your quest. This help from the government particularly focuses on low-income families, ones that are living in fuel poverty. If you qualify, you might get a brand-new combi boiler for your small house totally free of charge. 

Why are combi boilers good to go for small houses?

Well, mostly because of their compact design, combi boilers are the go-to choice for heating small houses and flats. They're small enough, but powerful, and super efficient. Consequently, they can save you money on your heating costs. Moreover, you can run your combi boiler on different fuels like natural gas, LPG, oil, or electricity.

Now, oil and LPG boilers need extra space for fuel storage. That's not ideal if your home is tight on space. So, for small places like the ones we're talking about here, they might not be the best option. Electric combi boilers, though, are perfect for small flats without gas. They're compact, easy to install, and can even cut down on your overall boiler costs.

What size combi boiler should you have?

The main thing that affects the size or power, which is measured in kilowatts – kW of the boiler you need is the heat it needs to put out. This depends on a couple of things like the number of radiators you have, how big the rooms are, and how well they're insulated. But hey, there are some handy rules of thumb to get you started! For gas combi boilers, which are popular in the UK, you can estimate that you'll need around 2kW for each radiator in your house. So, for example, if you have a small house with 6 radiators, a boiler with a central heating output of around 12kW should do the trick.

Now, the lowest power rating you'll typically find for a gas combi boiler in the UK is 18kW. That might sound like overkill for a small flat, but there's a catch! These boilers don't just blast out heat at full power all the time. They actually have a range they can work in - for example, a boiler might say it has a minimum output of 3.2kW and a maximum of 19kW. So it can adjust the heat it puts out depending on what your house needs.

Other factors affecting the size

There are other factors that can affect the size you'll need, like how well-insulated your house is and how high your ceilings are. For example, a studio apartment with 2-3 radiators would likely need a gas combi boiler with a minimum output of 18kW. This might seem high, but gas combi boilers can adjust their output depending on how much heat is needed. However, an electric combi boiler for the same size space would likely need a lower output, somewhere between 3kW and 4.5kW. Plus, as the number of radiators increases, so does the recommended boiler size. A 2-bedroom house with up to 6 radiators would need a gas combi boiler with a minimum output of 18kW and an electric combi boiler with around 9kW.

Remember, this is just a starting point. It's always best to consult with a qualified heating engineer to determine the perfect size boiler for your specific home.

Best combi boiler models for small-size houses

Though there are several combi model available in the market that could best suit your small house, below are a few recommended models that you can choose.

Worcester Bosch Greenstar 2000 25kW combi

This is the most budget-friendly option at an estimated price of £750 (excluding installation). It comes with a warranty of up to 6 years. However, it has a slightly lower heating output (20kW). So it is best suited for properties with fewer than 10 radiators and a single bathroom.

Viessmann Vitodens 100-W 19kW

Viessmann Vitodens has an efficiency of 94%. Moreover, it has good hot water output compared to the Ideal Vogue. It's suitable for homes with 1 bathroom and up to 10 radiators. The estimated price is £1125 (excluding installation) and comes with a 5-year warranty with an extension option.

Ideal Vogue Max C26

Boasting a 93% efficiency rating, this boiler is suitable for homes with around 10 radiators. Moreover, it comes with a 10-year warranty, extendable to 12 years with specific installation conditions. While the estimated price is £1089 (excluding installation), it might be a good choice for those seeking a longer warranty.

Vaillant eco FIT pure 825

This boiler is the most affordable option on the list at an estimated price of £907 (excluding installation). It maintains a high 94% efficiency rating. Plus, it is suitable for slightly larger homes with up to 15 radiators and 1 bathroom. The warranty is 2 years standard but can be extended up to 10 years with specific servicing conditions.

Bottom line

Always take a look at the market and do a little bit of research before buying a boiler for your small house. There are several options and you can get confused. So to avoid any trouble, consult an engineer and asses your property's size where you want to install a boiler. Moreover, never forget to apply for free boiler grants. These grants are helping low-income families to replace older, in-efficient boilers with brand-new, more energy-efficient models.