Here’s What You Should Know About the Best Combi Boilers

If you’re looking for the best combi boiler for your home, you’re not short on choice. But that can make things more confusing than helpful.

Every brand claims to be “the best.” Every model looks the same. And unless you install boilers for a living, comparing them can feel a little too technical… all jargon and no real answers.

In this guide, we’ll cut through the noise. We’ll look at what makes the best combination boiler, how to match one to your property, and what to expect from a modern installation. We’ll also share why working with a local, Gas Safe registered installer like KD Jones Heating Engineers can make all the difference.

What is a combi boiler?

A combi boiler (short for combination boiler) provides both heating and hot water from a single, compact unit. Unlike system boilers, it doesn’t require a separate hot water cylinder or cold water tank.

That makes combi boilers ideal for smaller homes or properties where space is at a premium. They're also typically faster and more efficient to install, making them a popular choice across the UK.

But not all combis are created equal.

What makes a boiler the “best”?

There’s no one-size-fits-all best boiler. The right choice depends on:

• The size of your home
• How many bathrooms you have
• Your hot water usage
• Existing pipework and controls
• Whether you’re on gas or oil

The best boiler for your home is one that meets your needs efficiently, runs quietly and reliably, and offers a strong warranty, all at a competitive price. Ideally, it should be backed by a local installer who knows your area and your system.

What are the top boiler brands?

Some of the most popular boiler brands we work with at KD Jones include:

• Worcester Bosch – A long-standing favourite for reliability and parts availability
• Vaillant – Known for energy efficiency and quiet operation
• Ideal – Strong warranties and solid performance at a good price point
• Viessmann – Efficient German engineering with high-end components

Each of these brands offers a full boiler range, including combi, system, and heat-only models, so it’s more about finding the right match than chasing the badge.

What size boiler do I need?

Boiler size is measured in kilowatts (kW). Most combis range from 24kW to 40kW.

• A 24–30kW combi is perfect for small homes or flats with one bathroom
• A 30–35kW model suits medium-sized homes with two bathrooms
• For larger homes, we may recommend a higher-output combi, a system boiler, or a hybrid setup

If your boiler is undersized, it will struggle to meet demand. Oversized, and you’ll waste fuel and money. We’ll assess your usage and recommend the best boiler for your layout, central heating, and future plans.

What about energy saving?

Modern combis are highly efficient, especially condensing models that recover heat from exhaust gases. This can reduce your energy bills, cut emissions, and give you peace of mind over long-term costs.

We also install system filters as standard to protect your new boiler from debris and sludge, helping extend its life and maintain performance.

What does boiler installation involve?

A typical boiler installation takes one to two days. We remove your old gas boiler, fit the new one, flush the system, install controls, and test everything thoroughly.

We’ll also advise on whether your home would benefit from upgraded radiators, thermostats, or pipework to get the best from your new heating system.

At KD Jones, we offer full transparency on pricing and timing, and if you need help spreading the cost, we offer 0% boiler finance with no interest or hidden fees.

So what’s the best combi boiler?

The best combi boiler is the one that fits your home, your needs, and your budget, and is installed properly by a qualified team.

We’ll help you find it, install it to the highest standard, and support you long after the job is done.

📞 Call us on 01737 211376

🌐 Visit our contact page to request a quote online

📍 Based in Redhill, we cover homes across Surrey and the surrounding areas

FAQs

What is the best combi boiler for a small home?

A 24–30kW combi boiler from Ideal or Worcester Bosch is usually more than enough for a flat or one-bathroom home.

Can a combi boiler handle two bathrooms?

Yes, if you choose the right output. A 35kW or higher model can often serve two bathrooms, but we’ll assess your water flow to be sure.

How long do combi boilers last?

Most last 10–15 years with proper servicing. Modern models with system filters and regular maintenance can go even longer.

Is a combi boiler right for me?

If you want to save space and have a straightforward heating system, yes. But for homes with high demand or poor water pressure, a system boiler may be better.

What brands do you recommend?

We work predominantly with Worcester Bosch, a reliable, well-supported brand with strong warranties.

How much does a new boiler cost?

It depends on the brand, size, and complexity of the job. We’ll provide a fixed quote after your site visit.

Are combi boilers energy efficient?

Very. Most modern combis are over 90% efficient and are designed to save fuel compared to older boilers.

Can you replace my old system boiler with a combi?

Yes, in many cases. We’ll evaluate your setup and advise on the best way to make the switch.

Do you include system filters in your installs?

We fit a magnetic filter as standard to keep your boiler protected from sludge and debris.

Can I get finance on a new boiler?

Absolutely. We offer 0% boiler finance, helping you spread the cost with no interest or extra fees.