How we're operating during the COVID-19 pandemic

Find out more How we’re operating during COVID-19
  • Get the best quotes, fast!
  • Over 5,000 engineers across the UK
  • Gas Safe registered engineers

Need a New Boiler?

Get FREE no-obligation quotes now!

  • No delays! Get quotes today
  • Compare quotes & get the best prices
  • Gas Safe & OFTEC registered engineers
 4.8 stars

1,490 reviews

 4.8 stars

1,490 reviews

Ideal Isar Boilers: How to Get a Reliable Replacement

Adam Cherry
By: Adam Cherry
Updated: 10th November 2021

You won’t find many better boilers than those made by Ideal Heating. However, in the mid-2000s, they were asked by the government to make a range of combination (combi) boilers on the cheap.

These boilers weren't their best work.

They were made to meet a deadline so that they could be quickly fitted into homes that needed them. Unsurprisingly, they're no longer being made and those that were fitted haven't stood the test of time.

Isar owners have found that they run into any number of problems over they years but, rather than getting yours repaired, now is the time for a brand new boiler.

Need a new boiler?



Get FREE quotes for a replacement boiler today


The Ideal Isar combi boiler range

There were three combi boilers in the Ideal Isar range: the HE24, HE30 and HE35. All of which had a central heating output rating of 23.4 kW (in non-condensing mode) making them a great choice for homes with around 11-12 radiators (2 kW per radiator).

The output rating is a measurement of the boiler’s power and is often known as the size of the boiler. You can read more about that in this guide to boiler sizing.

Ideal Isar HE24 HE30 HE35
CH output rating (Condensing) 25.1 kW
CH output rating (Non-condensing) 23.4 kW
DHW output rating 23.4 kW 29.3 kW 35.2 kW
Domestic hot water flow rate (35C) 9.6 l/min 12 l/min 14.4 l/min
Seasonal efficiency (SEDBUK) 90.1%

CH = Central Heating. DHW = Domestic Hot Water.
Since these boilers were manufactured, the SEDBUK efficiency rating has been replaced by the Energy related Products Directive (ErP). So, they're not likely to be as efficient as the specifications suggest – especially as they were installed 10+ years ago.

Why you should replace an Ideal Isar

Chances are your Isar was installed more than 10 years ago which means you should really be thinking about a replacement boiler. It's recommended to replace even the most high-end boiler after 10-15 years and the Isar boilers don't fall into this category.

Looking for a similar boiler?

If your heating and hot water demands haven't changed since the Ideal Isar was installed (your home has the same number of radiators and bathrooms) then you can get a combi with the same output.

Ideal has a number of reliable and efficient boiler ranges including the Logic Max and Logic Plus. These boilers have very similar output ratings to the Ideal Isar boilers but are much more efficient and come with lengthy warranties.

Ideal Logic Max

This is Ideal's most efficient and reliable range of combi boilers.

They're also certified to run on a 20% hydrogen blend which is great news if hydrogen is added to the gas network to help lower carbon emissions.

Ideal Logic Max C24 C30 C35
CH output rating 24.2 kW
DHW output rating 24.2 kW 30.3 kW 35.3 kW
Flow rate 9.9 l/min 12.4 l/min 14.5 l/min
Efficiency 94%
Warranty 10 years

Ideal Logic Plus

The Logic Plus range came out before the Logic Max range but these combi boilers still hold their own.

Ideal Logic Plus C24 C30 C35
CH output rating 24.2 kW
DHW output rating 24.2 kW 30.3 kW 35.3 kW
Flow rate 9.9 l/min 12.4 l/min 14.5 l/min
Efficiency 94%
Warranty 7 years

Do you need a bigger boiler?

You'll need a more powerful boiler if your heating and hot water demands have increased since your Ideal Isar was installed. By that, we mean more radiators or a new bathroom.

Here are some of Ideals more powerful combi boilers:

Vogue Max C40 GEN2 C40
CH output rating 32 kW 32 kW
DHW output rating 40 kW 40 kW
Flow rate 16.4 l/min 16.4 l/min
Efficiency 93% 93%
Warranty 12 years 10 years

Two or more bathrooms? Then go for a system boiler

As a combi boiler, the Ideal gives your home heating and hot water on demand. This means they can struggle to meet demand for hot water from two water outlets at the same time. So, if you have two or more bathrooms, then a system boiler is the better option.

Now, system boiler sizing (that's the output rating) works a little differently to combi boilers. The table below shows the output rating you need based on the number of radiators in your home.

Radiators Recommended system boiler size
Up to 10 9-18 kW
10-15 18-26 kW
15-20 27-40 kW

The Ideal Vogue Max range of system boilers includes a number of models with different outputs.

Ideal Vogue Max S15 S18 S26 S32
CH output rating 15 kW 18 kW 26 kW 32 kW
Efficiency 92% 93% 93% 93%
Warranty 10 years

System boilers don't have a hot water output rating or flow rate. This is because domestic hot water is stored in a hot water cylinder and sent to taps from there.

Visit our Boiler Comparison Tool to compare all Ideal system boilers.

Need a new boiler?



Get FREE quotes for a replacement boiler today


How much do new Ideal boilers cost?

Most Ideal combi boilers are priced around the £1,000 mark. Then around £1,5000 – £2,000 with the installation costs added on top. But this will all vary depending on the type of boiler, model and how many quotes you compare for the installation.

Ideal combi boiler prices

Logic Plus combi boilers tend to come with the lowest price tag. But if you spend extra to get a Logic Max or Vogue Max, you'll be covered by a longer warranty (10-12 years compared to 7).

Cost of boiler Installation costs Total
Logic Max combi £968 – £1,156 £500 – £1,000 £1,468 – £2,156
Logic Plus combi £847 – £1,039 £500 – £1,000 £1,347 – £2,039
Vogue Max combi £1,089 – £1,323 £500 – £1,000 £1,589 – £2,323

Ideal system boiler prices

Alongside the system boiler, you'll also need an unvented hot water cylinder. Hot water cylinders can cost can range from £300 up to £2,000 depending on the model and its capacity. That's without installation.

Cost of boiler Installation costs Total
Vogue Max system £1,030 – £1,258 £500 – £1,000 £1,530 – £2,258

Compare the Best Unvented Cylinders to go with your new system boiler.

Find an installer to replace your Ideal Isar

You'll need a Gas Safe registered engineer to replace your old Ideal Isar boiler. This means that they're listed on the Gas Safe Register. Making them the only people qualified to replace gas boilers.

You can get free quotes from as many as 3 Gas Safe registered engineers in your area by letting us know that you need a new boiler. To do that, you'll need to complete our simple online form – it should only take a moment.

Soon after you've done that, Gas Safe registered engineers in your area will be in touch to arrange a quote for your new boiler.

Adam Cherry

About the author

Adam Cherry

Adam is our resident home heating expert. His experience and advice has helped millions of customers improve the efficiency of their homes and save money.

Need a new boiler?

Get FREE no-obligation quotes now!

Excellent 4.8 out of 5

Find local heating engineers

Find approved boiler engineers
in your area.

Begin your search by entering your postcode below.