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Heat Only Boiler Guide | We Compare Prices on 67 Boiler Models

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  • Heat Only Boiler Guide | We Compare Prices on 67 Boiler Models
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QUICK GUIDE SUMMARY

What is a heat only boiler? Who offers the best heat only boiler prices in 2019?

A heat-only boiler, aka a conventional or regular boiler, works with a hot water cylinder in the airing cupboard on an open vented (tanks in the loft) or sealed heating system. Heat only boilers can be a cost effective replacement, from £480 for a small, entry-level boiler to £1,600 for a premium model. In this guide, we compare the prices, sizes, efficiencies and warranty lengths of 67 models from nine of the leading boiler manufacturers in the UK, including Worcester Bosch, Baxi, Ideal and Vaillant. The best heat only boiler for you will be based on your property size and your budget. After you have reviewed individual boiler prices, why not try our Boiler Quote Calculator for a bespoke installation cost, including the cost of the boiler.

Overview of Heat Only Boilers

What is a Heat Only Boiler?

A heat only boiler provides heating and works with a cylinder to provide hot water. They can work on an open vented system (you will have tanks in loft) or sealed system. Read our Guide to Open Vented and Sealed Systems for more help.

Find your Best Heat Only Boiler

Use the tables below to find your best boiler based on price, efficiency and warranty length. For example, similarly priced boilers offer 2 and 5 year warranties; it's easy to see which one is better value!

Found your boiler? What's next?

Get an estimate of installation cost with our Boiler Quote Calculator. Are you looking for flexible ways to pay for a new boiler? Read our comprehensive guide: Ways to Pay for Your New Boiler.

How to use this Guide

Guide to using the boiler tables

Find your property size

Find your best boiler according to budget

What is a Heat Only boiler?

A heat only boiler (also known as a Regular boiler or Conventional boiler) provides heat directly to the radiators and works with a vented hot water tank to provide hot water. Heat only boilers can work on 'open vented' or 'sealed systems' (to work out which system you have and the advantages and disadvantages of each read our Guide to Open Vented and Sealed Systems). Replacing a heat only boiler is very cost effective, however long term maintenance costs will be higher as many of the systems components (pumps, valves etc) are external to the boiler.

When is a heat only boiler right for my home?

Heat only (regular) boilers are occasionally installed in a new build home, but they are usually only a replacement for an existing heat only boiler. This is because it is more cost effective in terms of long term maintenance to install a combi or system boiler as more the system's components are integral to the boiler (pump, valves etc) and therefore covered by the manufacturer's warranty. If you are replacing your heat only boiler and considering other boiler types, the main two things to remember are 1) a heat only boiler can work on an 'open vented' system (you will have water tanks in the loft). If you wish to retain your open vented system then you will have to go with one of the heat only boilers that can work in this system configuration (see also our Guide to Open Vented and Sealed Systems). 2) If you have poor incoming water pressure then a combi or system boiler may not work. For more read our Guide to Boiler Types.

Sizing your heat only boiler

Modern boilers are almost universally oversized. The average UK home requires just 6-8kW of heat at peak times. The most popular heat only boiler is around 15kW, more than twice the capacity most homes will ever need. So what is wrong with oversizing, just in case? Firstly the boiler will cycle on and off more than it was ever designed to, accelerating wear and tear. Secondly it will rarely operate at its most efficient, i.e. in 'condensing mode', because the return temperatures to the boiler will be too hot. Condensing boilers need the temperature of the water as it flows back to the boiler to be 50 degrees C or less. This requires a correctly sized boiler AND a perfectly balanced system with TRVs that signal the boiler to reduce its output further (modulate) as each room gets warm enough. The good news is that most modern boilers can be 'ranged rated' down, i.e. the output reduced to more closely match your property's heat requirement, which is calculated by the attending engineer. Make sure you check that the engineer has done this. For more see our Guide to Boiler Sizing.

Find your best heat only boiler

The tables are arranged so that you can easily find your property size and then find who offers the best boiler package for your budget. The tables show boiler price alongside warranty period and efficiency so you can find the best value boiler. Most boiler manufacturers produce one or two models of regular boiler with outputs between 12kW and 40KW and everything inbetween. Unlike combi and system boilers, there is not such a great disparity between prices at the lower and upper ends. That is not to say that they are all the same, we have still found great value boilers in all categories.

Best Buys and Best Performance

We have identified ‘best buys’ in each size group (highlighted yellow). These reflect an all-round great package. We have also highlighted best performance boilers (highlighted green), which are not necessarily the cheapest but offer great efficiencies and warranties.

Guide to using the boiler tables

In the example below you can see that there is little between the boilers in price. The Ideal Logic at £828 is great value with a 7 year warranty, however Vaillant and Worcester offer exceptional value in terms of warranty cover and for £90 more you could purchase a Worcester Bosch and get 8 years cover and a 3% increase in efficiency. 

4 bed house   Price Standard warranty Free extended warranty Central heating output Efficiency
Ideal Logic + Heat 24 £828.00 7 7 24 89%
Vaillant ecoFIT pure regular

 

25 £874.00 2 7-10 25 89%
Worcester Bosch Greenstar Ri

 

24 £909.00 7 8 24 92%
Viessmans Vitodens 100-W Regular 26 £915.00 5 5 26 90%

Find your property size and open up the table to find your best heat only boiler.

1-3 bed properties

As outlined above, the average UK home needs 6-8kW of heat at peak times. As is evident below, it is not currently possible to buy a 6-8kW boiler, the smallest heat only boiler available is 12kW. The good news is that you can range rate it down (see boiler sizing section above). In terms of product, if you are on a tight budget then the Main boiler offers incredible value for around £480, but only two year's warranty. The prices are pretty close after the Main, so our best buy is the Vaillant EcoFIT pure because of the great warranty available

ExpandClose Table

1-3 bed properties

    Price Standard warranty Free extended warranty Central heating output Efficiency
Main heat only boiler 12 £480.00 2 2 12 89%
Baxi 200 Heat 12 £653.00 3 3 13 89%
Baxi 400 Heat 12 £669.00 5 5 13 89%
Potterton Promax SL Heat 12 £674.00 2 2 12 89%
Ideal Logic Heat 12 £695.00 2 2 12 89%
Vaillant ecoFIT pure regular

 

12 £702.00 2 7-10 12 89%
Glow Worm Energy Regular 12 £704.00 2 2 12 89%
Vaillant ecoTEC plus regular 12 £730.00 5 7-10 12 89%
Ideal Logic + Heat 12 £765.00 7 7 12 89%
Baxi Ecoblue Advance Heat 13 £776.00 7 7 13 89%
Worcester Bosch Greenstar Ri

 

12 £786.00 7 8 12 91%
Baxi Ecoblue Heat 12 £795.00 2 2 13 89%
Viessmans Vitodens 100-W Regular 13 £816.00 5 5 13 90%

4 bed houses

The Main boiler is a great price but only a 2 year warranty. The Vaillant ecoFIT pure offers great all round value but nothing beats the Worcester Ri on performance.

ExpandClose Table

4 bed house

    Price Standard warranty Free extended warranty Central heating output Efficiency
Main heat only boiler 15 £505.00 2 2 15 89%
Baxi 200 Heat 15 £677.00 3 3 16 89%
Baxi 400 Heat 15 £691.00 5 5 16 89%
Glow Worm Energy Regular 15 £722.00 2 2 15 89%
Ideal Logic Heat 15 £730.00 2 2 15 89%
Vaillant ecoFIT pure regular

 

15 £733.00 2 7-10 15 89%
Potterton Promax SL Heat 15 £751.00 2 2 15 89%
Ideal Logic + Heat 15 £796.00 7 7 15 89%
Worcester Bosch Greenstar Ri

 

15 £801.00 7 8 15 91%
Vaillant ecoTEC plus regular 15 £822.00 5 7-10 15 89%
Viessmans Vitodens 100-W Regular 16 £841.00 5 5 16 90%
Baxi Ecoblue Heat 15 £843.00 2 2 16 89%
Baxi Ecoblue Advance Heat 16 £855.00 7 7 16 89%

5 bed houses

There is so little between the cheapest and most expensive, that if you can afford more than the Main boiler then the Vaillant ecoFIT is a great package with 7-10 boiler guarantee. You certainly do not need to venture higher than the Worcester Greenstar Ri; it is the most efficient and far from the most expensive.

ExpandClose Table

5 bed house

    Price Standard warranty Free extended warranty Central heating output Efficiency
Main heat only boiler 18 £539.00 2 2 18 89%
Baxi 200 Heat 18 £708.00 3 3 19 89%
Baxi 400 Heat 18 £720.00 5 5 19 89%
Baxi 200 Heat 24 £749.00 3 3 21 89%
Glow Worm Energy Regular 18 £755.00 2 2 18 89%
Ideal Logic Heat 18 £763.00 2 2 18 89%
Potterton Promax SL Heat 18 £780.00 2 2 18 89%
Vaillant ecoFIT pure regular

 

18 £802.00 2 7-10 18 89%
Viessmans Vitodens 100-W Regular 19 £858.00 5 5 19 90%
Worcester Bosch Greenstar Ri

 

18 £859.00 7 8 18 91%
Baxi Ecoblue Heat 18 £860.00 2 2 19 89%
Vaillant ecoTEC plus regular 18 £894.00 5 7-10 18 89%
Baxi Ecoblue Advance Heat 19 £908.00 7 7 19 89%
Baxi Ecoblue Heat 21 £913.00 2 2 21 89%

Really big houses

Unless you are on a tight budget, in which ase the Main boiler is great value, you can opt for the Vaillant ecoFIT or Worcester Greenstar Ri for very little extra cost and get 7-10 guarantee on the boiler.

ExpandClose Table

Really big houses

4 bed house   Price Standard warranty Free extended warranty Central heating output Efficiency
Main heat only boiler 24 £593.00 2 2 24 89%
Baxi 200 Heat 30 £756.00 3 3 25 89%
Baxi 400 Heat 24 £763.00 5 5 25 89%
Glow Worm Energy Regular 24 £788.00 2 2 25 89%
Ideal Logic Heat 24 £796.00 2 2 24 89%
Potterton Promax SL Heat 24 £822.00 2 2 22 89%
Ideal Logic + Heat 24 £828.00 7 7 24 89%
Vaillant ecoFIT pure regular

 

25 £874.00 2 7-10 25 89%
Worcester Bosch Greenstar Ri

 

24 £909.00 7 8 24 92%
Viessmans Vitodens 100-W Regular 26 £915.00 5 5 26 90%
Baxi Ecoblue Advance Heat 25 £925.00 7 7 25 89%
Vaillant ecoTEC plus regular 24 £959.00 5 7-10 24 89%
Worcester Bosch Greenstar Ri 27 £1,021.00 7 8 27 92%
Baxi Ecoblue Heat 24 £1,103.00 2 2 25 89%

Massive houses

The Baxi 400 represents amazing value with a 5 year warranty. This group gets expensive quickly, but the Vaillant ecoFIT pure is still available in the mid range prices with a 7-10 year warranty when fitted by an accredited installer. 

ExpandClose Table

Massive houses

    Price Standard warranty Free extended warranty Central heating output Efficiency
Glow Worm Energy Regular 30 £826.00 2 2 30 89%
Baxi 400 Heat 30 £834.00 5 5 30 89%
Ideal Logic Heat 30 £905.00 2 2 30 89%
Vaillant ecoFIT pure regular

 

30 £932.00 2 7-10 30 89%
Baxi Ecoblue Advance Heat 30 £981.00 7 7 30 89%
Ideal Logic + Heat 30 £889.00 7 7 30 89%
Vaillant ecoTEC plus regular 30 £1,000.00 5 7-10 30 89%
Worcester Bosch Greenstar Ri

 

30 £1,065.00 7 8 30 93%
Worcester Bosch Greenstar Classic Cdi 30 £1,141.00 7 10 30 92%

'Castles'

We are not really joking. A 40kW heat only boiler will heat a huge house. Boiler sizing must be based on a heat loss calculation. It is slim pickings for larger properties but the Viessmann is the best priced with a decent 5 year warranty and a good efficiency rating. 

ExpandClose Table

'Castles'

Larger properties   Price Standard warranty Free extended warranty Central heating output Efficiency
Viessmans Vitodens 100-W Regular

 

35 £1,325.00 5 5 35 90%
Vaillant ecoFIT pure regular 35 £1,449.00 2 7-10 35 89%
Vaillant ecoTEC plus regular 35 £1,535.00 5 7-10 35 89%
Worcester Bosch Greenstar Classic Cdi

 

40 £1,589.00 7 10 41 92%

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