Leading Boiler Advice, Quotes and Installations
Heat Only Boiler Guide | We Compare Prices on 67 Boiler Models
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
| 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.
| 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.
| 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.
| 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.
| 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.
| 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% |
