Best Combi Boilers - Find the Best Combi for your Budget

Which is the best combi boiler? Well it depends on your criteria. We think a better question is “which is the best combi boiler for my property's size and budget?”.

We have undertaken an in depth comparison of combi boilers that considers the price, capacity, warranty and efficiency of the best boiler brands in the UK. We have then arranged the information so it is simple to find your best combi boiler, as follows:

1. Find your property size

2. Find your price range

 Entry level (cheapest)
 Economy (one-up from Entry level)
 Mid-Range
​ Premium, the most expensive

3. Find your best combi boiler based on your criteria

  • We have organised the boilers into handy tables according to property size and budget.
  • The first boiler on each table is what we consider to be the Overall Best Boiler, i.e. it offers a great all round performance, warranty and price.
  • We have then listed the best boiler in each of the following categories
    • Best Boiler Price
    • Best Efficiency
    • Best Output 
    • Best Hot Water Flow Rate
    • Best Warranty (or Guarantee)
  • In some categories one boiler ticks all the boxes, so only one boiler is listed for everything.. impressive!

TOP TIP: The tables below list the 'best boilers' from our full review of 83 models of combi boiler. To view all 83 boilers visit our Boiler Prices Comarison page.

Best combi boiler for a large house

Even a big combi can only do so much. If you have five or more bedrooms and/or three or more bathrooms that are often in use simultaneously then you may want to consider a larger floor standing boiler, a small ‘commercial’ boiler or a system boiler with large hot water tank (assuming your water pressure is good enough). For more on finding the best boiler 'type' use our Guide to Boiler Types and Selection.

bedroom flats

These boilers work will in smaller properties with one bathroom. If you have a two bedroom flat with two bathrooms you may wish to consider a boiler from the two or three bedroom range with a better hot water flow rate.

ENTRY LEVEL RANGE – £570-£628
  Manufacturer / Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Main Eco Elite 25 £606 5 5 26 10.1 90%
Best Boiler Price Glow Worm / Easicom 24 £570 2 4 20 10 90%
Best Boiler Efficiency Potterton / Gold 24 £628 2 2 20 9.8 91%
Best Boiler Heating Output Main Eco Elite 25 £606 5 5 26 10.1 90%
Best Hot Water Flow Rate Main Eco Elite 25 £606 5 5 26 10.1 90%
Best Boiler Warranty Main Eco Elite 25 £606 5 5 26 10.1 90%
ECONOMY RANGE – £675-£738
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Baxi/Duotec 24 £675 7 7 20 9.8 89%
Best Boiler Price Baxi/Duotec 24 £675 7 7 20 9.8 89%
Best Boiler Efficiency Potterton/Titanium 24 £738 7 7 20 9.8 91%
Best Boiler Heating Output Potterton/Titanium 24 £738 7 7 20 9.8 91%
Best Hot Water Flow Rate Glow Worm/Energy 25kW £700 2 2 18 10.4 89%
Best Boiler Warranty Baxi/Duotec 24 £675 7 7 20 9.8 89%
MID RANGE – £794 - £1010
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Worcester Bosch/Greenstar Professional 25i £875 5 7 24 9.8 94%
Best Boiler Price Ideal/ Logic+ Combi C24 £794 7 7 24 9.9 90%
Best Boiler Efficiency Worcestster Bosch/Si 25Si £1,010 7 9 24 9.8 94%
Best Boiler Heating Output Worcestster Bosch/Si 25Si £1,010 7 9 24 9.8 94%
Best Hot Water Flow Rate Ideal/ Logic+ Combi C24 £794 7 7 24 9.9 90%
Best Boiler Warranty Vaillant/EcoTEC pro 24 £942 2 5-10 19 9.6 89%
PREMIUM RANGE – £850-£1,358
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Worcester Greenstar Compact 28CDi £1,045 7 10 24 10.0 94%
Best Boiler Price Baxi Platinum 24 £850 10 10 24 9.8 89%
Best Boiler Efficiency Worcester Greenstar Compact 28CDi £1,045 7 10 24 10.0 94%
Best Boiler Heating Output Viessmann Vitodens 200 26kW £1,358 3 5 26 10.7 90%
Best Hot Water Flow Rate Viessmann Vitodens 200 26kW £1,358 3 5 26 10.7 90%
Best Boiler Warranty Worcester Greenstar Compact 28CDi £1,045 7 10 24 10.0 94%

 

bedroom house

These boilers work will in standard two bedroom properties with one bathroom. If you have a large two bedroom house with two bathrooms you may wish to consider a boiler from the three bedroom range with a better hot water flow rate.

ENTRY LEVEL RANGE – £577-£668
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Main Eco Elite 30 £668 5 5 30 12.3 88%
Best Boiler Price Ferroli/Modena 27kW £577 5 5 24 11.1 89%
Best Boiler Efficiency Glow Worm/Easicom 28 £605 2 4 24 11.7 90%
Best Boiler Heating Output Main Eco Elite 30 £668 5 5 30 12.3 88%
Best Hot Water Flow Rate Ideal Independent C30 £651 5 5 24 12.4 89%
Best Boiler Warranty Main Eco Elite 30 £668 5 5 30 12.3 88
ECONOMY RANGE – £694-£798
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Potterton/Titanium 28 £798 7 7 24 11.5 91%
Best Boiler Price Glow Worm/Ultimate 2 30 £694 5 5 25 12.5 89%
Best Boiler Efficiency Potterton/Titanium 28 £798 7 7 24 11.5 91%
Best Boiler Heating Output Glow Worm/Energy 30kW £787 2 2 25 12.5 89%
Best Hot Water Flow Rate Glow Worm/Energy 30kW £787 2 2 25 12.5 89%
Best Boiler Warranty Potterton/Titanium 28 £798 7 7 24 11.5 91%
MID RANGE – £827-£1135
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Ideal/ Logic+ Combi C30 £830 7 7 24 12.4 90%
Best Boiler Price Viessmann/Vitodens 050 29kW £827 3 7 22 12.4 89%
Best Boiler Efficiency Worcestster Bosch/Si 30Si £1,135 7 9 24 11.5 94%
Best Boiler Heating Output Viessmann/Vitodens 100 30kW £1,100 5 10 27 11.2 89%
Best Hot Water Flow Rate Ideal/ Logic+ Combi C30 £830 7 7 24 12.4 90%
Best Boiler Warranty Vaillant/EcoFITpure 825 £865 2 7-10 18 12.1 89%
PREMIUM RANGE – £955-£1245
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Worcester Greenstar Classic 29CDi £1,100 7 10 30 11.0 92%
Best Boiler Price Baxi Platinum 28 £955 10 10 28 11.5 89%
Best Boiler Efficiency Worcester Greenstar Compact 32CDi £1,140 7 10 24 11.5 94%
Best Boiler Heating Output Worcester Greenstar Classic 34CDi £1,225 7 10 30 12.0 92%
Best Hot Water Flow Rate Ideal/Vogue C32 £1,245 10 10 26 13.1 91%
Best Boiler Warranty Worcester Greenstar Classic 29CDi £1,100 7 10 30 11.0 92%

 

bedroom house

These are good capacity boilers for three bedroom houses with 1-3 bathrooms.

ENTRY LEVEL RANGE – £632-£727
3 bedroom house Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Ideal Independent C35 £727 5 5 24 14.5 89%
Best Boiler Price Ferroli/Modena 32kW £632 5 5 28 13.1 89%
Best Boiler Efficiency Potterton/Gold 28 £696 2 2 24 13.3 91%
Best Boiler Heating Output Ferroli/Modena 32kW £632 5 5 28 13.1 89%
Best Hot Water Flow Rate Ideal Independent C35 £727 5 5 24 14.5 89%
Best Boiler Warranty Ideal Independent C35 £727 5 5 24 14.5 89%
ECONOMY RANGE£ – £766-£915
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Potterton/Titanium 33 £858 7 7 28 13.5 91%
Best Boiler Price Potterton/Titanium 33 £858 7 7 28 13.5 91%
Best Boiler Efficiency Potterton/Titanium 33 £858 7 7 28 13.5 91%
Best Boiler Heating Output Baxi/Duotec 33 £915 7 7 28 13.5 89%
Best Hot Water Flow Rate Glow Worm/Ultimate 2 35 £766 5 5 25 14.4 89%
Best Boiler Warranty Potterton/Titanium 33 £858 7 7 28 13.5 91%
​MID RANGE RANGE – £906-£1160
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Vaillant/EcoFITpure 830 £980 2 7-10 25 14.2 89%
Best Boiler Price Viessmann/Vitodens 050 35kW £906 3 7 30 14.5 89%
Best Boiler Efficiency Ideal/ Logic+ Combi C35 £985 7 7 24 14.5 90%
Best Boiler Heating Output Viessmann/Vitodens 100 35kW £1,160 5 10 32 13.5 89%
Best Hot Water Flow Rate Ideal/ Logic+ Combi C35 £985 7 7 24 14.5 90%
Best Boiler Warranty Vaillant/EcoFITpure 830 £980 2 7-10 25 14.2 89%
PREMIUM RANGE – £1100-£1651
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Vaillant ecoTEC plus 835 £1,110 5 7-10 30 14.3 89%
Best Boiler Price Baxi Platinum 33 £1,110 10 10 33 13.5 89%
Best Boiler Efficiency Vaillant ecoTEC Green iQ 835 £1,651 5 7-10 25 14.5 94%
Best Boiler Heating Output Viessmann Vitodens 200 35kW £1,620 3 5 35 14.3 90%
Best Hot Water Flow Rate Vaillant ecoTEC Green iQ 835 £1,651 5 7-10 25 14.5 94%
Best Boiler Warranty Worcester Greenstar Classic 38CDi £1,395 7 10 30 14

92%

 

 

bedroom house

These are big capacity boilers capable of running 4-5 bedroom heating systems with multiple bathrooms.

ENTRY LEVEL RANGE – £764

4 bedroom house Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Ferroli/Modena 38kW £764 5 5 34 16 89%
Best Boiler Price Ferroli/Modena 38kW £764 5 5 34 16 89%
Best Boiler Efficiency Potterton/Gold 33 £764 2 2 28 15.7 91%
Best Boiler Heating Output Ferroli/Modena 38kW £764 5 5 34 16 89%
Best Hot Water Flow Rate Ferroli/Modena 38kW £764 5 5 34 16 89%
Best Boiler Warranty Ferroli/Modena 38kW £764 5 5 34 16 89%
​ECONOMY RANGE – £930
4 bedroom house Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Potterton/Titanium 40 £930 7 7 32 16.4 91%
Best Boiler Price Potterton/Titanium 40 £930 7 7 32 16.4 91%
Best Boiler Efficiency Potterton/Titanium 40 £930 7 7 32 16.4 91%
Best Boiler Heating Output Potterton/Titanium 40 £930 7 7 32 16.4 91%
Best Hot Water Flow Rate Potterton/Titanium 40 £930 7 7 32 16.4 91%
Best Boiler Warranty Potterton/Titanium 40 £930 7 7 32 16.4 91%
MID RANGE – £1,095
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Vaillant/EcoFITpure 835 £1,095 2 7-10 25 16.5 89%
Best Boiler Price Vaillant/EcoFITpure 835 £1,095 2 7-10 25 16.5 89%
Best Boiler Efficiency Vaillant/EcoFITpure 835 £1,095 2 7-10 25 16.5 89%
Best Boiler Heating Output Vaillant/EcoFITpure 835 £1,095 2 7-10 25 16.5 89%
Best Hot Water Flow Rate Vaillant/EcoFITpure 835 £1,095 2 7-10 25 16.5 89%
Best Boiler Warranty Vaillant/EcoFITpure 835 £1,095 2 7-10 25 16.5 89%
PREMIUM – £1,225-£1,979
  Manufacturer/Model Code Price Standard warranty Free Extended Warranty Boiler output kW (Size) Litres per minute for hot water Efficiency
Overall Best Boiler Baxi Platinum 40 £1,225 10 10 40 16.4 89%
Best Boiler Price Baxi Platinum 40 £1,225 10 10 40 16.4 89%
Best Boiler Efficiency Vaillant ecoTEC Green iQ 843 £1,979 5 7-10 33 17.8 94%
Best Boiler Heating Output Baxi Platinum 40 £1,225 10 10 40 16.4 89%
Best Hot Water Flow Rate Vaillant ecoTEC Green iQ 843 £1,979 5 7-10 33 17.8 94%
Best Boiler Warranty Worcester Greenstar Classic 42CDi £1,665 7 10 30 15.0 92%

 

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