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Which is the best boiler for a 3 bedroom house?

03/06/2020

 

We have found the best combi, system and heat only boilers for a 3 bed house, for every budget. Sometimes the most expensive boilers are not the best or most efficient. We are 100% impartial. We have cast aside the marketing blurb and reviewed the technical performance of boilers from 11 manufacturers to find out which are truly the best boilers with the best warranty back up.

CONTENTS

  1. Sizing a combi boiler for a 3 bed house
  2. Sizing a heat only or system boiler for a 3 bed house
  3. Our research
  4. How we judge our boilers
  5. Our findings
  6. Best combi boilers for 3 bed houses
  7. Pick of the pack combi boilers
  8. Best heat-only boilers for 3 bed houses
  9. Pick of the pack heat only boilers
  10. Best system boilers for 3 bed houses
  11. Pick of the pack for system boilers
  12. Getting the best efficiencies from your boiler

 

1) Sizing a combi boiler for a 3 bedroom house

The average heat requirement for a 3-bedroom house on a very cold day is surprising quite low, around 4-8kW depending on the age of the property and how well insulated it is. Combi boilers show figures of 24kW commonly up to 38kW, but this is for hot water production. Whilst the heating side of the smallest combi boiler is much lower - around 18kW - it is still big enough to heat any 3 bedroom home.

The main factor to consider for combi boilers is the number of bathrooms you have and how often they are in use at the same time. If you have two or more showers going in the morning for example, you definitely want to consider a combi with higher hot water production. We have grouped together combi boilers in the tables below according to hot water flow rates

2) Sizing a heat only or system boiler for a 3 bedroom house

It is surprising to learn that the average 3 bedroom house will only need 4-8kW of heat on a very cold day. We are so used to seeing big outputs on boilers that we think its much greater. In the UK the smallest heat-only and system boilers available to buy are 11-13kW - easily big enough.

The main factor for sizing the boiler is the hot water cylinder coil. The vast majority of cylinders are heated by the boiler via an internal coil (a bit like a kettle element). The coil has a kW capacity that it needs from the boiler in order to heat the cylinder in a reasonable amount of time (known as hot water recovery time). This might be 12kW or 25kW. Whatever it is will determine what size boiler you need.

As a general guide, the bigger the cylinder the more kW power you will need to reheat it. Cylinders commonly range between 120 litres and 300 litres, so it follows that a 300 litres cylinder will need twice as much as power at 150-litre cylinder. Of course 300 litres is enormous and in reality cylinders in the smaller sizes are sufficient.

3) Our boiler research

Forget the marketing blurb found on boiler manufacturers' websites. We have trawled through the technical datasheets of the vast majority of boilers available in the UK to find truly the best value boilers and the most efficient boilers.

4) How do we judge our boilers?

We judge our boilers by how low they can go (in kW output), warranty and price.

All boilers operate within a range, for example, 2kW - 20kW or 8kW - 30kW. Boilers that have a low minimum output can operate efficiently all year round.

As there are very few homes in the UK with a heat requirement over 10kW on a very cold day, so it is that all boilers are too big for the heating requirements by a 3 bedroom house. The important factor here is the minimum heating output of the boiler - the lower the better.

For example, a 3-bed house may need 7kW on a very cold day and 1-2kW during spring and autumn. A boiler with a minimum output of 8kW is simply too big all year round. A boiler with a minimum output of 3kW will be able to reduce its output during spring and autumn and operate more efficiently. So we have determined which are the best boilers by how low they can go.

5) Our findings

We have found that the most expensive boilers are not always the best. We have also found familiar boiler brands doing great work and some much smaller brands probably not getting the credit they are due. We bring them all to you to review.

We are unbiased and without sponsorship. We simply want you to buy with your eyes wide open and get the best value for your budget. We have put our overall best buys after the tables.

 

Jo & Caroline - Heating Heroes

Hero Support

We get you the best boiler and the best installer with our pioneering service

 

6) Best combi boilers for 3 bedroom homes

As all combi boilers are too big for our heating systems, we have grouped boilers together instead based on the number of bathrooms as this is the more important factor for determining which is best for you. If you have a three-bedroom home with one bathroom then the smallest combi boiler will absolutely meet your needs. If you have two or more bathrooms in use at the same time, for example you all take showers in the morning, then opt for a larger output combi that can go down low on the heating side.

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Litres per minute for hot water Minimum output
Ravenheat HE80 25 £649 5 5 21kW 10.2 3.6kW
Glow Worm Energy 25 £700 7 7 19kW 10.4 5.0kW
Vaillant EcoFit Pure 825 £910 2 7 19kW 10.4 5.2kW
Intergas Xclusive 24 £969 10 10 19kW

10.1

3.6kW
Baxi Ecoblue Advance 24 £1,020 10 10 21kW 9.8 4.9kW
Viessmann 100-W 26 £1,070 5 10 26kW 8.9 4.7kW
Ideal Vogue C26 £1,005 10 10 19kW 10.6 4.0kW
Intergas Xtreme 24 £1,209 7 7 19kW 11.0 3.6kW
Worcester 8000 30kW £1,275 5 10 30kW 10.7 3.0kW

1 bathroom properties - 9-10 litres per minute

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Litres per minute for hot water Minimum output
Ravenheat HE98 30 £719 5 5 26kW 12.1 3.7kW
Vailliant / EcoFITpure 830 £1,110 2 7 26kW 12.4 6.3kW
ATAG iC Economiser 27 plus NK 10 10 23kW 12.6 5.0kW
Intergas Xclusive 30 £1,029 10 10 23kW 12.2 3.6kW
Ideal Vogue C32 £1,115 8 10 26kW 13.1 4.6kW
Intergas Xclusive 36 £1,149 10 10 27kW 13.5 3.6kW
Intergas Xtreme 30 £1,269 7 7 26kW 13.3 3.6kW
Vaillant EcoTEC Plus 832 £1,290 5 10 25kW 13.0 5.2kW

1 bathroom properties - 11-13 litres per minute

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Litres per minute for hot water Minimum output
Glow Worm Energy 30 £800 7 7 26kW 14.2 6.1kW
Vaillant EcoTEC Plus 835 £1,470 5 10 30kW 14.3 5.8kW
Intergas Xtreme 36 £1,389 7 7 27kW 14.5 3.6kW
Vaillant ecoTEC Green iQ 835 £1,465 5 10 26kW 14.5 3.4kW
Worcester 8000 35kW £1,405 5 10 35kW 14.3 3.5kW
Viessmann Vitodens 200-W 200-W £1,602 3 10 25kW 15.7 1.9kW

1-2 bathroom properties - 14-15 litres per minute.

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Litres per minute for hot water Minimum output
Glow Worm Energy 35 £900 7 7 26kW 16.5 7.2kW
Ideal Vogue 40 £1,225 10 10 32kW 16.4 5.7kW
Worcester 8000 40 £1,600 5 10 35kW 16.4 3.5kW
Vaillant ecoTEC Green iQ 843 £1,700 5 10 33kW 17.8 4.3kW
Worcester 8000 45kW £1,904 5 10 35kW 18.3 3.5kW
Worcester Highflow 440CDi £2,115 5 10 29kW 20.0 7.4kW

2 bathrooms in use at the same time - 16 litres per minute or more

7) Best combi boilers 3 bed house

BEST OVERALL COMBI

Hands down the Viessmann 200-W combi. With the lowest output of 1.9kW this boiler will be incredibly efficient all year round and still gives an impressive 15.7 litres per minute for hot water.

BEST BUDGET COMBI

A long way out front is the Ravenheat HE80 and HE98. A great minimum output of 3.6kW for under £650 for the smaller model. Amazing value!

BEST FOR HOT WATER

If you need massive amounts of hot water then the Worcester 8000 is a great option. 18 litres per minute for hot water and it still drops down to 3.2kW for heating. Great work.

BEST MID RANGE COMBI

The Intergas Xclusive 30 gives a low heating output of 3.6kW and a decent hot water performance of 13.3kW for a lot less £££ than others in its group.

8) Best heat only boilers for 3 bedroom homes

As your heat requirement will be lower than the smallest boilers, size of your boiler will be determined by your hot water cylinder. If you have multiple bathrooms and a 250 or 300 litre hot water cylinder then you will definitely have a larger coil. If you have a 120 litre cylinder, which is common in 3 bedroom, single bathroom homes, then a small coil is likely to be present.

The tables below show suitable boilers for 3 bed houses according to hot water requirements. Your installer will be able to guide you. NB some bigger output boilers appear in the first table because they can go down really low which makes them suitable for 3 bedroom homes with smaller hot water requirements.

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Vaillant ecoFIT Pure Regular 412 £768 2 7 12kW 4.5kW
Glow Worm Energy Regular 12 £740 7 7 12kW 4.5kW
Ideal Logic Heat+ 12 £705 7 7 12kW 5.1kW
Vaillant ecoTEC Plus 412 £805 5 10 12kW 4.5kW
Worcester Bosch Greenstar Ri 12i £810 5 10 12kW 5.0kW
Worcester Bosch 8000 30 £1,275 5 10 30kW 3.0kW

3 BEDROOM PROPERTIES, SMALL CYLINDER

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Glow Worm Energy Regular 15 £755 7 7 15kW 4.5kW
Vaillant ecoFIT Pure 415 £775 2 7 15kW 4.5kW
Ideal Logic Heat+ 15 £740 7 7 15kW 4.9kW
Worcester Bosch Greenstar Ri 15i £830 5 10 15kW 5.0kW
Vaillant ecoTEC Plus  415 £880 5 10 15kW 4.5kW
Worcester Bosch 8000 30 £1,275 5 10 30kW 3kW

3 BEDROOM PROPERTIES, LARGER CYLINDER

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Glow Worm Energy Regular 18 £790 7 7 18kW 5.0kW
Ideal Logic Heat + 18 £780 7 7 18kW 5.1kW
Intergas HRE 18 £759 10 10 18kW 6.1kW
Worcester Bosch 8000 30 £1,275 5 10 30kW 3.0kW

3 BEDROOM PROPERTIES, MULTIPLE BATHROOMS

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Ideal Logic Heat + 24 £880 7 7 24kW 5.1kW
Vaillant ecoFIT pure 425 £935 10 10 26kW 6.1kW
Worcester Bosch 8000 30 £1,275 5 10 30kW 3.0kW

3 BEDROOM WITH MULTIPLE BATHROOMS, V LARGE CYLINDER

9) Best heat only boilers 3 bed house

BEST HEAT-ONLY 3 BED HOMES

The Ideal Logic Heat 12 is brilliant value at £695 with a 7-year warranty and lowest output of 3.9kW

BEST HEAT-ONLY MULTIPLE BATHROOMS

The Glow Worm Energy gives a great lower output of 4.5kW and 7 year warranty for £722!

BEST FOR A BIG HOT WATER CYLINDER

The Worcester 8000 will give upto 30kW to a hot water cylinder but still goes down to 3.2kW on the heating.

MOST EFFICIENT HEAT ONLY

The Worcester 8000. It goes down to 3.2kW and has upto 10 years of warranty, although it's a pricey £1,235.

10) Best system boilers for 3 bedroom homes

As the vast majority of 3 bedroom homes will require around 4-8kW of heat on a very cold day, so even the smallest system boilers will comfortably heat most homes. The size of the hot water cylinder and the cylinder coil will determine the size of the boiler.

If you have a 3 bedroom house with a single bathroom and a small hot water cylinder then one of the smaller boilers will likely be sufficient, although it will be for the attending engineer to confirm that. For 3 bedroom houses with 2 or more bathrooms in use at the same time then a large hot water cylinder will be used with a coil that needs perhaps 18-25kW. Hence you will need a larger boiler.

The tables below show suitable boilers for 3 bedroom homes grouped together according to hot water requirements. NB some bigger output boilers appear in the first table because they can go down really low which makes them suitable for 3 bedroom homes with smaller hot water requirements.

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Ravenheat CS system boiler 24 £546 2 2 26kW 4.0kW
Glow Worm Energy  12 £690 7 7 12kW 4.5kW
Worcester Bosch Greenstar System i 9i £903 5 7-10 9kW 3.0kW
Vaillant ecoTEC Plus system 612 £910 5 10 12kW 3.3kW
Ideal Vogue System 15 £905 10 10 15kW 3.2kW
Worcester Bosch Greenstar System i 12i £900 5 10 12kW 3.1kW
Worcester 8000 system 30 £1310 5 10 30kW 3.0kW
Viessmann Vitodens 200-W 11 £1,375 5 10 11kW 1.9kW

3 BEDROOM PROPERTIES, SMALL CYLINDER

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Ideal Logic + system 15 £809 7 7 15kW 4.8kW
Ideal Vogue 15 £902 8 10 15kW 3.2kW
Baxi 600 system 15 £903 7 7 16kW 4.9kW
Vaillant EcoTEC plus system 615 £925 5 7-10 15kW 3.2kW
Worcester 8000 30 £1,305 5 10 30kW 3.2kW
Viessmann Vitodens 200-W 19 £1,470 5 10 19kW 1.9kW

3 BEDROOM PROPERTIES, LARGER CYLINDER

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Ravenheat HE system boiler 98S £649 5 5 25kW 3.7kW
Ideal Logic + 18 £804 7 7 18kW 4.8kW
Ideal Vogue  18 £981 8 10 18kW 3.6kW
Vaillant ecoTEC plus system 618 £1,070 5 7-10 18kW 4.0kW
Worcester 8000 system 30 £1,305 5 10 30kW 3.2kW
Viessmann Vitodens 200-W 19 £1,470 5 10 19kW 1.9kW

3 BEDROOM PROPERTIES, MULTIPLE BATHROOMS

Budget Range Manufacturer / Model Code Price Standard warranty Free Extended Warranty Maximum output Minimum output
Ravenheat HE System 98S £659 5 5 25kW 3.7kW
Ideal Logic + 24 £860 7 7 24kW 5.1kW
Viessmann 100-W 26 £1,095 5 10 26kW 4.3kW
Ideal Vogue  26 £1,110 10 10 26kW 5.6kW
Vaillant ecoTEC plus system 624 £1,225 5 10 24kW 5.7kW
Worcester 8000 system 30 £1,305 5 10 30kW 3.0kW
Viessmann Vitodens 200-W 25 £1,465 3 10 25kW 1.9kW

3 BEDROOM WITH MULTIPLE BATHROOMS, V LARGE CYLINDER

11) BEST SYSTEM BOILERS FOR 3 BED HOUSE

BEST BUDGET SYSTEM BOILER

Glow Worm Energy system boiler. Not the cheapest in the pack but decent low output and impressive 7 year warranty

BEST ALL ROUND SYSTEM BOILER

Hands down the Ideal Vogue 15. Upto ten years of warranty plus a very low 3kW minimum output for £944.

BEST FOR BIG HOT WATER CYLINDERS

Worcester 8000 gives amazing hot water outputs of up to 30kW but goes down to 3.1kW for heating.

MOST EFFICIENT SYSTEM BOILER

The Viessmann Vitodens 200-W. A low output of 19kW and up to 10 years of warranty, but the most expensive.

 

12) Getting the most from your boiler

As set out above, all boilers operate within a range of outputs, say 2kW-20kW or 6kW-18kW. Boilers run at their most efficient when they can be reduced down to their lower outputs at warmer times of the year.

To achieve true efficiency, variable boilers need to be paired with compatible 'compensation' controls. These can reduce the output of the boiler when temperatures increase. When boilers can run for longer at lower outputs they can operate more efficiently. For more on pairing your chosen boiler with a compatible compensation control, read our Guide to advances heating controls.

Jo Alsop

Heating Hero

The Heating Hub

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