Which is the best boiler for a 3 bedroom house?
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
- Sizing a combi boiler for a 3 bed house
- Sizing a heat only or system boiler for a 3 bed house
- Our research
- How we judge our boilers
- Our findings
- Best combi boilers for 3 bed houses
- Pick of the pack combi boilers
- Best heat-only boilers for 3 bed houses
- Pick of the pack heat only boilers
- Best system boilers for 3 bed houses
- Pick of the pack for system boilers
- 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.
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.