Guide to oil boiler prices, models, warranties and sizes

 

Oil boilers prices vary according to size and quality, internal and external. Combi boilers range from £2,225 - £2,950; heat only boilers from £1,200 - £2,500 and system boilers from £1,450 - £2,600. We guide you on oil boiler prices, models, warranty periods and sizes in our comprehensive guide. Our pricing tables are ordered by size of property (this is a rough guide) and range from lowest to highest. We include oil boilers from Grant, Firebird, Warmflow and Worcester Bosch. For more on fitted oil boiler costs see our Guide to oil boiler installation costs. Also try our Guide to oil tank installation costs.

Oil boiler types

Combi boiler

Provide heating and hot water via a single unit (no hot water tank). Advantages are instant hot water and space saving. Disadvantages are no electric immersion back up for hot water and do not work well with poor water pressure.

Heat only boiler

Provides heating only and hot water in conjunction with a hot water tank. Advantages are more economical to replace and electric immersion back up for hot water. Disadvantage is higher maintenance requirements for hot water system not covered by boiler manufacturer’s warranty

System boiler

Provides heating only and hot water in conjunction with a hot water tank. Main advantage is that more system components are integral to the boiler and therefore cover by the manufacturer’s warranty. Disadvantage is that unlike a combi there is a maintenance cost to a separate hot water system

Guide to oil boiler sizes

Oil boilers will almost always be variable in output. A 15/21 boiler means it can be adjusted to output from 15kW to 21kW, as most homes have a heat loss of under 10kW, so this boiler will cover most homes. The vast majority of oil boilers serve older, rural properties and we have grouped together boiler sizes accordingly. 

Sizing hot water flow rates for combi boilers

The hot water flow rate for a combi is not adjustable, but it does vary from boiler to boiler. For example, under 2 bed internal oil boilers, flow rates vary between 12 litres per minutes and 18 litres per minute. Flow rate is important particularly if you have multiple bathrooms when you may wish to opt for one of the higher flow rate models.

 

 

Internal oil boilers

Combi boilers

Most homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Firebird Envirogreen Internal Combi HEC20	Combi	ECE020DLX	£2,025.00	2	5-10	12/20	16
Firebird Envirogreen Internal Slimline Combi C20	Combi	ECE020SLM	£2,050.00	2	5-10	12/20	12
Grant VortexPro Internal Combi 21	Combi	VTXCOMBI21	£2,175.00	2	5	15/21	15
Warmflow Utility HEE Combi 15-21	Combi	UC70HEE	£2,275.00	2	5-7	15/21	18
Worcester Bosch Heatslave II 12/18	Combi		£2,350.00	5	10	12/18	15
Worcester Bosch Heatslave II 18/25	Combi		£2,450.00	5	10	18/25	18
Grant VortexBlue Internal Combi 21	Combi	VTXBFCOMBI21	£2,500.00	2	10	15/21	15

 

Massive homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Firebird Envirogreen Internal Combi HEC26	Combi	ECE026DLX	£2,075.00	2	5-10	20/26	16
Firebird Envirogreen Internal Slimline Combi C26	Combi	ECE026SLM	£2,100.00	2	5-10	20/26	16
Grant VortexPro Internal Combi 26	Combi	VTXCOMBI26	£2,200.00	2	5	21/26	17
Grant VortexPro Internal Combi XS 26	Combi	VTXXSCOMBI26	£2,200.00	2	5	21/26	17
Worcester Bosch Heatslave II 18/25	Combi		£2,450.00	5	10	18/25	18
Warmflow Utility HEE Combi 21-26	Combi	UC90HEE	£2,450.00	2	5-7	21/26	24
Grant VortexBlue Internal Combi 26	Combi	VTXBFCOMBI26	£2,600.00	2	10	21/26	17
Worcester Bosch Heatslave II 25/32	Combi		£2,650.00	5	10	25/32	22

 

Heat only boilers

Most homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Grant VortexEco Internal Utility 15-21	Regular	VTXECO15/21	£1,200.00	2	5	15/21	N/A
Firebird Envirogreen Kitchen 12-18	Regular	EGE018KIT	£1,300.00	2	5-10	12/18	N/A
Grant VorteXPro Internal Utility 15-21	Regular	VTX15/21	£1,325.00	2	10	15/21	N/A
Firebird Envirogreen Kitchen C20	Regular	EGE020KIT	£1,325.00	2	5-10	12/20	N/A
Warmflow Utility HE Pre-Wired Utility Series 15-21	Regular	U70HE	£1,350.00	2	5-7	15/21	N/A
Firebird Envirogreen Popular 12-18kw	Regular- Boilerhouse	EGE018POP	£1,350.00	2	5-10	12-18	N/A
Grant Grant VortexEco Wall Hung Internal 12-16	Regular	VTXWH12/16	£1,375.00	2	5	12/16	N/A
Grant Grant VortexEco Wall Hung Internal 16-21	Regular	VTXWH16/21	£1,400.00	2	5	16/21	N/A
Firebird Envirogreen Popular C20	Regular- Boilerhouse	EGE020POP	£1,400.00	2	5-10	12/20	N/A
Worcester Bosch Danesmoor Utility Regular 12/18	Regular		£1,450.00	5	10	12/18	N/A
Worcester Bosch Danesmoor 12/18	Regular		£1,625.00	5	10	12/18	N/A
Warmflow Utility HE Pre-Pumped 15-21	Regular	UP70HE	£1,650.00	2	5-7	15/21	N/A
Grant VortexBlue Internal 21	Regular	VTXBF21	£1,825.00	2	10	15/21	N/A
Warmflow B-Series Pre-wired 15-21	Regular	B70HE	£1,875.00	2	5-7	15/21	N/A
Firebird Blue Supreme Utility C20	Regular	EBS020CUT	£2,750.00	5	5-10	12/20	N/A

 

Massive homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Warmflow B-Series Pre-wired 21-26	Regular	B90HE	£1,225.00	2	5-7	21/26	N/A
Warmflow Utility HE Pre-Wired Utility Series 21-26	Regular	U90HE	£1,250.00	2	5-7	21/26	N/A
Grant VortexEco Internal Utility 21-26	Regular	VTXECO21/26	£1,300.00	2	5	21/26	N/A
Firebird Envirogreen Popular C26	Regular- Boilerhouse	EGE026POP	£1,475.00	2	5-10	20/26	N/A
Firebird Envirogreen Kitchen C26	Regular	EGE026KIT	£1,525.00	2	5-10	20/26	N/A
Worcester Bosch Danesmoor Utility Regular 18/25	Regular		£1,575.00	5	10	18/25	N/A
Grant VortexPro Internal Utility 15-26	Regular	VTX15/26	£1,600.00	2	10	15/26	N/A
Worcester Bosch Danesmoor 18/25	Regular		£1,700.00	5	10	18/25	N/A
Warmflow Utility HE Pre-Pumped 21-26	Regular	UP90HE	£1,725.00	2	5-7	21/26	N/A
Grant VortexBlue Internal 26	Regular	VTXBF26	£1,825.00	2	10	21/26	N/A
Firebird Blue Supreme Utility C26	Regular	EBS026CUT	£2,525.00	5	5-10	20/26	N/A

 

System Boilers

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Most homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Sapphire Internal	System	23	£3,500	5	5	23-32	N/A
Grant VortexEco Internal Utility System 15-21	System	VTXSECO15/21	1450	2	5	15/21	N/A
Firebird Envirogreen Internal System C20	System	ESE020DLX	1525	2	5-10	12/20	N/A
Grant VortexPro Internal Utility System 15-26	System	VTXS15/21	1600	2	10	15/26	N/A
Grant Grant VortexEco Wall Hunt internal System 12-16	System	VTXSWH12/16	1625	2	5	12/16	N/A
Grant Grant VortexEco Wall Hung Internal System 16-21	System	VTXSWH16/21	1650	2	5	16/21	N/A
Worcester Bosch Danesmoor System Utility 12/18	System		1675	5	10	12/18	N/A
Warmflow Utility HE System 15-21	System	US70HE	1700	2	5-7	15/21	NA
Worcester Bosch Danesmoor System 12/18	System		1750	5	10	12/18	N/A
Grant VortexBlue Internal System 21	System	VTXSBF21	2025	2	10	15/21	N/A

 

Massive homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Sapphire Internal	System	28-32	£3,500	5	5	23-32	N/A
Grant VortexEco Internal Utility System 21-26	System	VTXSECO21/26	1550	2	5	21/26	N/A
Firebird Envirogreen Internal System C26	System	ESE026DLX	1550	2	5-10	20/26	N/A
Grant VortexPro Internal Utility System 15-26	System	VTXS15/21	1600	2	10	15/26	N/A
Grant Grant VortexEco Wall Hung Internal System 16-21	System	VTXSWH16/21	1650	2	5	16/21	N/A
Warmflow Utility HE System 21-26	System	US90HE	1775	2	5-7	21/26	N/A
Worcester Bosch Danesmoor System Utility 18/25	System		1850	5	10	18/25	N/A
Worcester Bosch Danesmoor System 18/25	System		1900	5	10	18/25	N/A
Grant VortexBlue Internal System 26	System	VTXSBF26	2050	2	10	21/26	N/A

 

External oil boiler prices

Combi boilers

Most homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Firebird Envirogreen External Combipac HEC20	Combi	ECE020CPK	£2,125.00	2	5-10	12/20	16
Grant VortexPro External Combi 21	Combi	VTXOMCOMBI21	£2,225.00	2	5	15/21	15
Warmflow K-Series Combi External 15-21	Combi	KC70HEE	£2,325.00	2	5-7	15/21	18
Worcester Bosch Heatslave II External 12/18	Combi		£2,450.00	5	10	12/18	15
Grant VortexBlue External Combi 21	Combi	VTXBFOMCOMB21	£2,550.00	2	10	15/21	15
Worcester Bosch Heatslave II External 18/25	Combi		£2,600.00	5	10	18/25	18

 

Massive homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Firebird Envirogreen External Combipac HEC26	Combi	ECE026CPK	£2,200.00	2	5-10	20/26	16
Grant VortexPro External Combi 26	Combi	VTXOMCOMBI26	£2,400.00	2	5	21/26	17
Grant VortexBlue External Combi 26	Combi	VTXBFOMCOMB26	£2,525.00	2	10	21/26	17
Warmflow K-Series Combi External 21-26	Combi	KC90HEE	£2,550.00	2	5-7	21/26	24
Worcester Bosch Heatslave II External 18/25	Combi		£2,600.00	5	10	18/25	18
Worcester Bosch Heatslave II External 25/32	Combi		£2,750.00	5	10	25/32	22

 

Heat only boilers

Most homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Grant Vortex Boiler House 15-21	Regular	VTXBH1521	£1,175.00	2	5	15/21	N/A
Grant VortexEco External 15-21	Regular	VTXOMECO15-21	£1,400.00	2	5	15/21	N/A
Warmflow K-Series Pre-Wired External 15-21	Regular	K70HE	£1,450.00	2	5-7	15/21	N/A
Grant VortexPro External 15-21	Regular	VTXOM15/21	£1,550.00	2	5	15/21	N/A
Firebird Envirogreen External Slimline Heatpac C20	Regular	EGE020SLM	£1,600.00	2	5-10	12/20	N/A
Grant VortexEco Wall Hung External 12-16	Regular	VTXOMWH12/16	£1,725.00	2	5	12/16	N/A
Firebird Envirogreen External Heatpac 12-18kw	Regular	EGE018HPK	£1,725.00	2	5-10	12-18	N/A
Worcester Bosch Danesmoor Regular External 12/18	Regular		£1,825.00	5	10	12/18	N/A
Warmflow K-Series Pre-Pumped External 15-21	Regular	KP70HE	£1,875.00	2	5-7	15/21	N/A
Firebird Envirogreen External Heatpac C20	Regular	EGE020HPK	£1,900.00	2	5-10	12/20	N/A
Grant VortexEco Wall Hung External 16-21	Regular	VTXOMWH16/21	£1,975.00	2	5	16/21	N/A
Grant VortexBlue External 21	Regular	VTXBFOM21	£2,025.00	2	5	15/21	N/A
Firebird Blue Supreme External Slimline Heatpac C20	Regular	EBS020SLM	£2,400.00	2	5-10	12/20	N/A

 

Massive homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Grant Vortex Boiler House 21-26	Regular	VTXBH2125	£1,150.00	2	5	21/26	N/A
Grant VortexEco External 21-26	Regular	VTXOMECO21-26	£1,550.00	2	5	21/26	N/A
Firebird Envirogreen External Slimline Heatpac C26	Regular	EGE026SLM	£1,625.00	2	5-10	20/26	N/A
Warmflow K-Series Pre-Wired External 21-26	Regular	K90HE	£1,700.00	2	5-7	21/26	N/A
Grant VortexPro External 15-26	Regular	VTXOM15/26	£1,725.00	2	5	15/26	N/A
Worcester Bosch Danesmoor Regular External 18/25	Regular		£1,900.00	5	10	18/25	N/A
Warmflow K-Series Pre-Pumped External 21-26	Regular	KP90HE	£1,925.00	2	5-7	21/26	N/A
Firebird Envirogreen External Heatpac C26	Regular	EGE026HPK	£2,000.00	2	5-10	20/26	N/A
Grant VortexBlue External 26	Regular	VTXBFOM26	£2,100.00	2	5	26/36	N/A
Firebird Blue Supreme External Slimline Heatpac C26	Regular	EBS026SLM	£2,475.00	2	5-10	20/26	N/A

System boilers

Most homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Sapphire External	System	23	£3,500	5	5	23	N/A
Grant VortexEco External System 15-21	System	VTXSOMECO15-21	1675	2	5	15/21	N/A
Firebird Envirogreen External Systempac C20	System	ESE020NKT	1775	2	5-10	12/20	N/A
Firebird Envirogreen External Slimline Systempac C20	System	ESE020SLM	1775	2	5-10	12/20	N/A
Grant VortexEco Wall Hung External System 12-16	System	VTXSOMWH12/16	1875	2	5	12/16	N/A
Warmflow K-Series System External 15-21	System	KS70HE	1925	2	5-7	15/21	N/A
Grant VortexEco Wall Hung External System 16-21	System	VTXSOMWH16/21	2000	2	5	16/21	N/A
Worcester Bosch Danesmoor External System 12/18	System		2075	5	10	12/18	N/A

 

 

Massive homes	Boiler type	Model	Price	Warranty	Free extended warranty	KW output range	Hot water flow rate
Sapphire External	System	28-32	£3,500	5	5	28-32	N/A
Grant VortexEco External System 21-26	System	VTXSOMECO21-26	1800	2	5	21/26	N/A
Firebird Envirogreen External Systempac C26	System	ESE026NKT	1850	2	5-10	20/26	N/A
Firebird Envirogreen External Slimline Systempac C26	System	ESE026SLM	1850	2	5-10	20/26	N/A
Warmflow K-Series System External 21-26	System	KS90HE	1975	2	5-7	21/26	N/A
Grant VortexEco Wall Hung External System 16-21	System	VTXSOMWH16/21	2000	2	5	16/21	N/A
Worcester Bosch Danesmoor External System 18/25	System		2250	5	10	18/25	N/A