Alpha Evoke NX Combi Boiler Cost with Installation

The Evoke NX is Alpha’s smallest combi boiler. It comes in two outputs, fits comfortably in a standard kitchen cupboard at 255mm deep, and carries a stainless steel heat exchanger and Grundfos pump at a price point that sits below most direct rivals. 

The trade-off is the warranty – 7 years parts and labour, solid for a boiler at this price but not extendable beyond that. For a home that doesn’t need the 33kW’s output but wants premium components without the premium price tag, the 28kW Evoke NX is one of the stronger choices in this bracket.

Alpha Evoke NX Combi Product Table
	Available outputs	28kW	33kW
	Type	Combi
	Fuel	Gas
	Condensing	Yes
	Efficiency rating (%)	94
	ErP	A
	LPG compatible	Yes
	Standard warranty	7 years*
	Max output (kW)	28	33
	Flow rate (l/min)	12.1	14.1
	Mounting	Wall-mounted
	Dimensions (mm)	712 x 440 x 255
	Typical price (incl. VAT)	£700	£800
	Typical installation cost (incl. VAT)	£800 – £1,400
	Total cost	£1,500 – £2,200

*Terms and conditions apply.

Alpha Evoke NX combi overview

The 28kW model, with a flow rate of 12.1 l/min, works well for homes with a single bathroom and moderate hot water use. The 33kW, at 14.1 l/min, is better suited to homes where the bathroom sees heavier use, or where two people are likely to be running hot water at the same time.

If your home has two bathrooms in simultaneous regular use, the range tops out here and a system boiler with a cylinder is the more appropriate solution.

Alpha Evoke NX Combi Range
Model output size	House size	Bathrooms	Radiators
28kW	Small to medium homes, 2 to 3 bedrooms	1 & ensuite	Up to 15
33kW	Medium homes, 3 to 4 bedrooms	1-2	Up to 20

Key benefits at a glance

• ErP A-rated efficiency (94%)
• Stainless steel heat exchanger in thermoplastic casing  
• Weather compensation probe included as standard
• Integrated filling loop (no separate loop required at installation)
• Combined condensate and pressure relief valve 
• OpenTherm compatible
• 1:6 modulation ratio
• 7-year warranty parts and labour*
• LPG model available 
• 255mm deep (compact, fits standard kitchen cupboards)

Alpha Evoke NX combi technical specifications

The heat exchanger is the component that most distinguishes the Evoke NX from boilers at a similar price. The stainless steel coil is more resistant to corrosion and limescale than aluminium exchangers, and maintains its heat transfer efficiency over a longer service life. Alpha’s current version moulds the stainless steel coil inside a composite thermoplastic casing, which reduces the weight of the assembly without compromising the exchanger itself. The result is a boiler that’s lighter to handle and harder to corrode than its price would suggest is typical.

Like all modern condensing boilers, the Evoke NX recovers heat from the flue gases that would otherwise be lost, which is what allows it to achieve its 94% ErP efficiency rating. Combined with the adjustable heating flow temperature and the included weather compensation probe, a well-installed Evoke NX will use less gas in mild weather than a fixed-output boiler, because it adjusts output to match what the house actually needs rather than firing at full capacity every time.

Output and efficiency ratings

All models in the Alpha Evoke NX series are ErP A-rated for both heating and hot water, operating at an impressive 94% efficiency. 

This efficiency is supported by a 1:6 modulation ratio, in plain English, this allows the boiler to reduce its power output to as low as 5kW during periods of low demand to avoid unnecessary energy waste. By tuning itself to use less gas, this clever little boiler helps homeowners lower their carbon footprint and reduce monthly bills. 

Dimensions 

All Evoke NX models share the same footprint: 712mm high, 440mm wide, 255mm deep. 

At 255mm this is one of the shallowest combis available in the UK market. It fits a standard kitchen cupboard without modification and is light enough for a single engineer to position on a high bracket without assistance.

Components included

Alpha pair the Grundfos pump with their hydroblock assembly, which manages water flow between the heating and hot water circuits. The Delta T variable speed operation means the pump responds to actual temperature differential rather than running at a fixed speed, which reduces energy consumption from the pump itself and contributes to the 94% efficiency figure by avoiding unnecessary circulation.

The weather compensation probe is included in the box, which is unusual at this price. It mounts externally and sends outdoor temperature data to the boiler, which then adjusts its flow temperature accordingly (running cooler on a mild day and harder on a cold one). 

Most boilers require a separate filling loop to be purchased and fitted when the system pressure drops. The Evoke NX has one built in, which removes a component from the installation list and means a homeowner can repressurise the system themselves without needing an additional valve assembly.

With a clear push-button interface with digital operating status and diagnostic display, fault codes are readable without specialist equipment, which means a first diagnostic check can happen before an engineer is called. The drop-down control panel keeps the front face clean when not in use.

Prices and installation costs

The Alpha Evoke NX sits at the budget end of the combi boiler market, offering strong value for money when its component specification is taken into account. Unit prices typically start at around £700 for the 28kW model, rising to approximately £800 for the 33kW.

These prices include the boiler unit as well as a standard horizontal flue. The flue is a critical component that safely directs combustion gases outside. A standard side-wall flue costs roughly £100, and this is the most common type of flue, but a vertical roof flue can cost up to £500 due to the increased complexity of the installation and roofing work required.

When installation is included, total costs typically fall between £1,900 and £2,000 depending on the model chosen. As with all boiler replacements, prices can vary based on factors such as flue position, pipework upgrades, and whether a system flush or magnetic filter is required.

Alpha Evoke NX Combi Costs
Output size	Unit cost (incl. flue)	Total (incl. installation)
28kW	£700	£1,900
33kW	£800	£2,000

Warranty and support

The Evoke NX comes with a 7-year parts and labour warranty. To keep it valid throughout that period, the boiler must be registered with Alpha after installation and serviced annually by a Gas Safe registered engineer. Alpha do not accept invoices for repairs carried out by third parties, any warranty call-out must be handled by Alpha or one of their approved agents.

The warranty covers manufacturing defects and component failures under normal use. It does not cover faults arising from poor system water quality, inadequate installation, or failure to maintain the annual servicing requirement. 

Seven years is a solid baseline for a boiler at this price. For homeowners who want longer cover, Alpha’s E-Tec Plus NX is the model to look at – it carries a 10-year standard warranty extendable to 13 years.

Installation information

With combination boiler installation costs typically standing at £1,200, the next thing to understand is the requirements for installation and what to expect on the day of installation. A lot can depend on your individual home, so it’s important you have a vetted Gas Safe registered installer who will be able to give you an idea of the timeline and cost of installation depending on your specific home.  

What to expect on installation day

If additional work is required – such as upgrading pipework or relocating the boiler – your installer should explain this clearly beforehand, including any impact on cost or installation time.

Do you need a system flush or filter?

A magnetic filter is mandatory under UK Building Regulations. The Evoke NX’s stainless steel heat exchanger is more resistant to scale and corrosion than aluminium alternatives, but a filter still protects the wider system and is required regardless.

A flush removes “sludge” (iron oxide) that has accumulated in your radiators over the years. A powerflush is strongly recommended on systems over ten years old, budget £350-£800.

Finding a Gas Safe registered engineer

All gas boiler installations must be carried out by a Gas Safe registered engineer. Use the WhatPrice quote service to be matched with vetted, Gas Safe registered installers in your area.

Reviews and ratings

Alpha has an impressive 4.7/5 stars on Trustpilot – for a smaller brand, that’s a sure sign of customer confidence. Let’s take a closer look at what homeowners have to say about Alpha and the Evoke NX combi:

Positive reviews

The Evoke is praised for being straightforward to commission and for generating very few callbacks after installation. One engineer who has been fitting Alpha combis for 27 years notes that the backup service on warranty work has been consistently reliable throughout. 

Another, who installs Alpha as their primary boiler choice, describes “little to no call backs whatsoever” on the Evoke and E-Tec range, and specifically calls out the component quality as something other manufacturers at this price cannot match. 

A third installer who fitted several of both the Evoke and E-Tec noted being “very impressed” with both the product and the customer service. The 7-year warranty and ease of installation are cited consistently, one engineer summarised it as “nice warranty length and easy to fit, what more can you ask for.”

On the homeowner side, one Evoke owner whose heat exchanger developed a fault at four years old reported that Alpha responded promptly and had a new heat exchanger fitted under warranty within three working days, which is about as straightforward as warranty work gets.

Negative reviews

Early component failures appear in more than one Evoke review. One homeowner had a new Evoke 33 break down on day two of installation, requiring a new motherboard. Another reported heat exchanger difficulties early in the boiler’s life, though the eventual repair itself was handled well. These are not widespread patterns, but they do appear more than once in the Evoke-specific filtered results, which is worth noting given how few reviews there are.

The integrated smart control drew criticism from one experienced installer; two engineers found the interface harder to navigate than expected. Alpha have updated the control in subsequent NX versions, but it’s a reminder that ease of installation and ease of control aren’t always the same thing.

The 33kW’s flow rate of 14.1 l/min draws occasional criticism from homeowners in homes with two bathrooms used simultaneously. It handles one bathroom comfortably and occasional two-bathroom use adequately, but under sustained simultaneous demand it can feel stretched. For a home where both bathrooms are in genuine heavy morning use, a 35kW or 40kW boiler, or a system boiler with a cylinder, is a better answer.

How the Alpha Evoke NX combi compares

Alpha Evoke NX Combi Comparison Table
Model	Alpha Evoke NX combi	Baxi 400 Combi 2.1 combi	Glow-worm Energy combi
Typical unit price	£800	£800	£1,100
Heat exchanger	Stainless steel	Stainless steel	Aluminum
Standard warranty	7 years	5 years	7 years
Max warranty	7 years	5 years	10 years
Built-in WiFi	No	No	No
App control	Alpha Connect (via OpenTherm)	Baxi uSense (sold separately)	MiGo (via gateway, sold separately)
Cupboard fit	Yes	Yes	Yes
Max output/bathrooms	33kW 1-2 bathrooms	36kW 2 bathrooms	35kW 2 bathrooms

For personalised guidance on which model suits your home, we recommend speaking with a Gas Safe registered engineer.

Final thoughts – is the Alpha Evoke NX combi right for you?

At £700 for the 28kW, the Evoke NX is in almost exactly the same price bracket as the Baxi 400 Combi 2.1, and the two are worth comparing directly. Both use stainless steel heat exchangers, both are compact enough for a standard kitchen cupboard, and both carry OpenTherm compatibility. 

The difference that matters most is the warranty. The Baxi 400 Combi 2.1 comes with 5 years, with no extension route. The Evoke NX comes with 7 years. For a boiler you’re likely to live with for 12 to 15 years, that additional 2 years of parts and labour cover is a meaningful advantage at an identical price point. The Evoke NX also ships with an integrated filling loop and a weather compensation probe; the Baxi does not include either.

The Glow-worm Energy sits around £300 more expensive at 30kW and uses an aluminium heat exchanger where the Evoke NX uses stainless steel. Aluminium scales up faster in hard water areas and requires a filter to work harder to protect it over time. The Glow-worm does offer a path to 10 years’ cover via a Club Energy installer and Power Filter, and its range extends to 35kW, which is useful for homes with higher hot water demand where the Evoke NX’s 33kW ceiling is a constraint. But for homes the 33kW can comfortably serve, the Evoke NX delivers superior heat exchanger material, an included weather compensation probe, and a 7-year warranty at significantly lower cost.

The honest ceiling is the warranty. Seven years is the maximum the Evoke NX offers, and there’s no accredited installer scheme, no filter upgrade, no route to 10 or 12 years. For homeowners for whom long warranty cover is the deciding factor, the Glow-worm Energy’s 10-year route or the Ideal Vogue Max’s 10-year standard are the more appropriate choices. For homeowners whose priority is component quality at a realistic entry-level price, with a warranty that holds up well at this bracket, the Evoke NX’s case is difficult to dismiss.

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