The best storage combi boilers in 2026 are the Viessmann Vitodens 111-W, the Viessmann Vitodens 222-F, the Vaillant ecoTEC plus Combi Store, the Glow-worm Energy Store 35, and the Worcester Bosch Greenstar 8000 Style Combi.
These five models lead the category because they solve a genuine gap in the market, giving larger homes strong, consistent hot water flow without needing the full loft tank and separate cylinder that a traditional system boiler requires.
Below, we break down each of these boilers in detail so you can decide whether one genuinely suits your home.
5 Best Storage Combi Boilers: A Quick Look
The best storage combi boilers all deliver stronger simultaneous hot water flow than a standard combi, but they differ noticeably on internal cylinder size, dimensions, and price. Here’s a quick comparison to help you narrow things down.
| Boiler | Best For | Internal Cylinder | Flow Rate | Efficiency | Installed Cost | Warranty | Trustpilot Score |
| Viessmann Vitodens 111-W | Wall mounted flexibility with strong flow | 46 litres | 18 litres/min | A-rated | £3,200–£4,200 | 10 years | 4.6/5 |
| Viessmann Vitodens 222-F | Largest homes with heaviest demand | 100 litres | Equivalent to 300L cylinder | A-rated | £3,800–£4,800 | 10 years | 4.6/5 |
| Vaillant ecoTEC Plus Combi Store | Balanced performance and efficiency | 15 litres | 20 litres/min | A-rated, 89% | £3,000–£4,000 | 10 years | 4.5/5 |
| Glow-worm Energy Store 35 | Budget friendly stored hot water | 2 x 21 litres | Strong dual tank flow | A-rated | £2,800–£3,700 | 8–10 years | 4.1/5 |
| Worcester Bosch Greenstar 8000 Style Combi | Trusted brand with premium finish | Built in storage | Strong flow rate | A-rated, 94% | £3,300–£4,300 | 10–12 years | 4.5/5 |
5 Best Storage Combi Boilers Reviewed By Our Experts
The best storage combi boilers each suit slightly different property sizes and hot water demands, so it’s worth understanding what genuinely sets each one apart. Here’s our detailed breakdown of each model.
1. Viessmann Vitodens 111-W: Best For Wall Mounted Flexibility With Strong Flow
The Viessmann Vitodens 111-W has become the benchmark storage combi boiler for larger flats and family homes that need genuinely strong hot water flow without sacrificing wall mounted convenience.
Viessmann built this model around its cylinder loading system technology, which continuously draws cooler water from the bottom of the internal cylinder and reheats it through a plate heat exchanger, keeping the stored water consistently hot and ready.
Despite housing a 46 litre stainless steel cylinder internally, the unit still mounts on the wall like a standard combi boiler, saving valuable floor space.
| Feature | Detail |
| Dimensions | 950 x 600 x 500mm |
| Internal cylinder | 46 litres, stainless steel |
| Flow rate | 18 litres per minute |
| Efficiency | A-rated |
| Warranty | 10 years |
| Installed price | £3,200–£4,200 |
Specs and features: The boiler includes a 46 litre stainless steel loading cylinder, a stainless steel Inox-Radial heat exchanger, a variable speed combustion fan, and full compatibility with tado smart thermostats for remote control.
Efficiency: It carries an A-rated efficiency, with the stainless steel heat exchanger helping the unit retain that performance more consistently than boilers using cheaper aluminium components.
Estimated cost of the unit: The boiler alone typically costs between £1,800 and £2,600, reflecting the added complexity of the internal cylinder and loading system.
Cost with installation: Once fitted, most households pay between £3,200 and £4,200, higher than a standard combi given the additional engineering involved in the storage element.
Running costs: Running costs sit competitively for a storage combi boiler, and the strong 18 litres per minute flow rate means multiple outlets can run simultaneously without the pressure drop seen in a standard combi boiler under heavy demand.
Which? and Trustpilot ratings: Viessmann holds Which? Recommended Provider status and an excellent 4.6 out of 5 on Trustpilot, with customers regularly highlighting strong hot water performance and long term reliability.
Should You Choose The Viessmann Vitodens 111-W?
Choose the Viessmann Vitodens 111-W if…
- You want strong simultaneous hot water flow without a separate tank and cylinder
- Your property has limited floor space but can accommodate a wall mounted unit
- You have two or more bathrooms with regular simultaneous use
- You value stainless steel construction for long term durability
Do not choose the Viessmann Vitodens 111-W if…
- Your household has light hot water demand better served by a standard combi
- You want the absolute lowest unit and installation price
- Floor space isn’t restricted and a full system boiler with cylinder would suit better
2. Viessmann Vitodens 222-F: Best For Largest Homes With Heaviest Demand
The Viessmann Vitodens 222-F sits at the top of the storage combi category, designed specifically for large family homes where even the strongest wall mounted models simply wouldn’t provide enough stored hot water.
This floor standing unit houses a genuinely substantial 100 litre hot water tank, delivering performance equivalent to a stand alone 300 litre system cylinder, all while remaining compact enough to fit into a kitchen or utility room.
It’s the model Viessmann recommends when a household’s hot water demand genuinely exceeds what any wall mounted combi, storage or otherwise, could reasonably handle.
| Feature | Detail |
| Type | Floor standing |
| Internal cylinder | 100 litres |
| Equivalent to | 300 litre system cylinder |
| Efficiency | A-rated |
| Warranty | 10 years |
| Installed price | £3,800–£4,800 |
Specs and features: The boiler includes a 100 litre internal hot water tank, a stainless steel heat exchanger, floor standing installation, and full compatibility with smart thermostat controls for remote scheduling.
Efficiency: It carries an A-rated efficiency, matching the performance of Viessmann’s wall mounted range despite the significantly larger storage capacity.
Estimated cost of the unit: The boiler alone typically costs between £2,400 and £3,300, reflecting the substantially larger cylinder capacity and floor standing build.
Cost with installation: Installed costs typically range from £3,800 to £4,800, the highest on this list, but genuinely justified for households that would otherwise struggle with any smaller alternative.
Running costs: Running costs sit in line with other A-rated storage combi boilers, and the large internal tank means the unit rarely runs out of hot water even during periods of exceptionally heavy simultaneous use across multiple bathrooms.
Which? and Trustpilot ratings: Viessmann holds Which? Recommended Provider status and an excellent 4.6 out of 5 on Trustpilot, with customers regularly highlighting the model’s ability to handle large family demand without compromise.
Should You Choose The Viessmann Vitodens 222-F?
Choose the Viessmann Vitodens 222-F if…
- Your household has genuinely exceptional hot water demand across several bathrooms
- You have suitable floor space in a kitchen or utility room
- You’ve outgrown even a strong wall mounted storage combi
- Long term reliability matters more to you than the lowest upfront cost
Do not choose the Viessmann Vitodens 222-F if…
- You need a wall mounted unit due to limited floor space
- Your household’s hot water demand is moderate rather than exceptional
- You want the lowest installed price among storage combi options
3. Vaillant ecoTEC Plus Combi Store: Best Balanced Performance And Efficiency
The Vaillant ecoTEC plus Combi Store has earned a strong reputation for delivering an impressively high flow rate relative to its more modest internal cylinder size, making it a genuinely clever engineering solution for homes with strong but not extreme hot water demand.
Vaillant designed this model to produce 20 litres per minute of hot water when needed, then modulate down to use as little as 16% of its full power once demand drops, balancing performance with sensible energy use. It’s a popular choice for households that want storage combi benefits without the largest, most expensive units on this list.
| Feature | Detail |
| Available outputs | 25kW, 32kW |
| Internal cylinder | 15 litres |
| Flow rate | 20 litres per minute |
| Efficiency | A-rated, 89% |
| Warranty | 10 years |
| Installed price | £3,000–£4,000 |
Specs and features: The boiler includes a 15 litre internal cylinder, a fully modulating pump, wifi connectivity for remote scheduling, and compact enough dimensions to fit into most standard installation spaces.
Efficiency: It carries an A-rated efficiency of around 89%, slightly behind the Viessmann models but still comfortably meeting current UK regulatory standards for new gas boiler installations.
Estimated cost of the unit: Pricing for the boiler alone generally sits between £1,600 and £2,300.
Cost with installation: Installed costs typically range from £3,000 to £4,000, making it one of the more accessible storage combi options despite its strong flow rate.
Running costs: Running costs benefit from the boiler’s ability to modulate down significantly once hot water demand eases, helping keep energy use sensible compared to running at full power constantly.
Which? and Trustpilot ratings: Vaillant holds Which? Recommended Provider status and scores 4.5 out of 5 on Trustpilot, with reviewers often mentioning strong flow rate performance relative to the unit’s price.
Should You Choose The Vaillant ecoTEC Plus Combi Store?
Choose the Vaillant ecoTEC plus Combi Store if…
- You want a strong flow rate without the largest, most expensive storage combi on the market
- Your household has good but not extreme simultaneous hot water demand
- You value smart modulation that reduces energy use once demand eases
- You want proven German engineering with a strong UK track record
Do not choose the Vaillant ecoTEC plus Combi Store if…
- Your household has genuinely exceptional hot water demand across several bathrooms
- You want the very highest efficiency figure on this list
- You’d prefer the largest available internal cylinder capacity
4. Glow-worm Energy Store 35: Best Budget Friendly Stored Hot Water
The Glow-worm Energy Store 35 gives homeowners a genuinely more affordable route into storage combi technology, using an unusual dual tank design with two separate 21 litre cylinders rather than the single larger tank found in rival models.
Glow-worm is part of the same manufacturing group as Vaillant, which means it benefits from shared engineering knowledge while sitting at a noticeably lower price point across the range. It’s a sensible option for households that want stronger hot water flow than a standard combi without stretching to the premium Viessmann or Vaillant storage models.
| Feature | Detail |
| Internal cylinder | 2 x 21 litres |
| Efficiency | A-rated |
| Warranty | 8–10 years |
| Installed price | £2,800–£3,700 |
Specs and features: The boiler includes two separate 21 litre cylinders working together, a straightforward digital display, and reliable modulation across its available output range.
Efficiency: It carries an A-rated efficiency, a solid figure that keeps it competitive against pricier storage combi alternatives despite the lower unit cost.
Estimated cost of the unit: The boiler alone typically costs between £1,200 and £1,800, among the most affordable storage combi options available.
Cost with installation: Installed pricing generally runs from £2,800 to £3,700, making it the most accessible entry point into storage combi technology on this list.
Running costs: Running costs are broadly comparable to other A-rated storage combi boilers, and the dual tank design provides a sensible buffer for moderate to strong simultaneous hot water use.
Which? and Trustpilot ratings: Glow-worm has not featured prominently in recent Which? surveys, but it holds a reasonable 4.1 out of 5 on Trustpilot, with reviewers often mentioning good value for money as a key strength.
Should You Choose The Glow-worm Energy Store 35?
Choose the Glow-worm Energy Store 35 if…
- You want the lowest entry price into storage combi technology
- Your household has moderate rather than exceptional hot water demand
- You’re comfortable with a shorter warranty than the premium options on this list
- You don’t need the very largest internal cylinder capacity available
Do not choose the Glow-worm Energy Store 35 if…
- You want the longest possible warranty on this list
- Brand recognition matters to you for future resale value
- Your household has genuinely exceptional simultaneous hot water demand
5. Worcester Bosch Greenstar 8000 Style Combi: Best Trusted Brand With Premium Finish
The Worcester Bosch Greenstar 8000 Style Combi rounds out this list by bringing the brand’s decades of trust and enormous nationwide installer network into the storage combi category, appealing to homeowners who value brand reassurance alongside genuine performance.
Worcester Bosch has built this model to compete directly with the premium Viessmann and Vaillant storage combi offerings, backing it with the same extensive UK aftercare network the brand is known for across its entire boiler range. It’s a strong choice for households that want the storage combi benefits without straying from Britain’s most recognised heating brand.
| Feature | Detail |
| Efficiency | A-rated, 94% |
| Warranty | 10–12 years |
| Installed price | £3,300–£4,300 |
Specs and features: The unit includes built-in storage for stronger simultaneous hot water flow, a premium colour display, and full compatibility with Worcester’s own EasyControl smart thermostat range.
Efficiency: It carries an ErP A rating with a 94% efficiency score, among the strongest figures of any storage combi boiler on this list.
Estimated cost of the unit: The boiler alone typically costs between £1,900 and £2,700 depending on output and configuration.
Cost with installation: Once fitted, most households pay between £3,300 and £4,300, reflecting the brand’s premium positioning within the storage combi category.
Running costs: Running costs stay competitive thanks to the strong efficiency rating, matching the performance you’d expect from Worcester’s standard combi range despite the added storage element.
Which? and Trustpilot ratings: Worcester Bosch holds Which? Recommended Provider status and a strong 4.5 out of 5 rating on Trustpilot, with reviewers consistently praising the brand’s aftercare and long term dependability.
Should You Choose The Worcester Bosch Greenstar 8000 Style Combi?
Choose the Worcester Bosch Greenstar 8000 Style Combi if…
- You want a well known, trusted brand backed by a huge installer network
- You value the highest efficiency figure available in this category
- You’re comfortable extending your warranty through a qualifying installation
- Brand reassurance matters for tenant satisfaction or future resale
Do not choose the Worcester Bosch Greenstar 8000 Style Combi if…
- You want the lowest possible entry price into storage combi technology
- You’re prioritising the largest internal cylinder capacity available
- You’d prefer a heat exchanger built specifically for long term corrosion resistance
How We Choose The Best Storage Combi Boilers
We chose the best storage combi boilers by combining hands-on installation experience gathered from fitting these specialist units in larger UK homes with independent data from trusted third party sources. As nationwide installers working with homeowners and landlords every single day, our recommendations reflect what genuinely performs well under real heavy hot water demand, not just impressive sounding spec sheets.
- Verified manufacturer data on internal cylinder size, flow rate, and warranty terms directly against official documentation from Viessmann, Vaillant, Glow-worm, and Worcester Bosch
- Cross referenced independent scoring from Which? and Trustpilot to balance technical performance against genuine customer satisfaction
- Drew on feedback from our own Gas Safe registered installer team, who fit these exact models regularly in larger UK properties with heavy simultaneous hot water demand
- Compared unit and installed pricing across multiple UK suppliers to ensure figures reflect real market conditions rather than inflated list prices
- Prioritised boilers genuinely suited to households that have outgrown a standard combi but don’t have space or need for a full system boiler with separate cylinder
- Considered the needs of both homeowners and landlords, including larger rental properties with multiple bathrooms where consistent hot water pressure matters
How To Choose The Best Storage Combi Boiler For Your Property
Choosing the best storage combi boiler for your property comes down to confirming your household genuinely has the kind of heavy simultaneous hot water demand this boiler type is designed to solve. Work through this checklist before making your final decision.
- Confirm a storage combi genuinely suits your needs, since they work best for homes that have outgrown a standard combi but don’t have the space or requirement for a full system boiler with a separate loft tank
- Check your available installation space, since wall mounted models like the Viessmann Vitodens 111-W suit tighter spaces while floor standing units like the Vitodens 222-F need more room in a kitchen or utility area
- Compare internal cylinder sizes carefully, since a larger stored capacity supports more simultaneous outlets without a pressure drop during particularly busy periods
- Think about your household size and bathroom count, since storage combi boilers particularly shine in homes with two or more bathrooms used at the same time
- Factor in the higher installation cost compared to a standard combi, since the added engineering and specialist internal cylinder typically increases the overall price
- Compare warranty terms across models, since some manufacturers offer a full 10 year warranty as standard while others provide shorter cover on entry level storage combi models
- Ask about smart thermostat compatibility if you want to manage your heating and stored hot water remotely across a larger property
- Get a proper home survey before committing, since correctly sizing the internal cylinder and output for your specific household’s hot water habits is essential for reliable long term performance
Get The Right Storage Combi Boiler Installed Without The Hassle
Choosing the right storage combi boiler is only half the job. To get the best performance, efficiency, and lifespan, it also needs to be correctly sized and professionally installed. At Eazy Heat, we install high-quality storage combi boilers for homeowners and landlords across the UK, helping you find the right solution for properties with higher hot water demands.
With our simple online quotation tool, you can receive a fixed-price boiler installation quote in just a few minutes. Every installation is carried out by a Gas Safe registered engineer and comes with a market-leading 12-year parts and labour warranty, giving you complete confidence in your investment.
Whether you’re replacing an ageing boiler or upgrading to a storage combi for improved hot water performance, Eazy Heat makes the process fast, straightforward, and stress-free. Get your free online boiler quote today and discover how affordable your new storage combi boiler installation could be.
FAQs
Does a storage combi boiler run out of hot water like a traditional cylinder eventually would?
A storage combi boiler is designed to continuously reheat its internal cylinder using cylinder loading technology, drawing cooler water from the bottom and reheating it through the heat exchanger, so it’s far less likely to run out of hot water compared to a traditional stand alone cylinder that simply depletes once its stored supply is used. This continuous reheating is what allows a storage combi to supply significantly more simultaneous hot water than a standard combi boiler drawing purely from the mains.
Can a storage combi boiler be fitted where a standard combi previously was?
A storage combi boiler can often replace a standard combi boiler in the same general location, though the larger case size and internal cylinder mean the available space needs to be checked carefully, particularly for wall mounted models with a greater depth than typical combi boilers. Floor standing storage combi models will usually require different positioning than a wall mounted standard combi previously occupied.
Do storage combi boilers need more frequent servicing than standard combi boilers?
Storage combi boilers generally follow the same annual servicing schedule as standard combi boilers, though the additional internal cylinder and cylinder loading components mean a Gas Safe engineer may need slightly longer to complete a thorough inspection. It’s worth confirming with your installer whether the specific model you choose has any manufacturer specific servicing recommendations beyond the standard annual check.
Is a storage combi boiler noisier than a standard combi boiler due to the internal cylinder?
Storage combi boilers are not inherently noisier than standard combi boilers, since the continuous reheating process using the cylinder loading system typically runs quietly in the background rather than producing noticeable noise during normal operation. Premium models with well engineered pumps and fans, such as those from Viessmann, tend to run particularly quietly despite the added internal complexity.
Can a storage combi boiler be combined with solar thermal panels for extra efficiency?
Some storage combi boiler models can be integrated with solar thermal panels to pre-heat the internal cylinder before the boiler tops up any remaining shortfall, potentially reducing gas usage during sunnier months, though this compatibility varies by manufacturer and specific model. It’s worth checking directly with your installer whether your chosen storage combi boiler supports solar thermal integration before committing to this combination.