UK landlords searching for the best storage combi boilers need space-saving solutions that deliver strong hot water flow rates for multiple bathrooms or high-demand tenancies, combining combi convenience with integrated small-cylinder storage to reduce pressure drops and improve tenant satisfaction while supporting EPC improvements.
The 2 Best Storage Combi Boilers: At a Glance
The top storage combi boilers for landlords in 2026 feature integrated hot water stores of 46 to 100 litres, A-rated condensing efficiency for EPC C compliance, extended warranties to limit repair risk in rentals, and reliable Gas Safe servicing networks. These models suit larger flats, family homes, or HMOs without needing a full separate cylinder.
| Model | Efficiency (ErP) | Typical Unit Cost | Installed Cost (approx.) | Warranty (accredited install) | Owner Reviews | Key Landlord Benefit |
| Viessmann Vitodens 111-W | A-rated | £2,250–£2,425 (list price) | Quote-based | Up to 12 years | Highly rated | 46-litre store in a compact wall-hung unit |
| Viessmann Vitodens 222-F | A-rated | Price on request | Quote-based | Up to 7 years | — | 100-litre integrated cylinder for higher demand |
Notes: Storage combis are now a niche product in the UK. Models that used to appear on lists like this one, including the Worcester Bosch Greenstar Highflow 440CDi and 550CDi, the Vaillant ecoTEC plus 937 and the Glow-worm Energy Store, are no longer part of their manufacturers’ current ranges, which is why only two current models make this list. Unit prices are list or indicative prices at the time of writing; installed costs depend on the property, flue and any system upgrades.
Landlords upgrading heating in high-demand rental properties can request a combi boiler installation quote for expert sizing advice, EPC compliance support and professional installation.
1. Viessmann Vitodens 111-W
The Viessmann Vitodens 111-W is a wall-hung storage combi with a 46-litre stainless steel store built into the casing. It gives stronger hot water delivery than a standard combi without needing a separate cylinder, which suits flats and family rentals where only wall space is available. Our full Viessmann Vitodens 111-W review covers it in more detail.
Specifications and features: 25kW and 32kW models, a 46-litre stainless steel integrated store, and a compact wall-hung design with front-accessible connections and no side clearances needed for servicing.
Efficiency: ErP A-rated for heating.
Boiler unit cost: around £2,250 (25kW) to £2,425 (32kW) including VAT at Viessmann’s list price at the time of writing. Installed cost depends on the property, so get a fixed quote.
Warranty: up to 12 years when registered through Viessmann’s VPlus installer programme (terms apply). It is well reviewed by owners.
2. Viessmann Vitodens 222-F
The Viessmann Vitodens 222-F is a floor-standing storage combi with a 100-litre integrated hot water cylinder. Its larger store makes it the better fit of the two for busier homes and rentals with more than one bathroom, provided there is floor space for the unit. See our Viessmann Vitodens 222-F review for more.
Specifications and features: 1.9 to 32kW heating output range, a 100-litre integrated cylinder, and Lambda Pro Plus combustion control.
Efficiency: ErP A-rated for heating.
Boiler unit cost: varies by output and supplier, so ask your installer for a current price. Installed cost depends on the property, so get a fixed quote.
Warranty: up to 7 years when registered through Viessmann’s VPlus installer programme (terms apply).
How to Choose the Best Storage Combi Boiler
Choosing the best storage combi boiler for a landlord’s rental property means balancing integrated store size against hot water demand, efficiency for EPC ratings, warranty length to minimise repairs during tenancies, and service network coverage.
Choose the Viessmann Vitodens 111-W if you need better hot water performance than a standard combi but only have wall space for the boiler.
Don’t choose the Vitodens 111-W if several showers are regularly used at the same time for long periods, as its 46-litre store is the smaller of the two.
Choose the Viessmann Vitodens 222-F if you have floor space and want the larger 100-litre store for a busier home or rental.
Don’t choose the Vitodens 222-F if the boiler has to fit on a wall or in a small kitchen cupboard.
As both models are made by Viessmann, it’s worth checking that local installers are experienced with the brand before committing.
Alternatives to a Storage Combi Boiler
Storage combi boilers are one option among several worth weighing up depending on a property’s specific hot water demand.
For a smaller property where a storage combi is not needed, our guide to the best combi boilers covers standard combi options instead, while the best 40kW combi boilers are worth comparing for a property with high simultaneous demand that a storage combi still might not fully cover.
Need a New Storage Combi Boiler Quote?
Upgrading to one of the best storage combi boilers helps landlords provide reliable, high-flow hot water in rentals, improve EPC scores, and reduce complaints. Requesting a new boiler quote is a good next step for tailored advice, transparent pricing, and accredited Gas Safe installation. Landlords managing a portfolio can also compare our pick of the best boilers for landlords. Any installation should be carried out by an engineer listed on the Gas Safe Register.
Best Storage Combi Boilers: FAQs
Are Storage Combi Boilers Suitable for Very High Simultaneous Hot Water Demand?
Yes, the integrated store provides a buffer for multiple showers or taps, but an extremely high-demand HMO may still benefit from one of the best system boilers paired with a larger cylinder instead.
How Do Storage Combi Boilers Affect EPC Ratings Compared With Standard Combis?
The higher effective hot water efficiency can improve SAP calculations and EPC scores, helping landlords meet the 2030 EPC C minimum more easily.
Are Storage Combi Boilers Hydrogen-Ready?
Many top models, such as the Viessmann Vitodens 111-W, are 20% hydrogen blend ready, offering a low-disruption route to lower carbon emissions should hydrogen blending be introduced to the gas grid.
What Servicing Do Storage Combi Boilers Need in Rented Properties?
Annual Gas Safe checks are mandatory, and the integrated store adds only minimal extra maintenance, though it does need periodic checks for scale and pressure to keep performing at its rated output.
Can Landlords Deduct Storage Combi Boiler Costs as Tax Expenses?
Yes, replacement boilers generally qualify as revenue repairs, deductible against rental income, while some efficiency upgrades may qualify for grants. It is worth checking current guidance or consulting an accountant for a specific property’s situation.
Are Storage Combi Boilers Bigger Than Standard Combis?
Storage combi boilers are noticeably larger and heavier than a standard combi of the same output, due to the built-in cylinder, so it is worth confirming the unit will fit the intended cupboard or utility space before committing to a specific model, particularly in a smaller flat.
Do Storage Combi Boilers Cost More to Run Than a Standard Combi?
Running costs are broadly comparable, since both are A-rated condensing units, though the storage combi’s integrated cylinder does lose a small amount of standing heat over time. In practice, this is generally offset by more consistent, efficient operation during peak demand, when a standard combi might otherwise struggle to keep up.
I’m Penny North, a home energy heating expert. My mission is to demystify new boilers and complex heating systems to help you achieve a warm, cosy home with lower energy bills and a smaller environmental footprint.