Opus Octave 90i 13kW Inset Wood Burning Stove

Opus

Opus Octave 90i 13kW Inset Wood Burning Stove

Customers rate us 4.9 out of 5 (103 reviews)

£1,995.00

Free delivery to England and Wales on orders over £50.

Is it right for you?

Room size: one room of up to about 76 m² with a 2.4m ceiling (rule of thumb). Check your room
Chimney: fits into a fireplace opening with a chimney, which will usually need a liner.
Fuel: dry logs only.
Fitting: must be fitted by a HETAS registered installer. Find one by postcode

What else will I need?

Free delivery to England and WalesUsually 3 to 10 working days. The courier usually contacts you to book a day. Scotland and Northern Ireland charges are shown at checkout.

Questions before you buy? Ask us on WhatsApp

30 days to change your mind
Manufacturer's UK warranty
UK suppliers

13kWHeat output
Wood BurningFuel
Ecodesign2022 compliant
81.3%Efficiency
3 yearsWarranty

The Opus Octave 90i is a wide inset wood burning stove with an almost metre-wide window, built into a wall or chamber so the fire becomes part of the room. It runs at 13kW nominal, or down to 4.3kW, at 81.3% efficiency, enough for large open-plan spaces.

Why choose the Octave 90i

Window close to a metre wide, with a 50mm four-sided frame included.
13kW nominal, turning down to 4.3kW; 81.3% efficient, energy class A+, Ecodesign ready.
Takes logs up to 800mm long.
Adjustable flue baffle that your installer can tune to the chimney.
200mm top flue and an optional 100mm outside air kit.

Full details and specifications

What you'll need

Everything to get this stove lit

A stove on its own isn't enough. Here's what comes in the box, what else you'll need, and what your installer brings.

In the box

Heat-resistant glove; baffle plate

You'll also need

A carbon monoxide alarm. Required by law in the room with the stove.
Stove pipe to connect it to the flue. Your installer will tell you the length.
A hearth for it to stand on, if you don't already have one.
A chimney liner or twin-wall flue. Your installer supplies this.

Your installer brings

A liner sized to the stove, fitted up your chimney, after the chimney has been swept and checked.

Fitting, testing and a certificate showing it meets Building Regulations. Keep it for your home insurer and for when you sell.

Ask for one quote that covers the survey, flue, fitting and certificate. Using someone who isn't HETAS registered? Your local building control must approve the work before you use the stove.

Find a HETAS installer by postcode Got your installer's parts list? Email it and we'll price what we sell How flues and installation work

How buying a stove works

Check it fitsUse our size calculator, or email us a photo of your fireplace and the room size and we'll suggest stoves that suit.
Book a HETAS installerThey survey the chimney, quote for the flue and fitting, and tell you which parts to order.
We deliverFree to England and Wales, usually within 3 to 10 working days. It weighs 150kg, so have help and a sack truck ready. Book the fitting date once it has arrived.
Your installer fits itThey fit the stove and CO alarm, test it and register it. You get a certificate to keep.

The numbers, in plain English

13kW heat output: Enough for a room of about 76 m² with a 2.4m ceiling (rule of thumb)
81.3% efficient: How much of the fuel's heat it turns into useful heat
200mm flue: The flue size your installer needs
80cm logs: The longest log it takes
H 535 x W 940 x D 440 mm: Size (height x width x depth)
150kg: Heavy: it needs at least two people and a sack truck to move

Full specifications, clearances and the manual are further down the page.

About this product

Will it suit your space?

As a rough guide, an average room needs about 1kW for every 14 cubic metres, so its 13kW suits around 182 cubic metres. Older, draughty or high-ceilinged rooms need more, and a heat-loss check by your installer gives the right answer.

The 90i is 535mm high, 940mm wide and 440mm deep, and it weighs 150kg. The opening needs at least 80mm clearance round the casing, and optional vents at the top and bottom of the chamber recover more heat.

Specifications

Model	Opus Octave 90i inset
Heat output	13kW nominal; down to 4.3kW
Efficiency	81.3%, energy class A+
Fuel	Wood logs only, up to 800mm long
Dimensions	H 535 x W 940 x D 440mm
Weight	150kg
Frame	50mm four-sided frame included
Flue	200mm, top outlet (centre 194mm from the back)
Outside air	100mm, with the optional direct air kit
Installation gap	At least 80mm between the casing and the chamber walls
Ecodesign	Ecodesign ready
Smoke control	Not on DEFRA's exempt list for England
Warranty	3 years (glass, seals, grate and firebricks excluded)

What's in the box

A heat-resistant glove; the baffle plate is packed inside the firebox.

Installation and safety

Have it fitted by a HETAS-registered installer or signed off by Building Control, with a carbon monoxide alarm in the same room. Leave at least 80mm between the casing and the walls of the opening, never block the casing slots, and keep 400mm to combustibles at the sides and 1500mm in front.

Questions

Can I use it in a smoke control area?

No. Unlike the Octave 70 models, the 90i is not on DEFRA's list of exempt appliances for England.

What does the adjustable flue baffle do?

It stops the stove over-drawing and gives more control over the burn rate. It opens automatically when you open the door, and your installer can set its closed position to suit a strong or weak chimney draught.

How long can the logs be?

Up to 800mm, according to Opus.

See more inset stoves, the full Opus range and Ecodesign stoves.

Delivery

Free delivery to England and Wales. Standard items usually arrive in 3 to 7 working days; large and heavy items in 3 to 10 working days. The courier normally contacts you to book a day. Scotland and Northern Ireland charges are shown at checkout.

Delivery policy

Returns

You have 30 days from delivery to change your mind, with no restocking fees. Returns after day 14 must be unused, uninstalled and in the original packaging. If we collect, it costs £90 for a single pallet item or £150 for two-person and multi-pallet deliveries; garden buildings, and collections from Scotland, Northern Ireland, the Highlands and islands, are priced before booking and never cost more than £250. Items made to your specification are excluded, and faulty or damaged goods are collected free.

Return and refund policy

Warranty

3 year manufacturer's warranty. The manufacturer's warranty terms apply, which can include registering the product, professional installation and annual servicing. Your rights under the Consumer Rights Act are not affected.

Installation and safety

In England and Wales, installing a solid fuel appliance is notifiable building work: use a HETAS registered installer, or apply to Building Control before the work starts. Scotland and Northern Ireland have their own building standards.
Building Regulations require a carbon monoxide alarm in the room when a solid fuel appliance is installed.
In a smoke control area you can only burn wood in an exempt appliance; otherwise you must use an authorised smokeless fuel. Check before you buy.

Not sure it will fit?

Send us a photo and the measurements of your room, fireplace or garden and we’ll check it for you.

Ask on WhatsApp

Why buy from Glowing Flames?

Free delivery

Free to England and Wales on orders over £50 (£9.99 below that). Large items come on a pallet and the courier books a day with you.
Real advice

Not sure it will fit or work with your chimney? Send us a photo and we will check.
UK warranties

Supplied by the manufacturer or its UK distributor, with the manufacturer’s UK warranty and spares.
30 days to change your mind

Change your mind up to 30 days after delivery, with no restocking fees and fixed collection prices for large items.

Opus Octave 90i 13kW Inset Wood Burning Stove