Cozy Heat OG Thru-Wall 18 Sauna Stove Cozy Heat

Cozy Heat OG Thru-Wall 18 Sauna Stove (18 kW)

Name: Cozy Heat OG Thru-Wall 18 Sauna Stove (18 kW)
Brand: Cozy Heat
SKU: COZYOGTW18
Price: 2857.50 USD
Availability: InStock

$2,857.50 USD

$3,175.00 USD

You Save $317.50 (10% Off)

Cozy Heat

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Complete your sauna

Your complete setup

We’ve already picked everything this model needs. Change anything you like, then add it all in one go.

Chimney

Stones

Holds 240 lb of stones — 6 × 44 lb boxes covers it.

Nice to haveOptional. Tick anything you’d like included.

Cozy Heat Chimney Cover OG H500 $715.50

Cozy Heat Chimney Cover OG H700 $787.50

Harvia Smoke Pipe, Sauna Wood Stove, 1m, 115mm (WZ100M) $161.00

Harvia Sauna, Smoke Pipe, 0.5M/115MM (WZ050M) $115.00

Harvia Wood-Burning Sauna Stove Firewood Carrier, Black (SASPO102) $210.00

Harvia Sauna Bucket and Ladle Set (SA011M) $97.00

Harvia Steel Bucket and Ladle w/ Thermometer and Hygrometer (SA007) $300.00

Harvia Sauna Thermometer, Thermo-Aspen, Celsius (SASPO104) $94.00

Harvia Sauna Wood Paraffin Oil, 16.9oz (500ml) (SAC25060) $31.00

Total—

Description

The Cozy Heat OG Thru-Wall 18 is an 18 kW wood-burning sauna stove for rooms of 317–635 cubic feet. It holds 240 lb of stones (sold separately), needs no electrical supply, and requires a code-compliant chimney. The firebox extends through the sauna wall, so wood is loaded from the room next door.

Wood-fired sauna stoves create a mild and long-lasting heat. Designed for pouring water over hot stones for an intense steam and a more satisfying sauna experience.

Smoke gases are 6x cleaner
Stove utilizes 25%-40% less fuel than comparable sauna stoves
Boasts minimal safety distances
Floor mount thru-wall

What's Included

In the Box
Outer frame of the heater, Chimney pipe, Heater body, Cleaning hatch, Heater door with glass, Ash box, Installation and operation manual

Required to Operate

These are not included. You need them before the sauna will run.

Sauna Stones
240 lb capacity. Cozy Heat specifies split-face or rounded stones: 6 boxes of Cozy Stone (split-face, 44 lb each — 264 lb) or 8 boxes of Cozy Round (rounded, 33 lb each — 264 lb). Never fire the stove empty. Chimney
A listed, code-compliant chimney system, plus floor protection where the manual or local code requires it. Cozy Heat supplies no chimney kit — the file lists Harvia chimney kits for this stove.

Product Specifications

Cozy Heat Part Number	COZYOGTW18
Power Output	18 kW
Sauna Room Volume	317–635 cu ft
Stone Capacity	240 lbs
Primary Fuel	Wood
Maximum Firewood Length	15.74" (400mm)
Firewood Diameter	3.15" to 4.72" (80mm-120mm)
Flue Connection	Top
Color / Finish	Black Steel
Material	STEEL
Dimensions	30.11" - 31.69"D x 22.04"W x 29.72"H
Weight	199 lbs
Shipping Weight	463 lbs
Installation	FLOOR/THRU-WALL
Certification	German BIMSCH certificate
Warranty	2 years (limited)
Ships	LTL freight, curbside
Made In	Estonia

Marks as supplied by Cozy Heat: German BIMSCH certificate. Requirements vary by jurisdiction — confirm with your building department and insurer before you install.

Clearances & Safety Distances

The minimum distance to combustible surfaces, as published by Cozy Heat. Measure before you frame the bench.

To the Sides
9.05" (230mm) Behind
9.05" (230mm) In Front
19.68" (500mm) Minimum Room Height
82" (2096mm)

These are minimums to combustible material, not recommendations. Your installation manual and local code take precedence, and a solid-fuel appliance normally needs a permit and an inspection in the US.

Sizing

The Cozy Heat OG Thru-Wall 18 is rated for 317–635 cubic feet.

Measure width × depth × height in feet. Add extra volume for anything that soaks up heat rather than reflecting it — glass, tile, concrete, stone and exposed log all make a room behave larger than its raw measurement. Size to the larger number.

Model	Output	Room Volume	Stones	Loading
OG 12	12 kW	210–423 cu ft	175 lbs	Inside the room
OG 18	18 kW	317–635 cu ft	240 lbs	Inside the room
OG Thru-Wall 12	12 kW	210–423 cu ft	175 lbs	Through the wall
OG Thru-Wall 18	18 kW	317–635 cu ft	240 lbs	Through the wall

Work out your room with the sauna heater size calculator

Accessories for This Model

What Cozy Heat lists for this stove. All sold separately.

Chimney Cover
Cozy Heat Chimney Cover OG H500, Cozy Heat Chimney Cover OG H700 Sauna Stones
Cozy Stone, Cozy Round Chimney Kit
Harvia Chimney & Assembly Kit, Barrel, Flat Roof — Cozy Heat supplies no chimney system of its own, so the file lists Harvia

Installation & Use Notes

Mount to the clearances published above. They are minimums to combustible material, not recommendations.
The firebox extension passes through the sauna wall, so wood is loaded from the next room and no smoke, ash or cold air enters the hot room. The wall opening has to be framed to the manual before the stove goes in.
Confirm your flue diameter and that a top connection suits your build before ordering chimney components.
A solid-fuel appliance normally needs a permit and an inspection in the US, and your insurer will usually want to see the sign-off.
Load stones loosely by hand so air moves between them, and re-stack once a year, replacing any that have cracked.

FAQs

How does the Thru-Wall version work?

The firebox extends through the sauna wall so you load wood from the adjoining room. No smoke, ash or cold air enters the hot room, and you are not stepping over bathers to feed the fire. The wall opening has to be framed to the installation manual before the stove is set.

How many boxes of stones do I need?

The stove holds 240 lb. That is 6 boxes of split-face Cozy Stone at 44 lb, or 8 boxes of rounded Cozy Round at 33 lb. Stones are not included, and Cozy Heat recommends ordering one spare box so you can pick the best-fitting stones.

Is a chimney included?

No. Cozy Heat supplies the stove with its own chimney pipe section, but not a full chimney system. Your supplier file lists Harvia chimney kits for this stove, and they are linked above. A solid-fuel installation normally needs a permit and an inspection.

Downloads

Installation & Operation Manual
Cozy Heat Warranty

Cozy Heat OG Thru-Wall 18 Sauna Stove (18 kW)

$2,857.50 USD

$3,175.00 USD

FAQ

Ordering & Payment

Are you an authorized dealer?

Yes. We're an authorized dealer for every brand we carry, so your purchase includes the full manufacturer warranty.

Do you offer financing?

Yes. You can pay over time with Shop Pay Installments at checkout on orders up to $30,000. Available plans and rates depend on your order total and approval, and you'll see your options before you pay.

Shipping & Delivery

Where do you ship?

We currently ship within the continental United States only. We don't ship to Alaska, Hawaii or Canada at this time.

How long will my order take?

Orders are processed within 1-2 business days, and orders placed before 2 PM EST start processing the same day. Orders don't process or ship on weekends or holidays, so anything placed after 2 PM on Friday or over the weekend starts processing the next business day. In-stock items usually arrive within 3-9 business days.

Some products are made to order and take longer. When that's the case, the lead time is listed on the product page.

How does freight delivery work?

Larger items ship by freight. Here's what to expect:

The carrier will call to schedule a delivery window, Monday to Friday
Someone 18 or older needs to be there to receive and sign for it
Delivery is curbside, lowered by liftgate to your driveway or nearest accessible spot
Please double check your phone number at checkout so you don't miss the carrier's call

Installation

Does it come assembled?

It depends on the product. Some items arrive ready to use, while others need assembly. Check the product page for what's included, and download the manual for full setup instructions.

Do I need a professional to install it?

Many products can be set up yourself. For anything involving a natural gas line, hardwired electrical or built-in installation, we recommend a licensed professional and checking your local codes.