# Sauna Door Guide: Glass, Wood, Sizes, Windows and Safety

Source: https://www.mars-sauna-room.com/guides/sauna-doors-and-windows/

Published 2026-10-11, updated 2026-10-20.

A good sauna door swings outward, has no lock, closes with a simple catch and is made of either tempered safety glass or solid softwood with heat-tolerant hardware and a wooden handle. Glass doors and windows add light and make small saunas feel larger, while wooden doors hold heat better. Size the opening small, typically about 60-70 cm (24-28 in) wide, to keep heat in.

## What makes a sauna door different from a regular door?

A sauna door works in a room that may sit at 80-90 °C (176-194 °F) with bursts of steam, then cools to room temperature, several times a week. That cycle rules out most household doors.

A proper sauna door has:

- **Outward swing**, so nobody gets trapped if they feel faint.
- **No lock**, only a friction, roller or magnetic catch that opens with a push.
- **Tempered glass or solid softwood**, never ordinary annealed glass, hollow-core doors or MDF.
- **Heat-tolerant hinges**, often stainless steel or brass, that do not sag as the frame expands.
- **A wooden handle** on the inside and outside, since metal handles get hot enough to burn.
- **Close-fitting seals on three sides** with a gap at the bottom in many designs, which can form part of the room's ventilation path.

Ventilation layout varies by heater and room; our [sauna ventilation guide](/guides/sauna-ventilation/) explains where intake and exhaust vents go.

## Sauna glass door vs cedar sauna door

The biggest choice is glass or wood. Here is how the main types compare.

| Door type | Heat retention | Look and light | Maintenance | Typical use |
|---|---|---|---|---|
| Full tempered glass, frameless or in a slim frame | lower | bright, modern, makes small rooms feel larger | wipe water spots and fingerprints | indoor home saunas, infrared cabins, bathroom saunas |
| Wood frame with glass insert | medium | warm, partial view | wood sanding, glass cleaning | indoor and covered outdoor saunas |
| Solid wood (cedar, hemlock, spruce or pine) | highest | traditional, private | occasional sanding; watch for warping | outdoor saunas, cold climates, traditional builds |
| Insulated exterior door with glass | high | depends on glazing | weather seals, exterior finish | outdoor cabins exposed to rain and snow |

### Tempered glass sauna doors

Almost every modern sauna glass door is fully tempered safety glass, commonly around 8 mm (5/16 in) thick. Tempering puts the surface into compression, which makes the glass far stronger than annealed glass and causes it to crumble into small granules if it does break.

In the US, glazing in doors and in shower and bathtub enclosures is covered by the Consumer Product Safety Commission's [Safety Standard for Architectural Glazing Materials, 16 CFR 1201](https://www.ecfr.gov/current/title-16/chapter-II/subchapter-B/part-1201). It sorts glazed doors into Category I (no single pane over 9 sq ft, or 0.84 m², per side) and Category II (larger panes and sliding glass doors, tested to a higher 400 ft-lb impact). Model building codes, including the International Residential Code, also treat glazing near saunas, steam rooms, showers and tubs as a hazardous location that generally requires safety glazing; check the edition your jurisdiction has adopted.

Look for a permanent safety-glazing mark etched in a corner of the pane. A frameless glass sauna door also needs hinges designed for glass, clamped through pre-drilled holes made before tempering, since tempered glass cannot be drilled afterward.

### Cedar and wooden sauna doors

A cedar sauna door feels traditional and holds heat well. Western red cedar is dimensionally stable and naturally resistant to decay, which helps in a room that swings between hot-dry, hot-humid and cool. Canadian hemlock is a lighter, low-odor alternative. Compare species in [red cedar vs hemlock](/guides/red-cedar-vs-hemlock/).

All wood moves as its moisture content changes. The USDA Forest Products Laboratory's [Wood Handbook](https://research.fs.usda.gov/treesearch/62200) explains that wood shrinks and swells far more across the grain than along it, which is why sauna doors use narrow tongue-and-groove boards with small expansion gaps rather than wide glued panels.

## What size should a sauna door be?

Smaller openings lose less heat each time the door opens. Common sizes:

| Application | Typical width | Typical height | Notes |
|---|---|---|---|
| 1-2 person home sauna | 60-65 cm (24-26 in) | 180-190 cm (71-75 in) | most common pre-hung size range |
| 3-6 person home sauna | 65-70 cm (26-28 in) | 185-195 cm (73-77 in) | wider for easier entry |
| Commercial or accessible sauna | per local accessibility code | per local code | often 81 cm (32 in) or more clear width |
| Barrel sauna | 60-70 cm (24-28 in) | limited by barrel curve | often arched or set in a flat end wall |

A pre-hung sauna door arrives already mounted in its frame with hinges and a catch, which makes installation much easier. Measure the rough opening, wall thickness (framing plus insulation plus paneling) and swing clearance before ordering.

## Sauna windows and glass walls

A sauna window or full glass wall turns a closed wooden box into a room with a view, which is especially appealing in outdoor saunas facing a garden, lake or forest. Indoor, a glass front connects the sauna to the bathroom or gym around it.

Plan glass with these rules:

1. **Use tempered safety glass only.** For outdoor saunas, insulated double-pane tempered units reduce heat loss and condensation.
2. **Respect heater clearances.** Sauna heaters listed to [UL 875](https://www.shopulstandards.com/ProductDetail.aspx?productId=UL875) or [IEC 60335-2-53](https://webstore.iec.ch/en/publication/68677) come with minimum distances to walls, ceilings and glass; follow the heater manual exactly.
3. **Expect a larger heater.** Glass is a poor insulator compared with an insulated wall, so many heater makers recommend adding capacity for glazed areas. See the [sauna heater guide](/guides/sauna-heater-guide/).
4. **Allow for wood movement.** Set panes in frames with gaskets or stops, not glued tight against wood.
5. **Place windows at eye level or lower.** Glass high on the wall loses the hottest air's heat.

Infrared cabins commonly use a tempered glass front panel, because infrared heaters warm the occupant directly and the cabin does not depend on very hot air as much as a stove sauna.

## Outdoor sauna doors vs indoor sauna doors

Indoor vs outdoor sauna doors face different stresses. Indoors, the challenge is heat and humidity from the sauna side only. Outdoors, the exterior face also sees rain, snow, UV and freezing temperatures.

- **Weather sealing:** exterior sauna doors need a drip edge or overhang, durable weather stripping and a threshold that sheds water.
- **Finish:** use an exterior-grade finish on the outside face only; leave interior surfaces unfinished or use a sauna-specific treatment.
- **Glass:** double-pane tempered units reduce condensation on cold days.
- **Moisture management:** keep the floor and threshold dry, since standing water and trapped humidity promote decay and mold. The [EPA](https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home) advises drying wet areas within 24-48 hours to prevent mold growth.

A sound base matters just as much: an outdoor sauna foundation that settles unevenly will rack the door frame so the door binds or gaps. See the [outdoor sauna buying guide](/guides/outdoor-sauna-buying-guide/) for foundation options, or browse [outdoor saunas](/saunas/outdoor-saunas/).

## DIY sauna door: how to build one

Building a sauna door is a manageable project for a confident woodworker.

1. Mill or buy kiln-dried tongue-and-groove softwood, typically 14-19 mm (about 9/16-3/4 in) thick.
2. Build a frame of stiles and rails, or a ledged-and-braced door with Z-braces on the outside face.
3. Leave small expansion gaps between boards; do not glue the tongues.
4. Fit stainless or brass hinges sized for the door's weight, with three hinges on taller doors.
5. Add a roller or magnetic catch, never a lock.
6. Fit wooden handles inside and out with concealed screws, so no metal touches skin.
7. Check that the door swings outward freely and that the bottom gap matches your ventilation plan.

If you prefer a ready-made option, many sauna door kits and pre-hung units come with glass, hinges and handles matched. If you are considering used sauna doors for sale, check for cracked glass edges, chipped tempered glass, and warped frames; our [buying a used sauna](/guides/buying-a-used-sauna/) checklist applies to parts as well as complete rooms.

## Ordering doors and windows for sauna projects

Mars Sauna builds cabins in Canadian hemlock and western red cedar and offers OEM/ODM customization of wood, size, heaters and other specifications. Distributors and builders can browse [sauna accessories and parts](/saunas/sauna-accessories/) or [request a quote](/contact/) for custom cabin configurations.

## Key takeaways

- A sauna door must swing outward, have no lock and use heat-tolerant hinges with wooden handles.
- Use only tempered safety glass, commonly about 8 mm (5/16 in) thick, marked to a safety-glazing standard such as 16 CFR 1201.
- Glass doors and walls add light but lose more heat; size the heater accordingly and follow its clearances.
- Typical sauna doors are 60-70 cm (24-28 in) wide and 180-190 cm (71-75 in) tall.
- Outdoor sauna doors need weather sealing, exterior finishes and double-pane glass on a level, stable foundation.

## FAQ
### What kind of door do you need for a sauna?
A sauna door should swing outward, close with a friction or magnetic catch rather than a lock, and be made of tempered safety glass or solid softwood such as cedar or hemlock. It should also use heat-tolerant hinges and a wooden handle, because metal hardware becomes too hot to touch at 80-90 °C (176-194 °F).

### Should a sauna door open in or out?
A sauna door should open outward. If someone feels faint or collapses against the door, an outward-swinging door lets them, or a helper, get out quickly. Outward swing also keeps the door from hitting benches or the heater guard inside a small room. Never fit a lock or a latch that requires a key.

### Is a glass sauna door better than a wood door?
A glass sauna door makes a small room feel open and lets light in, but it loses more heat than an insulated wooden door and shows fingerprints and water spots. A solid cedar door keeps heat better and feels more traditional. Many home saunas use a full tempered glass door for looks; cabins in cold outdoor locations often favor wood.

### How thick should sauna door glass be?
Sauna door glass is typically fully tempered safety glass about 8 mm (5/16 in) thick, with 6-10 mm used depending on door size and hinge design. Tempering matters more than thickness: tempered glass is several times stronger than ordinary annealed glass and breaks into small granules rather than sharp shards.

### What size is a sauna door?
Sauna doors are usually smaller than house doors to keep heat in. Common sizes are about 60-70 cm (24-28 in) wide and 180-190 cm (71-75 in) tall, with a gap of roughly 1-2 cm under the door in many designs for airflow. Accessible or commercial saunas may need wider openings under local code.

### Can a sauna have a window?
Yes. Sauna windows and glass walls are common, as long as the glazing is tempered safety glass, kept clear of the heater's required clearances and sealed into a frame that allows for wood movement. Outdoor saunas usually use insulated double-pane tempered units to reduce heat loss and condensation.


## Sources
- [16 CFR Part 1201: Safety standard for architectural glazing materials (eCFR)](https://www.ecfr.gov/current/title-16/chapter-II/subchapter-B/part-1201)
- [UL 875: Electric Dry-Bath Heaters](https://www.shopulstandards.com/ProductDetail.aspx?productId=UL875)
- [IEC 60335-2-53: Particular requirements for sauna heating appliances and infrared cabins](https://webstore.iec.ch/en/publication/68677)
- [USDA Forest Products Laboratory (2021). Wood handbook: wood as an engineering material, FPL-GTR-282](https://research.fs.usda.gov/treesearch/62200)
- [U.S. EPA: A brief guide to mold, moisture and your home](https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home)