How Long Does It Take for a Sauna to Heat Up? Times by Type Explained
Few things are more disappointing than arriving home after a long day, eagerly anticipating your sauna session, only to discover you need to wait an hour or more before it’s ready.
The truth is that heating times vary dramatically depending on sauna type, size, heater power, insulation quality, and target temperature. A properly sized heater should heat up a sauna in about 20 – 30 minutes.
Small infrareds might heat up in 10 – 20 minutes, while large traditional sauna require 20 minutes or more to heat up. In this comprehensive guide, we’ll break down heating times for every sauna type, explain the factors that affect warm-up duration, and provide strategies for optimizing your sauna’s heating efficiency.
What Does “Heated Up” Mean?
For a sauna to be ready, it must reach both your target air temperature and have thoroughly warmed the interior materials—benches, walls, and (in traditional saunas) the rocks. Air temperature alone doesn’t tell the full story. You can achieve 170°F air temperature relatively quickly, but if the bench wood is still cool and the stones haven’t absorbed adequate heat, your experience won’t be optimal.
Think of it like preheating an oven. The temperature indicator might reach 400°F, but the oven chamber and racks need time to heat fully for proper cooking. Similarly, your sauna needs time for all elements to reach operating temperature, not just the air itself.
How Long Does It Take for a Sauna to Heat Up: By Type
Let’s break down heating times for each major sauna type, from fastest to slowest.
Infrared Saunas: The Speed Champions (10-20 Minutes)
Infrared saunas are remarkably quick to heat, making them ideal for busy schedules or spontaneous relaxation sessions.
Far Infrared Models: These typically require 10-15 minutes to reach operating temperature (120-140°F). Because they heat your body directly rather than warming the air extensively, they feel ready to use once the infrared panels reach operating temperature. Even at 10 minutes, you’ll experience the full infrared heating effect, though the air may not be quiet as hot as it will get after a little more time.
Full Spectrum Infrared Models: These combine near, mid, and far infrared wavelengths and may require 15-20 minutes for optimal performance. The additional heating elements need slightly longer to reach their ideal operating range, but they provide a broader infrared spectrum that some users prefer for targeting different tissue depths.
Single-Person Portable Units: The smallest infrared saunas can be ready in as little as 8-10 minutes. Their compact size means less space to heat and fewer panels to warm up, allowing nearly instant gratification.
Why They’re So Fast: Infrared panels reach operating temperature quickly because they’re not trying to heat large volumes of air or massive stone piles. They focus on what matters, producing infrared radiation that penetrates your skin and warms your body directly. This efficiency makes them extremely popular for home use, where spontaneity matters.
At Chinook Hot Tubs & Saunas, we’ve seen infrared saunas become increasingly popular precisely because of this convenience factor. After a hard workout or stressful day, waiting only 10-15 minutes feels manageable, while a 30-minute wait might discourage regular use.
Electric Traditional Saunas: The Middle Ground (30-45 Minutes)
Traditional saunas with electric heaters require more time than infrared models but offer the classic high-heat sauna experience many people prefer.
Traditional Saunas: With an appropriately sized heater (about 1kw per 50 cubic feet), expect 20-30 minutes to reach 170-180°F with properly heated stones. The smaller air volume heats relatively quickly, and a properly matched heater provides adequate power for efficient warm-up.
Factors Affecting Electric Sauna Heating:
Heater Power: This is the primary determinant of heating speed. Undersized heaters struggle to heat larger spaces efficiently, sometimes taking 60-90 minutes or never quite reaching the desired temperature. At Chinook Hot Tubs & Saunas, we carefully match heater capacity to sauna volume during installation to ensure optimal performance.
The general rule: you need approximately 1 kW of heater power per 45-50 cubic feet of sauna space. A 200 cubic foot sauna requires at least a 4 kW heater for efficient heating. Oversizing slightly (going to 5 kW in this example) provides faster heating and better performance at no operational cost increase since the thermostat limits runtime once the temperature is achieved. Oversizing the heater too much can result in inconsistent heating, the temperature probe at the ceiling will reach temperature long before the rest of the sauna, so the portion of the sauna you will sit in can feel too cool due to a heater that’s too large.
Insulation Quality: Well-insulated saunas heat faster and maintain temperature more efficiently, but over insulated saunas can have the same inconsistent heat as oversized heaters. Quality insulation (About R12 is ideal) in walls and ceiling prevents heat from escaping before it warms the interior while allowing for the most even heating. Our custom-built saunas at Chinook use premium insulation specifically chosen for sauna applications, dramatically improving heating efficiency.
Stone Mass: Traditional sauna heaters heat a pile of stones that then radiate heat and provide thermal mass. Larger stone piles (60-80 lbs) take longer to heat than smaller piles (25-30 lbs), but they provide better heat retention and more satisfying steam (löyly) when water is added. This is why high-quality heaters with substantial stone capacity take longer to heat initially but provide superior performance once ready.
Electrical Supply: Heaters require adequate electrical service. A 6 kW heater needs 240V and typically 30-40 amps. If your electrical supply is too small, the heater may not be able to be installed. Professional installation, as we provide at Chinook Hot Tubs & Saunas, ensures proper electrical service for optimal heater performance.
Wood-Fired Saunas: The Traditional Choice (20-30 Minutes)
Wood-fired saunas offer an authentic, traditional experience and can operate off-grid, but they require specific types of firewood to avoid long heat up times. Anything pitchy, lightweight, and dry that will burn fast and hot works very well, lots of small stuff as well as pine, cedar, spruce, and other similar pitchy softwoods work very well. Hardwoods tend to burn slowly, so you don’t get the same fast heat up. It’s a great way to get rid of the softwoods you don’t want to use to heat your cottage.
Wood-Fired Saunas: These require 25 – 35 minutes to heat when using the correct type of firewoods, and sometimes a little longer in cold weather or when starting from completely cold conditions. Wood-fired heaters heat more gradually than electric models, and the substantial stone mass they typically incorporate takes a little more time to reach optimal temperature.
Why They Take Longer:
Wood-fired heaters build heat gradually as the fire develops. You start with kindling, build to larger wood pieces, and wait for substantial coal development before peak heating occurs. This process is inherently slower than electric heaters that deliver full power immediately.
However, many enthusiasts argue the wait is worth it. Wood-fired saunas provide exceptionally pleasant heat quality, create a wonderful ambiance, and offer self-sufficiency from electrical infrastructure. For cottage or remote property installations, they’re often the only practical option.
The ritual of building and tending the fire also becomes part of the sauna experience for many people, a meditative practice in itself that complements the later relaxation.
Steam Rooms: A Different Category (15-30 Minutes)
While not technically saunas, steam rooms are often discussed alongside them and have their own heating characteristics.
Steam generators heat water to produce steam, which then fills and heats the enclosure. Small residential steam rooms (50-100 cubic feet) typically require 15-20 minutes to reach operating conditions (110-115°F with near 100% humidity). Larger installations may need 25-30 minutes.
Steam rooms feel ready to use sooner than their temperature suggests because high humidity makes heat feel more intense. Even at 110°F, near-saturated air can feel as hot as a 160°F dry sauna.
How Much Does a Sauna Heater Cost? Understanding Your Investment
Understanding heating times naturally leads to questions about heater quality and cost. The heater is your sauna’s heart, and choosing the right one affects both performance and operating costs.
Residential Electric Heater Costs
At Chinook Hot Tubs & Saunas, we stock quality heaters across various price points to match different needs and budgets:
Entry-Level Models ($1,250-$1,500): Our Saunacore Special Edition Heaters start at $1,250 and provide reliable performance for small to medium home saunas. These heaters include essential features, quality construction, and good warranties, making them excellent value for residential use.
Mid-Range Models ($1,550-$2,390): The Saunacore Ultimate and Steam Vaporizer Heaters fall in this range, offering enhanced features, larger stone capacity, and improved heat distribution. These heaters provide faster heating times and more even temperature control than entry-level models.
Premium Residential Models ($1,950-$2,570): Our Saunacore Elite Heaters represent top-tier residential performance with advanced controls, maximum stone capacity, and superior build quality, ensuring decades of reliable service.
Commercial Heater Costs
For gyms, spas, wellness centers, or high-use home saunas, commercial-grade heaters provide the durability and capacity necessary:
Standard Commercial Models ($2,550-$3,900): These heavy-duty heaters handle frequent use and larger spaces, built with commercial-grade components that withstand continuous operation.
Ultimate Commercial Models ($3,150-$4,450): Our top commercial offerings provide maximum power, the largest stone capacity, and features like quick-heat modes that reduce warm-up time even for large installations.
Factors Affecting Heater Cost
Power Output: Higher-wattage heaters cost more but heat faster and handle larger spaces. The difference between a 4 kW and an 8 kW heater might be $500-$1000, but for appropriate applications, that investment pays dividends in performance and user satisfaction.
Control Systems: Basic heaters use simple thermostats, while premium models offer digital controls, timer functions, and even WiFi connectivity for remote operation. Advanced controls add $200-$500 to the cost but dramatically improve convenience.
Build Quality: Premium heaters use heavier-gauge stainless steel, more durable heating elements, better electrical components, and superior assembly methods. This quality translates to longer life, fewer repairs, and better warranties—ultimately lower lifetime cost despite higher initial investment.
Stone Capacity: Heaters designed for larger stone masses cost more due to stronger construction and higher power requirements, but they provide superior heat quality and better steam production.
Operating Costs: Energy Efficiency Matters
Beyond purchase price, consider operating costs. A typical 6 kW electric sauna heater running for one hour uses 6 kWh of electricity. At average Canadian electricity rates (around $0.12-$0.15 per kWh), this costs roughly $0.72-$0.90 per hour.
For a typical usage pattern of 3 sessions weekly, 45 minutes each, including heat-up time, the monthly operating cost is approximately:
- Heat-up time: 30 minutes at full power (3 kWh) = $0.45
- Session time: 15 minutes at partial power (1 kWh average) = $0.15
- Total per session: $0.60
- Weekly (3 sessions): $1.80
- Monthly: $7.20
This modest cost makes regular sauna use affordable for most households. Infrared saunas cost even less to operate due to lower power requirements and faster heating.
The False Economy of Undersized Heaters
Some people try to save money by purchasing an undersized heater. This is almost always a mistake. An undersized heater runs continuously, trying to reach the target temperature, using maximum energy for extended periods while providing suboptimal performance.
A properly sized heater reaches temperature efficiently, then cycles on and off to maintain it, actually using less energy over time. It also provides the intended sauna experience—proper temperature, good steam, and comfortable heat distribution.
How Hot Should a 20-Minute Sauna Be? Temperature Guidelines
Understanding heating times leads naturally to questions about target temperature and the relationship between duration and heat intensity.
Temperature Ranges by Sauna Type
Traditional Finnish Saunas:
- Beginner-friendly: 150-160°F
- Standard comfortable range: 160-175°F
- Enthusiast range: 175-190°F
- Maximum safe: 195°F (though rarely necessary or comfortable)
For a 20-minute session, most people find 165-175°F ideal. This provides sufficient heat stimulus without being overwhelming, allowing you to complete the full duration comfortably.
Infrared Saunas:
- Beginner-friendly: 120-130°F
- Standard comfortable range: 130-145°F
- Upper range: 145-150°F
For a 20-minute infrared session, 135-145°F works well for most users. Remember that infrared saunas heat your body directly, so lower air temperatures produce similar physiological effects to much higher temperatures in traditional saunas.
Steam Rooms:
- Standard range: 110-120°F with 100% humidity
Twenty minutes in a steam room at 115°F feels intensely hot due to the saturated air, comparable to 165-170°F dry heat in a traditional sauna.
Adjusting Temperature to Duration
There’s an inverse relationship between temperature and comfortable duration. Higher temperatures mandate shorter sessions, while moderate temperatures allow longer stays.
Short Sessions (10-15 minutes): You can tolerate higher temperatures. For traditional saunas, 180-190°F for experienced users. The brief duration prevents excessive heat accumulation in your body.
Medium Sessions (15-20 minutes): Moderate temperatures work best. For traditional saunas, 165-175°F provides enough heat stimulus to induce benefits without becoming uncomfortable before your time is complete.
Long Sessions (20-30 minutes): Lower temperatures are necessary. For traditional saunas, 155-165°F. For infrared saunas, 130-140°F. The extended duration provides cumulative heat exposure even at moderate temperatures.
Personal Factors Affecting Ideal Temperature
Your ideal temperature varies based on several factors:
Experience Level: Beginners tolerate less heat than seasoned users. Your body adapts to heat stress over time, improving your tolerance and comfort at higher temperatures.
Body Size and Composition: Larger individuals and those with more muscle mass typically tolerate heat better and may prefer higher temperatures. Smaller individuals often find moderate temperatures more comfortable.
Health Status: Cardiovascular fitness, age, medications, and various health conditions all affect heat tolerance. Always err on the conservative side and adjust based on how you feel.
Hydration: Well-hydrated individuals tolerate heat better. If you’re dehydrated, lower the temperature or reduce session duration.
Daily Variation: Your heat tolerance varies day to day based on sleep quality, stress levels, recent exercise, and other factors. Some days you’ll crave intense heat; other days moderate warmth feels better. Honor these variations rather than rigidly adhering to a fixed temperature.
The Temperature Sweet Spot
For most people using a traditional sauna for a 20-minute session, 170°F represents the ideal balance, hot enough to induce substantial sweating and physiological benefits, but not so hot that it becomes uncomfortable or unsafe. This temperature allows you to complete your full 20 minutes comfortably, exit feeling refreshed rather than exhausted, and return for another round if desired.
Can Sauna Cause Heat Rash? Understanding Skin Reactions
While we’re discussing sauna heat and heating times, let’s address a common concern: can sauna use cause skin problems like heat rash?
What Is Heat Rash?
Heat rash (prickly heat or miliaria) occurs when sweat ducts become blocked, trapping sweat beneath your skin. This causes small red bumps, itching, and sometimes stinging sensations. It’s more common in humid environments or when something prevents sweat from evaporating normally.
Sauna Use and Heat Rash Risk
Pure sauna use rarely causes heat rash because the dry heat of traditional saunas (or the infrared heat of infrared saunas) allows sweat to evaporate efficiently from your skin surface. However, several sauna-related factors can increase risk:
Prolonged Sessions: Extremely long sauna sessions (over 30-40 minutes continuously) increase heat rash risk, especially if you’re sitting in a way that blocks sweat evaporation (like sitting pressed against a back wall).
Inadequate Breaks: Using a sauna for multiple rounds without sufficient cooling breaks between them can overwhelm your sweat glands’ ability to function normally.
Tight Clothing: Wearing tight swimsuits or other garments in the sauna prevents sweat from evaporating and increases heat rash risk. Traditional sauna culture involves nudity or very loose wraps for this reason, though personal comfort and cultural norms obviously take precedence.
Poor Hygiene: Entering a sauna with lotions, oils, or other products on your skin can block pores and sweat ducts. Always shower before sauna use and avoid applying products until after you’ve completed your session and final cool-down shower.
Pre-Existing Conditions: If you’re prone to heat rash or have certain skin conditions, you may be more susceptible even with appropriate sauna use.
Preventing Heat Rash in the Sauna
Shower Before and After: Cleanse thoroughly before entering to remove anything that might block pores. Shower afterward to rinse away sweat and prevent irritation.
Limit Duration: Follow appropriate session lengths for your experience level. For most people, individual rounds shouldn’t exceed 20-25 minutes.
Cool Down Properly: Take adequate breaks between rounds to allow your skin to cool and your sweat glands to recover normal function.
Stay Hydrated: Adequate hydration supports healthy sweating and reduces skin irritation risk.
Wear Minimal Clothing: In private saunas, consider using the sauna nude or with a loose towel wrap. In shared facilities, choose loose-fitting natural fiber garments.
Pat Dry During Sessions: Use a towel to periodically pat away excess sweat, preventing it from accumulating on your skin surface.
When Sauna Isn’t the Cause
Sometimes people blame the sauna for skin issues that actually stem from other causes:
Chlorine or Chemical Exposure: If you swim before using a sauna, pool chemicals may cause skin reactions that you incorrectly attribute to sauna heat.
Detergent Reactions: Towels or clothing washed in harsh detergents can cause skin irritation during sauna use.
Fungal Conditions: In shared sauna facilities, athlete’s foot or other fungal infections can spread. Always wear shower shoes and sit on your personal towel to reduce risk.
Underlying Skin Conditions: Conditions like eczema, psoriasis, or rosacea may be exacerbated by heat exposure. If you have these conditions, consult your dermatologist about appropriate sauna use.
Treating Heat Rash from Sauna Use
If you do develop heat rash:
Cool and Dry: Allow your skin to cool completely and stay dry for 24 hours. Avoid further sauna use until the rash resolves.
Loose Clothing: Wear loose, breathable clothing to prevent friction and allow air circulation.
Cool Compresses: Apply cool, damp cloths to affected areas for relief.
Calamine Lotion: This can soothe itching and help dry the rash.
Avoid Irritants: Don’t apply heavy lotions, oils, or other products that might block pores.
Conclusion
Knowing how long it takes for a sauna to heat up might seem like a mundane detail, but it’s actually central to whether you’ll use your sauna regularly and get maximum enjoyment from it. A sauna that heats too slowly becomes an obstacle rather than an invitation to relaxation.