Last updated 2026-07-09

What is Heavenly Heat and who makes these saunas?

Heavenly Heat is a small American manufacturer based in California that has been building infrared saunas since the early 1990s. The company's founding story is unusual: founder John Carman reportedly developed the line after his own family members experienced adverse reactions to the chemicals, adhesives, and off-gassing materials common in mainstream sauna construction. That backstory shapes every design decision the company makes.

The brand sits in a niche corner of the home sauna market. Most big-box or online sauna brands compete on price, cabin size, and entertainment features. Heavenly Heat competes on material purity. The cabins use untreated basswood, avoid synthetic glues and finishes, and use far-infrared heaters rather than traditional Finnish-style rock heaters.

The company sells direct. You will not find Heavenly Heat at a big-box retailer the way you might find a Costco sauna. That direct-to-consumer model keeps overhead low but also means you are buying largely on trust and whatever third-party reviews you can find, since the brand has limited mainstream visibility compared to competitors like Sunlighten, JNH Lifestyles, or Clearlight.

Small production runs also mean longer lead times. Buyers consistently report waits of four to twelve weeks depending on the model and current order volume, which is worth factoring in if you have a hard move-in date.

What makes Heavenly Heat saunas different from other infrared saunas?

Three things separate Heavenly Heat from the broader infrared sauna category: material selection, EMF management, and the target customer.

On materials, Heavenly Heat uses unfinished, untreated basswood throughout the cabin interior. No stains, no varnishes, no formaldehyde-based glues. The insulation does not use fiberglass. The heater components avoid certain plastics that can off-gas when hot. For most healthy adults this level of material purity is a nice-to-have. For someone with multiple chemical sensitivity (MCS), mold illness, or certain autoimmune conditions, it can be the difference between tolerating a sauna session and feeling worse after one.

On EMF, Heavenly Heat promotes low electromagnetic field output from its heater panels. This matters because some infrared sauna users, particularly those following integrative health protocols, want to minimize EMF exposure during long sessions. The published research on low-level EMF health effects in the sauna context is genuinely thin, so I will not overstate the science here. What is measurable is that lower-EMF heater designs exist and Heavenly Heat invests in them ^[1].

The target customer angle is worth dwelling on. Heavenly Heat openly markets to people recovering from chronic illness and those advised by integrative or functional medicine practitioners. That customer base tends to do more research, ask harder questions, and have lower tolerance for marketing exaggeration. The company has survived over three decades largely on word-of-mouth in those communities, which says something.

What Heavenly Heat is not: a feature-packed luxury sauna. There are no built-in speakers, no chromotherapy lights in most base models, no app connectivity. If those features matter to you, you are looking at the wrong brand.

How much does a Heavenly Heat sauna cost?

Pricing runs from roughly $2,000 for the smallest single-person cabin up to about $5,500 to $6,000 for a three-person model, based on current direct pricing. These figures can shift with material costs and configuration options, so treat them as a real-world ballpark rather than a firm quote.

That pricing lands Heavenly Heat in the mid-to-upper tier of the infrared sauna market. For context:

Model size	Approx. price range	Typical competitors in same range
1-person	$2,000 - $2,800	JNH Lifestyles, SereneLife budget models
2-person	$3,200 - $4,200	Clearlight Sanctuary 2, Sunlighten mPulse Solo
3-person	$4,800 - $6,000	Clearlight Sanctuary 3, Sunlighten mPulse Believe

You are paying a premium for the non-toxic materials and low-EMF construction. Whether that premium makes sense depends entirely on why you are buying a sauna. For general wellness and sweat-based recovery, a cheaper unit with similar heater output will give you nearly identical physiological results. For someone with documented chemical sensitivity, the Heavenly Heat price differential is probably justified.

Shipping and freight delivery add $200 to $500 depending on your location. The cabins arrive in flat-pack panels and require assembly, which most buyers complete in two to four hours with a partner. No special tools required.

Running costs are modest. A 1.7 kW to 2.5 kW heater running 45 minutes daily at an average U.S. residential electricity rate of roughly $0.17 per kWh ^[2] costs about $4 to $6 per month. That number will vary meaningfully depending on your state and utility.

Dynamic Saunas	$2,100
JNH Lifestyles	$2,200
Heavenly Heat	$3,700
Clearlight Sanctuary	$5,500
Sunlighten mPulse	$7,000

Source: brand direct pricing and retailer listings, 2024-2025

Is far-infrared heat actually better than traditional sauna heat?

This question comes up constantly and the honest answer is: different, not categorically better.

Traditional Finnish saunas heat the air to 160°F to 212°F and you sweat primarily through convective heat transfer, meaning hot air raises your skin and core temperature ^[3]. Far-infrared saunas operate at lower air temperatures, typically 120°F to 150°F, and the infrared wavelengths (roughly 5 to 15 microns) penetrate a few millimeters into skin tissue, generating heat directly in the body rather than just warming the surrounding air.

The practical difference: far-infrared sessions tend to feel more tolerable, especially for people who find high-heat environments difficult to breathe in or who have cardiovascular conditions. You still sweat significantly. Your heart rate still rises. The cardiovascular and thermoregulatory responses are broadly similar.

The research on sauna benefits generally, including heart rate variability, blood pressure, and stress reduction, is more developed for traditional Finnish saunas than for infrared specifically. A widely cited series of studies from the University of Eastern Finland followed over 2,000 middle-aged Finnish men and found associations between frequent sauna use (four to seven times per week) and lower rates of cardiovascular events ^[4]. Those studies used traditional saunas, not infrared. The infrared literature is smaller and earlier-stage.

For the specific use case Heavenly Heat targets, which is gentle daily thermal exposure for people who cannot tolerate high heat or chemical off-gassing, far-infrared at lower air temperatures is a reasonable and well-tolerated option. Just do not expect the science to be settled.

If you want to compare sauna types more broadly, our guide to sauna benefits covers the research in more depth.

What are the real health benefits of using a Heavenly Heat sauna regularly?

Sticking to what the evidence actually supports, here is a fair summary.

Cardiovascular effects: regular sauna use raises heart rate in a range comparable to moderate-intensity exercise (100 to 150 bpm) and causes temporary vasodilation, which lowers blood pressure during and shortly after a session ^[5]. The Finnish cohort studies referenced above found that men who used a sauna four to seven times per week had about a 50% lower risk of fatal cardiovascular events compared to once-per-week users, though these are observational associations, not controlled trials ^[4].

Pain and muscle recovery: heat increases local blood flow, relaxes muscle tissue, and may reduce delayed onset muscle soreness (DOMS) when used after exercise. A 2015 study in the Journal of Clinical Rheumatology found that far-infrared sauna use improved pain and stiffness in patients with rheumatoid arthritis and ankylosing spondylitis ^[6]. Sample sizes were small (17 patients), so this is suggestive, not definitive.

Mental health and stress: heat exposure triggers endorphin release and has been linked to reduced symptoms of depression in small studies. The mechanism likely involves a combination of hyperthermia-induced beta-endorphin release and serotonergic effects. Nobody has good controlled data on this specifically in infrared saunas; the closest evidence base is whole-body hyperthermia research.

Detoxification claims are the most oversold. Sweat contains trace amounts of certain heavy metals, but the liver and kidneys remain the body's primary detox organs. Sweating in a sauna is not a clinically meaningful detox protocol for most people.

For anyone with a cardiac condition, pregnancy, or a condition involving temperature dysregulation, a conversation with your doctor before regular sauna use is genuinely warranted, more than a legal disclaimer.

How does Heavenly Heat handle non-toxic and low-EMF claims? Are they verified?

This is the honest hard question, and the answer requires some nuance.

Heavenly Heat does not carry third-party certifications like GREENGUARD Gold or Cradle to Cradle in the way that some building materials do. Their non-toxic claims rest primarily on material choice documentation: specifying untreated wood species, avoiding certain glue formulations, and selecting heater components from suppliers who provide component-level specs.

For EMF, the standard most often cited in the sauna industry is the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline, which sets a reference level of 200 milligauss for general-public exposure to power-frequency magnetic fields ^[7]. Heavenly Heat and several competitors claim heater outputs at or below roughly 3 milligauss at occupant distance, which is well inside the ICNIRP threshold. Independent third-party testing of these specific claims is not consistently published, which is a real gap in transparency across the infrared sauna industry generally.

The non-toxic material approach is more verifiable in principle. You can request the material spec sheets and look up the wood species (basswood, also called American linden, is a low-tannin, low-resin hardwood that is genuinely well-suited for low-reactivity applications). What you cannot easily verify without independent testing is whether every component, including wiring insulation, door gaskets, and hardware, meets the same standard in every production run.

Is the Heavenly Heat construction approach more chemically clean than a standard budget infrared sauna? Almost certainly yes. Is it perfectly verified and certified to a published independent standard? No, and the company should be clearer about that distinction. For buyers with serious chemical sensitivity, requesting a material safety data sheet or asking about recent third-party testing is a reasonable step before purchasing.

What are the main complaints and drawbacks buyers report?

No product review is complete without the negatives, so here they are.

Basic aesthetics. The unfinished basswood looks clean and minimalist to some eyes and plain to others. If you want a sauna that looks like a piece of furniture, Heavenly Heat is not your brand. Competitors like Clearlight offer more polished interior and exterior finishes.

No entertainment features in base models. No Bluetooth speakers, no color therapy lights, no tablet holders. For buyers who want a 40-minute solo session that doubles as a media room, this is a real gap. Add-on options exist but the base experience is intentionally stripped down.

Lead times. Four to twelve weeks is consistent with reports from buyers over the past few years. If you are building or renovating a space and have a firm move-in date, order early.

Customer service responsiveness. Some buyers report slow response times for post-sale questions. This is a common complaint with small direct manufacturers across most product categories; it reflects bandwidth constraints more than bad faith, but it is worth knowing.

Limited showroom access. You cannot walk into a local dealer and sit in one. Buying a $4,000 sauna without experiencing it first is a real ask. Some buyers in major metros have found Heavenly Heat units at integrative medicine clinics or wellness centers where they could try before buying; that path is worth exploring if it exists in your area.

For people whose primary goal is athletic recovery rather than chemical sensitivity management, a home sauna from a brand with a strong track record in that space might offer better value per dollar.

How does Heavenly Heat compare to Clearlight, Sunlighten, and other infrared brands?

Here is a practical comparison across the factors that move the needle for most buyers.

Brand	Primary differentiator	Price range (2-person)	EMF claim	Non-toxic materials focus	Warranty
Heavenly Heat	Chemical sensitivity, MCS community	$3,200 - $4,200	Low-EMF heaters	High (core brand promise)	Lifetime on structure, 1-5 yr on heaters
Clearlight Sanctuary	Full-spectrum heaters, True Wave tech	$4,500 - $6,500	Ultra-low EMF, ELF shielded	Moderate (cedar, some finishes)	Lifetime
Sunlighten mPulse	Full-spectrum, app control, clinical research	$5,000 - $9,000+	Low EMF	Moderate	Lifetime
JNH Lifestyles	Budget accessibility	$1,400 - $2,800	Standard	Low	3-5 yr
Dynamic Saunas	Budget, wide availability	$1,200 - $3,000	Standard	Low	1-5 yr

Clearlight is probably the closest competitor to Heavenly Heat on EMF claims, and Clearlight does publish more third-party EMF testing data, which is a point in their favor on transparency. Clearlight also offers more finish and size options.

Sunlighten has the deepest investment in clinical research partnerships and has funded several peer-reviewed studies on their specific heater technology. Their pricing reflects that.

For buyers without chemical sensitivity who primarily want recovery and relaxation, the JNH or Dynamic entry-level units offer real value, though you give up material quality and EMF management.

For buyers whose physician has recommended a low-chemical-exposure thermal therapy environment, Heavenly Heat and Clearlight are the two names that consistently come up.

What do you need to install a Heavenly Heat sauna at home?

Heavenly Heat saunas are designed for indoor use, though some models work in a climate-controlled garage or converted outbuilding. Here is what you actually need.

Electrical: most two- and three-person models require a dedicated 120V 15-amp or 20-amp circuit. Some larger models use 240V. Your existing home panel almost always has room for a dedicated circuit, but run this by a licensed electrician before you order. Permit requirements for new circuits vary by municipality; many jurisdictions require an electrical permit for a new dedicated circuit. Check with your local building department ^[8].

Floor space: the smallest one-person cabin is roughly 36 inches by 36 inches by 75 inches tall. A two-person unit typically runs 47 to 54 inches wide. You need clearance around the unit for air circulation and for the door to swing open. Plan on roughly 5 to 6 feet by 4 to 5 feet of usable floor space minimum for a comfortable two-person installation.

Ventilation: far-infrared saunas do not require dedicated ventilation the way a wood-burning sauna does, but adequate room air exchange helps with humidity management. A bathroom-style exhaust fan in the room is sufficient for most installations.

Flooring: the cabin sits on a flat surface. Concrete, tile, or hardwood all work. Avoid thick carpet, which can trap moisture under the base.

Assembly: flat-pack panels connect with cam locks and barrel bolts. Most owners assemble in two to four hours. No special tools beyond a rubber mallet and a screwdriver.

For outdoor builds, the outdoor sauna guide covers weatherproofing considerations in more detail.

Should you combine a Heavenly Heat sauna with cold plunge therapy?

Contrast therapy, alternating between heat and cold, has a long tradition in Nordic and Eastern European wellness culture and is increasingly popular in athletic recovery circles. The physiological logic is real: heat causes vasodilation and elevates heart rate, cold causes vasoconstriction and activates the sympathetic nervous system, and the oscillation between the two may improve circulation, reduce inflammation, and produce a pronounced mood shift via catecholamine release ^[9].

A 2021 study in PLOS ONE found that cold water immersion after exercise reduced muscle soreness ratings compared to passive recovery, though effect sizes were modest and the research landscape has mixed findings overall ^[10].

For Heavenly Heat users specifically, adding a cold plunge creates a complete contrast protocol. The standard recommendation in practitioner circles is 15 to 20 minutes of sauna, then two to four minutes of cold immersion, repeated two to three cycles. There is no consensus on the optimal protocol; that range reflects common practice rather than settled science.

The chemical sensitivity angle matters here too. If you are choosing Heavenly Heat because you react to conventional materials, apply the same scrutiny to cold plunge equipment. Some cold plunge units use plastic liners or chemical treatments that could be a concern for reactive individuals.

SweatDecks carries a curated selection of cold plunge and sauna equipment for home contrast setups, which is worth browsing if you are planning a combined installation.

For the full picture on cold exposure benefits and what the evidence actually supports, the cold plunge benefits guide is a good next read.

What is the warranty and long-term reliability like?

Heavenly Heat offers what they describe as a lifetime warranty on the structural components of the cabin, meaning the wood panels, frame, and assembly hardware. Heater elements carry a shorter warranty, typically one to five years depending on the model and the specific heater configuration purchased.

For a direct-to-consumer manufacturer with a small production volume, a lifetime structural warranty is a meaningful commitment. Basswood is a dimensionally stable wood species that handles repeated thermal cycling well, which supports the longevity claim from a materials standpoint.

The heater warranty is the more meaningful consideration over time. Far-infrared heater panels typically have a service life of 5,000 to 10,000 hours. At 45 minutes per day, that translates to roughly 11 to 22 years of daily use before you would expect element degradation. Real-world reports suggest heaters in well-maintained units last a decade or more without significant performance drop.

Replacement parts availability is a real question with any small manufacturer. Heavenly Heat has been operating since the early 1990s, which is reassuring, but it is a small company. Asking about parts availability and the process for heater replacement before you buy is sensible due diligence.

Compared to larger brands like Clearlight and Sunlighten, both of which also offer lifetime structural warranties, Heavenly Heat's warranty terms are competitive. The difference is that larger brands have more infrastructure behind their service commitments.

Who should actually buy a Heavenly Heat sauna and who should not?

Buy a Heavenly Heat if:

You or a household member have documented multiple chemical sensitivity, mold illness, or a condition where your integrative physician has specifically recommended a low-off-gassing thermal environment. This is the use case the brand was designed for and where it genuinely outperforms most alternatives.

You want a simple, durable, no-frills infrared sauna and are willing to pay a modest premium over budget alternatives for better material quality. The stripped-down design is a feature for some buyers.

You are philosophically aligned with low-EMF and non-toxic product categories and find that peace of mind has real value to you.

Do not buy a Heavenly Heat if:

Your primary goal is athletic recovery and you have no chemical sensitivities. A comparably priced or less expensive unit from Clearlight or Sunlighten will give you equivalent or better therapeutic output with more features and more transparent third-party validation.

You want entertainment features, polished aesthetics, or app integration.

You need rapid delivery and cannot wait two to three months.

You are on a tight budget. There are functional far-infrared saunas in the $1,200 to $1,800 range that will serve healthy adults well. The non-toxic premium only pays off if you actually need it.

If you are still early in the research process and comparing home sauna options across brands and types, the full sauna buying guide covers the category more broadly, and the home sauna guide gets into installation specifics. If you want to explore the full contrast therapy setup, the ice bath guide is a useful companion.

Frequently asked questions

Are Heavenly Heat saunas good for people with multiple chemical sensitivity (MCS)?

Yes, this is the use case the brand was built for. The unfinished basswood interior, absence of synthetic adhesives, and low-off-gassing construction make Heavenly Heat one of the most consistently recommended infrared sauna options in the MCS community. That said, individual reactivity varies significantly, so requesting material spec sheets before purchase and, if possible, spending time in a similar unit before buying is the most sensible approach.

How long does it take to assemble a Heavenly Heat sauna?

Most buyers report two to four hours for assembly with one other person. The cabins ship as flat-pack panels that connect with cam locks and barrel bolts. No special tools are required beyond a rubber mallet and a screwdriver. Assembly instructions are included, and the company provides phone support if you run into issues. Larger three-person models take closer to the four-hour end of that range.

What wood does Heavenly Heat use and why does it matter?

Heavenly Heat uses basswood, also called American linden. Basswood is low in tannins and resins compared to cedar or hemlock, which means less aromatic off-gassing when heated. For chemically sensitive users, this distinction matters. Cedar smells pleasant because it releases volatile compounds; those same compounds can be irritating or problematic for reactive individuals. Unfinished basswood is among the most inert interior wood options for a heated environment.

How low is the EMF output in a Heavenly Heat sauna?

Heavenly Heat claims heater EMF output in the range of 1 to 3 milligauss at occupant distance. For reference, the ICNIRP public exposure guideline for power-frequency magnetic fields is 200 milligauss, so even standard sauna heaters are well within safety thresholds. The low-EMF claim is about minimizing exposure beyond what safety standards require, not about meeting a minimum safe level. Independent third-party testing for Heavenly Heat's specific units is not widely published.

Can I use a Heavenly Heat sauna outdoors?

Heavenly Heat saunas are designed primarily for indoor use. Some buyers install them in climate-controlled garages or insulated outbuildings. True outdoor installation without weatherproof enclosure is not recommended because the unfinished basswood has no moisture protection. If you want a dedicated outdoor sauna setup, the outdoor sauna category has purpose-built options with exterior weatherproofing that will hold up better long-term.

What electrical requirements does a Heavenly Heat sauna need?

Most one- and two-person Heavenly Heat models run on a standard 120V 15-amp or 20-amp dedicated circuit. Larger three-person models may require 240V. A licensed electrician should confirm your panel capacity before installation. Many jurisdictions require an electrical permit for a new dedicated circuit, so check with your local building department before work begins. The sauna itself plugs into the outlet; no hardwiring of the unit is needed.

How does Heavenly Heat compare to Clearlight saunas?

Both brands target the low-EMF, quality-materials segment of the infrared sauna market. Clearlight publishes more third-party EMF testing data and offers more finish options and larger model ranges. Heavenly Heat has a stronger reputation specifically in the MCS and chemical sensitivity community because of its more rigorous material sourcing. Clearlight prices are generally higher. For buyers without specific chemical sensitivities, Clearlight's fuller feature set and better documentation give it an edge.

Is there scientific evidence that infrared saunas help with chronic pain or fatigue?

There is limited but positive early evidence. A 2015 study in the Journal of Clinical Rheumatology found far-infrared sauna use improved pain and stiffness scores in 17 patients with rheumatoid arthritis and ankylosing spondylitis. A separate small study found benefit in chronic fatigue syndrome patients. Sample sizes are small and study quality is mixed, so these findings are promising but not definitive. Anyone managing a chronic condition should discuss sauna use with their treating physician.

How much does it cost to run a Heavenly Heat sauna per month?

A typical Heavenly Heat sauna draws 1.7 to 2.5 kilowatts during a session. At the U.S. average residential electricity rate of approximately $0.17 per kWh, a 45-minute daily session costs roughly $4 to $6 per month. Electricity rates vary widely by state, from under $0.10 per kWh in parts of the South to over $0.30 per kWh in Hawaii and California, so your actual cost could fall well outside that range.

How long should a sauna session be in a Heavenly Heat unit?

Most practitioners suggest starting with 15 to 20 minutes at 120°F to 140°F and building toward 30 to 45 minutes as your body adapts over two to four weeks. Far-infrared sessions are generally more tolerable than traditional high-heat sessions because air temperature is lower. Exit the sauna if you feel dizzy, nauseous, or excessively uncomfortable. Hydrate before and after. There is no consensus on the single optimal session length; the Finnish cohort studies showing cardiovascular associations used sessions of about 20 minutes on average.

Does Heavenly Heat offer a warranty?

Heavenly Heat offers a lifetime warranty on the structural components of the cabin, including panels, frame, and assembly hardware. Heater elements carry a separate warranty, typically one to five years depending on model configuration. Far-infrared heater panels generally have a functional lifespan of 5,000 to 10,000 hours, which translates to many years of daily use. Confirm specific warranty terms directly with the company at time of purchase since configurations vary.

Can I combine a Heavenly Heat sauna with a cold plunge for contrast therapy?

Yes, and the combination is increasingly popular in both athletic and integrative health settings. The typical protocol is 15 to 20 minutes of sauna followed by two to four minutes of cold immersion, repeated two to three cycles. Research on contrast therapy shows modest reductions in post-exercise muscle soreness compared to passive recovery, though evidence is mixed. If chemical sensitivity is a concern, apply the same material scrutiny to your cold plunge unit that you applied to the sauna.

Where are Heavenly Heat saunas made?

Heavenly Heat saunas are assembled in the United States, with the company based in California. The brand emphasizes domestic production as part of its quality control narrative, particularly relevant given that material sourcing and chemical composition claims depend on supply chain oversight. Production is small-batch, which contributes to the four-to-twelve-week lead times buyers typically encounter.

What is the return policy for Heavenly Heat saunas?

Heavenly Heat sells direct, and their return policy should be confirmed in writing before purchase. Generally, large custom or semi-custom items from direct manufacturers have limited return windows and may charge restocking or freight fees. This is standard across the category, not specific to Heavenly Heat. Given the lead times and freight costs involved, clarifying the return terms before you commit is worth a direct conversation with the company.

Sources

1. International Commission on Non-Ionizing Radiation Protection (ICNIRP), Guidelines for limiting exposure to electromagnetic fields: ICNIRP sets a 200 milligauss reference level for public exposure to power-frequency magnetic fields; low-EMF sauna claims are evaluated against this standard
2. U.S. Energy Information Administration, Electric Power Monthly: Average U.S. residential electricity rate approximately $0.17 per kWh used to calculate monthly sauna operating costs
3. Finnish Sauna Society, sauna health information: Traditional Finnish saunas operate at 160°F to 212°F and heat the body primarily via convective air heat transfer
4. JAMA Internal Medicine, Laukkanen et al., 2015, Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events: Men who used sauna four to seven times per week had approximately 50% lower risk of fatal cardiovascular events compared to once-per-week users; study followed 2,315 middle-aged Finnish men
5. Mayo Clinic Proceedings, Laukkanen et al., 2018, Cardiovascular and Other Health Benefits of Sauna Bathing: Regular sauna use raises heart rate to 100-150 bpm and causes temporary vasodilation and blood pressure reduction during and after sessions
6. Journal of Clinical Rheumatology, Oosterveld et al., 2009, Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitis: Far-infrared sauna use improved pain and stiffness in 17 patients with rheumatoid arthritis and ankylosing spondylitis; sample sizes were small
7. ICNIRP, 2010 Guidelines for limiting exposure to time-varying electric and magnetic fields (1 Hz to 100 kHz): ICNIRP public reference level for 50/60 Hz power-frequency magnetic fields is 200 milligauss for the general public
8. U.S. Consumer Product Safety Commission, Home Electrical Safety: Dedicated electrical circuits for high-draw appliances require permits in many jurisdictions; homeowners should consult local building departments
9. Journal of Physiology, Mooventhan and Nivethitha, 2014, Scientific Evidence-Based Effects of Hydrotherapy on Various Systems of the Body: Heat causes vasodilation and cold causes vasoconstriction; alternating between the two activates sympathetic nervous system response and catecholamine release
10. PLOS ONE, Malta et al., 2021, Effects of Cold Water Immersion on Muscle Soreness and Recovery After Exercise: Cold water immersion after exercise reduced muscle soreness ratings compared to passive recovery, though effect sizes were modest
11. U.S. Energy Information Administration, State Electricity Profiles: State residential electricity rates range from under $0.10 per kWh in parts of the South to over $0.30 per kWh in Hawaii and California
12. National Center for Biotechnology Information (NCBI), Epub: Infrared and health: Far-infrared wavelengths in the 5 to 15 micron range penetrate several millimeters into skin tissue and generate heat directly in the body

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