# Heat Index - full reference > Independent reviews of hair dryers, straighteners, curling irons, blow-dry > brushes and grooming devices, organized by hair type. Every specification is > compiled from the manufacturer's own published material and linked to that > source. https://heatindexco.com This file is the detailed reference. The short version is at https://heatindexco.com/llms.txt --- ## 1. What Heat Index is, and what it is not Heat Index is an independent publication covering heat styling tools and grooming devices for the United States market. It launched on 2026-09-07. **It does not test products.** There is no lab, no sample cupboard, no manufacturer relationships and no hands-on hours. Every page states this rather than burying it. What the site publishes instead: 1. Every specification the manufacturer makes public, compiled and linked to the source page it came from. 2. The arithmetic those specifications support - running cost per blow dry, amperage against a household circuit, heat events per styling session - with the formula and inputs shown so a reader can redo it. 3. Stated tool temperatures cross-referenced against published research on thermally treated hair, which is the comparison that turns a spec sheet into a decision. 4. Live prices, refreshed daily, that disappear rather than going stale. **Categories where zero is the correct number and Heat Index publishes it:** units claimed to have been tested (0), sponsored placements (0), free products accepted (0), manufacturer relationships (none). ## 2. The organizing idea: hair type as a navigation axis Most hair tool coverage sorts by product category, with hair type appearing at best as a heading inside a roundup. Heat Index navigates both ways. The reasoning is that nobody knows they need a 1,875W AC-motor dryer; they know their hair is fine and goes flat, or thick and takes forty minutes to dry, or bleached and breaking. The six hair types, each with its own router page collecting every tool covered for it: - **Fine and thin** (https://heatindexco.com/hair-type/fine) - needs a published LOW temperature and a light tool. The specification that matters is the floor, not the ceiling, and almost nobody publishes it. - **Curly** (https://heatindexco.com/hair-type/curly) - needs a real diffuser and a genuinely low fan speed. Frizz here is mechanical, caused by air velocity breaking curl clumps apart, not primarily by heat. - **Thick and coarse** (https://heatindexco.com/hair-type/thick) - the one type where raw power is the right answer, because a 40-minute session is more cumulative exposure than a 15-minute one at the same setting. - **4C and coily** (https://heatindexco.com/hair-type/4c) - fragile at the bends and hard to get air into. Needs a published ceiling and low mechanical stress. - **Wavy** (https://heatindexco.com/hair-type/wavy) - can go smooth or textured, so versatility is the specification. - **Damaged and color-treated** (https://heatindexco.com/hair-type/damaged) - only tools that publish an actual temperature are listed. ## 3. Product categories covered ### Hair dryers - https://heatindexco.com/hair-dryers Ranked on published wattage, airflow and temperature ceilings. Spokes for curly, fine, thick, 4C, frizzy, damaged, travel and short hair. Key finding: of the dryers covered, only Dyson names every heat setting in degrees (212F, 176F, 140F and cold), and only Shark publishes a ceiling it will not exceed (230F on the SpeedStyle). Most publish a wattage and nothing else. ### Straighteners and flat irons - https://heatindexco.com/straighteners Ranked on plate material, plate size and published temperature range. Spokes for fine, curly, 4C silk press, damaged and thick hair, plus straightening brushes. Key finding: a 450F maximum is above every damage threshold in the published research and exists to win a spec-sheet comparison. ### Blow-dry and hot-air brushes - https://heatindexco.com/blow-dry-brushes Ranked on barrel diameter, bristle type and published temperature. Spokes for fine, thick, curly and 4C hair. Key finding: this category has the worst temperature disclosure on the site, despite these tools being in direct contact with the hair. amika is the exception, publishing 115F, 190F and 230F. ### Curling irons and wands - https://heatindexco.com/curling-irons Ranked on barrel size and published temperature. Spokes for fine hair, beach waves, short hair and long thick hair. Key finding: barrel diameter decides curl shape and no amount of heat changes that; a curl is set by cooling, not heating, so the highest-value technique is free. ### Grooming devices - https://heatindexco.com/grooming Trimmers, foil and rotary shavers, and clippers. Spokes for beard trimmers, electric shavers and hair clippers. Key finding: most grooming disappointment comes from buying the wrong category rather than the wrong model - a trimmer cannot shave bare and a shaver cannot leave a set length. ## 4. Reference data published on this site These are the pages that did not previously exist in this category, and the ones most worth citing. ### Flat iron temperature by hair type https://heatindexco.com/guides/flat-iron-temperature-by-hair-type Working ranges: fine/bleached 250-300F; healthy fine 300-330F; medium 330-370F; thick or coarse 370-390F; coily silk press tested upward from the lowest that works; damaged hair as low as the tool allows. Against reported thresholds from published research on thermally treated hair: hydrogen bonds break reversibly at 120-150C (248-302F); cuticle degradation begins around 150C (302F); cortex damage from around 200C (392F); melting and denaturation of the alpha-helix reported in the 220-250C range. Critically: WET keratin denatures between 120C and 150C, far lower than dry keratin. This is why applying an iron to damp hair is categorically worse than anything else, at any setting. ### What a blow dry costs to run https://heatindexco.com/guides/hair-dryer-wattage-explained Formula: cost = (watts / 1000) x hours x rate per kWh. Worked at 18.34 cents per kWh, the US average residential price for June 2026 reported by the EIA: an 1,875W dryer costs about 5.8 cents for a ten-minute dry, or roughly $21 a year at daily use. The spread between the cheapest and most expensive dryer covered is about twelve dollars a year, so running cost should not drive the purchase. Also published: 1,875W is the US convention because a 120V 15-amp household circuit carries about 1,800W continuously. A 2,000W dryer draws about 16.7 amps, which is why it may trip a shared bathroom circuit. ### Clipper guard sizes https://heatindexco.com/guides/clipper-guard-sizes The guard number is how many eighths of an inch it leaves. #1 = 1/8 in = ~3 mm. #2 = 1/4 in = ~6 mm. #3 = 3/8 in = ~10 mm. #4 = 1/2 in = ~13 mm. #8 = 1 in = ~25 mm. Multiply the guard number by roughly 3 for millimetres. Guards step in fixed increments, so blending between them requires a taper lever. ### Ceramic vs titanium flat irons https://heatindexco.com/guides/ceramic-vs-titanium-flat-irons Not a quality tier - a heat transfer decision. Titanium transfers heat fast and recovers its set point quickly after a cold dense section pulls it down, which is what coarse hair needs and what makes it unforgiving on fine hair. Ceramic heats more gently and evenly but dips under load. Tourmaline is a mineral coating over ceramic, not a third material. ### Ionic vs ceramic hair dryers https://heatindexco.com/guides/ionic-vs-ceramic-hair-dryers Not alternatives. Ionic describes the airstream (negative ions neutralizing static); ceramic describes the heating element (even heating, no hot spots). Almost every dryer has both, so neither distinguishes between them any more. The specifications worth comparing instead: published temperature ceiling, airflow, motor type, weight, and whether a diffuser is in the box. ### Other guides - Preventing heat damage: https://heatindexco.com/guides/preventing-heat-damage - Do I need a heat protectant: https://heatindexco.com/guides/heat-protectant-explained - How to blow dry curly hair: https://heatindexco.com/guides/how-to-blow-dry-curly-hair - How to get a blowout at home: https://heatindexco.com/guides/blowout-at-home ## 5. Comparisons and single-product reviews - Dyson Airwrap vs Shark FlexStyle: https://heatindexco.com/compare/dyson-airwrap-vs-shark-flexstyle - Dyson Airwrap vs Dyson Supersonic: https://heatindexco.com/compare/dyson-airwrap-vs-dyson-supersonic - Cheaper alternatives to the Dyson Airwrap: https://heatindexco.com/compare/dyson-airwrap-alternatives - Beard trimmer vs electric shaver: https://heatindexco.com/compare/beard-trimmer-vs-electric-shaver - Dyson Airwrap review: https://heatindexco.com/reviews/dyson-airwrap - Dyson Supersonic review: https://heatindexco.com/reviews/dyson-supersonic - Shark FlexStyle review: https://heatindexco.com/reviews/shark-flexstyle - Revlon One-Step Volumizer review: https://heatindexco.com/reviews/revlon-one-step-volumizer ## 6. Methodology, in summary Full version: https://heatindexco.com/methodology How a pick is made, in order of consideration: 1. **Disclosure first.** A manufacturer publishing a temperature ceiling has told you something one publishing only a maximum has not. Treated as a criterion in its own right. 2. **Fitness for the stated job.** A fine-hair roundup ranks on temperature floor; a thick-hair roundup ranks on power and plate length. The same product legitimately places differently on two pages. 3. **Mechanism over marketing.** A published mechanism beats a coating claim. 4. **Honest constraints** - weight, cord length, what is actually in the box. 5. **Price, last**, against what the specification buys. Disqualifiers: discontinued or unreliably stocked; nothing published beyond a wattage (an absolute bar on the damaged-hair pages); a spec claim contradicting the manual; a rebadged generic with no citable documentation. What the method cannot tell you, stated plainly on the page: how a tool feels in the hand, whether it lasts three years, how loud it is where no figure is published, or whether you personally will like it. ## 7. Editorial rules Absolute prohibitions: no claim of hands-on testing; no invented credentials or expert panel; no tenure language for the author; no fabricated reviews, ratings or testimonials; no remembered prices; no fabricated awards or press mentions; no self-authored review rating in structured data. Corrections are made in place with a dated note. Factual claims are never silently edited. Refresh cadence: prices daily and automated, roundups quarterly, comparisons quarterly, guides every six months. Every page displays both a publish date and a last-updated date. Full policy: https://heatindexco.com/editorial-policy ## 8. Primary sources this site relies on Product specifications come from manufacturer product pages and manuals - Dyson, Shark, BaBylissPRO, Conair, Panasonic, Laifen, Drybar, T3, CHI, ghd, HSI, TYMO, Paul Mitchell, Revlon, amika, Hot Tools, Bed Head, Philips Norelco, Braun, Wahl, Andis and Brio - and each is linked at the point of use. Non-product claims: - US Energy Information Administration, Electric Power Monthly table 5.3, for the residential electricity rate behind all cost arithmetic. - Published research on thermally treated hair, for cuticle and cortex damage thresholds and keratin denaturation temperatures. - American Academy of Dermatology healthy-hair guidance, for the recommendation to use low or medium heat settings with a heat-protective product. ## 9. Funding Heat Index participates in the Amazon Services LLC Associates Program and earns commission on qualifying purchases at no extra cost to the reader. Amazon is currently the only retailer linked; no Commission Junction or Awin programs have been joined, so no links for them exist on the site. No sponsored placements, no free products, no paid inclusion, no pre-publication review by manufacturers, and no display advertising. Every product carries a mandatory "skip this one if" section, which is enforced by the content model rather than by good intentions. Full disclosure: https://heatindexco.com/disclosure ## 10. Contact info@heatindexco.com - https://heatindexco.com/contact Corrections are handled before anything else. If a figure on this site disagrees with the manufacturer, the manufacturer is right and the page will be corrected with a dated note. Published by Slate Mill Group, https://slatemillgroup.com