# How to blow dry hair straight with a round brush

Source: https://airandbarrel.com/blog/how-to-blow-dry-hair-straight
Published: 2026-10-10
Publisher: Air & Barrel

**Short answer:** Rough dry to about 80 percent dry, then section the hair and work from the nape up. Put a round brush under each section at the root, point the dryer's concentrator nozzle down the hair shaft, and pull the brush slowly to the ends with the dryer following it. Finish each section with the cool shot before you release it.

A dryer and round brush blowout is the classic way to get straight, smooth hair with some movement. It takes more coordination than a hot air brush, but it gives more control and works with any dryer that has a concentrator nozzle. This guide is for anyone learning the technique, or whose blowouts come out frizzy, flat or bent in the wrong places. It covers what tools you need, brush size, the hand positions, the angle of the nozzle, settings by hair type and how to fix the most common problems.

## What you need

You need a hair dryer with a concentrator nozzle, a round brush, a few section clips and a wide-tooth comb. The concentrator is the narrow flat nozzle that comes with most dryers. It focuses the airflow into a slot so you can aim it down a single section instead of blowing the hair around.

Many dryers in our guides come with more than one concentrator. The BaBylissPRO Falco lists small and large concentrator nozzles, a straightening comb and a diffuser. The Drybar Buttercup lists two concentrator nozzles. The ghd Helios lists a contoured nozzle. A dryer with strong airflow makes the job faster, which is why thick hair benefits from the models in [best hair dryers for thick hair](https://airandbarrel.com/best/best-hair-dryer-for-thick-hair).

[Compare the best hair dryers](https://airandbarrel.com/best/best-hair-dryer)

## Choosing a round brush size

Brush diameter decides how much bend you get. For straight hair with a soft bevel at the ends, a medium to large brush works for most people. Smaller brushes make more curve and are better for short hair, bangs and the face frame.

A boar or mixed bristle brush grips the hair for tension and smoothing. A vented ceramic barrel heats up from the dryer and helps shape the section, but it gets hot, so hold it by the handle.

| Hair length | Brush diameter | Result |
| --- | --- | --- |
| Short, above chin | About 1 to 1.5 in | Smooth with some bend |
| Chin to shoulder | About 1.5 to 2 in | Straight with a soft bevel |
| Past shoulders | About 2 to 3 in | Straight and smooth with body |

Typical round brush sizes by hair length

## Step by step: a straight blowout

1. Towel blot, apply your styling product and detangle with a wide-tooth comb.
2. Rough dry with the nozzle off, using medium heat and high airflow and your fingers, until hair is about 80 percent dry.
3. Clip on the concentrator and divide the hair into sections: nape, two sides, crown and front.
4. Take a section about as wide as the brush and 1 to 2 in deep. Place the brush under it at the root.
5. Point the concentrator down the hair shaft, from root toward ends, with the slot parallel to the brush. Keep the nozzle a few inches from the hair.
6. Pull the brush slowly down while the dryer follows right behind it. Keep firm, even tension.
7. Make two or three passes until the section is fully dry. Damp spots frizz later.
8. At the ends, turn the brush under slightly for a bevel or keep it flat for poker straight.
9. Hit the section with the cool shot for several seconds while it is still on the brush, then release.
10. Repeat up the head, finishing with the front pieces.

Note: Keep the dryer moving and do not press the nozzle against the brush or hair. Holding hot air on one spot is what causes scorching and a burnt smell.

## Why the nozzle angle matters

Each hair has an outer layer called the cuticle, made of overlapping cells that point from root to tip. Air blown down the hair shaft, in the same direction as those cells, helps the surface lie flat and look smoother. Air blown up from below or straight at the head tends to rough it up, which shows as frizz.

That is why stylists point the concentrator down the section and keep the dryer moving with the brush. If you only change one thing in your blowout, change this. Read [frizz after blow drying](https://airandbarrel.com/blog/frizz-after-blow-drying) for other causes.

## Heat and airflow settings

Use high airflow and medium heat for rough drying, then whatever heat gives a smooth result in two or three passes for styling. Fine hair usually needs less heat. Thick or coarse hair often needs more heat and stronger airflow to straighten. As hair gets close to dry, drop the heat a step.

Dyson lists its Supersonic heat settings as 100 C (212 F) fast drying, 80 C (176 F) regular and 60 C (140 F) gentle, plus a constant cold shot of 28 C (82 F). Most other makers do not publish degrees, so use dial positions. Our [heat setting guide](https://airandbarrel.com/tools/heat-setting-guide) suggests a starting band by hair type, and [hair dryer temperature explained](https://airandbarrel.com/blog/hair-dryer-temperature-explained) covers the details.

| Hair type | Heat | Airflow |
| --- | --- | --- |
| Fine | Low to medium | Low to medium |
| Medium | Medium | Medium to high |
| Thick or coarse | Medium to high | High |
| Curly, stretching straight | Medium | Medium, with smaller sections |

Typical styling settings

## Fixing common problems

If two-handed technique is the main problem, a hot air brush may suit you better. See [how to use a hot air brush](https://airandbarrel.com/blog/how-to-use-a-hot-air-brush) and [blow dryer brush vs blow dryer](https://airandbarrel.com/blog/blow-dryer-brush-vs-blow-dryer).

- Frizz on top: you blew air upward or left the section damp. Angle the nozzle down and dry fully.
- Ends flip the wrong way: you rolled the brush too early. Keep tension straight to the tips, then turn.
- Roots look flat: start each pass at the scalp and lift the section up before pulling through.
- It takes forever: rough dry longer before using the brush, and use smaller sections on thick hair.
- Arm fatigue: a lighter dryer helps. See [best lightweight hair dryers](https://airandbarrel.com/best/best-lightweight-hair-dryer).

## Frequently asked questions

**Do I need a concentrator nozzle to blow dry straight?** It helps a lot. The narrow slot lets you aim air down one section and keeps the dryer from blowing other hair around.

**Should I blow dry straight from soaking wet?** Rough dry first without the brush. Brushing very wet hair takes longer and pulls more on the hair.

**What does the cool shot do at the end?** Hair holds its shape better once it cools in place. A few seconds of cool air on each section helps the straight shape set. See [cool shot button explained](https://airandbarrel.com/blog/cool-shot-button-explained).

**Is a round brush or paddle brush better for straight hair?** A paddle brush is good for rough drying and a sleek, flat finish. A round brush adds tension and a little bend for a more finished blowout.

## Buying guides for this topic

- https://airandbarrel.com/best/best-hair-dryer
- https://airandbarrel.com/best/best-hair-dryer-for-thick-hair
- https://airandbarrel.com/best/best-lightweight-hair-dryer