Acier → Behr
The closest Behr matches for Sherwin Williams Acier (SW 9170-2), ranked by perceptual color distance.
Finding a Behr Equivalent for Acier
If you love Sherwin Williams Acier but need a Behr alternative, you are not alone. This is one of the most common cross-brand paint matching searches, whether you are working with a painter who prefers Behr, your local store does not carry Sherwin Williams, or you simply want to compare prices across brands before committing.
Acier (SW 9170-2) is a medium-dark gray with cool steel gray undertones. A cool, steely gray. Named for the French word for steel. Neutral and industrial. Between Magnetic Gray and Dovetail. To find a good Behr match, we need a color that captures not just the right depth (LRV 25) but also that specific undertone character. That is where Delta E color science comes in.
We calculated the perceptual color distance between Acier and every Behr color using the CIE2000 Delta E formula, which measures how different two colors look to the human eye. A Delta E under 2 means most people cannot tell the colors apart. Between 2 and 4, you might notice a difference in certain lighting. Above 5, the difference is clearly visible side by side.
The results are decent but not perfect. The closest Behr option is Tin Foil (PPU18-06) with a Delta E of 3.8, which is a "good match" level match. Tin Foil is similar. You will want to test a sample before committing, as the difference may be noticeable in certain lighting.
Behr Matches for Acier
Tin Foil is similar.
| Acier | Tin Foil | |
|---|---|---|
| LRV | 25 | 32 |
| Hex | #9D9D9A | #AAA8A4 |
| Undertone | Cool Steel Gray | Cool Gray |
| Family | Gray | Gray |
Undertone Comparison
Acier has cool steel gray undertones. A cool, steely gray. Named for the French word for steel. Neutral and industrial. Between Magnetic Gray and Dovetail.
Tin Foil has cool gray undertones. A cool, clean mid-tone gray. Named for its metallic, silvery quality. Neutral and modern.
These two colors share the same undertone family, which is a good sign for a cross-brand swap. The undertone similarity means they will behave similarly as lighting changes throughout the day, and they should coordinate well with the same accent colors, trim, and furnishings.
How These Colors Behave in Different Lighting
Acier in Your Room
Cool and clean. A neutral gray that reads as steel in all conditions.
Tin Foil in Your Room
Neutral and clean. In bright rooms, a cool silver-gray. In dim rooms, a clean, balanced gray.
LRV and Brightness
Acier has an LRV of 25, while Tin Foil has an LRV of 32. That means Tin Foil reflects more light. If you switch from Acier to Tin Foil, the room should feel slightly brighter and more open.
Best Rooms for Acier
Sherwin Williams recommends Acier for: office, bathroom, hallway, accent wall, exterior. With an LRV of 25, this is a medium-dark color that is in the medium range, adding real depth and presence to a room. It works best in rooms with good natural light or as an accent wall color. In smaller or darker rooms, pair it with bright white trim to keep the space from feeling closed in.
Tin Foil is recommended for: bathroom, bedroom, office, hallway, living room. The recommended applications differ slightly between brands, but the color's properties should work in the same rooms regardless of which brand you choose. Trust the LRV and undertone data more than the specific room suggestions, and always test in your actual space.
Acier in Other Brands
Looking for Acier equivalents in other brands besides Behr? We have matches across all major paint brands.
Frequently Asked Questions
The closest Behr match for Acier (SW 9170-2) is Tin Foil (PPU18-06) with a Delta E of 3.8, which rates as a "good match" match. Tin Foil is similar. Delta E measures perceptual color distance on a scale where under 2 means nearly identical, 2 to 4 means close with subtle differences, and over 5 means clearly noticeable.
No, they are not identical. Acier is a Sherwin Williams color with cool steel gray undertones and an LRV of 25. Tin Foil is a Behr color with cool gray undertones and an LRV of 32. With a Delta E of 3.8, the difference is subtle and mainly visible in direct side-by-side comparison. Paint formulations differ between brands, so even colors with similar values can look slightly different due to pigment concentration, binders, and finish.
With a Delta E of 3.8, the difference is enough that they should not be used on adjacent walls in the same room. You can use them in separate rooms of the same house, but be aware that walking from one room to the other may reveal the difference, especially if the rooms have similar lighting. For the most consistent look, pick one brand for all connected living spaces and reserve the other brand for visually separate rooms like bathrooms or bedrooms behind closed doors.
There are several practical reasons to look for a Behr equivalent. Price differences between brands can be significant on large projects. Availability matters if your nearest paint store or home center specializes in Behr. Some painters have strong preferences for one brand's formula based on coverage, dry time, or workability. And if you are touching up existing Behr work, matching within the same brand gives you the best consistency for seamless results.
Match calculations use Delta E (CIE2000) computed from Lab color space conversion. Color data sourced from manufacturer specifications. Last reviewed: March 22, 2026.