Best way to test price sensitivity for a new household cleaning product?

For a premium cleaning brand, I'd go Van Westendorp first — it's faster, cheaper, and gives you a solid acceptable price range without needing a complex conjoint design. Once you have that range (say $8–$14), you can run a simple monadic price test at 2-3 points to validate purchase intent. Conjoint is great if you're also testing pack size or scent variants at the same time, otherwise it's overkill for just pricing.