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About C-Wire Check
C-Wire Check exists because smart thermostats are sold by their apps, and returned because of their wires. Whether one works in your home depends on what is behind the old thermostat: a C wire or not, a heat pump or a furnace, thin 24 volt wires or thick line voltage ones. Several listings say no C wire is needed in most homes. The same makers' support pages list heat only, cool only and heat pump systems as the exceptions. This site reads those pages for you, and its checker turns the wire labels you see into a short list of picks that fit, with or without an adapter.
Who runs this site
C-Wire Check is run by one independent publisher who also runs the sister guides listed at plainbuyguides.com. We are not owned by, paid by or partnered with any brand we write about. Amazon is the only company we have an affiliate relationship with, and it has no say in what we write.
How picks are made
We choose every product from public information: the manufacturer's spec sheet and Amazon listing, safety certifications, warranty terms, and recurring themes in what owners report. We read the listing numbers closely, run them through the same math as the calculator on this site, and leave out products whose listings hide the numbers that matter. We only list products sold on Amazon. If a number on this site is a manufacturer claim, we label it as a claim.
We do not test products
We have not bought, used or tested these products, and we do not receive free samples. Nothing here is a hands-on review. When we describe what owners like or complain about, that is our own summary of recurring themes in public owner feedback, not our experience and not a quote.
How this site makes money
As an Amazon Associate I earn from qualifying purchases. When you click a link to Amazon and buy something, we may earn a small commission from Amazon. It costs you nothing extra. Commissions never decide which products we list or the order we list them in, and we do not accept payment for placement. There are no ads and no sponsored posts on this site.
Prices
We do not print prices because they change daily. Use the buttons to see the current price on Amazon.
Corrections
Listings change and we make mistakes. If you spot a wrong number, a dead link or a product that is no longer sold, tell us. We check every report against the current listing, fix confirmed errors as soon as we can, and change the "Updated" date on that page when we do. If a correction changes a recommendation, we say so on the page.
Contact
Email us at hello@plainbuyguides.com, or message us on Pinterest: https://www.pinterest.com/smartbuyguideshq/