The Home Depot and Amazon.com both sell millivolt thermostats, and shoppers can also purchase them through Honeywell directly using the manufacturer's online store, as of 2015. All three vendors offer multiple options for users looking to install millivolt thermostats in their homes or offices.
The Home Depot offers purchasers the ability to have thermostats shipped directly to a local brick-and-mortar store in their areas for free as well as free shipping on orders costing $45 or more. The retailer's website lets users create custom lists to compare the features of each thermostat side by side and determine which is best for a specific home or business setup. Honeywell maintains an online store that sells directly to consumers and carries many of its millivolt thermostats. The Honeywell store offers demo videos that help instruct users in use of the thermostat as well as reviews from customers.
Amazon.com provides millivolt thermostats from a number of different vendors, and its site allows users to filter results by manufacturer, material and cost to help shoppers quickly find the best choices. Users on Amazon.com can also leave feedback about their experiences with purchasing from the vendors on the online marketplace as well as the quality of the purchased products.