**Yes—a sous vide circulator can heat a bain-marie containing a second bowl or pot.** That arrangement can cook stews, braises and other dishes slowly. The main limits are temperature, heating time and container size.

Use a heatproof inner container, preferably stainless steel, with a lid. Keep the surrounding water roughly level with the food inside, while preventing water from entering the container. Leave room for water to circulate and keep the machine within its marked water-level limits. The circulator belongs in the clean outer water bath.

There are a few practical differences from a slow cooker:

- **Temperature:** The food inside approaches the bath temperature gradually. Slow-cooker recipes often assume temperatures close to simmering; Crock-Pot says some of its models stabilize around 98°C/209°F. Check the circulator’s maximum temperature before buying. A lower setting can substantially lengthen cooking, especially for vegetables. [Crock-Pot temperature information](https://www.crock-pot.com/slow-cookers/7-quart-up/crock-pot-programmable-7-quart-slow-cooker/SP_528883.html?bvstate=pg%3A2%2Fct%3Aq)
- **Heating time:** A large bowl of thick stew heats more slowly than a thin sous vide bag. Standard sous vide timing tables therefore won’t directly apply. For a stew, bringing it to cooking temperature on the stove before transferring it to the preheated bath makes the process more predictable. Sous vide safety depends on both temperature and time throughout the food. [Douglas Baldwin’s cooking guide](https://douglasbaldwin.com/sous-vide.html)
- **Evaporation:** Cover the bath during long cooks and monitor its water level. Sauces in a covered inner pot will reduce very little.

**Energy consumption needn’t be unreasonable.** The heater cycles to maintain temperature; its rated wattage is its maximum power, not necessarily its continuous consumption. An open bath near boiling loses considerable heat through evaporation. A covered, appropriately insulated bath reduces those losses. The extra water also requires energy during initial heating. Actual consumption depends on the setup; a plug-in energy meter can measure it.

For equipment cost:

- If you buy the circulator anyway, using existing pots for the bain-marie could mean **no additional equipment cost**.
- If you want conventional slow-cooker convenience too, compare a basic slow cooker plus an inexpensive circulator with a combined appliance.
- Combined models exist: [Crock-Pot sells slow cookers with a dedicated sous vide mode](https://www.crock-pot.com/specialty-products/sous-vide/).

The cheapest purchase depends on local prices and what you already own. For the setup you describe, the bain-marie is a workable starting point.