When working with 3D renders then the most common file format is either jpg or png. The latter has benefits over a jpg as the background can be saved as a transparent, these are especially good when working with product renders so they can be overplayed on different colours easily.
Both of these file types are great for drafts and final outputs after post production. On the other hand they are not very good for the 3D Rendering output as they do not contain as much information as needed. These should be outputted as EXR and compiled in a software such as Adobe Photoshop. EXR are also much better when prints are required of the images. If images are ever needed to be edited then the original PSD (Photoshop file) file is always best to work with.
If, for that matter, you are planning to print your house render or any other images, please make sure that your file is in adequate resolution for the printing needed. Additionally, be sure to check the file type that printers require. One of the safer printing file formats is a PDF format. Make sure you get this information directly from the printing company to make sure you can ask for that in advance from the 3D rendering company.