Welcome! You’re actually already house hacking, so you’re starting from a great place. Three renters helping cover the mortgage while allowing you to spend more time with your daughter is exactly the kind of flexibility house hacking can create. Before getting too deep into financing, I’d first figure out which expansion option is actually feasible and what each one will cost. For the tiny home/ADU, Colorado has become much more ADU-friendly, but I would still start with your specific city/county zoning department. Being “near Denver” can mean several different jurisdictions. Confirm that an ADU is allowed on your specific lot, what type is allowed, size/setback requirements, utility requirements, permits, and whether what you’re calling a tiny home would actually qualify as a legal dwelling unit. Some areas only allow you to rent the main house or ADU not both. I wouldn’t spend money on plans until you know exactly what the jurisdiction will approve. The basement may end up being the easier project. If the space already exists, framing, electrical and water supply can often be fairly straightforward. One of the first things I’d investigate is the sewer. If you’re adding a bathroom and there isn’t already a drain where you need it, cutting concrete and tying into the existing sewer can add quite a bit to the project. I’d also confirm ceiling height, egress, fire separation, HVAC and permitting requirements. Once you know something like “the basement will cost $40k and should rent for $1,400/month,” THEN I think it makes sense to figure out the best financing for that specific project. With your current DTI and unsecured business debt, I’d be careful about piling on expensive personal or business debt just because someone is willing to lend it. 0% business funding can sound great, but you really need to understand the promotional period, fees, payments and what happens if the project runs long. If you want, post roughly where you're located (city/county), your basement setup, estimated project costs and what you think each new unit could rent for. We can start breaking down the two options and see which one makes the most sense.