However, it is an old home and you are thinking about major cosmetic upgrades too.    

In some cases, it might even mean you can buy your next house all cash.Financing Home ImprovementsThinking about upgrading your kitchen, adding a home office, or tackling other projects?

I am currently in the market to purchase a tri-plex with the plan to live in one unit, make upgrades, and rent the other two out.

., the 2006 or 2009 IECC — International Energy Conservation Code).Cost Considerations for a 90-unit or 112-unit Project:The actual cost of qualifying for the 45L tax credit depends on various factors, including:Energy Efficiency Compliance: The primary cost will come from ensuring that each unit meets the required energy efficiency standards, which typically involve energy modeling, certification from third-party energy raters, and potentially upgrading insulation, HVAC systems, windows, and other components of the building to meet the necessary performance levels.Energy Modeling: Typically, you'll need to pay for an energy consultant or engineer to model the building's energy performance and ensure it qualifies for the credit.

The house includes high-end upgrades such as custom cabinetry, granite countertops and energy efficient appliances.

Document all improvements with before/after photos and receipts, highlight upgrades that add value (kitchen, baths, etc.), and research comps in your area to ensure your property aligns.

I think I will not let him make this upgrade as a 5 year payoff would require over $100/month additional rent.  

.- Value-Add Investments: Beyond cosmetic upgrades, think about adding amenities like solar panels, EV charging stations, or smart home tech.

Anyone has a recommendation for affordable yet experience designer to help with few hours of consulting to upgrade the look of   new airbnb?

The electrical panel is original, so an upgrade might be needed in the future.