Seller Financing in Burbank, CA and should I add central air?

[Shiloh Lundahl]

My family currently lives in Burbank, California and I am planning on moving them back to Gilbert, Arizona next year. We live in a house that is around 100 years old that has no central air. We have a few window units that work decently but the house still doesn’t heat or cool evenly.

We received a quote to add an AC and heating unit for about 10k. My question is if we add a new unit, will it increase my homes value by 10k or will I lose money by adding one?

Also, we bought the property in 2017 for about 800k and got an 80% loan on it for a fixed rate of 4.25%.  The house is a 2 bedroom, 2 bathroom home (1360 square feet) and it has a studio apartment in the back around 300 square feet that we rent out for $1500 a month. Rather than selling the property outright when we move, I have considered doing seller financing for probably around 920k with 10% down at 6.25% and wrapping the mortgage until the new buyer can refinance. 

So this post has 2 questions:

1. Will the home likely appraise for 10k more if I put in a new HVAC unit?

2. Besides the due on sale clause, do you see any other issues with doing seller financing by creating a wrap around mortgage in California?