The biggest issue causing housing prices to go up is the demand. Its crazy how many people can and want to buy. There's just not enough homes to go around. A research question I'm going to dive into is; do airbnb, codi, etc., types of investment property have longer sales cycles (decreasing available inventory thereby increasing price), or do they turnover even faster, increasing supply, e.g., buyer's market. Its probably the former. Typical rental properties, I do know, decrease the value of homes / hurt housing prices. The 'rental grade' condition of a property is typically much worse than that of an owner-occupied. Some lenders wont do fha loans and require a minimum of 20% down in communities where half the homes are rentals, because they appreciate in value so poorly.