"Your house is not an asset, it is a libailityliability. Assets feed you. Liabilites eat you." Robert Kiyosaki
From a cash flow perspective your primary residence (ie your house) is an investment but it is not an asset. If you add up all the income your primary residence generates and subtract all the expenses it incurs, you will see why investment gurus claim this. Perform the same calculations for a rental property and you're more likely to find it has a positive cash flow. If it has a negative cash flow, it's not an asset either; it's a liability. A rental property with a negative cash flow is still an investment, but cash flow gurus will tell you it's a bad investment.
While it is possible that your house may increase in value and you may be able to sell it for more than you paid, will you be able to sell it for more than all of the expenses incurred while living there? If so, you have an asset.
Some people will purchase a home in need of repair, live in it and upgrade it, sell it for profit exceeding all expenses, and repeat. These people are flipping houses and generating positive cash flowcapital gains based on their own hard work. In this instance a person's primary residence can be an asset. How much of an asset is calculated when the renovated house is sold.