Refinancing a home is one of those things where people understand what it is but have trouble explaining how it works. To put it simply, refinancing your home allows you to access the equity you have built up, by changing the mortgage amount.
Let's say you bought a $300,000 condo and you paid 20% ($60,000) as your down payment and had a mortgage of $240,000. Over the next 4 years, you continue making payments and pay down the $240,000 you owed and now that amount is only $230,000. Your mortgage is up for renewal in a year, but you want to do some renovations and you need to access the equity in your home- this is where a refinance could come into play.
What this means is you will get an appraisal of your current home and submit that to a lender. Let's say your $300,000 condo is now worth $350,000 and you owe $230,000. You have built up an additional $60,000 in equity ($350,000 - $230,000 owing - $60,000 initial down payment= $60,000). You have a mortgage of $230,000 on a home worth $350,000, therefor your equity in the home is $120,000.
To access that $120,000, you can refinance your mortgage. So let's say you want to go back and take $50,000 from the $120,000 you have built up. Your new mortgage would go from $230,000 to $280,000, and that $50,000 is going to go from the lender to you. You are borrowing money from the lender, but adding that money back on top of your mortgage.
This is why people will refinance their home to make larger purchases. The bank will lend you the money now and get it back in the future, plus interest, because it is being added to the mortgage.
This is just one way people are able to use their home to access cash. Other ways people can do this, especially if they are looking to complete renovations, is through home equity lines of credit, collateral charges, and purchase plus mortgages. Knowing this before you buy can be extremely beneficial, that is why it is important to work with a qualified broker!