Around here, if your house is appreciating, that's an expense! We're taxed as a percentage of the assessed value of the home.
This is very commonly misunderstood. General property appreciation doesn't increase the amount of property taxes. Budget increases do.
The way property taxes are generally set in the US is:
A) the jurisdiction determines how much money they need from the property tax levy, based on their budget (e.g. The county needs $1 million in property tax revenue to cover their budget)
B) They determine the total appraised value of all properties in that jurisdiction (e.g. $2 billion total assessed value of all properties in the county)
C) Divide A by B to determine the "mill rate" (e.g $0.50 per $1000 of assessed value. This gives $1 million in revenue assuming everyone pays their taxes).
D) They send you your tax bill based on that mill rate. (e.g. $500 on a $100,000 home)
If the budget remains constant, and all properties appreciate at the same rate, then your mill rate goes down, and your total tax assessed is flat. For the above example, if all the properties doubled in value, to 4 billion, then the mill rate would decrease to $0.25 per $1000 of assessed value of your home. (i.e. $500 on your home that has doubled in value to $200,000)
Your taxes should only go up if your home increases more than the other homes around you, or (the most common reason) the jurisdiction increases their budget and decide they need more revenue. Since the budget will increase most years (inflation and expansion), the budget increase will often outstrip the general rate of home appreciation, so everyone's taxes go up every year.
It gets more complicated because you could have multiple entities assessing taxes - county, city, utility district, school district, etc.
Here's a
specific example from Guilford, CT.
{edited to add link and more specific numbers}