Depends on how your locality assesses the value of your home. You can probably do a web search for where you live specifically if you want to get into the nitty gritty. In the places I've lived, unless I added more square footage, these won't trigger an automatic property tax increase.

But if the improvements on your house makes the neighborhood more desirable and your neighbor's house sell for a higher price then your locality expects, then your house will be assessed at a higher value the next time the locality does their assessments, which means higher taxes.

Of course, improvements to your home that increase a sale value will affect the taxes, but the buyer has to deal with that.

Do some localities assess homes individually every so often? I wonder...