International Tax

W and H, wife and husband, are citizens of Canada.  They do not have U.S. citizenship nor do they hold a U.S. green card.  They maintain homes in both Quebec and Florida.  W and the couple’s minor children spend about nine months each year at the Florida home, and the children attend school in Florida public schools.  W and the children spend the summer months (80 days) in Quebec.  H, who owns a construction company in Quebec, spends most of the year in Quebec, but makes several trips to Florida each year, aggregating 70 days annually.  H’s income comes from the construction business.  W owns several farms in Quebec which are rented to tenants and produce a significant amount of rental income.  H & W do not file a joint return in the U.S.

Question1: How are H and W taxed by the U.S.?

Question2: How does the analysis of H’s situation change if he stays in the U.S. a total of 125 days annually.