關於房子的fireplace insert, 邊界,房子的擴建permit的幾個問

看了個房子想買來自住，有以下幾個問題請教下
1:"Is fireplace insert certified by the us environmental protection agency 
as
clean burning appliances to improve air quality and public health?" 回答“
dont know”這個問題大麽？怎麽解決？

2:"are there any encroachment, boundary agreements, or boundary disputes?"回
答don't know
"is there a boundary survey for the property"回答don't know
這個房子周圍有fence，但是以上回答是否意味著房子boundary有問題？如何處理呢？


3：房子擴建了兩間屋子，據listing agent說有permit，但是在政府網站上的permit 
history一欄看不到permit記錄。這個問題大麽？怎麽處理？

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