Many people fail to asses heat leakage. Often houses are badly sealed - think of a balloon - blow it like a flat tire, and spray it with soapy water and look fo

Many people fail to asses heat leakage. Often houses are badly sealed - think of a balloon - blow it like a flat tire, and spray it with soapy water and look for bubbles. Older houses are full of leaks, especially around foundation, corners of walls, windows and attic. These are often long linear seams that were never well sealed. If you take them as areas and sum them up. many old houses have a 1-3 square foot hole(equivalent) that vents upwards. Out at the top goes all the air you paid to heat and in at the bottom comes cold air, add $$ to heat. There are people with FLIR cameras. A pack of ideas here. https://www.google.com/search?q=FLIR+heat+leak&rlz=1C1CHBF_enCA924CA924&oq=FLIR+heat+leak&aqs=chrome..69i57.8804j0j15&sourceid=chrome&ie=UTF-8 https://www.google.com/search?q=FLIR+heat+leak&rlz=1C1CHBF_e... Sadly there are a lot of scammers out there, but the cost has dropped a lot, so many people/groups could buy one, or rent one of the costly ones for a week and test all your houses. Works best on a cold night where the heat loss shows up well and the sun does not hinder reading. There are also apps for android and ios phone that let you record data. There are also FLIR plugins etc via Aliexpress etc. https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20220226141407&isPremium=y&SearchText=FLIR+android https://www.aliexpress.com/wholesale?catId=0&initiative_id=S... At some of the larger (LA, SF etc) swapmeets there are importers who sell them, so you can look-see in advance