You need a load analysis to size an HVAC unit correctly, not guessing. It calculates heat loss and gain based on your home's insulation, windows, and orientation. Home improvements like better insulation can mean you need a smaller unit than the original.
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How do I know what size unit I should be using in my home?
You would do what is called a load analysis or a heat loss, heat gain, which is what we do at every single changeout, every single installation. We do a heat loss, heat gain, and that's what's supposed to be done. Now, we get the question quite a bit, "Hey, I've had this unit for 30 years. I don't need the heat loss, heat gain." Well, the reason we do it is because in those 30 years you might have improved the insulation in the house. You might have went from single-pane to double-pane windows. You might have gone to insulated doors. You might have put some insulation in the walls. So you might need a smaller unit than you did 30 years ago. Does that make sense? So we do a heat loss, heat gain for that reason. Sometimes you do run into that situation where you need to upsize, downsize the unit depending on the house. But again, every house is different. I mean, you think about these subdivisions you go to, and the back door is facing south. On the other side of the street, the front door is facing south. So there's different load requirements for this house versus that