I am a contractor and whenever I am working on a new build, I tell my clients they need to have good insulation.
There is no sense in going cheap and under insulating your house.
When you don’t have good insulation around the windows, doors, and in the walls and roof, your house won’t be comfortable. You can have the best HVAC system, and yet your home will never be warm enough or cool enough. I tried to tell this to a friend of mine, but he didn’t listen. He swore he had a problem with his HVAC system because the heating was so uneven. He wanted me to put in a new furnace, but I said it had nothing to do with his furnace. He even called the HVAC company and had them do another inspection. They told him his furnace was working well. I kept telling him that without good insulation, he wasn’t going to have good heating and air conditioning. He finally had a heat loss test done on his home. They showed right where all of the heat was going. Instead of staying in the house, it was going out through the windows and doors. He needed fresh insulation put around all the doors and windows. He was also losing heat in the attic. The heat was rising up through the floor and going right out of the roof. He put insulation in the floor of the attic and on the drop door entrance to the attic. Now his house is warmer in the winter and cooler in the summer.