I am GC'ing my house and I hired an HVAC company but I have a lot of questions about the way they are doing things. They are nice people, but they seem to really be focusing on quick and cheap, but with my ICF house I want to make sure it's done right. Your guidance and opinions will either put my mind to ease to make me seek out another local pro.
I have a goodman 95% variable speed 115K BTU furnace and American Aldes 300DD HRV ducted to the basement and main floor. We are about to fire the systems, and the contractors put in the vent in today. They have a 3" furnace exhaust pipe running out, but they said the intake will draw air from the utility room. They also connected a 6" make-up air vent from the outside wall to the return air trunk. Keep in mind my HRV's fresh air port is also connected to the return air vent, and it exhausts from the bathrooms.
Question 1: Shouldn't the furnace get it's combustion air from outside? I also have a power vent water heater in the mechanical room, but I assumed it would also have pipes to get it's combustion air from the outside.
Question 2: If the combustion air is taken from the outside, is there any reason to have a makeup air vent connected to the return? It seems almost pointless to have that with an HRV, especially an expensive dual core one if it's just going to draw air thru a 6" hole in the wall.
Question 3: Should I go back and mastic all of the joints? I've heard it's good to do, but I am busy with other parts of this project and when I brought it up with them it sounded like they either didn't want to do it or would want to charge me a lot.