Understanding Heating and Cooling in Addition
Hi hope everyone is well. Currently planning a 2nd floor addition that is adding 2 bedrooms. I currently have central air. I’m thinking of installing a mini split to heat and cool the 2 rooms. The architect is saying the unit has to be well ventilated outside, that it can’t be too far from rooms, and it can’t be too close to my neighbor. I’m confused how close does the outside unit need to be to inside units. I’m also curious why they don’t have a wall unit that runs on electricity only and would not need an outside condenser. I’m not quite understanding the mini split option. Is their something less complicated to heat and cool single rooms at a time?
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OK, bear in mind that HVAC is a skilled profession, so any answer you're going to get here is going to be abbreviated and probably somewhat wrong. And you definitely want to plan for your HVAC before anything is built, it's much easier to change a piece of paper than to redo construction.
In many cases the most cost-effective thing to do is to tie into the existing system. It's not always possible, but I would speak to someone knowledgeable before ruling it out.
Without seeing your design, if I were doing a 2-room addition I would put a ducted minisplit in the hallway between the two rooms (or in a closet if there's no hall) and a duct going off to each room.
The reason the outdoor unit has to be within a certain distance of the indoor units is that refrigerant is pumped from outdoors to indoors, the line it's pumped through is thin, and there's a limit to both how far and how high the refrigerant can be pumped. The installer will know those limits without having to think about it.
It's probably a good idea at this point to get in contact with an installer and ask him what kind of equipment he typically installs for a job like this and what the length limit is.