I am in climate zone 4 (Southern New Jersey – outside Philadelphia) and have a 2-story house built in 1983. I have been working on various improvements and am in the process of upgrading the HVAC. I’ve been wanting to do this for quite a while, so I wasn’t too upset when the compressor failed in my existing unit. My plan is to do everything myself. I know that this affects the warranty for Mitsubishi equipment, but I’m okay with that. I enjoy taking on new projects and learning different skills.

After a lot of research over the last year, I’ve been interested in the idea of going ductless. My thinking was that it would give me flexibility, good efficiency, and would eliminate issues with the existing ductwork. I don’t know for sure, but I assume that my ducts (original to the house) are less than optimal. From what I’ve observed, there is a 20×14 main trunk that runs in a soffit from the air handler in the laundry room through the front of my living room. From there, there are 6″ metal runs to all the rooms, both upstairs and downstairs. There are a few areas in the attic with flex ducts, and they have severely deteriorated. The kitchen/eating area on the first floor has a high/sloped ceiling and is supplied by 6″ flex ducts that run through my unconditioned garage attic. The upstairs return is also flex and goes through the unconditioned upstairs attic.

I reached out to Energy Vanguard, and they completed a Manual J/S. The plan calls for 4 Mitsubishi MSZ-FS splits downstairs and a mid static ducted unit for the upstairs (PEAD-A09AA9). The load is too small for splits on the second floor hence the ducted unit. There was initially some confusion about my family and dining room. They had selected a 12k unit not realizing that there is a partition wall between the rooms, so they told me to use two 6k units instead. There would be a 9k for the kitchen and a 9k for the living room. They chose a multi-split, but I thought I would go with 1 to 1 units for redundancy and maximum efficiency. The way my property is situated, it’s easy for me to conceal the condensers.

The 6k units were out of stock for quite a while, but I bought two 9k’s and planned to install these while I was waiting. I ended up installing just one so far and mounted it to the left of the fireplace in my kitchen area. I didn’t know quite what to expect, but it has been great in the week that I’ve used it. The whole kitchen area is cool, and I noticed that cool air is even bleeding into the family and living rooms. My old thermostat is in the family room, and it’s actually maintaining the same temperature as my split setpoint, with the exception of a couple hours at the hottest time of the day.

Now that the 6k’s are back in stock, I was going to order and install the one for the family room and then install the 9k unit in the living room. I was thinking about holding off on the dining room unit at this point, because we never use that room (or the office that’s adjacent to it). Nearly all of our time is spent in the family room and kitchen, though I don’t know if it still makes sense to heat/cool all the rooms.

For some reason though, I’m hesitating. I’m indecisive by nature, and the more reading I do on this forum, the more I’m worried that I’m making a big mistake by going ductless. I keep holding off buying the family room split, because I’m wondering if I would have been better off with a ducted air handler.

Whatever I do, I feel like it will be an improvement over what I had. I’m just trying to make the best possible decision and avoid doing something that I regret. I’ve attached my floor plans and Manual J. I’m looking for any thoughts or input both positive and negative. Any advice on whether everything looks good, or if I should make changes for the upstairs or downstairs would be greatly appreciated. I haven’t bought all of the equipment yet, so I’m still at the point where I can make changes if necessary. Energy Vanguard did mention that everything is sized for heating, and as a result, additional dehumidification may be needed. My plan down the line is to add a Zehnder ERV.