Do you have a mini-split system? Do you like it?

[Louisville Slugger]

Originally Posted by wolfgang239

How much more is another single zone instead? If you read the spec sheets on mylinkdrive the mxz units can only ramp down so low which is one of the biggest efficiency features of the Mitsu heat pumps. If you are only running one unit with the multi, it will no longer be able to ramp down to such a low BTU rate.

Look at the submittal sheets (.pdf warning):

MSZ-FH09NA, look at Heating/Cooling "minimum capacity".

MXZ-2C20NAHZ2, look at Heating/Cooling "capacity range".

If it is close in price you may come out ahead in the long run. Something to ask the installer. Almost none of them know this little fact and will dismiss it. But you will need at minimum 6k BTU of Cooling and 7.4k BTU of heating if running one unit....

Wow thanks for that piece of information. I reached out to the installer to see what his thoughts are. I thought it would be easier to install another single zone and just leave what I have for the first floor. The second compressor could be mounted in the back and I believe the wiring could be run through the existing 1/2" conduit to my panel unless each compressor needs it's own conduit. My neighbor has 3/4" conduit with his two zone unit. I have 1/2" with my single zone currently. If the installer insists on a two zone unit I bet the electrician will have to replace all the 1/2" conduit with 3/4". Then the shut off will have to be moved from the side of the house to the back.

We'll see what his thoughts are. I already mailed the deposit for the dual zone unit before reading your post.

[Louisville Slugger]

Update:

So I received feedback from the installer. He acknowledged I was correct and said we can certainly install another compressor. So the plan now is to install another compressor with another air-handler for the basement instead of replacing my existing compressor with a two zone one.

The MUZ-FH09NA & MSZ-FH09NA will be installed and everything I currently have will be left untouched. Question now is will another set of conduit will need to be run for the other compressor or can we tap into the existing 1/2" conduit that was installed when I had my first floor done? Not sure if that is code, but we'll see once they come and do the install.

I asked him to void out the other proposal and use the check I already sent him towards the new proposal (which I just accepted).

The thing I like about having two compressors is if one requires maintenance I won't lose heat and AC for the entire house. Would it be more efficient compared to one big one? Possibly, if the units can throttle down more.

BIG thanks to wolfgang239 for catching this. I would have never thought to ask the installer.

Thanks man.

[OutdoorLover]

One thing to keep in mind when using a mini-split system for heating, is that often, the number of outlets is far smaller than is used in a true central heating system (which will have at least one in each room). That's okay if the house if well insulated and sealed, as the heat will find its way into other rooms before too much is lost through the building envelope. But if the house isn't well insulated, the rooms that lack the outlets may not be comfortable in the dead of winter.

[berkshiregrl]

I find our mini split system which we use downstairs far superior to the window units we use upstairs. It maintains a comfortable temperature much easier and is super quiet compared to window units. We have a 1960's house where we gutted the downstairs and made it more open concept but we still have a dining room and library as separate rooms as well as a kitchen, keeping room and family room and it really keeps the whole downstairs comfortable. We installed it in 2005 when we did the renovation and have never had a problem with it.

These units are much more common in other countries. I had never even heard of them back in 2005 when I started researching what what we could use. We only have one for cooling but they do have ones that provide heat also. We had an installer come in to size the unit and then install it. I was concerned it would look bad on the wall but I soon realized I didn't even notice it after a few days.