I just bought a 3700sf 2-story home in Arizona. The home was built in 2001, and the HVAC (gas) units are original. Compressors are outside, Air Handlers are in the attic. I have a 170sf home office with my computer equipment I'm in all day, and it's easily 5-10 degrees warmer in there throughout the day, especially in our scorching summers. I keep the door to the room shut generally to keep kids/noise out while I'm working. I need to cool this one room down much more than the rest of the house. Not worried about heat in the winters- it's always just fine.

I'm considering installing a Mini Split for that one room- but now am curious if zoning is a better option for me? The HVAC is practically on life support, and I fear is going to go out completely soon anyways- probably will need full replacement. If a mini-split is going to cost me ~$1400 or so, maybe zoned is about the same and would perform better anyways? I'm VERY concerned about the upcoming power bill, so I'd like to keep it as efficient as possible.

Many rooms in our house go un-used throughout the day, so it'd be great if we could turn the air up in those rooms, saving on AC use during those times.

-OR- I could just make the office a ZONE with it's own thermostat, and not even zone the rest of the house.

What would you guys recommend?

 

Welcome to the forums.

Without seeing or knowing how the ductwork is setup it would be hard to comment on zoning.

I personally would recommend a small split for that home office.

 

Thanks for the reply...

Not sure if it helps any- but the ducts are all flexible. Is there more information I can give you that would help?

Thank you!

 

Flexible ductwork is a sign of a low-cost installation. I personally do not advocate zoning in residential systems as it can cause other problems. Further, zoning is not inexpensive. The mini-split IS a good idea. One other possibility is a small window unit, assuming both that a window is available AND that the noise from the window unit is not objectionable.

 

If attic space is above the office another option could be to have an extra supply and return register installed in the room.

 

thanks for the replies...

I just realized I DO NOT have a return in this room. So me closing the door certainly makes it much warmer on top.

Not sure of the attic space above. I have a strong feeling there isn't any.

Is a larger, flexible duct/return something I can DIY, assuming I have access to it all?

A window unit isn't an option for a few reasons- mainly HOA/Cosmetic/Noise reasons.

With all that said, is a mini-split the best option here? I'd hate to install one, only to have to install an entirely new system in a few months if/when this one dies on me, and I miss an opportunity to go to Zoning.

Any recommendations on the mini-split systems?

 

Lack of a return air duct AND a closed door is most assuredly a large part of the problem. I would first try leaving the door open while you are working to see if it makes a significant difference. If it does, then adding the RA duct is the next step.

 

Absolutely no way to zone a room that small. To zone a system you would take all the air from the rest of the system and send it to this one room. No way would this ever work. You would freeze the coil with all the bypassed air, condenser pressures would be all over the place. Bad idea IMO. Plus what you going to do in winter? Heat an already hot room? Put in the ductless and be done with it. NO LG Please!

 

Thanks for all the replies...

Leaving the door open does help- not sure if I would say it's significant, but it's noticeable for sure. I'm pretty handy- is a RA something I can do myself? How/where do I duct it to if I do that?

Any thoughts on Mini-Split types/brands? ie- ceiling cassette or wall mount? Mr Cool or any other brand?

THANK YOU!!!

 

The other cheapskate way to help is to cut an inch off of the bottom of the door. Also have seen louvered doors installed.

 

FUJITSU, Mitsubishi top of the line Gree mid of the road Sea breeze lower end we have had great luck with