Any tips for using these things so that it doesn’t damage your HVAC system? I have many issues with hot spots in the house but the house isn’t big enough for another zone.
Also have the ecobee thermostat with sensors in all the problem areas. It’s a good start but, I can see that venting is going to be a major factor to stop these hot zones while rooms are not occupied.
What would you do?
After reading a lot about the issues you can cause by closing too many vents (mostly related to air pressure and the undue strain on the blower), I changed my mind on wanting to install smart vents. An HVAC company may be able to help you by potentially installing return vents in the problematic rooms, and/or adding an inline blower to areas that are not getting enough air. This, of course, is if the balancing of the air duct baffles doesn’t fix the issue. I am not an AC expert but this is what I concluded after doing my research to resolve your same issue.
That is the problem with this house. The duct and return system was just redone, maybe not properly but it was just done. The office averages 7 degrees hotter than the rest of the house and it’s to the point where I have a fan blowing cooler air from the living room to the office.
It’s 110+ in Phoenix these days, so, it’s just not much fun to work in the office during the summer months, even at night.
At this point, I’m out of options and think I could steal some air from the master bedroom, kitchen and living room to push more air out in the office. Which is also the smallest room and vent in the house.
Is there a return duct in the office? Do you keep the door open or closed most of the time?
My office is way hotter too as it has the attic above and 2 walls exposed to the outside. On top of that I have lots of electronics running 24/7. I have 3 large return ducts, 2 downstairs and 1 upstairs in common areas. I then have a small 12"x12" return duct in the media room (3 exposed walls and attic above) and one in the master suite. I do not know how much they are helping as I still have issues in both rooms, but they are there to mitigate it. I am guessing that these vents really only do something if the doors are shut… otherwise air moves easier via the open door. Once I started leaving the media room doors open, the imbalance was a lot smaller. Same goes with the master suite but I prefer to keep the door shut at all times… I believe my only option is to add an inline blower to push more air.
EDIT: Do you replace all filters at least every 90 days? What filters do you use? The ones that say they filter everything out also cut down on your airflow quite a bit and potentially causing trouble to your blower as well. I usually stick with 1000 (see below). Less would likely end up causing HVAC inefficiency and failure by allowing stuff to collect inside the coils/blower/etc.
Yes, there is a return in the office. They suggested another one over the door, also to cut 2 inches off the bottom of the door. The door remains open because, if it was closed, it would be 90 when the rest of the house was 78 or less.
The window is on the east side of the house. It will get most sun until around 11am, although, it’s hot all the time in the summer months.
“The room is uncoolable unless there was a window unit” is the answer from George Brazil (the most trusted name in HVAC in the Phoenix area)
Although, I expect they are just throwing money at problems without finding a real answer. Relieving too much air pressure out of the room isn’t working, relieving very little out of the room isn’t working. It’s time to get a better answer, that is for sure.
Wow, 2 inches on the bottom of the door would look a bit off… I am surprised they suggested 2 returns in the same room unless it is very large but I am not an expert.
You might want to consider, if HOA/etc allows, to install a film on the window(s) that reflect some of the light to reduce heat build up through the window. Blinds/curtains might help too.
Is the insulation in the attic sufficient? I used a FLIR One (https://www.flir.com/products/flir-one-gen-3) to help me figure out where the issues are.
Air leaks? You might have duct air leaks, or hot air making its way from the attic into the room. With a thermal camera you can find the leaks. Some I found were around electrical related perforations. They are also obvious if you remove the covers and find dust collecting around the opening. Sealing is required for switch/outlet boxes on exterior walls but I do it on my interior ones too as I can clearly see signs of air flow.
Sorry, I am all over the place, but these are all things I considered when troubleshooting our shared issue.
It doesn’t help that I have a 4-drive NAS, a 3 drive Xeon server, a pfsense firewall and a laptop running all in the same room but, there have been other people in this room before it was an office and it’s always been the coldest (winter) and hottest (summer) in the house.
The room is very small but it also is storage for a lot of things. It’s extremely ‘neat’ not messy at all, there is an 82" DLP basically covering the window.
There is a problem that might actually be outside the room. There is a cat door on the garage that is adjacent to the office door. As I know air will pick the path of least resistance, that return in my office seems like the best way to go. So, I will pick up a shrink-wrap window film to cover it. It was from a previous owner of the house and it seems that everything in the room makes sense, it’s time to start looking for things that are contributing to the heat outside of it.
You might be able to rent a thermal camera from your local hardware store. If you do, I would pick a very hot day and jack up the AC inside to maximize the temperature difference… then happy hunting. Take lots of pictures so you can review them later or have an expert give their opinion.
These were taken in December 2018:
Shows cold air leaking in under and around the patio door
Shows lack of insulation in master suite where the ceiling slants down
Window is not that efficient at keeping the cold out… a similar picture to this one lead me to find that the window was not properly shut and the locking mechanism was pushing the windows apart causing a draft of cold air. The draft was there for quite a long time until I pulled out my Flir and found it. Just running my hand over the leak would have detected it as well but who knew it was even there, all I knew is that the room was freezing and hard to warm up.
One of my return vents downstairs. This one is inside the shared attic of the master suite so exposed to the outside cold however the image is deceiving in this case… the blueish area is that color due to the hot light and Unifi AP being in the field of view. Either way, you can see traces of poor insulation around the return
This one shows the ceiling in the garage. I added insulation to try to even out extremes (I live in TX) as I like to do stuff in the garage. The blueish areas are where I have not placed insulation as it is still work in progress. At least I know it is doing something 
