In a column published in July, I wrote about the Mitsubishi mini-split heating/air conditioning system that was just installed in my house. In addition to the required outdoor heat pump, there is a 9,000 BTU unit upstairs, which did a great job keeping our 208-square-foot bedroom cool this summer and has been doing an equally good job heating the bedroom this winter. The 18,000 BTU unit in our much larger downstairs area was adequate during the summer but not quite strong enough to heat the entire area on colder winter days.
I wasn’t surprised by the problem downstairs. I live in one of the thousands of 1950s-era Eichler houses in the Bay Area that was built with radiant heating under the floor. It worked great, but it takes hours for the radiant heat to kick in. It also used natural gas, which is not as environmentally friendly as electricity, so we disconnected the gas line and went all electric.
Heating a big space
Much of our downstairs area is a big open space, but there is an 80-inch-high partition wall between the living room and the kitchen/dining room area. The configuration leaves only 27 inches of space above the wall for the heated air to get from the unit on the living room side to the cooking and eating space. Another challenge is that the outside facing “wall” of both the living room and kitchen/dining room is mostly single-pane glass, which is not a very good insulator.
When I cranked up the heat, the living room would get warm but less so for the kitchen and dining room. I asked our contractor, Michael Calvey of Calvey Heating & Air, for advice, and he suggested a few options. One, which would cost about $4,000, was to install a second unit in the dining area. But, as a cheaper alternative, he suggested we put a relatively large and powerful fan on top of the partial wall between the rooms to blow the air from the unit into the kitchen/dining area.
Solution
I realize these instructions may seem complicated, but with help from ChatGPT, I created a simple 6-step set of instructions you can find at larrysworld.com/HVAC.
Using a fan to redirect the heat worked, especially once I purchased a Dreo 16-inch 25 DB smart air circulator fan ($99.99 on Amazon). It has nine speeds and the ability to swivel up to 120 degrees both left to right and up and down. That swivel, also known as oscillation, turned out to be very useful, because it can distribute the air to every corner of the kitchen/dining room. Best of all, it comes with a smartphone app and is compatible with Amazon Alexa and Google Assistant, which enables not only voice commands but the ability to set up routines to adjust the fan speeds and other factors, depending on the temperature in the room. There is also a remote control. The app and remote are especially useful, because the fan is out of reach on top of that partial wall. I opted for Dreo, because I earlier bought two Dreo smart heaters and was impressed with their email support when I had a problem connecting one of them to Wi-Fi. They responded quickly and replaced the unit with one that easily connected. The same app controls both heaters and the fan, which is a plus. My phone already has too many apps.
Not measuring temperature in the dining room
Another problem is that the thermostat on the Mitsubishi is built into the unit, so it only measures the temperature near where the unit is located and not the dining and kitchen area, which is often several degrees cooler. Mitsubishi’s overpriced solution is a $450 wireless thermostat, but I found a less expensive solution that should work with any heating or cooling system that has an infrared remote control.
I tested two competing smart controllers. Both Sensibo and Cielo offer Wi-Fi enabled devices that upgrade traditional air conditioners and heat pumps by allowing remote control via a smartphone app or voice assistants like Alexa and Google Assistant. They are also easier to use than the Mitsubishi remote control and a lot less expensive than Mitsubishi’s Wi-Fi adapter. Both work well, and both companies offer email support. The $100 Cielo Breeze Plus looks and works like a regular thermostat with on-device and in-app controls that can be wall mounted or stand on a table. Cielo also offers phone support, which to my delight, answered when I called and helped me solve a problem when some of its features weren’t initially working right on my system. Speaking with a patient human is usually better than going back and forth with support via email.
Some HVAC systems don’t even have Wi-Fi adapters, so devices such as this one are the only way to make them “smart.” Although these devices are a great way to control the unit, they didn’t solve my problem by themselves, because they have to be within a few feet and in line of sight of the split unit for the infrared signal to reach the device. So, when it senses the temperature, it’s measuring it at the split unit, which is usually several degrees higher than my dining and kitchen area.
But I had an Echo Dot that solved that problem. Amazon’s fourth- and fifth-generation Echo Dot have a temperature sensor, as does Amazon’s $50 Air Quality Monitor. These devices can send out signals via Wi-Fi to many smart devices, including the controllers from Cielo and Sensibo. The next thing I needed to do was create an Alexa routine that tells Alexa to turn on the heater when the temperature gets below a certain point and back off when it gets above that point. In the summer, I’ll create a different routine to do the opposite.
That solution worked. The Echo dot functions like a thermostat and the Sensibo or Cielo device finishes the job by sending a command to the split unit. In addition to turning it on and off, it can also set the temperature, the fan speed and the position of the “vanes” or louvers that control air flow.
The Sensibo starts at $99 and the Cielo at $59. I bought an Echo Dot on sale for $22, so this is a pretty inexpensive solution. But if you don’t need to measure temperature in a different room as I do, you don’t need the Echo. Either the Sensibo or Cielo will do the job by itself.
There is one other solution to the remote room monitoring. You can get what’s called an IR blaster to pick up the infared signal from the Cielo or Sensibo and transmit it to the heating/cooling unit.
Easy instructions
I may be a techie, but I don’t have a lot of patience for complicated coding or configuring. So, if you want to try this on your system, check out the simplified instructions at Larrysworld.com/HVAC.
Wishing you a warm and cozy holiday season.
Larry Magid is a tech journalist and internet safety activist. Contact him at larry@larrymagid.com.