ST Compatible Thermostat w/ Heat Pump Balance


(Kurt Backlund) #1

Nest has a great feature called heat pump balance that limits the use of the (very expensive) electric aux heat, particularly when warming the house from a cooler state. Do any ST compatible thermostats incorporate this feature or something similar? I can’t seem to find this answer anywhere.


(Bob) #2

The Nest thermostat works fine in SmartThings with the community-written device type (AKA, device handler). Just do a search for “dianoga nest” (dianoga is the screen name of the original author). I’ve been using a modified (by me) version of his original code in cooling and heating seasons, and it works great.

Disclaimer: I don’t have a heat pump, and don’t believe it can be individually controlled within ST. From the description you linked though, it sounds like it happens automagically once configured on the thermostat.


(jotto) #3

I use the Ecobee they also have features which allow you to set many aspects of heat pump/aux heat control (I use Ecobee Smart Si thermostat, Ecobee 3 is newest version of their product, assume they have all the same if not more features than I have with Smart Si).

Ecobee allows you to control heat pump/aux settings at a much more granular level. This may be a positive or negative for you.

Off the top of my head in the Ecobee settings you can set the following; aux heat lockout, maximum temperature aux heat will turn on, if heat pump can run with assist of aux heat (you can also set time interval, i.e. if it senses heat pump has been running 30min with no change in temperature allow aux heat to help).

Let me know if you have any questions.


(Greg) #4

Thats very interesting to me. My HVAC guy keeps telling me that there is no good reason to put a smart thermostat on my heat pump, even though I keep telling him I want one. Have you seen significant savings? Winter is brutal for my electric use.


(jotto) #5

Short answer, yes, i have seen a meaningful savings since installing the Ecobee thermostats (got them in Jun. 2014). I also value the convenience and comfort they add to my home.

The reality, it’s complicated and your mileage may vary.

A little bit about my home, it’s a 1,260sqft 2bed/2bath single floor condo, new construction (2012) concrete/high-rise in North East. I have 4 GE Zoneline PTAC units, they are controlled by 4 individual Ecobee Smart Si thermostats.

Why do I start with this… every aspect of a home (construction, materials, windows, doors, insulation, etc.), AC/Heat set-up, location is different and could help or hinder your available savings.

If I look at my billing data I am running about 20-25% less, using Nov.-Mar. (cold enough for heat to run) average per year, than I was pre-thermostat install. I consider my home a fairly easy use case to push limits of available savings. Can I attribute all my savings to the ‘smart thermostat’, absolutely not. I did a lot of things around my home around the same time that help contribute to my savings (e.g. all recessed lighting and lamps are now LED, SmartThings ensures things are off when were away, I re-caulked around PTAC units, installed whole home energy meter).

What I can say is having Ecobee Thermostats and SmartThings has made me more self-aware and I began accounting for energy usage. I believe this is a critical factor to maximize your savings potential.


(Kurt Backlund) #6

Responses from various manufacturers below…

Kurt,

Thank you for contacting Honeywell.
Our Tradeline Vision PRO WiFi thermostats have the recovery staging options you are looking for. The TH8320WF and the TH8321WF both can be configured so back up heat does not engage during recovery. This setting is called Economy mode, which can be found under droop options in the manual. Recovery in this case means changing from one scheduled period to another. An example would be switching from the nighttime schedule to the morning schedule.

Vision PRO thermostats also have lock outs and up stage timers. Lock outs will prevent either the heat pump or the back up heat from running based on the outdoor temperature. (If it’s 20 F outside, the heat pump will not be efficient.) Up stage timers will force the thermostat to run for X amount of time before upstaging into stage 2. This can be set to 30 minutes, an hour, or several hours.

A link to the Vision PRO thermostat can be found here.

Vision PRO thermostats are Tradeline thermostats. That means they are not sold at retail locations. Only authorized distributors and dealers sell Tradeline thermostats. A few distributors have online webstores. These thermostats have a 5 year warranty. Retail thermostats come with only a 1 year warranty.

Regards,


Hi Kurt,
Thank you for contacting Sensi Technical Support. The Sensi does not have a heat pump balance. The Sensi thermostat uses an algorithm to determine the optimum time for the thermostat to bring on additional stages. The Sensi microprocessor constantly monitors the 1st stage performance and produces a time delay based on the result. The time element of the delay can vary between 0-30 minutes depending on how well the 1st stage is performing.

The net effect of the staging algorithm is when the first stage is capable of maintaining the set point, the second stage will delay longer. When the thermostat calculates that the first stage cannot reach or maintain the set point within a reasonable time, the second stage will turn on sooner.

I hope that answers your question. If you have any other comments or questions, please contact us via e-mail or give our Sensi Technical Support team a call at 1-888-605-7131, 7:00am – 8:00pm CST, Monday-Friday, and 8:00am – 6:00pm CST, Saturday-Sunday. Thank you again, and have a great day!
Sincerely,

Sensi Support Team
support@sensicomfort.com
1.888.605.7131


#7

@Jotto, can you tell me more about how you connected your PTAC to the Ecobee? Typically PTAC units have controls directly on the unit. Did you run wires from the PTAC to the Ecobee thermostat?

I am looking for a way to connect my PTAC to an Ecobee wirelessly. Hoping you found a way to do that which can be replicated.

Cheers
-Roy


(jotto) #8

Hey @royNYC - The GE Zoneline PTAC units I have are thermostat capable. The builder ran wires to individual thermostats to control each unit (cheap ~$25 non programable thermostats which I replaces with the Ecobees). When thermostat wiring is hooked up to units the controls direct on the units is disabled (i.e. can then only control with thermostat).

You would have to lookup the manual on your unit and see if it is thermostat capable. Some units also have RF technology to allow remote control (wirelessly). Take a look or shoot me your PTAC model info and I will take a look if its an option for you.