Honeywell Pro thermostat programing for heat droop

[rjacobs]

Weve been in our house for 4 years now and every winter our electric bill is higher than in the summer... We live in Texas, our summers are brutal our winters, overall, are mild. I always questioned it.

In the winter we run the house during the day at 66 and at night let it cool down to 60. I read something recently that if you let your temp difference get to great that your heat strip backup will kick in and can cause really high electricity usage... The air coming out of our vents when the heat comes on is hot... I dont remember that to be the case in my old house that had "emergency heat" on a switch which activated the heat strips if it got to cold outside. I also dont remember that in the house I grew up in that had heat pump heat with "emergency heat" strips on a switch.

Im FINALLY looking at this so I went into the advanced menu in the Honeywell T6 Pro thermostats and see that code 340 "backup heat droop" is set to zero. This to me means that my heat is 100% coming from my heat strips and I am never letting my heat pump do anything basically. I checked code 205 "heating equipment type" and its set to 7 for "air to air heat pump".

So I am thinking I need to set my "backup heat droop" number to something other than 0 in order to let my heat pump actually work without having my heat strips kick in... Is there something scientific to picking this number?

I think I would be ok with bumping up my night temp if it means keeping my heat strips off and relying on the heat pump(which is what we SHOULD be doing)...

 

[chinboys]

Look at your heat pump's heating specs to find out the unit's minimum operating temperature.
New systems will get you heat below 20 F. before your emergency or Aux heating strips assist or bypass the main system's heating cycle relative to a setpoint temperature.

You have to set the above set point and the backup heat droop for your Honeywell thermostat.
From Google, So it's a function of the setpoint and the "droop" (number of degrees you will allow below the setpoint before aux heat "kicks in").

 

[dcg9381]

I'm in TX too. The deal is that the "heat pumps" builders install here are not designed to really be efficient in cold weather. So they'll run 24/7 in cold weather and at best "maintain temp".

I don't know what the correct differential in commanded and ambient temp is to engage the heat strips... It seems to me like it's a bit of a hack to maintain inside temperature instead of taking into consideration the efficiency of the heat pump and outside temperature.

On the few "really cold" days I just manage it manually as I've got that "emergency heat" mode. More recently (with the massive sustained power outage that we had in 2021) I installed drops for ventless propane heaters and use those if it's below 25.

 

[rjacobs]

I'm in TX too. The deal is that the "heat pumps" builders install here are not designed to really be efficient in cold weather. So they'll run 24/7 in cold weather and at best "maintain temp".

Well basically right now any time heat is demanded my heat strips come on which is a huge power waste and thus my bill is stupid high...

I need to grab the model numbers off my Goodman units and see if I can find their data.

Im thinking of trying a 4 degrees split and modifying my night temp to 63 from 60. If it doesnt do what I think then I can just change it back or play with it a little.

 

[dcg9381]

Yea, powering those strips 100% is not right. I just think our basic thermostats are "hacks" for figuring the real problem out... I'd definitely change the differential.

 

[PFSard]

Weve been in our house for 4 years now and every winter our electric bill is higher than in the summer... We live in Texas, our summers are brutal our winters, overall, are mild. I always questioned it.

* Curiosity killed the cat? I've been in my current house for 13+ years in AZ. Just a 4-ton heat pump for my 1400 square foot house with no "backup heat strips". No issues with keeping warm in the winter months. Nor high electric bills. Especially compared with my summer bills.

* Are your winters colder than ours around the Phoenix area? Do you need heat strips to supplement the heat pump?

 

[rjacobs]

* Are your winters colder than ours around the Phoenix area? Do you need heat strips to supplement the heat pump?

I believe the answers would be "yes" and "I dont know".

We get a lot of nights below freezing. We get 1-2 weeks per year of sub freezing weather usually associated with ice storms. Looks like(at least the last 3 years of data) the coldest Phoenix has seen is 36 in January(dec and feb were both like min 39-40), and I would guess thats an overnight min temp. I saw nothing looking at "full month" that would show highs below 32 which we do have "occasionally". I know sub ~40 heat pumps get out of their range, sub 32 they really get out of their range. So for maybe 1-2 weeks per year, yes I would say heat strips are needed. Also quite a bit, first thing in the morning, I would say heat strips would be needed. I dont think, however that I need heat strips as my main heat, which I believe is how my thermostat is currently set.

 

[rjacobs]

i talked to a guy from another forum I am on. He's an HVAC tech and walked me through what these things meant and what to setup.

He had me check a few things in my thermostat and then explained how it really worked. It is setup/programmed to have a 3 degree variance allowance(+- 1.5 degrees) so that you arent constantly cycling AC or heat. There were other settings, but he said 3 degree variance is fine. I think the other setting was a 5 degree variance.

With the "droop" set to zero before "backup heat" as soon as the thermostat would ask for heat it would ask for heat strips. He had me set it to 2. Now when heat is called for, lets say its set at 70 degrees, it will come on at 68.5 degrees on the heat pump. If the heat pump cant provide "heat" and the temp continues to drop 2 more degrees(66.5) then the backup heat strips will kick in.

We then looked at another setting called "upstage timer" which is basically a timer to say "give the heat pump time to work". It was set to 0 i.e. "dont give the heat pump time to work". We set it to the lowest setting which was 30 minutes. So from what he understands of Honeywell if after 30 minutes or 2 degrees the temp is still outside of the "limit" of say 66.5 in our example above, it will turn on the heat strips.

Then we made sure adaptive recovery was turned on(which I thought it was). Thats the "smart" feature of this semi-dumb thermostat. You have to use a programmable mode for "adaptive recovery" to work. He says it will learn how long it takes to bring temps up and down and what not, thats about as smart as it is.

 

[dcg9381]

i talked to a guy from another forum I am on. He's an HVAC tech and walked me through what these things meant and what to setup.

Thanks for that. I've got those same thermostats. That's an excellent set of cliffs notes.

* Are your winters colder than ours around the Phoenix area? Do you need heat strips to supplement the heat pump?

I dunno what the deal is, I suspect "builder grade" heat pumps, but my home is foam insulated and partially underground. If it gets below about 28 outside, the heat pumps will run 24/7 - that seems to be their "sustainable" temperature. Colder than than, say around 20 (like we had in 2021) and you're going to be losing ground.

My heating bills can be higher than summer also, so it's a little nuts.. Between this and the possibility of "no power" - that's why I've got a propane "backup" heat system.

 

[rjacobs]

Thanks for that. I've got those same thermostats. That's an excellent set of cliffs notes.




I dunno what the deal is, I suspect "builder grade" heat pumps, but my home is foam insulated and partially underground.

My heating bills can be higher than summer also, so it's a little nuts.. Between this and the possibility of "no power" - that's why I've got a propane "backup" heat system.

Yes these are Goodman units which are made by somebody, but their low end builder grade line. When they **** the bed everything is getting torn out for multi head mini split setups.

I also have a foam roof, but not walls. I couldnt ROI the walls...hell the roof was hard enough to ROI.

I went through the "I need a huge generator" thing after 2021 when we lost power for 4 days. What I came up with was a 3.5kw Honda and an oil radiator heater and I have a portable A/C unit in my garage that will run off of it I can bring in the house. We also can power our network rack so we still have wifi and I have a USB-C charger on it so we can use that to recharge phones. The only other thing I give a **** about is my fridge in the kitchen if we are being honest and it will run off the 3.5kw just fine as well. We heat/cool only one room. We have 100 gallons of hot water and it was still "warm" on day 3 a few years ago and the hot tub was still 85 when the power came back on.

 

[dcg9381]

Yes these are Goodman units which are made by somebody, but their low end builder grade line. When they **** the bed everything is getting torn out for multi head mini split setups.

When I built, I got a bid for multi-head mini splits during construction. It was well over what it cost for traditional HVAC.
I own two mini-splits and love them, but when stuff goes wrong with them, often you're looking at replacing the whole unit. Traditional HVAC seems to have a longer service life. And you can get units that will heat in cold weather. Goodman is a brand I see on spec homes a lot...

I also have a foam roof, but not walls. I couldnt ROI the walls...hell the roof was hard enough to ROI.

Well, you did the important thing.. And you get your air handler in heated/cooled space.

I went through the "I need a huge generator" thing after 2021 when we lost power for 4 days. What I came up with was a 3.5kw Honda and an oil radiator heater and I have a portable A/C unit in my garage that will run off of it I can bring in the house. We also can power our network rack so we still have wifi and I have a USB-C charger on it so we can use that to recharge phones.

We were living in the shop at the time. The mini-splits wouldn't keep up and it was dropping below 50 degrees inside. I added some 1500 watt heaters, but eventually brought in 30k BTU propane systems which solved it. Shop is only insulated R-12 though.

My whole network is POE attached to battery backups. Battery backups are tied to an auto-start generator. Power goes out and I don't even notice until the generator kicks in. I think having a smaller generator option is great as long as you've got enough fuel to power it.

 

[fitter30]

Heat pumps don't like set back. When stat goes from 60° to 66° 30 minutes might not be enough time to keep strip heat off. Air is easy to heat mass is harder. Floors,walls furniture is all mass.

 

[rjacobs]

I think having a smaller generator option is great as long as you've got enough fuel to power it.

At the end of the mowing season I fill my zero turn, thats 10 gallons of non-ethanol.

When I am done tracking my race car that free's up six 5 gallon jugs. So I then go get 30 gallons of non-ethanol fuel.

I generally also fill up my pontoon at the end of every season when I winterize and thats 45 gallons of non ethanol...

Got er covered LOL.

 

[rjacobs]

Heat pumps don't like set back. When stat goes from 60° to 66° 30 minutes might not be enough time to keep strip heat off. Air is easy to heat mass is harder. Floors,walls furniture is all mass.

He had me adjust my night temp to 63 instead of 60 to try to stay in the -1.5 + -2 window of the droop. He said the same. Even with the higher night temp, he thought my energy usage would go down by keeping it in the window of not letting the heat strips come on.

 

[PoorUB]

Heat pumps don't like set back. When stat goes from 60° to 66° 30 minutes might not be enough time to keep strip heat off. Air is easy to heat mass is harder. Floors,walls furniture is all mass.

He had me adjust my night temp to 63 instead of 60 to try to stay in the -1.5 + -2 window of the droop. He said the same. Even with the higher night temp, he thought my energy usage would go down by keeping it in the window of not letting the heat strips come on.

You might be better off not to do a set back and make certain the heat strips don't come on.

A few year back we did a school building, all heat pumps. We also did the building controls and we set the HPs to run at set point all the time. The school figured they were wasting energy and wanted to do a night set back, so I was there and helped them get it set up. The first cold snap everyone was complaining as it didn't get warm in the building until after lunch. We checked data longs and the HPs were running more hours a day with the set back, trying to reheat the building and contents. It was costing them more money with the set back. We removed the set back and just left the temp at the same setting.

 

[firebirdparts]

In Texas, you may want to just cut the wire.

I find that the heat droop settings don’t have enough range at all. My wife moves the tstat 5 degrees at a time in winter every day. Tstat can’t help you with that and it sounds like you have the same. I cut the wire but I did put a manual switch in it. If it gets down to 10 degrees I will let her use it that day.

I bet I’ve saved $20,000

 

[rjacobs]

In Texas, you may want to just cut the wire.

I find that the heat droop settings don’t have enough range at all. My wife moves the tstat 5 degrees at a time in winter every day. Tstat can’t help you with that and it sounds like you have the same.

same what?

wife? no... she doesnt change it. Its all in the programming.

Depending on what thermostat you have running it in manual mode only makes issues worse.

This honeywell is supposed to be "semi" smart in that it learns how long it takes to come to temp so it will come on at the proper time to get your temp to your requested by the time you requested it. If you run manual mode it will obviously not do this and will never learn. Gotta run the program.

I could set the droop as high as 15 degrees, but seems commonly that 2-3 degree's is a setting across the board that works pretty well to stay out of electric heat.

 

[PoorUB]

IMO, Intelligent Recovery mode is just a gimmick. Just set the stat to come up in temp and hour before you need the temp change, is is pretty much what Intelligent recovery is attempting to do. I doubt it will save any money, it is more of a comfort thing. Plus it you get wild temperature swings Intelligent Recovery can't "think" to over come the swings.

 

[PoorUB]

In Texas, you may want to just cut the wire.

I find that the heat droop settings don’t have enough range at all. My wife moves the tstat 5 degrees at a time in winter every day. Tstat can’t help you with that and it sounds like you have the same. I cut the wire but I did put a manual switch in it. If it gets down to 10 degrees I will let her use it that day.

I bet I’ve saved $20,000

A buddy just put a separate thermostat up for the electric heat and generally set it 3 to 5 degrees lower than the HP stat. But he left he HP stat set at the same temp all the time.

 

[Fav Onefour]

I'm basically running a heat pump. It's GEO, but same concept. I'm up north and have backup "emergency heat" and Honeywell controls.
System setup was a big part of getting things to run right. Our highest load is winter. Loop temps can run near freeze temps and the system is often at full capacity on cold days. Fiddling around with temp settings will kick it into the backup system.

The other side to being up north is that our highest load is heating. Our system is way oversized for cooling. Heating often needs to offset outside temps by eighty degrees. Cooling is only doing thirty five range.

@rjacobs , Your heat pump setup is probably sized to run a near balanced offset with summer and winter temps. You're not switching to backup cooling in summer, so it shouldn't need to run backup heating in winter unless you're in extreme cold.
Try running the "droop" with that in mind. Leave your thermostat at one temp and run bigger offset (droop) on the backup heat. Three degrees should do the trick. With those settings, it shouldn't use heat strips until it's out of capacity.

I have one stat that is in a sunny room. The room gets quite a bit of radiant during the day and when sun goes down the ****** cools down fast. In cold temps that stat will be often be around one degree off setpoint when the sun goes down. It takes time to recover when I'm running heat pump at full load. I'd be hitting auxiliary heat quite often if I ran setbacks on the stat.
Same thing with turning up the stat when it feels cold. My wife used to do that trick. Our backup heat is a gas furnace and it drove me nuts to hear that thing running. She now turns on a fireplace instead.
The backup furnace used to kick on daily when it was cold. The subtle changes in how we use the stats and settings made a big difference. It's been a couple years without the system hitting backup heating. We still use the same temp setting, but we leave it there. We let the sunny room stat drop a degree and recover on it's own. And droop is at three degrees.

 

[75gmck25]

Completely different system - read or ignore my "war story"

I have a natural gas boiler system with radiators, and even that relatively simple system does not like big changes with a setback thermostat.

- I had it set to 70 day and 62 night during weather in the teen's. The house cooled off and made it run long enough in the morning that it hit the high temperature cutoff of 140 degrees on the boiler before the house reached 70 degrees, and then the system cycled off. I discovered the problem when the control board malfunctioned and would not restart the heating once it hit 140 ad cycled off.

- As a temporary fix I changed it to 70 day/66 night (same weather) to see how it would work. With that 4 degree setback it could bring the house temp up from 66 to 70 in the morning and only rise from the 100 degree low limit to 135 degrees water temp. I'm not sure the smaller setback is any easier on the boiler system, but it was an effective work around until I got a new control board.