My Smart Recovery T Stat Experience


  #1  
Old 02-12-10, 07:19 AM
C
Member
Thread Starter
Join Date: Jan 2007
Location: West Central Indiana
Posts: 126
Upvotes: 0
Received 0 Upvotes on 0 Posts
My Smart Recovery T Stat Experience

We recently got a new Bryant air handler with Puron refrigerant and a 3 ton bryant prefered14 seer, 10.5 hspf heat pump with a legacy thermostat.

We have a 3000 square foot home, 1150 1st floor, 1150 basement and a 700 square foot 2nd floor, 2x6 walls, well insulated ceiling, minimal air leaks

I have tried for a month to use the smart recovery feature to drop the house about 4 degrees at night thru the following evening when we got home from work, the thermostat is set to start recovery 2.5 hours before the setpoint time. The thermostat would never start the recovery until about 1 hour to 1.25 hours before the setpoint and would usually require the 20 kw heatstrip backup to come on before getting the house to where it needs to be. So to go from 63 to 67 it would always require backup. Furthurmore the backup would usually kick on at the end of each cycle for the next few hours, probably because everything in the house was absorbing the heat to get it up to tempurature.

So I decided to try to set it to go from 63 to 65 and give it two hours advance time to do it, then i would set it to go to 67. the damn backup heat would still kick on.
Well now I just leave it at 66 and when I get home bump it to 67 and the heat strips barely ever kick on.

For example it is 9 degrees right now, the house is at 67 and the heatpump has been able to keep the house warm without backup heat except when it defrosts. Now the heatpump probably runs 45 minutes of every hour but that 4500 watt heat pump still is much cheaper to run than the 20 kw strips.

I have measured the hourly KW reading on my meter as well as daily usage for the past few months, it seems slightly cheaper to just leave the T Stat set at one point even with the "Smart" recovery.

I am home sick and have alot of time on my hands the past few days.
 
  #2  
Old 02-12-10, 07:47 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 19,281
Received 6 Upvotes on 6 Posts
Well...thats pretty much the normal advice with heatpumps...set it and forget it. Never had one, so I can't speak from experience. Now I had a old mercury T-stat in VA and after replacing with a cheap ($30) Hunter digital..it didn't help at all with my bills or run times. Per the techs advice...changed to a Honeywell with Smart recovery and saw an immediate increase in comfort and an almost 15% decrease in my electric bill. Couldn't believe it at first...but after running all the numbers and keeping track of usage for a few days..thats what it was. This was with a split system, not an HP.

I have seen written here, that there are t-stats with E-heat lockout during recovery...that might be a bit more what you want/need. Yours may even have it, but not be programmed correctly. Why don't you post the stat model and see what the Pro's have to say.
 
  #3  
Old 02-12-10, 09:54 AM
J
Member
Join Date: Jan 2008
Location: VA
Posts: 416
Received 1 Upvote on 1 Post
This sounds exactly like what I went through. My experience has been exactly the same!!

I haven't tried backing it off one degree though to see what happens. When I do play with setbacks, I check to see when the temperature is scheduled to be ~ 40F + and then set it back manually for that night.

I guess this all depends on the balance point of the heat pump though.
 
  #4  
Old 02-15-10, 05:28 PM
C
Member
Thread Starter
Join Date: Jan 2007
Location: West Central Indiana
Posts: 126
Upvotes: 0
Received 0 Upvotes on 0 Posts
I have seen written here, that there are t-stats with E-heat lockout during recovery...that might be a bit more what you want/need. Yours may even have it, but not be programmed correctly. Why don't you post the stat model and see what the Pro's have to say.[/QUOTE]

I have a bryant legacy T stat, it can be set to recover up to 2.5 hours before setpoint time, and the Aux doesn't come on, say I have it set to be 67 at 5pm, well the t stat starts recovering at 4 pm and the heat strips kick in to make it in time, I just don't get why the t stat doesn't kick on the HP instead at say 3pm to make it up, maybe it figures its better to run the strips, but from what I can tell it would be better to run the HP instead of the strips.

I am thinking of changing to a vision pro next winter.
 
  #5  
Old 02-21-10, 08:05 AM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by Civicminded
I am thinking of changing to a vision pro next winter.
Depends on what model of air handler and what not, I'd look into the Honeywell IAQ with outdoor sensor to lock out the Aux.

But honestly, there's no savings setting back on HP system.
 
  #6  
Old 03-15-10, 07:36 AM
J
Member
Join Date: Jan 2008
Location: VA
Posts: 416
Received 1 Upvote on 1 Post
Originally Posted by Civicminded
We recently got a new Bryant air handler with Puron refrigerant and a 3 ton bryant prefered14 seer, 10.5 hspf heat pump with a legacy thermostat.

We have a 3000 square foot home, 1150 1st floor, 1150 basement and a 700 square foot 2nd floor, 2x6 walls, well insulated ceiling, minimal air leaks

I have tried for a month to use the smart recovery feature to drop the house about 4 degrees at night thru the following evening when we got home from work, the thermostat is set to start recovery 2.5 hours before the setpoint time. The thermostat would never start the recovery until about 1 hour to 1.25 hours before the setpoint and would usually require the 20 kw heatstrip backup to come on before getting the house to where it needs to be. So to go from 63 to 67 it would always require backup. Furthurmore the backup would usually kick on at the end of each cycle for the next few hours, probably because everything in the house was absorbing the heat to get it up to tempurature.

So I decided to try to set it to go from 63 to 65 and give it two hours advance time to do it, then i would set it to go to 67. the damn backup heat would still kick on.
Well now I just leave it at 66 and when I get home bump it to 67 and the heat strips barely ever kick on.

For example it is 9 degrees right now, the house is at 67 and the heatpump has been able to keep the house warm without backup heat except when it defrosts. Now the heatpump probably runs 45 minutes of every hour but that 4500 watt heat pump still is much cheaper to run than the 20 kw strips.

I have measured the hourly KW reading on my meter as well as daily usage for the past few months, it seems slightly cheaper to just leave the T Stat set at one point even with the "Smart" recovery.

I am home sick and have alot of time on my hands the past few days.
I have a RTH7000...does this have the aux lockout during recovery? Even if it did, I am sort of willing to bet that the Honeywell smart recovery is making aux come on for a reason.

It would really stink to spend $$$ on a new thermostat and have the temperature not come up when it is time to recover.

Any thoughts?
 
  #7  
Old 03-15-10, 07:46 AM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by jj94auto
I have a RTH7000...does this have the aux lockout during recovery? Even if it did, I am sort of willing to bet that the Honeywell smart recovery is making aux come on for a reason.

It would really stink to spend $$$ on a new thermostat and have the temperature not come up when it is time to recover.
The RTH7000 or any of the retail t-stat don't have the outdoor sensor to lock out the Aux heat.


The smart recovery is going to try to keep the Aux off in recovery, but it depends on how far of a set back you set the stat back.
 
  #8  
Old 03-15-10, 07:52 AM
J
Member
Join Date: Jan 2008
Location: VA
Posts: 416
Received 1 Upvote on 1 Post
Originally Posted by Jay11J
The RTH7000 or any of the retail t-stat don't have the outdoor sensor to lock out the Aux heat.


The smart recovery is going to try to keep the Aux off in recovery, but it depends on how far of a set back you set the stat back.
Thanks for the info. I keep the temp at 66 all the time and AUX still has to come on quite a bit during the winter when it goes below ~ 40 degrees. This is for a ~ 1400 square foot home that was built in 1948 with about half of it not being insulated. Windows are double hung. The heatpump is a 10 SEER Goodman 2 ton unit.

Just giving you a history on the home before I mention that I try and do setbacks to 62 degrees. Even if I do a setback to 64 degrees AUX often pops on since it needs to do so periodically to maintain 66 degrees anyways.

All makes for a nice ~ $380 a month heating bill in this small house during the winter.
 
  #9  
Old 03-15-10, 09:24 AM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
When was the last time the unit been serviced?

Chances are, your home is the issue due to lack of insulation in the walls.

Do you have a basement or crawl space?
 
  #10  
Old 03-15-10, 12:19 PM
J
Member
Join Date: Jan 2008
Location: VA
Posts: 416
Received 1 Upvote on 1 Post
Originally Posted by Jay11J
When was the last time the unit been serviced?

Chances are, your home is the issue due to lack of insulation in the walls.

Do you have a basement or crawl space?
The unit has never been serviced since I moved in. That was about 2.5 yrs ago. I have a cellar arrangement. It is 6 feet high and unfinished. The air handler is mounted there. Thanks for your thoughts so far. Didn't mean to threadjack. Beer 4U2

Isn't the need for occasional Aux Heating about right? Wouldn't a balance point be about ~40F?

I personally think that I am a little bit too far north to have low heating expectations for a heat pump but that is just me. This is not my area of expertise but I am trying to learn!
 
  #11  
Old 03-15-10, 02:33 PM
D
Member
Join Date: Mar 2010
Location: USA
Posts: 11
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by jj94auto
Isn't the need for occasional Aux Heating about right? Wouldn't a balance point be about ~40F?

I personally think that I am a little bit too far north to have low heating expectations for a heat pump but that is just me. This is not my area of expertise but I am trying to learn!

The balance point depends on your house.

For my house 2600 Squ ft, 3 ton heat pump, 2 stage, Bryant evolution, well insulated, the balance point is around 31°F. It only uses the low stage until its lower than 34°F outside, then it uses the high stage heat pump. This is auto controlled.

I set my electric strips not to come on if its above 28°F outside. Efficiency mode (not comfort).
The strips only come in defrost mode for a few minutes, maybe that is what is happening with yours.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: