Programmable thermostat for heat pump system
 

I am hoping I can get a solid answer for this question...

I would like to replace my lever style thermostat with a programmable thermostat... I read around on the good old internet and all I see is a few universal thermostats are "compatible" with heat pumps. I don't know if that just means they will power the heat pump on or if there is an actual setting that allows me to turn on/off the backup heater and it will switch automatically or if it means it will just kind of work...

Anyone have suggestions? I basically want to program the thermostat to heat or cool the house so it's at a good temp when I get home. The HVAC will be at that temp maybe 6 hours out of the day.

Is there a good thermostat someone can recommend that works with heat pumps?

Thanks in advance!

Razor,

Your choice of heat pump thermostat is a choice of air to air or geothermal heat pumps. Then there is the need for two stages as many heat pumps have two stages. Almost all thermostats have the "emergency heat" feature that turns on an electrical resistance element.

I would call your heat pump manufacturer/local dealer, find out what thermostat they suggest and then hunt for it on e-bay. RobertShaw makes zillions of thermostats for different manufacturers - all under different names, but they are basically all the same.

Bear in mind, that heat pumps do not have a quick recovery. For example, on geothermal heat pumps, I recommend only a small setback (5 F). The amount of setback is determined by where you are, how long you are gone and what climate you are in (winter/summer, etc).

My wife works a lot on call so she must get up at all hours to go in and she HATES getting up on cold floors in a cold bathroom with cold air. I like coolish rooms to sleep in and the savings to boot. So if she gets up, I run to the thermostat to turn up the thermostat for our geothermal heat pump. It turns on, but realistically, it only heats up after she has gone (and I have turned it down again . . . )!

She "hears it" turn on and can feel the warmth from the air registers, but grumble, grumble, grumble . . . . .

Steve

So what's holding you back from getting a very small (9K BTU) mini-split to heat the bathroom for your dear wife?

They're really not very expensive...

-AC

The system is an air to air heat pump and is 11 years old. The furnace is almost 20 years old. Everyone I have asked has asked me back what is wrong with the mechanical thermostat.

Well, obviously the fact that you can't do set-back is what is wrong with the mechanical one, what part of "set-back" do they not understand?

All the stuff that SH said is right, with the addition that heat pump thermostats will all have an automatic delayed-ON, so that intermittent power will not damage your heat pump equipment.

It looks to me like the least feature-infested model (AKA:"cheapest") is what you need. You do need the delayed-start feature, but the other features, probably not.

There is also the question of how do you use your furnace and heat pump?

I would guess that you give top priority to your heat pump because it is the cheapest to run, and if it can't supply all the heat you need when the temperature takes a serious dive, you switch on your furnace to see you through those extra chilly times... correct?

If that is the case, then getting a programmable set-back thermostat would be perfect... and keep the mechanical one for your furnace.

Or, another approach, if your heat pump has resistance wires for emergency heating, would be to de-activate the resistance wires (there's probably a switch), and use your furnace for that purpose (it would most likely be much cheaper), by using one of the thermostats that SH described in the third sentence of his last post, and using the "emergency heat" terminals to fire your furnace.

A pretty cool way to make heat, I think.

BTW, my experience with the programmable thermostats has been very positive, compared to the mechanical type. The first thing that I really enjoyed about them is that the temperature swings were much less noticeable on the programmable units. The set-back feature really does save money.

Oh, I almost forgot, a very important feature of the programmable thermostats is that if they fail, they always fail "OFF". There was a gal who lived down the street who came running over hysterically needing help with her furnace. Turned out that her mechanical thermostat failed, and failed "ON"... so her house had gotten heated up to about 120F degrees... everything was hot.... well, except for her.

-AC

There is a selectable switch on the thermostat for emergency heat. The heat pump is used all the time unless the temp falls too low or if the heat pump isn't able to supply enough heat for the demand. Then emergency heat is used. The thermostat is smart enough to use emergency heat but it is a mechanical style with levers that you select one temp and it maintains that temp.

I want the option to maintain a different temp during certain hours of the day but it adjust the temp before i get home.

I just want to make sure if I get something it will be able to handle the heat pump appropriately and not burn it up.

I think you should get a few models you're looking at and go to the manufacturer's website. Download the user manual and make sure that it is going to work the way you want it to work, and do the things you want it to do.

I used a Honeywell VisionPro IAQ 7 day programmable on my split system heat pump with propane backup. This T-stat solved numerous problems for me. I installed the outside temp sensor, get rid of the mechanical temp sensor most times mounted on outside unit. It permits me to adjust my outside temp cutoff and also lets me monitor the outside temp on the T-stat. Allows control of humidifier, air cleaner and more. A great all in one thermostat.

VisionPRO IAQ | 7-Day Programmable Thermostat Comfort System

All-In-One Control - Controls temperature and Indoor Air Quality (IAQ) products such as humidification, dehumidification, ventilation, and air filtration monitoring - all from a single control in the living space

All-In-One Control - Controls temperature and Indoor Air Quality (IAQ) products such as humidification, dehumidification, ventilation, and air filtration monitoring - all from a single control in the living space

7-Day Programming - Allows separate programming for each day

Touchscreen Interaction - Easy-to-follow menu-driven operation simplifies programming by responding to your choices

Smart Change/Check Reminders - Let you know when to service or replace filters, UV bulbs (based on actual usage) and humidifier pads

Energy Savings - Program to save up to 33% on annual heating and cooling costs (If used as directed. Savings may vary depending on geographic region and usage)

Whole-House Telephone Access - Works with your existing telephone line to offer control of your home's temperature and Indoor Air Quality over the phone

Model Numbers - YTH9421C1010, YTH9421C1002, TH9421C1004

5-Year Warranty

The problem I have with my heat pump programmable thermostat is that when it goes to step up the temp in the AM, it does so in a single 62 to 68 degree jump which brings on the elec heat (and my elec bill!!) I think they do this when there is a 2 degree or so diff between set temp and actual.
It should be easy with a microprocessor controlled stat to bring it up in staggered 1 degree jumps.
The manual for mine says it "Learns" how long it takes to come to the newly set temp and adjusts the time it comes on so you'r up to temp by the time you set but that still doesn't avoid the elec heat.
Anyone know of an even smarter stat??

This thermostat has a timer feature built in that allows one to set a time before the Aux heat comes on. If the outside temp is below set point then the recovery timer starts when calling for heat. In my case outside temp below 30f then if temp isn't recovered in 1 hour then aux heat comes on. The T-stat is very capable and very flexible with settings. In the 3 years that I have had the thing I have not used aux heat. I do admit though that I have a good rate plan because I use fossil fuel as back up. My electric rate for the heat pump is 1/2 of normal from Oct. until April. It does have a separate meter and they bill that portion at the lower rate. There are so many features on this T-stat that it can accomaodate many different cost scenarios. Check out the manual in the link I posted, you may want to get one.