Programmable Thermostat with Ramp

I am using a programmable thermostat to turn off the heat and/or air condit ioning during the peak usage times as set by the ToU billing with my utilit y. The problem I have is the heat pump not ramping up the temperature fast enough when it comes back on and the backup straight electric heat coming on. This uses maybe three times the amount of electricity during the time it takes to get up to temperature.

I don't know if this is caused by the thermostat or the heat pump itself. I'm wondering if anyone makes a programmable thermostat that deals with thi s issue. If the problem is caused by the thermostat not letting the heat p ump run long enough that is easy to fix. If the problem is caused by the h eat pump itself, then the way to deal with it is for the thermostat to run the heat pump in bursts short enough to keep the back up heat from running.

Anyone familiar with this? Consumer Reports doesn't mention this in a quic k look at a few thermostats. The do list "Early recovery" which turns on t he heat/cooling ahead of the set time so the home is at the right temperatu re when you arrive (rather pointless in my opinion since I can just set the time early if that is what I wanted.)

They are starting to address the ToU billing issue in EV charging. Any sig n of this in home heating/cooling?

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My heatpump runs anytime the temperature is above 40F = 4.4C (this is adjustable). The thermostat calls for "aux" heat (oil furnace) when the outside temperature is below that. When aux heat runs, the heatpump is entirely off. It's a 2014 Carrier "edge" thermostat.

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Reply to
Winfield Hill

itioning during the peak usage times as set by the ToU billing with my util ity. The problem I have is the heat pump not ramping up the temperature fa st enough when it comes back on and the backup straight electric heat comin g on. This uses maybe three times the amount of electricity during the tim e it takes to get up to temperature.

I'm wondering if anyone makes a programmable thermostat that deals with t his issue. If the problem is caused by the thermostat not letting the heat pump run long enough that is easy to fix. If the problem is caused by the heat pump itself, then the way to deal with it is for the thermostat to ru n the heat pump in bursts short enough to keep the back up heat from runnin g.

ick look at a few thermostats. The do list "Early recovery" which turns on the heat/cooling ahead of the set time so the home is at the right tempera ture when you arrive (rather pointless in my opinion since I can just set t he time early if that is what I wanted.)

ign of this in home heating/cooling?

Honeywell VisionPro Series has adaptive recovery. You set the time and temp for what you want it to actually be and for recovery after setback it then figures out what time to fire it up to get it there. And it learns . It works excellent with the gas furnace here and it supports heat pumps, so I would expect it will work the same with those. IDK what algorithm they use, but obviously it's based on how big the delta is that it has to close and how fast the thermostat knows it takes to raise the temp one degree. Besides that, I would think it may factor in how fast the temp has dropped while in setback, to get some gauge as to how cold it is outside, to further refine the calculation. It always makes it to the desired temp by the desired time.

Reply to
Whoey Louie

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also r un under two other conditions. One is the system detects ice on the outsid e coils. With a 40 degree cut off, your system might not worry with deicin g. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, ano ther condition is if the inside temperature drops too far bellow the set te mperature.

The first heat pump I owned was very, very simple. It had a two bulb therm ostat. Set the temperature and bulb 1 would control the heat to keep the t emperature. But if the room (hallway as the case may be) temperature dropp ed too far the second bulb switch would close and the backup heat would com e on.

That is the condition I am trying to avoid with a thermostat which ramps th e temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your in staller. With the last system I bought I found I could not even get info f rom the company who made it. They always referred me to the "installer", l ike I was not worthy of information.

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nditioning during the peak usage times as set by the ToU billing with my ut ility. The problem I have is the heat pump not ramping up the temperature fast enough when it comes back on and the backup straight electric heat com ing on. This uses maybe three times the amount of electricity during the t ime it takes to get up to temperature.

f. I'm wondering if anyone makes a programmable thermostat that deals with this issue. If the problem is caused by the thermostat not letting the he at pump run long enough that is easy to fix. If the problem is caused by t he heat pump itself, then the way to deal with it is for the thermostat to run the heat pump in bursts short enough to keep the back up heat from runn ing.

quick look at a few thermostats. The do list "Early recovery" which turns on the heat/cooling ahead of the set time so the home is at the right tempe rature when you arrive (rather pointless in my opinion since I can just set the time early if that is what I wanted.)

sign of this in home heating/cooling?

ns.

That is exactly wrong for my situation. I mentioned that in my first post. Another company calls it "Early recovery".

Yeah, that sounds like it works well, but it's a great solution to the wron g problem.

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conditioning during the peak usage times as set by the ToU billing with my utility. The problem I have is the heat pump not ramping up the temperatur e fast enough when it comes back on and the backup straight electric heat c oming on. This uses maybe three times the amount of electricity during the time it takes to get up to temperature.

elf. I'm wondering if anyone makes a programmable thermostat that deals wi th this issue. If the problem is caused by the thermostat not letting the heat pump run long enough that is easy to fix. If the problem is caused by the heat pump itself, then the way to deal with it is for the thermostat t o run the heat pump in bursts short enough to keep the back up heat from ru nning.

a quick look at a few thermostats. The do list "Early recovery" which turn s on the heat/cooling ahead of the set time so the home is at the right tem perature when you arrive (rather pointless in my opinion since I can just s et the time early if that is what I wanted.)

ny sign of this in home heating/cooling?

arns.

t. Another company calls it "Early recovery".

,

ne

ong problem.

OK, you're right. But it's a similar problem, a very common problem and I would think you would have that too. How much does the temp drop during these high energy cost periods when you have the system off? The temp also drops if you set it back at night to save energy or maybe you just don't. But if you set it back, when it has to resume at 6AM, the same thing happens. If the temp delta is big enough, then it kicks on aux heat.

The VisionPros do have a programmable aux heat lockout which you can set for between 40 to 60F outside temp. It obviously then requires an outside temp sensor. If the outside temp is above the setting, then it locks out the electric aux heat. So you could have it locked out for above 40F. Do you need aux heat at all? If not, just disable it.

They should have more options, like an intelligent mode where it only kicks in aux heat if it's going to take longer than X mins to reach the new setting. That's the kind of setting it would have to have or a more primitive one based on just the temp delta. AFAIK the VisioPros just use the latter method and IDK if it can be programmed.

Reply to
Whoey Louie

r conditioning during the peak usage times as set by the ToU billing with m y utility. The problem I have is the heat pump not ramping up the temperat ure fast enough when it comes back on and the backup straight electric heat coming on. This uses maybe three times the amount of electricity during t he time it takes to get up to temperature.

tself. I'm wondering if anyone makes a programmable thermostat that deals with this issue. If the problem is caused by the thermostat not letting th e heat pump run long enough that is easy to fix. If the problem is caused by the heat pump itself, then the way to deal with it is for the thermostat to run the heat pump in bursts short enough to keep the back up heat from running.

n a quick look at a few thermostats. The do list "Early recovery" which tu rns on the heat/cooling ahead of the set time so the home is at the right t emperature when you arrive (rather pointless in my opinion since I can just set the time early if that is what I wanted.)

Any sign of this in home heating/cooling?

nd

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learns.

ost. Another company calls it "Early recovery".

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wrong problem.

Not trying to be rude, but if you think I have both problems, then you don' t understand the problem I am having.

I want the heat to be OFF during the peak times of my ToU rates. Not reduc ed, not cut back, OFF.

I can do that by programming the thermostat low enough that the heat never comes on. But when the peak time is over, the temperature setting is resto red to the intended setting and the heat comes on. After some time the bac k up heat comes on and the electric meter spins like a top.

If the house temperature were ramped up one degree at a time over an hour s ay, it might not kick in the back up heat and not waste the money I'm tryin g to save.

Sometimes three or four degrees.

I don't have enough settings to do that. Peak time is 6 to 9 in the mornin g and 5 to 8 in the evening. That's four sets per day, my max.

Not so worried about the night setting. It's already rather low. The room I spend my time in has more than an even amount of heat flowing to it and its comfy with the rest of the house some 4 degrees lower. The normal ther mostat setting is 62 degrees.

Exactly, but that's the time I turn the heat off, so I don't want it starti ng at a low temperature.

g,

That won't work. When the outside temps are in the teens (unusual, but not unheard of) the backup heat is required absolutely. In fact, I think the crossover point for my system is 26 degrees. I don't know if that is set b y the furnace or the thermostat. I suspect it is the furnace since I don't think the thermostat knows the outside temperature, but not sure.

One of the heat pumps I bought the manufacturer would not allow access to t hese settings. You had to contact the installer. I forget the brand, but that system would be running the backup heat in the middle of the afternoon

just run down the list of reasons to run the backup heat as if it would be one of those.

I don't care how long it takes to reach the new setting. It takes how ever long it takes. I just don't want it running backup heat unless it is actu ally needed to keep the house warm.

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Rick C

Good point, maybe. The instructions don't say anything about limitations or features if I lower the threshold. It may not have an ice-detection feature.

It's possible I don't have the first mode. It will add the aux heat, if inside temp drops below 45F. It does run the system differently with the heatpump (which draws 5kW when running), than with the furnace. In the former case it runs the forced-air blower much slower, and it appears to start the morning temp rampup much earlier.

I haven't been able to observe the heatpump unable to get the house up to temp on its own. Our heating/HVAC system started as an oil furnace and air-conditioner, but they upgraded the compressor to heat pump (modest low cost). But the hybrid thermostat labels the heat pump as primary, and the oil furnace as auxiliary.

The heat-pump compressor's 24-page manual mentions an optional Secondary Outdoor Thermostat, which can turn on a 3rd-stage of supplemental electric heaters, to avoid ice buildup, I suppose. I doubt we have that. So far I'm happy with the default 40-degree setting. But, if our aux heat was electric baseboard, etc., of course that'd be another matter entirely.

If we ever decide to forgo using oil, as some suggest, we'll upgrade to a proper geothermal heat pump system. But that might trigger a complete HVAC makeover, and could involve adding more roof solar panels as well. Our installer, next town over, in Melrose, MA, has such a system, and is a big fan of that approach.

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Reply to
Winfield Hill

You know, it's time to fire up your Arduino coding brain, and take back full control.

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Winfield Hill

Mine runs the blower fast with both types of heat, but runs it slower after the compressor has shut off to capture the last residual heat without lowe ring the temperature of the air from the vents.

Of course. Better to run the more economical heat source when you can.

If/when oil goes back up to $4 a gal you may rethink that.

Not sure why it might need more solar panels. If anything it would be less . I suppose since it will run all the time including really cold nights, i t will need to move more heat than your current heat pump, but with the con stant temperature of the ground it would have a much easier time of it. Th e whole point of the geothermal is to *reduce* your heating bill. If you n eed more solar panels you are doing something wrong.

Consider the actual work required. Lifting 2 tons of goods by 15 feet or l ifting 2 tons of good 5 feet. Which is more work?

on the heat pump. It's barely doing anything for you. It's just doing the light duty work and less of it.

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I would if I had a full spec on the heat pump. I still don't know where th e various decisions are made, thermostat vs. heat pump.

As I think I've mentioned, I've tried to get more info on another system be fore and the manufacturer won't talk to me as a customer. In fact, they wo uld not even talk to me unless I gave them a serial number that I could onl y access by taking the thermostat partially apart. lol

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Rick C

The issue here, is that no man can serve two masters, and no thermostat can be said to be doing the 'keep temperature constant' task when it is imperative that the heat be OFF.

You can always put a relay cutoff in series with the heat-element, timed for the service rates. Or, maybe install an electric subpanel on a timed contactor. I've seen dual-meter setups that did something comparable.

But informing the logic of a thermostat requires a level of control that can only be called intelligence. It won't be a thermostat any more.

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whit3rd

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

I'll would be willing to bet that there is an iPad for your wall, and an app for that. Should be able to be far more intelligant than the normal fare.

Reply to
DecadentLinuxUserNumeroUno

educed, not cut back, OFF.

can be said

at the

So??? There are different demands at different times. That's not exactly unique in the world of machines. Your car isn't taking you anywhere when i t is OFF. Your TV isn't showing you anything when it is OFF. Many objects are turned on and off automatically by timers, like dishwashers that come on late at night.

for the

ctor. I've seen

can only be called

Lol. Ok, call it intelligence. That doesn't change the task.

I'm not sure what you read. If you read my description of what I am asking for you might understand my present thermostat already turns the heat on a nd off as required. I'm looking for a way to do that so the backup heat do esn't turn on when ramping the temperature back up. A relay would very lik ely still kick in the backup heat.

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Rick C

How about adding a high-current contactor, with timer, to disable the backup heat when you want to do so.

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Reply to
Winfield Hill

I was thinking of something less intrusive, like a properly programmable th ermostat.

I just thought someone here might have seen this before. I did a search of thermostats, but all the hype and BS gets in the way of seeing what many o f them actually do. Even Consumer Reports doesn't seem to have considered this issue and they seem to reflect what the thermostat makers provide, so maybe it's not out there and I need to roll my own.

There is a fairly cost effective FPGA board with a large LCD display. That might be a good choice, but I'm not ready to start designing just yet.

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Rick C

What is your quest? You need to save money, or what?

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John S

fter the compressor has shut off to capture the last residual heat without lowering the temperature of the air from the vents.

less. I suppose since it will run all the time including really cold night s, it will need to move more heat than your current heat pump, but with the constant temperature of the ground it would have a much easier time of it. The whole point of the geothermal is to *reduce* your heating bill. If y ou need more solar panels you are doing something wrong.

or lifting 2 tons of good 5 feet. Which is more work?

off on the heat pump. It's barely doing anything for you. It's just doing the light duty work and less of it.

Why does that matter? Are you going to analyze my justification for wantin g this?

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Rick C

the various decisions are made, thermostat vs. heat pump.

Not hard to figure out. RTFM. The thermostat almost certainly has a wire that calls for heat and a wire that calls for aux heat. If it's two stage, then it has two heat call wires.

before and the manufacturer won't talk to me as a customer. In fact, they would not even talk to me unless I gave them a serial number that I could o nly access by taking the thermostat partially apart. lol

Well, I suppose if you buy a thermostat that made by the heat pump manufacturer, that's locked to their equipment, etc, then you're at their mercy. It's Trane and similar that want you to think they are superior that generally do that and they soak you too. That's why I have a Rheem.

If you really want to get creative, I suppose you could get a wifi thermost at and then write a program that talks to it and raises the set temp one or two deg at a time when you want it to recover, so that aux heat is not triggered. It's funny, today we even have wifi thermostats, but apparently most of them can't handle the obvious things, like giving you flexibility and control over how aux heat is called for. Time to download the manuals for the smart thermostats and see if they do. That is assuming you can replace your thermostat, that it's not tied to the eqpt by the manufacturer .

Reply to
Whoey Louie

Yes. Why else would I ask? Can you answer civilly? Or are you just being a troll?

Reply to
John S

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