I have a programmable thermostat that is, well, dumb. It is willing to set times and abide by those, but it doesn't take in to account the weather.  What I'm looking for is a smart thermostat that can learn my behavior and also make decisions based on the humidity inside the house and the temperature outside.

NEST and other smart thermostats seem to be able to predict temperature but not more advanced analytics. Does anyone know a thermostat that can move with the weather? Especially for sudden warm or cold fronts, it makes sense to set thermostat based on temperature and not hours of the day. We generally keep our thermostat warmer in the summer due to the wide difference between RH and temperature inside and out. 80 feels so much cooler on a hot summer day than in a late spring heat wave.

Ideally it would be a thermostat that can raise the setpoint with the outside temperature (say 15degrees trailing, max 85 degrees) throughout the day and also based on relative humidity (say 60%).  Then, as the day cools down, lower the setpoint based on the outside temperature and the relative humidity (Leading 15 degrees with a floor at 72, 40%RH). This way I could minimize the deltaT while keeping my house relatively dry.  

Tags: Thermostat

Views: 1036

Reply to This

Replies to This Discussion

There are three settings on the Nest.  Heat Only == Cool Only == Heat Cool.  I have several customers on the H/C setting during these shoulder seasons.  It does that.  Not as sophisticated  as your description above. Effective, yes.

The best equipment for doing this "communicating" equipment.  I'm most familiar with Carrier Infinity series, but American Standard and Goodman offer similar control I believe.

Infinity can manage airflow and staging.  This allows it to adjust focus from removing sensible to removing latent.  If you really want air conditioning to have that "doesn't feel like air conditioning, just feels comfortable" outcome, you need to go this direction.  

Some Inverter Driven Mini-Splits can operate using the same principals.  

If you can't afford/justify changing equipment, you can adjust certain set up features of Ecobee and Continuous commissioning/ watching performance.  http://bit.ly/4ecobeethermostats.

Ted,  Without using name brands or proprietary terms,  how would you suggest specifying 'communicating equipment'?  

Very easy to spec 'Builder's Grade'  80 AFUE, single speed draft induced gas fired furnace with 13 SEER AC.  Or Upgrade to 90+ AFUE sealed combustion with 15 SEER or Upgrade 2 to 94+ sealed combustion with 16+ SEER AC.  and so on.

I could use an Upgrade Level III in my arsenal.

Hi John,

That is stretching me a fair distance outside my expertise.  Let me convey the idea, then you can design to it:

Imagine you have a milk jug with a few holes in it.  You want to keep it 1/2 full of water and place it under a tap.  Your design strategy is to keep it as close to 1/2 full without ever shutting the tap off.  Shut the tap off and you get a big penalty.  Turn the tap on like a fire hose, you get a big penalty.  

The water is proxy for thermal comfort and fresh air.  A modulating boiler outdoor reset on steroids. 

So your thermostat needs to know how to manage the throttle on a LOT of things.  BTU management AND adjusting airflow, and in the really sweet equipment, compressor adjusts and exv adjusts refrigerant efficiency. 

NOW we have to design so airflow stays above .08 and below .4-.5 if you really want optimal distribution, distribution cost, and even comfort.  Too high, costly and noisy.  Rare occasion too low, trickling/uneven distribution.  So we test ESP on existing equipment and hope we can bring that typically terrible number into line when we drastically down size the replacement.

Since you are constantly and cheaply (fans laws) mixing air, why not inject fresh, latent managed air into that btu circulation?  Sure, why not?  http://bit.ly/VentDehum 

All temps stay in line - Latent/Sensible/Mean Radiant.  Super efficient.  Super comfortable.  

Comfort - http://bit.ly/comfortcalculator

Super Efficient - http://bit.ly/rickchitwood

Hope that helps.  Let me know if it looks like Greek instead of English...

Some of the higher end Emerson thermostats do this. It's called "cool savings" and adjusts the setpoint automatically based on system run time. The more the system runs, the greater the offset.

http://hvac-talk.com/vbb/attachment.php?attachmentid=200842&d=1...

RSS

Forum Discussions

Psychrometric Chart Training

Started by John Krochmalny in Training 12 hours ago. 0 Replies

How would you insulate this roof?

Started by David Butler in General Forum. Last reply by David Butler on Monday. 2 Replies

Dirty solar panels

Started by Evan Mills in General Forum. Last reply by Stacie Bagnasco on Monday. 1 Reply

Latest Activity

David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"Hi Mike, it's good to get some feedback from the field, and thanks for confirming Gen 3 is now…"
1 hour ago
B Eric Bell liked Bob Krell's group Healthy Indoors (IAQ)
9 hours ago
John Krochmalny posted a discussion

Psychrometric Chart Training

Looking through the various areas of this site, I didn't see too much information or training on…See More
12 hours ago
Profile IconMike Malek, Avery T. Phillips and Sarah Burger joined Home Energy Pros Forum
13 hours ago
Dannie Jackson's blog post was featured

Core Heat And Other Concepts

  In some places the use of solar heated liquids from hot water solar panels are used to provide…See More
18 hours ago
Michael Duclos replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"I’ve been looking into Sanden for a multi-family PH near Laconia, NH, ASHRAE 99.6% temp is…"
18 hours ago
Profile IconTroy Spindler, Mike Berg, Andrew McDowell and 4 more joined Home Energy Pros Forum
yesterday
David Butler replied to Brad Cook's discussion Too many Heat Pump Water Heaters in a basement?
"theoretically, let's say you perfectly isolate the HPWH from a heat source. The HPWH's…"
Monday

Photos

Loading…
  • Add Photos
  • View All

© 2017   Created by Home Performance Coalition (HPC)   Powered by

Badges  |  Report an Issue  |  Terms of Service