DIY Home Improvement, Remodeling & Repair Forum > Appliances > HVAC > Digital vs old type thermostat

Thread Tools Search this Thread Display Modes
Old 02-01-2013, 07:18 AM  
Join Date: Oct 2009
Posts: 75
Liked 1 Times on 1 Posts

Default Digital vs old type thermostat

I have the older type thermostat with mercury and the heat anticipator. I was considering replacing my current thermostat with a digital one, but a friend said he thought the digital ones ran all the time due to keeping the temp within 1 degree. He said his unit runs a lot more than when he had his older thermostat, and he doesn't like that. What do you guys here recommend?

house92 is offline  
Reply With Quote
Old 02-01-2013, 08:03 AM  
Join Date: Jan 2010
Posts: 2,328
Liked 168 Times on 155 Posts
Likes Given: 94


The energy used to heat your house will be the same with the old or the new t'stats and the comfort level should be better with the new because the temp is more consistently maintained.
Short cycling of his new t'stat may have other causes than going to digital.

Wuzzat? is offline  
Reply With Quote
Old 02-01-2013, 08:53 AM  
Admin's Avatar
Join Date: Oct 2012
Posts: 1,098
Liked 55 Times on 48 Posts
Likes Given: 205


I have an electric and have noticed no differences in my heating/cooling cost.
Admin is offline  
Reply With Quote
Old 02-01-2013, 03:58 PM  
Supporting Member
Join Date: Nov 2007
Location: Grand Blanc, MI
Posts: 2,324
Liked 144 Times on 122 Posts
Likes Given: 71


If you purchase a digital stat, get one with a programmable offset/differential. This will prevent short cycling but, may prove to be a little uncomfortable with the wider swings of indoor temps.
kok328 is offline  
Austin Likes This 
Reply With Quote
Old 02-01-2013, 04:31 PM  
Join Date: Jan 2010
Posts: 2,328
Liked 168 Times on 155 Posts
Likes Given: 94


With my furnace problems and my oversize (168,000 input BTU/hr, 80% efficient) furnace being on only 1/3 of the time in winter, today I measured a cycle, once the setpoint had been reached.
It was the blower being four minutes on and 6 minutes off, a 40% duty cycle.

I have never been able to get a definition of short cycling but this sounds like an example of it.
Four minutes on is probably too short in any case but once the setpoint is reached I'd think a low duty cycle is expected.

Anybody have a short cycling definition for house HVAC, what it is and what it is not? It should probably involve both on-time and duty cycle. Maybe you'd also need a per hour basis to take into account the heat capacity of the house?

Last edited by Wuzzat?; 02-01-2013 at 04:39 PM.
Wuzzat? is offline  
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter DIY Home Repair Forum Replies Last Post
Replacing old white rodgers mercury thermostat with digital condoowner Electrical and Wiring 5 09-12-2012 08:30 AM
Installing digital thermostat crabman531 HVAC 5 03-03-2012 07:00 PM
Help with unknown wall type and unknown paint type needtofixwall Walls and Ceilings 2 09-16-2010 11:08 AM
Digital TV rickdi General Chit-Chat 6 06-17-2009 08:59 AM
Changing digital thermostat tractng Electrical and Wiring 3 08-11-2008 04:36 PM

Newest Threads