"I'd agree with Sean - we get wind effects regularly when measuring ventilation fan intake at the outdoor hood. And there's a notable difference if the capture hood is flush with the wall (eg around foundation wall) or if there are gaps,…"
"I installed/configured a couple Honeywell VisionPro 8k models recently in a commercial facility. It has governing ability for 4 stages of heat and 2 of cool. It triggers out from 1st stage when sensing 90% capacity of the furnace. "
"I was playing with a 2 stage carrier furnace last week. The staging is not bad on the condensing boilers. They camp out at low fire until the return air temp drops or they get past 5 minutes of run time. I am fine with them doing…"
"Ted -- The startup losses on modern furnaces are much smaller than the old days. I would suggest a modification to your statement to: "if the ducts are normal and in unconditioned space then the losses exceed the gains from long run…"
"We use reverse staging on ecobee.
Generally, the best comfort, energy savings, iaq, etc are achieved by doing what you can to avoid having the equipment ever shut off.
We suspect among other things, start/stop losses are significant.
"Thanks, John. The HVAC installers have actually responded to incentives and moved ducts within the building envelope on the vast majority of the furnaces we see, so losses to unconditioned space are less of a concern for us. Thanks for bringing up…"
"@Tray, the staging logic is described on pg 85 of the furnace installation manual. In particular, here's what it says:
"This furnace can operate as a two--stage furnace with a single-stage thermostat because the furnace control CPU…"
"Thanks for the quick feedback, David. I did find the furnace install manual earlier; there's no detail (that I was able to find) on staging logic or adjusting staging timing. Glad to understand the typical thermostat staging in a bit more…"
"I hate to be the one to bring this up, but two stage furnaces are quite capable of having lower installed efficiency than single stage furnaces with the same max input. This comes from two sources: 1) the fuel air mixture on low fire often has too…"
"David's comment is spot on. I would always prefer thermostat staging control over furnace staging control. (I am assuming the thermostat is making and breaking the control call for heating - not communicating the temperature back to the furnace…"
Welcome to Home Energy Pros Forum. Feel free to join the conversation in the Forum and Groups. And share your energy efficiency photos, videos and upcoming events. If you're blogging about home performance, this is the place for…"
"I'm not sure about the Ecobee Smart Si (I couldn't immediately find the install manual) but this FAQ (http://bit.ly/2Cf2UsR) describes Ecobee's staging logic -- it's selectable based on either elapsed time or temperature…"
Got called in recently to address thermostat and comfort issues for a local builder we work with. In reconfiguring the thermostat (Ecobee Smart Si), I noticed that it was wired up as a single stage for heating, although the furnace (Carrier 59TP6) is a two-stage model - that is, furnace staging decisions…See More
Welcome to Home Energy Pros Forum. Feel free to join the conversation in the Forum and Groups. And share your energy efficiency photos, videos and upcoming events. If you're blogging about home performance, this is the place for you!