26th October 2019


What does preheating mean on the nest?

The Nest Learning Thermostat's new Early-On feature is simple: it's like pre-heating your oven. Nest sees what temperatures are coming up on your schedule, knows how long it'll take to reach them, and turns the heat or AC on early so you'll be comfortable right on time. Easy.

Similarly, it is asked, when should my auxiliary heat come on?

The balance point (when it can no longer efficiently transfer heat from the outside air) of an air source heat pump, is usually about 35 degrees. The thermostat senses this and automatically turns on the electric heat strips to provide the additional heat needed. It signals this by turning on the "AUX" heat light.

What color wires go where on a thermostat?

Thermostat Wiring Color Code Chart
MarkingWire Color CodeDescription
MarkingWire Color CodeDescription
RhRedPower from heat, 24 Vac transformer
CBlack/BlueCommon of 24 Vac transformer
WWhitePrimary heat cell relay

What is EM heat on a Honeywell thermostat?

In short, if you have a heat pump with electric resistance heat as the supplemental heat source, keep the thermostat in the 'Heat' setting. Do NOT use the 'Emergency Heat' setting unless it's really an emergency; for example, when the heat pump doesn't work.
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