Thermostat Controls

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Description

In homes with central HVAC equipment, a programmable thermostat should be installed. This thermostat should be tested by the HERS rater to ensure that the fan, cooling, and heating settings operate.

If the system does not have cooling, this item does not need to be verified.

In cases where the condenser unit is installed after the inspection by the rater, the rater is exempt from verifying the cool air flow. If the condenser is part of a heat pump, the rater is also exempt from testing hot air flow.

To prevent potential equipment damage, the rater shall not conduct the cool air flow test if the outdoor temperature is less than 55°F or below the manufacturer-recommended minimum operating temperature for the cooling cycle, if that is known. When this occurs, the rater shall mark ‘N/A’ on the ENERGY STAR checklist for this item.

How to Test Air Flow

  1. Manually turn the fan to "on" at the thermostat
  2. Check for air flow at supply registers
  3. Reset the thermostat to the original settings before continuing.

How to Test Cooling Setting

  1. Manually set the system to “cool” at the thermostat and set the fan to "auto." If the system does not have air conditioning, this item does not need to be verified
  2. Change the set point temperature to 3°F below the ambient temperature
  3. Check for cool air flow at the supply registers
  4. Reset the thermostat to the original settings before continuing.

How to Test Heating Setting

  1. Manually set the system to "heat" at the thermostat and set the fan to “auto”
  2. Change the set point temperature to 3°F above the ambient temperature
  3. Check for warm air flow at the supply registers
  4. Reset the thermostat to the original settings.

The HERS rater should test the thermostat fan, cool, and heat settings to make sure the system blows ventilation, cooled, and warmed air.

Figure 1 - The HERS rater should test the thermostat fan, cool, and heat settings to make sure the system blows ventilation, cooled, and warmed air.  Reference

Ensuring Success

In homes with central HVAC equipment, a programmable thermostat should be installed. This thermostat should be tested by the HERS rater to ensure that the fan, cooling, and heating settings operate.

 

Scope

Air flow is produced when central HVAC fan is energized (set thermostat to “fan”)

Whole House Ventilation

Thermostat controls are defined as follows:

Air flow is produced when central HVAC fan is energized (set thermostat to “fan”):

  1. Turn the fan on at the thermostat.
  2. Reset the thermostat to the original settings before continuing.

Cool air flow is produced when the cooling cycle is energized (set thermostat to “cool”):

  1. Turn the system on to cool and change the set point temperature to 3 degrees below the ambient temperature.
  2. Reset the thermostat to the original settings before continuing.
  3. If the system does not have air conditioning, this item does not need to be verified.

Heated air flow is produced when the heating cycle is energized (set thermostat to heat):

  1. Turn the system on to heat and change the set point temperature to 3 degrees above the ambient temperature.
  2. Reset the thermostat to the original settings before continuing.

ENERGY STAR Notes:
     
In cases where the condenser unit is installed after the time of inspection by the rater, the rater is exempt from verifying the cool air flow when the condenser is for an AC unit and also heat air flow when the condenser is for a heat pump unit.

To prevent potential equipment damage, the rater shall not conduct the cool air flow test if the outdoor temperature is < 55°F or, if known, below the manufacturer-recommended minimum operating temperature for the cooling cycle. When this occurs, the rater shall mark ‘N/A’ on the ENERGY STAR checklist for this item.

Training

Right and Wrong Images

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Presentations

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Videos

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CAD Images

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Compliance

ENERGY STAR Version 3, (Rev. 07)

HVAC System Quality Checklist, Controls. Air flow is produced when central HVAC fan is energized (set thermostat to “fan”). Cool air flow is produced when the cooling cycle is energized (set thermostat to “cool”). In cases where the condenser unit is installed after the time of inspection by the Rater, the Rater is exempt from verifying cool air flow when the condenser is for an AC unit and also from heated air flow when the condenser is for a heat pump unit. To prevent potential equipment damage, the Rater shall not conduct this test if the outdoor temperature is <= 55°F or, if know, below the manufacturer-recommended minimum operating temperature for the cooling cycle. When this occurs, the Rater shall mark ‘N/A’ on the Checklist for this item. Heated air flow is produced when the heating cycle is energized (set thermostat to “heat”).

DOE Challenge Home

Exhibit 1: Mandatory Requirements. Certified under ENERGY STAR Qualified Homes Version 3.

2009 IECC

Section 403.1.1 Programmable thermostat. Where the primary heating system is a forced air-furnace, at least one programmable thermostat is installed to control the primary heating system and has set-points initialized at 70 degree F for the heating cycle and 78 degree F for the cooling cycle.*

2009 IRC

Section N1103.1.1 Programmable thermostat. Where the primary heating system is a forced air-furnace, at least one programmable thermostat is installed to control the primary heating system and has set-points initialized at 70 degree F for the heating cycle and 78 degree F for the cooling cycle.*

2012 IECC

Section R403.1.1 Programmable thermostat. Where the primary heating system is a forced air-furnace, at least one programmable thermostat is installed to control the primary heating system and has set-points initialized at 70 degree F for the heating cycle and 78 degree F for the cooling cycle.*

2012 IRC

Section N1103.1.1 Programmable thermostat. Where the primary heating system is a forced air-furnace, at least one programmable thermostat is installed to control the primary heating system and has set-points initialized at 70 degree F for the heating cycle and 78 degree F for the cooling cycle.*

*Due to copyright restrictions, exact code text is not provided.  For specific code text, refer to the applicable code.

More Info.

Case Studies

None Available

References and Resources*

  1. Author(s): DOE
    Organization(s): DOE
    Publication Date: June 2013

    Standard requirements for DOE's Challenge Home national program certification.

  2. Author(s): EPA
    Organization(s): EPA
    Publication Date: June 2013

    Standard document containing the rater checklists and national program requirements for ENERGY STAR Certified Homes, Version 3 (Rev. 7).

Last Updated: 08/15/2013

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